English | 简体中文
Episode 15: Natural, Organic, Semisynthetic, Synthetic
Natural, organic, semisynthetic, synthetic; what does it all mean?
You might be surprised to know that organic doesn’t actually mean safer, more nutritious or chemical free. You may also be surprised to know that not all things that are natural are organic.
Are you confused yet? Stay with me friends, it will all become clear very soon.
Most of my audiences worldwide have heard me speak about the dangers of thinking in absolutes. Here are some examples of why absolutism is a problem, particularly in science. The majority of people surveyed around the world believe that if it comes from a plant, it’s always healthier, natural always works better than synthetic and that synthetics are always bad for you. All of those assumptions are false. I know… Some of you are having of what I call yeah but moments right now. You’re thinking to yourself “yeah but so-and-so says, yeah but I heard that, yeah but my favorite Guru says… Control the yeah but moments please, we’re about to talk about objective facts.
The scientific definitions and commonly used marketing definitions are often very different. My purpose in this piece is to give you a clear understanding of what each of those categories means so you can make the best possible choices for your personal health program.
Let’s start with life on planet Earth. Nobody is sure what life might be like on other planets, but life on planet Earth is all carbon-based. Everything that is alive or ever was alive contains carbon molecules. One definition of organic is living organisms, but a more accurate scientific definition of organic would be anything that contains carbon molecules. Now someone is going to say, “but fossil fuels contain carbon molecules”. Keep in mind that fossil fuels were once plant material. The common misconception from marketing is that the dinosaurs were the source of today’s fossil fuels but that is not only incorrect it doesn’t even make sense. There were never enough dinosaurs to decompose into the enormous levels of fossil fuels on this planet, all fossil fuels came from living plants. That’s why fossil fuels contain carbon. And yes, that does mean that they would technically fit the definition organic. Realistically however no one would use that classification.
People all over the world have come to believe the marketing definition of organic, natural and synthetic. The common marketing definition of organic is that it is either plant or animal which has been raised without pesticides, hormones etc. the implication then is that the word organic means, safer and cleaner. People also believe that it means more nutritious. Theoretically if plants and animals are fed properly, they should end up being more nutritious, but that’s not guaranteed by the use of the word organic.
For many years, there were several US states that had their own definition of the word organic, each one was slightly different than the other. Finally, the US Department of Agriculture established their definition. They say that “Produce can be called organic if it’s certified to have grown on soil that had no prohibited substances applied for three years prior to harvest. Prohibited substances include most synthetic fertilizers and pesticides. In instances when a grower has to use a synthetic substance to achieve a specific purpose, the substance must first be approved according to criteria that examine its effects on human health and the environment.”
Understand my friends, this definition does not specify that there must be a guarantee that no prohibited substances such as pesticides are present on the produce you buy, because there is no possibility of making that guarantee on planet Earth. When you buy something labeled organic there is a measure of faith involved.
Since planet Earth is a closed ecosystem, and since you can find farm pesticides in the snow and ice at the North Pole as well as in the fatty tissues of penguins at the South pole, this suggests that there is no place on the planet that cannot be potentially exposed to farm pesticides and other toxins.
How did farm pesticides get to the North and the South poles. Obviously, the poles are thousands of miles or kilometers from the nearest farm. Various chemical toxins such as pesticides are carried in weather systems which are moving around the planet 24 hours a day. Often pesticides and other chemicals are carried in water currents fresh water and saltwater around the world.
Yes, I do choose organic food wherever possible. More details on that later.
Natural
What about natural? Almost everyone immediately says they want a natural product. I agree. Wherever possible I want to consume natural products and recommend them. Natural and organic however are not the same thing.
Animals that have been injected with hormones or antibiotics and possibly given feed that may have contained pesticides are still natural. Toxic metals like arsenic, cadmium and lead are all natural, even crude oil is natural.
All minerals are natural. There is no such thing as a synthetic mineral. Minerals however are not organic. I personally use and frequently recommend natural minerals in the form of amino acid chelates. Not all chelates are the same however, some are extremely effective and some have very low efficacy rates. For my personal health I select chelates for practical as well as scientific reasons. Many people consuming the modern diet are getting insufficient levels of minerals, this is potentially a health concern. Minerals are essential not only for your health, but for your life.
Plant materials generally have insufficient mineral by weight to be reasonable supplies for everyone’s mineral dietary requirement. This could, as an example, require 10 or more tablets of pure plant mineral to equal one tablet of the same size made of a natural chelate.
Dietary realities dictate the necessity for using a more efficient chelate versus a plant source. As an example, approximately 90% of the US population gets insufficient potassium every day. Potassium is vital for a healthy heart. Depending on which studies you read you may see between 50% and 70% of people are getting insufficient magnesium. The modern diet is providing only about 50% of the bare minimum requirement for magnesium daily. Depending on circumstances the net effect can certainly be higher than 50%. Magnesium is responsible for hundreds of vital functions in the body and is essential to your life.
Currently, the best science available shows us that bisglycinate’s are the best absorbed and utilized mineral forms available. As I like to say, “science marches on”, so who knows what the future will bring, but for now bisglycinate chelates are the most efficient way to get your minerals. Bisglycinate chelates are definitely safe as they are made of naturally occurring minerals and natural amino acids. No, they are not plant food. They are however absorbed at astonishing levels. Your digestive tract loves an amino acid called glycine and when combining two glycine molecules together it is a bisglycinate. One example of absorption that I will no doubt refer to in other podcasts would be zinc gluconate versus zinc bisglycinate. Zinc has been in the news a great deal and the most common form out there is gluconate. However, the latest science shows us that zinc in the form of bisglycinate absorbs approximately 44% better than gluconate. Natural, yes, safe, yes, well absorbed and utilized yes.
Another example of a synthetic being safe and effective, in fact more effective than its natural counterpart would be synthetic vitamin B9. Vitamin B9 in all of its various forms is often collectively referred to as folate. Some writers will be very specific and denote folate as the form of vitamin B9 as the naturally occurring form found in plant materials. This would be the most accurate description. However, keep in mind that some articles you read will use the word folate and folic acid interchangeably. European Union regulations as an example require that vitamin B9 always be listed as folic acid on the label regardless of its source. Every country is different so this can get confusing.
Studies have proven conclusively that folic acid which is the synthetic form of folate prevents neural tube defects. It is obviously well absorbed, safe and effective. Some comparative studies have shown that folate from diet was not effective in preventing neural tube defects or NTD’s, whereas folic acid in the same study was effective. Spina bifida and anencephaly are NTD’s.
I often talk about variables and it is certainly possible that folate from food does work effectively but that the pregnant women in the study were not consuming sufficient levels of it from food. Or perhaps possessed a gene defect. Regardless, synthetic folic acid is safe and effective and that’s why you will find it prenatal vitamins.
There is also the issue of methylation and the new science on a particular gene defect that prevents people from converting folate to its active form. Those individuals need to use a form of folic acid which is already methylated. There is a reduced form of folate containing 5-methyl-THF (aka methylfolate), used by some dietary supplement manufacturers which can be absorbed even by individuals with the specific methylation gene defect.
Folic acid merits its own podcast, so in enough detail on that for now.
Remember friends, my goal is always to bring you the best recommendations, based on the most objective scientific material, that results in the safest and most effective health support. I have no bias towards forms or philosophy. The only thing that counts is getting the safest and most effective supplements into your body and we do that through objective scientific analysis.
Semisynthetic
There is another category you may never have heard of and that is semisynthetic. Semisynthetic gets a little more complicated. If you start with two naturally occurring substances and semi-synthesize them, you have created a new structure. This new structure would be called semisynthetic. Even though you’re using two natural substances in this example you have artificially created a new structure, so it is no longer in its natural form.
When it comes to food to put on your plate, I try to choose organic whenever possible and recommend that you do the same because even though it’s not a guarantee that it will be the most nutritious and 100%
To summarize, natural isn’t always the best choice, synthetics are not always bad and organic doesn’t technically mean what marketing people want you to think it means. You now have a basic understanding of natural, organic, synthetics and semisynthetic’s. As I always say you cannot make informed decisions unless you’ve been informed. I hope now that you are better equipped to select your food supplements. As the world changes and pressures increase, scientists continue to try and compensate and adapt to the changes. Science marches on.
Until next time, this is Dr. Steve Nugent urging you to stay safe, be sensible and be objective.
Notes and Sources:
Terms:
- Produce can be called organic if it’s certified to have grown on soil that had no prohibited substances applied for three years prior to harvest. Prohibited substances include most synthetic fertilizers and pesticides. In instances when a grower has to use a synthetic substance to achieve a specific purpose, the substance must first be approved according to criteria that examine its effects on human health and the environment (see other considerations in “Organic 101: Allowed and Prohibited Substances”). https://www.usda.gov/media/blog/2012/03/22/organic-101-what-usda-organic-label-means?page=2
- In general, “natural” on a food label means that it has no artificial colors, flavors or preservatives. It does not refer to the methods or materials used to produce the food ingredients. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/organic-food/art-20043880#:~:text=Read%20food%20labels%20carefully.,%2C%20salt%2C%20fat%20or%20calories.
- Chelated minerals are inorganic minerals that have been chemically bound with amino acids.[1] “In nature, minerals are always bound to another compound.” “Some studies have shown that such chelated minerals are more effectively absorbed within the body.” “Minerals are essential, meaning the human body can’t make them, but requires them for normal, healthy function.” While there is no such thing as a synthetic mineral, there are organic and inorganic minerals found on planet Earth. Science defines organic simply as something that contains carbon molecules; meaning something that is alive or was once alive. There are also naturally occurring minerals that are not organic. https://www.webmd.com/vitamins/ai/ingredientmono-41/chelated-minerals
- Mannatech uses the most advanced science to create mineral supplements in a form that is safe and effective. Natural mineral chelates are approved in virtually all of our markets. Today, advanced science backed by human study now allows us to make and use naturally occurring minerals and bind them to natural amino acids using the latest science. We choose these powerful minerals and the wide array of premium vitamins at or above the recommended daily value levels to maximize your benefits with each dose.
- The term chelate (pronounced key-late) is derived from the Greek word chele (“χηλή “) meaning “claw-like”, and describes the structure of a certain mineral form in which a mineral molecule is held at more than one point of attachment and a ring structure is formed.
- Appropriate intake levels of certain nutritive minerals have been proven to be required to maintain optimal human health.
- Organic mineral amino acid chelates have been scientifically proven to be more easily absorbed into the human body and to cause less gastric upset than inorganic minerals. Part of the reason for this higher tolerance and bioavailability is that chelated minerals are absorbed intact and break apart in the intestinal cell for transport. With the highest quality chelated mineral ingredients on the market, Albion is the world leader in mineral nutrition. https://balchem.com/human-nutrition-health/technologies/mineral-chelation/
Deficiency stats:
- About 75% of the US population (ages ≥1 year) do not consume the recommended intake of fruit, and more than 80% do not consume the recommended intake of vegetables (1).
- Specifically, 94.3% of the US population do not meet the daily requirement for vitamin D, 88.5% for vitamin E, 52.2% for magnesium, 44.1% for calcium, 43.0% for vitamin A, and 38.9% for vitamin C. For the nutrients in which a requirement has not been set, 100% of the population had intakes lower than the AI for potassium, 91.7% for choline, and 66.9% for vitamin K. The prevalence of inadequacies was low for all of the B vitamins and several minerals, including copper, iron, phosphorus, selenium, sodium, and zinc (see Table 1). Moreover, more than 97% of the population had excessive intakes of sodium, defined as daily intakes greater than the age-specific UL (26).
- Overall, more than 40% of the US population do not meet the calcium requirement from diet alone (28)
- NHANES 2003-2006 found that about 36% of children and adolescents and 61% of adults had intakes lower than the EAR for magnesiumhttps://lpi.oregonstate.edu/mic/micronutrient-inadequacies/overview
- While the recommended daily allowance for magnesium is 420 mg for males and 320 mg for females, the standard diet in the United States contains only about 50 percent of that amount. As much as half of the total population is estimated to be consuming a magnesium-deficient diet. https://www.sciencedaily.com/releases/2018/02/180226122548.htm
- ‘Approximately 50% of Americans consume less than the Estimated Average Requirement (EAR) for magnesium, and some age groups consume substantially less’.20 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5786912/
- Less than 2% of Americans even get the recommended minimum adequate intake of 4,700 a day. To get even the adequate intake, the average American would have to eat like 5 more bananas worth of potassium a day. 98% of Americans eat potassium deficient diets because they don’t eat enough plants. https://nutritionfacts.org/2013/05/23/98-of-american-diets-potassium-deficient/
- Cholesterol also is needed to make vitamin D, hormones (including testosterone and estrogen), and fat-dissolving bile acids. In fact, cholesterol production is so important that your liver and intestines make about 80% of the cholesterol you need to stay healthy. Only about 20% comes from the foods you eat. https://www.health.harvard.edu/heart-health/how-its-made-cholesterol-production-in-your-body#:~:text=Cholesterol%20also%20is%20needed%20to,from%20the%20foods%20you%20eat.
- Bailey LB, Caudill MA. Folate. In: Erdman JW, Macdonald IA, Zeisel SH, eds. Present Knowledge in Nutrition. 10th ed. Washington, DC: Wiley-Blackwell; 2012:321-42.
- Institute of Medicine. Food and Nutrition Board. Dietary Reference Intakes: Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, DC: National Academy Press; 1998.
- Stover PJ. Folic acid. In: Ross AC, Caballero B, Cousins RJ, Tucker KL, Ziegler TR, eds. Modern Nutrition in Health and Disease. 11th ed. Baltimore, MD: Lippincott Williams & Wilkins; 2012:358-68.
- Carmel R. Folic acid. In: Shils M, Shike M, Ross A, Caballero B, Cousins RJ, eds. Modern Nutrition in Health and Disease. 11th ed. Baltimore, MD: Lippincott Williams & Wilkins; 2005:470-81.
- Paniz C, Bertinato JF, Lucena MR, et al. A daily dose of 5 mg folic acid for 90 days is associated with increased serum unmetabolized folic acid and reduced natural killer cell cytotoxicity in healthy Brazilian adults. J Nutr 2017;147:1677-85. [PubMed abstract]
- Crider KS, Bailey LB, Berry RJ. Folic acid food fortification-its history, effect, concerns, and future directions. Nutrients 2011;3:370-84. [PubMed abstract]
- Yetley EA, Pfeiffer CM, Phinney KW, et al. Biomarkers of folate status in NHANES: a roundtable summary. Am J Clin Nutr 2011;94:303S-12S. [PubMed abstract]
- Lakoff A, Fazili Z, Aufreiter S, et al. Folate is absorbed across the human colon: evidence by using enteric-coated caplets containing 13C-labeled [6S]-5-formyltetrahydrofolate. Am J Clin Nutr 2014;100:1278-86. [PubMed abstract]
- Bailey LB, Stover PJ, McNulty H, et al. Biomarkers of nutrition for development-folate review. J Nutr 2015;145:1636S-80S. [PubMed abstract]
- Green R. Indicators for assessing folate and vitamin B-12 status and for monitoring the efficacy of intervention strategies. Am J Clin Nutr 2011;94:666S-72S. [PubMed abstract]
- S. Food and Drug Administration. Food Labeling: Revision of the Nutrition and Supplement Facts Labels. external link disclaimer2016.
- S. Department of Agriculture, Agricultural Research Service. FoodData Centralexternal link disclaimer, 2019.
- S. Food and Drug Administration. Food Standards: Amendment of Standards of Identity For Enriched Grain Products to Require Addition of Folic Acid.external link disclaimer Federal Register 1996;61:8781-97.
- Choumenkovitch SF, Selhub J, Wilson PW, et al. Folic acid intake from fortification in United States exceeds predictions. J Nutr 2002;132:2792-8. [PubMed abstract]
- S. Food and Drug Administration. FDA approves folic acid fortification of corn masa flour.external link disclaimer 2016. [PubMed abstract]
- Government of Canada. Regulations amending the food and drug regulations (1066). Canada Gazette 1998;132.
- Centers for Disease Control and Prevention. CDC grand rounds: Additional opportunities to prevent neural tube defects with folic acid fortification. MMWR Morb Mortal Wkly Rep 2010;59:980-4. [PubMed abstract]
- Yeung LF, Cogswell ME, Carriquiry AL, et al. Contributions of enriched cereal-grain products, ready-to-eat cereals, and supplements to folic acid and vitamin B-12 usual intake and folate and vitamin B-12 status in US children: National Health and Nutrition Examination Survey (NHANES), 2003-2006. Am J Clin Nutr 2011;93:172-85. [PubMed abstract]
- National Institutes of Health. Dietary Supplement Label Database. 2018.
- Scaglione F, Panzavolta G. Folate, folic acid and 5-methyltetrahydrofolate are not the same thing. Xenobiotica 2014;44:480-8. [PubMed abstract]
- Greenberg JA, Bell SJ, Guan Y, et al. Folic acid supplementation and pregnancy: more than just neural tube defect prevention. Rev Obstet Gynecol 2011;4:52-9. [PubMed abstract]
- Henderson AM, Aleliunas RE, Loh SP, et al. l-5-Methyltetrahydrofolate supplementation increases blood folate concentrations to a greater extent than folic acid supplementation in Malaysian women. J Nutr 2018;148:885-90. [PubMed abstract]
- Green TJ, Liu Y, Dadgar S, et al. Wheat rolls fortified with microencapsulated L-5-methyltetrahydrofolic acid or equimolar folic acid increase blood folate concentrations to a similar extent in healthy men and women. J Nutr 2013;143:867-71. [PubMed abstract]
- Venn BJ, Green TJ, Moser R, et al. Comparison of the effect of low-dose supplementation with L-5-methyltetrahydrofolate or folic acid on plasma homocysteine: a randomized placebo-controlled study. Am J Clin Nutr 2003;77:658-62. [PubMed abstract]
- Venn BJ, Green TJ, Moser R, et al. Increases in blood folate indices are similar in women of childbearing age supplemented with [6S]-5-methyltetrahydrofolate and folic acid. J Nutr 2002;132:3353-5. [PubMed abstract]
- Lamers Y, Prinz-Langenohl R, Bramswig S, et al. Red blood cell folate concentrations increase more after supplementation with [6S]-5-methyltetrahydrofolate than with folic acid in women of childbearing age. Am J Clin Nutr 2006;84:156-61. [PubMed abstract]
- Pietrzik K, Bailey L, Shane B. Folic acid and L-5-methyltetrahydrofolate: comparison of clinical pharmacokinetics and pharmacodynamics. Clin Pharmacokinet 2010;49:535-48. [PubMed abstract]
- S. Department of Agriculture, Agricultural Research Service. What We Eat in America, 2013-2014.external link disclaimer 2017.
- Bailey RL, Dodd KW, Gahche JJ, et al. Total folate and folic acid intake from foods and dietary supplements in the United States: 2003-2006. Am J Clin Nutr 2010;91:231-7. [PubMed abstract]
- Bailey RL, McDowell MA, Dodd KW, et al. Total folate and folic acid intakes from foods and dietary supplements of US children aged 1-13 y. Am J Clin Nutr 2010;92:353-8. [PubMed abstract]
- Yang Q, Cogswell ME, Hamner HC, et al. Folic acid source, usual intake, and folate and vitamin B-12 status in US adults: National Health and Nutrition Examination Survey (NHANES) 2003-2006. Am J Clin Nutr 2010;91:64-72. [PubMed abstract]
- Ho RC, Cheung MW, Fu E, et al. Is high homocysteine level a risk factor for cognitive decline in elderly? A systematic review, meta-analysis, and meta-regression. Am J Geriatr Psychiatry 2011;19:607-17. [PubMed abstract]
- Scholl TO, Johnson WG. Folic acid: influence on the outcome of pregnancy. Am J Clin Nutr 2000;71:1295S-303S. [PubMed abstract]
- Gloria L, Cravo M, Camilo ME, et al. Nutritional deficiencies in chronic alcoholics: relation to dietary intake and alcohol consumption. Am J Gastroenterol 1997;92:485-9. [PubMed abstract]
- Gibson A, Woodside JV, Young IS, et al. Alcohol increases homocysteine and reduces B vitamin concentration in healthy male volunteers–a randomized, crossover intervention study. QJM 2008;101:881-7. [PubMed abstract]
- Centers for Disease Control and Prevention. Folic acid 2012.external link disclaimer
- S. Preventive Services Task Force, Bibbins-Domingo K, Grossman DC, et al. Folic acid supplementation for the prevention of neural tube defects: US Preventive Services Task Force recommendation statement. JAMA 2017;317:183-9. [PubMed abstract]
- American College of Obstetricians and Gynecologists. Frequently Asked Questions, FAQ001, Pregnancy, Nutrition During Pregnancy.external link disclaimer 2018.
- Rossi RE, Whyand T, Murray CD, et al. The role of dietary supplements in inflammatory bowel disease: a systematic review. Eur J Gastroenterol Hepatol 2016;28:1357-64. [PubMed abstract]
- Molloy AM, Pangilinan F, Brody LC. Genetic risk factors for folate-responsive neural tube defects. Annu Rev Nutr 2017;37:269-91. [PubMed abstract]
- National Institute of Mental Health. Autism spectrum disorder. 2018.
- Berry RJ, Crider KS, Yeargin-Allsopp M. Periconceptional folic acid and risk of autism spectrum disorders. JAMA 2013;309:611-3. [PubMed abstract]
- Bjork M, Riedel B, Spigset O, et al. Association of folic acid supplementation during pregnancy with the risk of autistic traits in children exposed to antiepileptic drugs in utero. JAMA Neurol 2018;75:160-8. [PubMed abstract]
- Schmidt RJ, Kogan V, Shelton JF, et al. Combined prenatal pesticide exposure and folic acid intake in relation to autism spectrum disorder. Environ Health Perspect 2017;125:097007. [PubMed abstract]
- Goodrich AJ, Volk HE, Tancredi DJ, et al. Joint effects of prenatal air pollutant exposure and maternal folic acid supplementation on risk of autism spectrum disorder. Autism Res 2018;11:69-80. [PubMed abstract]
- Roffman JL. Neuroprotective effects of prenatal folic acid supplementation: why timing matters. JAMA Psychiatry 2018;75:747-8. [PubMed abstract]
- Caffrey A, Irwin RE, McNulty H, et al. Gene-specific DNA methylation in newborns in response to folic acid supplementation during the second and third trimesters of pregnancy: epigenetic analysis from a randomized controlled trial. Am J Clin Nutr 2018;107:566-75. [PubMed abstract]
- DeVilbiss EA, Gardner RM, Newschaffer CJ, et al. Maternal folate status as a risk factor for autism spectrum disorders: a review of existing evidence. Br J Nutr 2015;114:663-72. [PubMed abstract]
- Suren P, Roth C, Bresnahan M, et al. Association between maternal use of folic acid supplements and risk of autism spectrum disorders in children. JAMA 2013;309:570-7. [PubMed abstract]
- Schmidt RJ, Tancredi DJ, Ozonoff S, et al. Maternal periconceptional folic acid intake and risk of autism spectrum disorders and developmental delay in the CHARGE (CHildhood Autism Risks from Genetics and Environment) case-control study. Am J Clin Nutr 2012;96:80-9. [PubMed abstract]
- Levine SZ, Kodesh A, Viktorin A, et al. Association of maternal use of folic acid and multivitamin supplements in the periods before and during pregnancy with the risk of autism spectrum disorder in offspring. JAMA Psychiatry 2018;75:176-84. [PubMed abstract]
- Virk J, Liew Z, Olsen J, et al. Preconceptional and prenatal supplementary folic acid and multivitamin intake and autism spectrum disorders. Autism 2016;20:710-8. [PubMed abstract]
- He H, Shui B. Folate intake and risk of bladder cancer: a meta-analysis of epidemiological studies. Int J Food Sci Nutr 2014;65:286-92. [PubMed abstract]
- Kim YI. Will mandatory folic acid fortification prevent or promote cancer? Am J Clin Nutr 2004;80:1123-8. [PubMed abstract]
- Kim YI. Folate and carcinogenesis: evidence, mechanisms, and implications. J Nutr Biochem 1999;10:66-88. [PubMed abstract]
- Kim YI. Folate and cancer: a tale of Dr. Jekyll and Mr. Hyde? Am J Clin Nutr 2018;107:139-42. [PubMed abstract]
- Andreeva VA, Touvier M, Kesse-Guyot E, et al. B vitamin and/or omega-3 fatty acid supplementation and cancer: ancillary findings from the supplementation with folate, vitamins B6 and B12, and/or omega-3 fatty acids (SU.FOL.OM3) randomized trial. Arch Intern Med 2012;172:540-7. [PubMed abstract]
- Ebbing M, Bonaa KH, Nygard O, et al. Cancer incidence and mortality after treatment with folic acid and vitamin B12. JAMA 2009;302:2119-26. [PubMed abstract]
- Mason JB. Unraveling the complex relationship between folate and cancer risk. Biofactors 2011;37:253-60. [PubMed abstract]
- Giovannucci E, Stampfer MJ, Colditz GA, et al. Folate, methionine, and alcohol intake and risk of colorectal adenoma. J Natl Cancer Inst 1993;85:875-84. [PubMed abstract]
- Gibson TM, Weinstein SJ, Pfeiffer RM, et al. Pre- and postfortification intake of folate and risk of colorectal cancer in a large prospective cohort study in the United States. Am J Clin Nutr 2011;94:1053-62. [PubMed abstract]
- Sanjoaquin MA, Allen N, Couto E, et al. Folate intake and colorectal cancer risk: a meta-analytical approach. Int J Cancer 2005;113:825-8. [PubMed abstract]
- Kennedy DA, Stern SJ, Moretti M, et al. Folate intake and the risk of colorectal cancer: a systematic review and meta-analysis. Cancer Epidemiol 2011;35:2-10. [PubMed abstract]
- Bassett JK, Severi G, Hodge AM, et al. Dietary intake of B vitamins and methionine and colorectal cancer risk. Nutr Cancer 2013;65:659-67. [PubMed abstract]
- de Vogel S, Dindore V, van Engeland M, et al. Dietary folate, methionine, riboflavin, and vitamin B-6 and risk of sporadic colorectal cancer. J Nutr 2008;138:2372-8. [PubMed abstract]
- Neuhouser ML, Cheng TY, Beresford SA, et al. Red blood cell folate and plasma folate are not associated with risk of incident colorectal cancer in the Women’s Health Initiative observational study. Int J Cancer 2015;137:930-9. [PubMed abstract]
- Chuang SC, Rota M, Gunter MJ, et al. Quantifying the dose-response relationship between circulating folate concentrations and colorectal cancer in cohort studies: a meta-analysis based on a flexible meta-regression model. Am J Epidemiol 2013;178:1028-37. [PubMed abstract]
- Song Y, Manson JE, Lee IM, et al. Effect of combined folic acid, vitamin B(6), and vitamin B(12) on colorectal adenoma. J Natl Cancer Inst 2012;104:1562-75. [PubMed abstract]
- Figueiredo JC, Mott LA, Giovannucci E, et al. Folic acid and prevention of colorectal adenomas: a combined analysis of randomized clinical trials. Int J Cancer 2011;129:192-203. [PubMed abstract]
- Cole BF, Baron JA, Sandler RS, et al. Folic acid for the prevention of colorectal adenomas: a randomized clinical trial. JAMA 2007;297:2351-9. [PubMed abstract]
- Vollset SE, Clarke R, Lewington S, et al. Effects of folic acid supplementation on overall and site-specific cancer incidence during the randomised trials: meta-analyses of data on 50,000 individuals. Lancet 2013;381:1029-36. [PubMed abstract]
- van Wijngaarden JP, Swart KM, Enneman AW, et al. Effect of daily vitamin B-12 and folic acid supplementation on fracture incidence in elderly individuals with an elevated plasma homocysteine concentration: B-PROOF, a randomized controlled trial. Am J Clin Nutr 2014;100:1578-86. [PubMed abstract]
- Tu H, Dinney CP, Ye Y, et al. Is folic acid safe for non-muscle-invasive bladder cancer patients? An evidence-based cohort study. Am J Clin Nutr 2018;107:208-16. [PubMed abstract]
- Kim SJ, Zuchniak A, Sohn KJ, et al. Plasma folate, vitamin B-6, and vitamin B-12 and breast cancer risk in BRCA1- and BRCA2-mutation carriers: a prospective study. Am J Clin Nutr 2016;104:671-7. [PubMed abstract]
- Figueiredo JC, Grau MV, Haile RW, et al. Folic acid and risk of prostate cancer: results from a randomized clinical trial. J Natl Cancer Inst 2009;101:432-5. [PubMed abstract]
- Tomaszewski JJ, Cummings JL, Parwani AV, et al. Increased cancer cell proliferation in prostate cancer patients with high levels of serum folate. Prostate 2011;71:1287-93. [PubMed abstract]
- Wien TN, Pike E, Wisloff T, et al. Cancer risk with folic acid supplements: a systematic review and meta-analysis. BMJ Open 2012;2:e000653. [PubMed abstract]
- Kim S, Choi BY, Nam JH, et al. Cognitive impairment is associated with elevated serum homocysteine levels among older adults. Eur J Nutr 2018. [PubMed abstract]
- Kim YI. Folate: a magic bullet or a double edged sword for colorectal cancer prevention? Gut 2006;55:1387-9. [PubMed abstract]
- Ulrich CM, Potter JD. Folate supplementation: too much of a good thing? Cancer Epidemiol Biomarkers Prev 2006;15:189-93. [PubMed abstract]
- Mason JB, Tang SY. Folate status and colorectal cancer risk: a 2016 update. Mol Aspects Med 2017;53:73-9. [PubMed abstract]
- Lee JE, Willett WC, Fuchs CS, et al. Folate intake and risk of colorectal cancer and adenoma: modification by time. Am J Clin Nutr 2011;93:817-25. [PubMed abstract]
- National Toxicology Program. NTP monograph: identifying research needs for assessing safe use of high intakes of folic acid. National Toxicology Program, 2015.
- Clarke R, Halsey J, Lewington S, et al. Effects of lowering homocysteine levels with B vitamins on cardiovascular disease, cancer, and cause-specific mortality: Meta-analysis of 8 randomized trials involving 37 485 individuals. Arch Intern Med 2010;170:1622-31. [PubMed abstract]
- Huang T, Chen Y, Yang B, et al. Meta-analysis of B vitamin supplementation on plasma homocysteine, cardiovascular and all-cause mortality. Clin Nutr 2012;31:448-54. [PubMed abstract]
- Toole JF, Malinow MR, Chambless LE, et al. Lowering homocysteine in patients with ischemic stroke to prevent recurrent stroke, myocardial infarction, and death: the Vitamin Intervention for Stroke Prevention (VISP) randomized controlled trial. JAMA 2004;291:565-75. [PubMed abstract]
- Lonn E, Yusuf S, Arnold MJ, et al. Homocysteine lowering with folic acid and B vitamins in vascular disease. N Engl J Med 2006;354:1567-77. [PubMed abstract]
- Albert CM, Cook NR, Gaziano JM, et al. Effect of folic acid and B vitamins on risk of cardiovascular events and total mortality among women at high risk for cardiovascular disease: a randomized trial. JAMA 2008;299:2027-36. [PubMed abstract]
- Ebbing M, Bleie O, Ueland PM, et al. Mortality and cardiovascular events in patients treated with homocysteine-lowering B vitamins after coronary angiography: a randomized controlled trial. JAMA 2008;300:795-804. [PubMed abstract]
- Christen WG, Cook NR, Van Denburgh M, et al. Effect of combined treatment with folic acid, vitamin B6, and vitamin B12 on plasma biomarkers of inflammation and endothelial dysfunction in women. J Am Heart Assoc 2018;7. [PubMed abstract]
- Huo Y, Li J, Qin X, et al. Efficacy of folic acid therapy in primary prevention of stroke among adults with hypertension in China: the CSPPT randomized clinical trial. JAMA 2015;313:1325-35. [PubMed abstract]
- Study of the Effectiveness of Additional Reductions in Cholesterol Homocysteine Collaborative Group, Armitage JM, Bowman L, et al. Effects of homocysteine-lowering with folic acid plus vitamin B12 vs placebo on mortality and major morbidity in myocardial infarction survivors: a randomized trial. JAMA 2010;303:2486-94. [PubMed abstract]
- Huo Y, Qin X, Wang J, et al. Efficacy of folic acid supplementation in stroke prevention: new insight from a meta-analysis. Int J Clin Pract 2012;66:544-51. [PubMed abstract]
- Kong X, Huang X, Zhao M, et al. Platelet count affects efficacy of folic acid in preventing first stroke. J Am Coll Cardiol 2018;71:2136-46. [PubMed abstract]
- Stampfer M, Willett W. Folate supplements for stroke prevention: targeted trial trumps the rest. JAMA 2015;313:1321-2. [PubMed abstract]
- Marti-Carvajal AJ, Sola I, Lathyris D, et al. Homocysteine-lowering interventions for preventing cardiovascular events. Cochrane Database Syst Rev 2017;8:CD006612. [PubMed abstract]
- Jenkins DJA, Spence JD, Giovannucci EL, et al. Supplemental Vitamins and minerals for CVD prevention and treatment. J Am Coll Cardiol 2018;71:2570-84. [PubMed abstract]
- Tian T, Yang KQ, Cui JG, et al. Folic acid supplementation for stroke prevention in patients with cardiovascular disease. Am J Med Sci 2017;354:379-87. [PubMed abstract]
- Seshadri S, Beiser A, Selhub J, et al. Plasma homocysteine as a risk factor for dementia and Alzheimer’s disease. N Engl J Med 2002;346:476-83. [PubMed abstract]
- Ravaglia G, Forti P, Maioli F, et al. Homocysteine and folate as risk factors for dementia and Alzheimer disease. Am J Clin Nutr 2005;82:636-43. [PubMed abstract]
- Clarke R. B-vitamins and prevention of dementia. Proc Nutr Soc 2008;67:75-81. [PubMed abstract]
- Smith AD, Refsum H. Homocysteine, B vitamins, and cognitive impairment. Annu Rev Nutr 2016;36:211-39. [PubMed abstract]
- Smith AD, Refsum H, Bottiglieri T, et al. Homocysteine and dementia: an international consensus statement. J Alzheimers Dis 2018;62:561-70. [PubMed abstract]
- Hooshmand B, Solomon A, Kareholt I, et al. Associations between serum homocysteine, holotranscobalamin, folate and cognition in the elderly: a longitudinal study. J Intern Med 2012;271:204-12. [PubMed abstract]
- Eussen SJ, de Groot LC, Joosten LW, et al. Effect of oral vitamin B-12 with or without folic acid on cognitive function in older people with mild vitamin B-12 deficiency: a randomized, placebo-controlled trial. Am J Clin Nutr 2006;84:361-70. [PubMed abstract]
- van der Zwaluw NL, Dhonukshe-Rutten RA, van Wijngaarden JP, et al. Results of 2-year vitamin B treatment on cognitive performance: secondary data from an RCT. Neurology 2014;83:2158-66. [PubMed abstract]
- Kang JH, Cook N, Manson J, et al. A trial of B vitamins and cognitive function among women at high risk of cardiovascular disease. Am J Clin Nutr 2008;88:1602-10. [PubMed abstract]
- Aisen PS, Schneider LS, Sano M, et al. High-dose B vitamin supplementation and cognitive decline in Alzheimer disease: a randomized controlled trial. JAMA 2008;300:1774-83. [PubMed abstract]
- Walker JG, Batterham PJ, Mackinnon AJ, et al. Oral folic acid and vitamin B-12 supplementation to prevent cognitive decline in community-dwelling older adults with depressive symptoms–the Beyond Ageing Project: a randomized controlled trial. Am J Clin Nutr 2012;95:194-203. [PubMed abstract]
- Clarke R, Bennett D, Parish S, et al. Effects of homocysteine lowering with B vitamins on cognitive aging: meta-analysis of 11 trials with cognitive data on 22,000 individuals. Am J Clin Nutr 2014;100:657-66. [PubMed abstract]
- Balk EM, Raman G, Tatsioni A, et al. Vitamin B6, B12, and folic acid supplementation and cognitive function: a systematic review of randomized trials. Arch Intern Med 2007;167:21-30. [PubMed abstract]
- Malouf R, Grimley Evans J. Folic acid with or without vitamin B12 for the prevention and treatment of healthy elderly and demented people. Cochrane Database Syst Rev 2008:CD004514. [PubMed abstract]
- Dangour AD, Whitehouse PJ, Rafferty K, et al. B-vitamins and fatty acids in the prevention and treatment of Alzheimer’s disease and dementia: a systematic review. J Alzheimers Dis 2010;22:205-24. [PubMed abstract]
- Ford AH, Almeida OP. Effect of homocysteine lowering treatment on cognitive function: a systematic review and meta-analysis of randomized controlled trials. J Alzheimers Dis 2012;29:133-49. [PubMed abstract]
- Durga J, van Boxtel MP, Schouten EG, et al. Effect of 3-year folic acid supplementation on cognitive function in older adults in the FACIT trial: a randomised, double blind, controlled trial. Lancet 2007;369:208-16. [PubMed abstract]
- Huang X, Fan Y, Han X, et al. Association between serum vitamin levels and depression in U.S. adults 20 years or older based on National Health and Nutrition Examination Survey 2005-2006. Int J Environ Res Public Health 2018;15. [PubMed abstract]
- Gougeon L, Payette H, Morais JA, et al. Intakes of folate, vitamin B6 and B12 and risk of depression in community-dwelling older adults: the Quebec Longitudinal Study on Nutrition and Aging. Eur J Clin Nutr 2016;70:380-5. [PubMed abstract]
- Morris MS, Fava M, Jacques PF, et al. Depression and folate status in the US population. Psychother Psychosom 2003;72:80-7. [PubMed abstract]
- Papakostas GI, Petersen T, Mischoulon D, et al. Serum folate, vitamin B12, and homocysteine in major depressive disorder, Part 1: predictors of clinical response in fluoxetine-resistant depression. J Clin Psychiatry 2004;65:1090-5. [PubMed abstract]
- Trujillo J, Vieira MC, Lepsch J, et al. A systematic review of the associations between maternal nutritional biomarkers and depression and/or anxiety during pregnancy and postpartum. J Affect Disord 2018;232:185-203. [PubMed abstract]
- Chong MF, Wong JX, Colega M, et al. Relationships of maternal folate and vitamin B12 status during pregnancy with perinatal depression: The GUSTO study. J Psychiatr Res 2014;55:110-6. [PubMed abstract]
- Blunden CH, Inskip HM, Robinson SM, et al. Postpartum depressive symptoms: the B-vitamin link. Ment Health Fam Med 2012;9:5-13. [PubMed abstract]
- Yan J, Liu Y, Cao L, et al. Association between duration of folic acid supplementation during pregnancy and risk of postpartum depression. Nutrients 2017;9. [PubMed abstract]
- Coppen A, Bailey J. Enhancement of the antidepressant action of fluoxetine by folic acid: a randomised, placebo controlled trial. J Affect Disord 2000;60:121-30. [PubMed abstract]
- Bedson E, Bell D, Carr D, et al. Folate Augmentation of Treatment–Evaluation for Depression (FolATED): randomised trial and economic evaluation. Health Technol Assess 2014;18:vii-viii, 1-159. [PubMed abstract]
- Roberts E, Carter B, Young AH. Caveat emptor: Folate in unipolar depressive illness, a systematic review and meta-analysis. J Psychopharmacol 2018;32:377-84. [PubMed abstract]
- Sarris J, Murphy J, Mischoulon D, et al. Adjunctive nutraceuticals for depression: A systematic review and meta-analyses. Am J Psychiatry 2016;173:575-87. [PubMed abstract]
- Cleare A, Pariante CM, Young AH, et al. Evidence-based guidelines for treating depressive disorders with antidepressants: a revision of the 2008 British Association for Psychopharmacology guidelines. J Psychopharmacol 2015;29:459-525. [PubMed abstract]
- Ravindran AV, Balneaves LG, Faulkner G, et al. Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 clinical guidelines for the management of adults with major depressive disorder: Section 5. Complementary and Alternative medicine treatments. Can J Psychiatry 2016;61:576-87. [PubMed abstract]
- Papakostas GI, Shelton RC, Zajecka JM, et al. L-methylfolate as adjunctive therapy for SSRI-resistant major depression: results of two randomized, double-blind, parallel-sequential trials. Am J Psychiatry 2012;169:1267-74. [PubMed abstract]
- Wilson RD, Genetics C, Motherisk. Pre-conceptional vitamin/folic acid supplementation 2007: the use of folic acid in combination with a multivitamin supplement for the prevention of neural tube defects and other congenital anomalies. J Obstet Gynaecol Can 2007;29:1003-13. [PubMed abstract]
- Pitkin RM. Folate and neural tube defects. Am J Clin Nutr 2007;85:285S-8S. [PubMed abstract]
- Williams J, Mai CT, Mulinare J, et al. Updated estimates of neural tube defects prevented by mandatory folic Acid fortification – United States, 1995-2011. MMWR Morb Mortal Wkly Rep 2015;64:1-5. [PubMed abstract]
- Lamers Y. Folate recommendations for pregnancy, lactation, and infancy. Ann Nutr Metab 2011;59:32-7. [PubMed abstract]
- Scott JM. Evidence of folic acid and folate in the prevention of neural tube defects. Bibl Nutr Dieta 2001:192-5. [PubMed abstract]
- Molloy AM, Kirke PN, Brody LC, et al. Effects of folate and vitamin B12 deficiencies during pregnancy on fetal, infant, and child development. Food Nutr Bull 2008;29:S101-11; discussion S12-5. [PubMed abstract]
- Williams LJ, Rasmussen SA, Flores A, et al. Decline in the prevalence of spina bifida and anencephaly by race/ethnicity: 1995-2002. Pediatrics 2005;116:580-6. [PubMed abstract]
- Rader JI, Schneeman BO. Prevalence of neural tube defects, folate status, and folate fortification of enriched cereal-grain products in the United States. Pediatrics 2006;117:1394-9. [PubMed abstract]
- Dary O. Nutritional interpretation of folic acid interventions. Nutr Rev 2009;67:235-44. [PubMed abstract]
- Shane B. Folate-responsive birth defects: of mice and women. Am J Clin Nutr 2012;95:1-2. [PubMed abstract]
- Viswanathan M, Treiman KA, Kish-Doto J, et al. Folic acid supplementation for the prevention of neural tube defects: an updated evidence report and systematic review for the US Preventive Services Task Force. JAMA 2017;317:190-203. [PubMed abstract]
- Centers for Disease Control and Prevention. Use of folic acid for prevention of spina bifida and other neural tube defects–1983-1991. MMWR Morb Mortal Wkly Rep 1991;40:513-6. [PubMed abstract]
- Czeizel AE, Puho EH, Langmar Z, et al. Possible association of folic acid supplementation during pregnancy with reduction of preterm birth: a population-based study. Eur J Obstet Gynecol Reprod Biol 2010;148:135-40. [PubMed abstract]
- Liu S, Joseph KS, Luo W, et al. Effect of folic acid food fortification in Canada on congenital heart disease subtypes. Circulation 2016;134:647-55. [PubMed abstract]
- Botto LD, Mulinare J, Erickson JD. Occurrence of congenital heart defects in relation to maternal mulitivitamin use. Am J Epidemiol 2000;151:878-84. [PubMed abstract]
- Shaw GM, O’Malley CD, Wasserman CR, et al. Maternal periconceptional use of multivitamins and reduced risk for conotruncal heart defects and limb deficiencies among offspring. Am J Med Genet 1995;59:536-45. [PubMed abstract]
- Johnson MA. If high folic acid aggravates vitamin B12 deficiency what should be done about it? Nutr Rev 2007;65:451-8. [PubMed abstract]
- Morris MS, Jacques PF, Rosenberg IH,et al. Folate and vitamin B-12 status in relation to anemia, macrocytosis, and cognitive impairment in older Americans in the age of folic acid fortification. Am J Clin Nutr 2007;85:193-200. [PubMed abstract]
- Selhub J, Morris MS, Jacques PF. In vitamin B12 deficiency, higher serum folate is associated with increased total homocysteine and methylmalonic acid concentrations. Proc Natl Acad Sci U S A 2007;104:19995-20000. [PubMed abstract]
- Selhub J, Morris MS, Jacques PF, et al. Folate-vitamin B-12 interaction in relation to cognitive impairment, anemia, and biochemical indicators of vitamin B-12 deficiency. Am J Clin Nutr 2009;89:702S-6S. [PubMed abstract]
- Berry RJ, Carter HK, Yang Q. Cognitive impairment in older Americans in the age of folic acid fortification. Am J Clin Nutr 2007;86:265-7; author reply 7-9. [PubMed abstract]
- Carmel R. Does high folic acid intake affect unrecognized cobalamin deficiency, and how will we know it if we see it? Am J Clin Nutr 2009;90:1449-50. [PubMed abstract]
- Valera-Gran D, Navarrete-Munoz EM, Garcia de la Hera M, Fernandez-Somoano A, Tardon A, Ibarluzea J, et al. Effect of maternal high dosages of folic acid supplements on neurocognitive development in children at 4-5 y of age: the prospective birth cohort Infancia y Medio Ambiente (INMA) study. Am J Clin Nutr 2017;106:878-87. [PubMed abstract]
- Troen AM, Mitchell B, Sorensen B, et al. Unmetabolized folic acid in plasma is associated with reduced natural killer cell cytotoxicity among postmenopausal women. J Nutr 2006;136:189-94. [PubMed abstract]
- Morris MS, Jacques PF, Rosenberg IH, Selhub J. Circulating unbetabolied folic acid and 5-methyltetrahydrofolate in relation to anemia, macrocytosis, and cognitive test performance in American seniors. Am J Clin Nutr. 2010 Jun;91(6):1733-44. [PubMed abstract]
- Pfeiffer CM, Sternberg MR, Fazili Z, et al. Unmetabolized folic acid is detected in nearly all serum samples from US children, adolescents, and adults. J Nutr 2015;145:520-31. [PubMed abstract]
- Stamm RA, March KM, Karakochuk CD, et al. Lactating Canadian women consuming 1000 µg folic acid daily have high circulating serum folic acid above a threshold concentration of serum total folate. J Nutr 2018;148:1103-8. [PubMed abstract]
- Page R, Robichaud A, Arbuckle TE, et al. Total folate and unmetabolized folic acid in the breast milk of a cross-section of Canadian women. Am J Clin Nutr 2017;105:1101-9. [PubMed abstract]
- Obeid R, Kasoha M, Kirsch SH, et al. Concentrations of unmetabolized folic acid and primary folate forms in pregnant women at delivery and in umbilical cord blood. Am J Clin Nutr 2010;92:1416-22. [PubMed abstract]
- Plumptre L, Masih SP, Ly A, et al. High concentrations of folate and unmetabolized folic acid in a cohort of pregnant Canadian women and umbilical cord blood. Am J Clin Nutr 2015;102:848-57. [PubMed abstract]
- Sweeney MR, McPartlin J, Scott J. Folic acid fortification and public health: report on threshold doses above which unmetabolised folic acid appear in serum. BMC Public Health 2007;7:41. [PubMed abstract]
- Kelly P, McPartlin J, Goggins M, et al. Unmetabolized folic acid in serum: acute studies in subjects consuming fortified food and supplements. Am J Clin Nutr 1997;65:1790-5. [PubMed abstract]
- Sweeney MR, McPartlin J, Weir DG, et al. Postprandial serum folic acid response to multiple doses of folic acid in fortified bread. Br J Nutr 2006;95:145-51. [PubMed abstract]
- S. Food and Drug Administration. Guidance for Industry: A Food Labeling Guide external link disclaimer(14. Appendix F: Calculate the Percent Daily Value for the Appropriate Nutrients). 2013.
- Natural Medicines. Folate.external link disclaimer 2018.
- Duhra P. Treatment of gastrointestinal symptoms associated with methotrexate therapy for psoriasis. J Am Acad Dermatol 1993;28:466-9. [PubMed abstract]
- Ortiz Z, Shea B, Suarez Almazor M, et al. Folic acid and folinic acid for reducing side effects in patients receiving methotrexate for rheumatoid arthritis. Cochrane Database Syst Rev 2000:CD000951. [PubMed abstract]
- Linnebank M, Moskau S, Semmler A, et al. Antiepileptic drugs interact with folate and vitamin B12 serum levels. Ann Neurol 2011;69:352-9. [PubMed abstract]
- Halsted CH, Gandhi G, Tamura T. Sulfasalazine inhibits the absorption of folates in ulcerative colitis. N Engl J Med 1981;305:1513-7. [PubMed abstract]
English | 简体中文|
天然、有机、半合成、合成,这些词语是什么意思?
你可能会惊讶地发现,有机,实际上并不意味着更安全、更有营养,或不含化学物质。你可能还会惊讶地发现,天然并不意味着有机。
你是不是已经有点困惑?听我细细讲来,你很快就会明白。
我在全球的大多数听众,都听过我的 “绝对思维的危险性”演讲。我来举一些例子,说明为什么绝对主义是个问题,特别是在科学领域。世界各地的大多数受访者认为,植物来源总是更健康,天然成分的效果总是优于合成成分,合成成分总是有害。但以上所有假设皆是错误的。我知道,有些人现在仍然游移不定,正在经理“虽然如此,但是……”时刻。你暗想,虽然如此,但某某说……虽然如此,但我听说……虽然如此,但我最敬重的专家说……请收起你的怀疑,我们现在要谈的是客观事实。
科学定义和常用营销定义往往大有差别。这篇文章的目的,是为让大家清楚了解每个类别的含义,从而为个人健康计划做出最佳选择。
我们从地球生命谈起。我们对其他星球的生命一无所知,但地球上的都是碳基生命。所有活着或曾经活着的生物都含碳分子。有机物的一个定义是“有生命的有机体”,但更准确的科学定义应是“含有碳分子的一切东西”。有人可能会说,“但化石燃料也含碳分子”。别忘记化石燃料是由植物形成。市场营销中的常见误解是:恐龙是当今化石燃料的来源,这简直是无稽之谈。恐龙数量有限,它们不足以分解成地球上巨量的化石燃料,所有化石燃料都来自活的植物。这也是化石燃料含碳的原因。是的,确切来说,它们确实符合有机物的定义。但现实中没有人会采用这种分类方式。
纵观全球,人们相信的是有机、天然和合成的营销定义。有机的常见营销定义是,不使用任何杀虫剂和激素等物质培育的植物或动物。人们还认为,“有机”这个词意味着更安全和更干净。理论上说,如果动植物培育得当,它们最终都会富含营养,但这并不是“有机”一词能够保证的。
多年来,美国多个州对“有机”一词进行了定义,各州略有不同。最后,美国农业部给出了确切定义。他们认为,“若能够证明农产品生长于收获前三年没有施用过任何禁用物质的土壤中,便可称其为有机产品。禁用物质包括大多数合成肥料和杀虫剂。若种植者必须使用合成物质以达到特定目的,该物质必须首先通过人类健康和环境影响审查标准。”
朋友们,请注意,这个定义并没有规定你所购买的农产品上不含杀虫剂等违禁物质,因为在这个地球上不可能实现这种保证。当购买带有有机标签的东西时,你需要具备一定的认识。
地球是一个封闭的生态系统,因此,无论是北极的冰雪还是南极企鹅的脂肪组织中,都能找到农业杀虫剂成分,这表明,地球上不存在不接触农业杀虫剂和其他毒素的地方。
那农业杀虫剂如何会到达南极和北极?很明显,两极离最近的农场都有几千英里或公里远。地球一天24小时移动的天气系统,携带着各种化学毒素,包括杀虫剂。通常情况下,杀虫剂和其他化学品会随着水流进入世界各地的淡水和咸水中。
当然,我确实会尽可能选择有机食品,稍后我会展开详谈。
天然
那么,天然食品呢?几乎所有人都会毫不迟疑地选择天然产品。我同意。只要有可能,我希望消费并向人们推荐天然产品。但天然并不等同于有机。
注射过激素或抗生素,进食过可能含有杀虫剂的饲料的动物,仍然是天然食品。砷、镉和铅等有毒金属都是天然的,甚至原油也是天然的。
所有矿物质都是天然的。合成矿物质这种东西不存在。但矿物质不是有机物。我个人使用并经常推荐氨基酸螯合剂形式的天然矿物质。然而,并非所有螯合剂都一样,有些非常有效,有些则不然。出于实用和科学的原因,我为自己的个人健康选择了螯合剂。现代饮食中许多人的矿物质摄入量不足,这可能会是一个健康问题。矿物质对你的健康乃至生命都至关重要。
植物材料中的矿物质含量,通常不足以满足每个人合理的矿物质膳食需求。例如,十片或更多片的纯植物矿物质营养剂,可能才相当于一片同样大小的天然螯合剂。
鉴于现实的饮食情况,我们需要更有效的螯合剂,而非植物来源。举例来说,约90%的美国人口每天摄入的钾不足。而钾对心脏健康至关重要。阅读不同的研究报告,你可能会得知,有50%到70%的人缺镁,而现代饮食每日只能满足最低镁需求量的50%。根据不同情况,最终影响肯定会高出50%。镁在人体内数百种重要功能中发挥作用,对生命至关重要。
目前,先进科学告诉我们,双甘氨酸是现有最好吸收和利用的矿物质形式。我总说“科学不断进步”,所以,我们不知未来会发生什么,但目前双甘氨酸螯合剂是获取矿物质的最有效方式。双甘氨酸螯合剂绝对安全,因为它们是由天然矿物质和天然氨基酸制成。它们虽然不是植物食品,但吸收率却十分惊人。人体消化道喜欢一种叫做甘氨酸的氨基酸,把两个甘氨酸分子结合起来,就会形成双甘氨酸。我在其他播客用葡萄糖酸锌与双甘氨酸锌来举过一个关于吸收的例子。锌常常出现在新闻报道中,最常见的形式是葡萄糖酸盐。但最新科学告诉我们,双甘氨酸锌的吸收率比葡萄糖酸盐的吸收率约高44%。绝对天然,绝对安全,绝对易于吸收和利用。
要证明合成物的安全有效性,另一个例子是合成维生素B9,合成维生素B9事实上比天然维生素B9更有效。各种维生素B9形式经常被统称为叶酸盐。一些作者会非常具体地将叶酸盐表示为维生素B9,因为它是在植物材料中发现的自然存在形式。这是最准确的描述。但别忘记,一些文章也会互用“叶酸”和“叶酸盐”。例如,欧盟法规要求必须在标签上将维生素B9列为叶酸,无论其来源如何。但各国情况不同,所以可能会引起混淆。
研究证实,叶酸(叶酸盐的合成形式)可以预防神经管缺陷。显然,它的吸收率很高,安全且有效。一些比较研究表明,饮食中的叶酸盐对预防神经管缺陷或NTD(如脊柱裂和无脑穹窿)无效,而同一研究中的叶酸却很有效。
我经常谈论各种变量,当然,食物中的叶酸盐也可能确实有效,只是研究中的孕妇没有从食物中摄取足量叶酸,或可能拥有基因缺陷。但无论如何,合成叶酸安全且有效,因此被用作产前维生素。
还有一个问题是甲基化问题,这是一种特殊的基因缺陷,使人们无法将叶酸转化为活性形式。具有这一问题的人群需要使用一种已经甲基化的叶酸形式。一些膳食补充剂制造商使用一种含有5-甲基-THF(又名甲基叶酸)还原形式的叶酸,让即使有特定甲基化基因缺陷的人也能吸收。
叶酸问题值得我专门做一期播客,所以,关于叶酸,我今天先讲这些。
朋友们别忘记,我的目标始终是基于客观的科学材料,为大家提供最佳建议,使你们获取最安全、最有效的健康支持。我对形式或哲学没有任何偏见。唯一重要的是通过客观的科学分析,为你的身体提供最安全、最有效的补充剂。
半合成
还有一个大家可能从未听说过的类别,即半合成物。半合成物有点复杂。对两种天然物质进行半合成处理,可以创造一种新结构。这种新结构就被称为半合成物。尽管采用的是两种天然物质,却人为创造出一种新结构,所以它就不再是天然形式。
至于端上餐桌的食物,我会尽可能地选择有机,我也建议大家如此,因为即使不能保证有机食物富含营养或100%不含毒素,但至少可以肯定,它们比不符合有机标准的食品更健康。由于世界各地的管辖法不同,有机的定义也千差万别。
总而言之,天然的不一定好,合成的不一定坏,并且严格来说,有机的含义可能与营销人员的话术大相径庭。现在,大家对天然、有机、合成物和半合成物有了基本了解。正如我常说的,要想做出明智的决定,就必须将情况了解得清清楚楚。我希望大家现在可以更好地选择食品补充剂。世界不断变化,压力日益增加,而科学家们会继续努力弥补和适应这些变化。科学进步永无止境。
下次再见,我是Steve Nugent医生,向你传递安全、理性、客观的理念。
注释与来源:
术语:
- 若能够证明农产品生长于收获前三年没有施用过任何禁用物质的土壤中,便可被称其为有机产品。禁用物质包括大多数合成肥料和杀虫剂。若种植者必须使用合成物质以达到特定目的,该物质必须首先通过人类健康和环境影响审查标准。(见其他考虑因素“有机常识:允许和禁止物质”)https://www.usda.gov/media/blog/2012/03/22/organic-101-what-usda-organic-label-means?page=2
- 一般来说,食品标签上的“天然”意味着产品不含人工色素、香料或防腐剂。它不是指生产食品的方法或材料。https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/organic-food/art-20043880#:~:text=Read%20food%20labels%20carefully.,%2C%20salt%2C%20fat%20or%20calories.
螯合矿物质是与氨基酸化学结合的无机矿物质。[1] “在自然界中,矿物质总是与另一种化合物结合。”“一些研究表明,这种螯合矿物质可在体内被更有效地被吸收。”“矿物质是必需营养素,这意味着,人体不能制造它们,但需要它们来实现正常健康的功能。”尽管不存在合成矿物质这种东西,但地球上有有机和无机矿物质。科学将有机物简单地定义为含有碳分子的东西,寓意其为有生命或曾经有生命的东西。还有一些天然矿物不是有机物。https://www.webmd.com/vitamins/ai/ingredientmono-41/chelated-minerals
- 美泰(Mannatech)使用最先进的科学,以安全有效的形式打造矿物质补充剂。天然矿物质螯合物几乎在所有美泰市场都得到了批准。今天,人类研究支持的先进科学,使我们可以制造和使用天然矿物质,并利用最新科学将它们与天然氨基酸结合起来。我们选择这些强大的矿物质和各种优质维生素来达到或超过每日建议摄入值,使每一剂量都能带来最大功效。
- 术语“螯合剂”(chelate,发音key-late)源自希腊语chele(”χηλή”),意为“爪状”,描述了某种矿物形式的结构,其中,矿物分子被固定在一个以上的附着点,并形成一个环状结构。
- 经证明,适量摄取某些营养性矿物质,可维持人类最佳健康状态。
- 科学证明,有机矿物质氨基酸螯合剂比无机矿物质更容易被人体吸收,且引起的胃部不适更少。这种较高的耐受性和生物利用率,部分原因在于,螯合矿物质被完整吸收,并在肠道细胞中分解运输。Albion 凭借市场上最优质的螯合矿物质成分,成为全球矿物质营养领域的领导者。https://balchem.com/human-nutrition-health/technologies/mineral-chelation/
不足统计:
- 大约75%的美国人口(年龄≥1岁)未摄入建议量水果,超过80%的人未摄入建议量蔬菜(1)。
- 具体而言,在美国人口中,有3%未达到维生素D每日需求量,88.5%未达到维生素E每日需求量,52.2%未达到镁每日需求量,44.1%未达到钙每日需求量,43.0%未达到维生素A每日需求量,38.9%未达到维生素C每日需求量。对于没有规定需要量的营养成分,100%人口摄入的钾、91.7%摄入的胆碱和66.7%摄入的维生素K,均低于允许摄入量。所有B族维生素和几种矿物质,包括铜、铁、磷、硒、钠和锌的摄入量都很低(见表1)。此外,97%以上的人口钠摄入量过高,即每日摄入量超过特定年龄段的可耐受最高摄入量(26)。
- 整体而言,超过40%的美国人口无法仅通过饮食满足钙需求(28)。
- NHANES 2003-2006发现,约36%的儿童和青少年以及61%的成年人,其镁摄入量低于平均需求量。
https://lpi.oregonstate.edu/mic/micronutrient-inadequacies/overview
- 尽管镁的推荐日摄入量为男性420毫克,女性320毫克,但美国的标准饮食只达到该数值的50%左右。据估计,一半以上的人口采用的饮食均缺乏镁。https://www.sciencedaily.com/releases/2018/02/180226122548.htm
- 约50%美国人的镁消费量低于预估的平均需求量(EAR),一些年龄组摄入的镁更少。20 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5786912/
- 不到2%的美国人满足建议的最低充足摄入量,即每天4700。为获得足够的摄入量,普通美国人每天必须多吃5根香蕉,才能补够钾元素。98%的美国人采用的饮食都缺乏钾,因为他们摄入的植物不足。https://nutritionfacts.org/2013/05/23/98-of-american-diets-potassium-deficient/
- 要制造维生素D、荷尔蒙(包括睾丸激素和雌激素)、溶解脂肪的胆汁酸,也需要胆固醇。事实上,胆固醇十分重要,人体肝脏和肠道制造了大约80%的胆固醇,以维持人体健康。而只有 20%的胆固醇源自食物。https://www.health.harvard.edu/heart-health/how-its-made-cholesterol-production-in-your-body#:~:text=Cholesterol%20also%20is%20needed%20to,from%20the%20foods%20you%20eat.
- Bailey LB, Caudill MA. Folate. In: Erdman JW, Macdonald IA, Zeisel SH, eds. Present Knowledge in Nutrition. 10th ed. Washington, DC: Wiley-Blackwell; 2012:321-42.
- Institute of Medicine. Food and Nutrition Board. Dietary Reference Intakes: Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, DC: National Academy Press; 1998.
- Stover PJ. Folic acid. In: Ross AC, Caballero B, Cousins RJ, Tucker KL, Ziegler TR, eds. Modern Nutrition in Health and Disease. 11th ed. Baltimore, MD: Lippincott Williams & Wilkins; 2012:358-68.
- Carmel R. Folic acid. In: Shils M, Shike M, Ross A, Caballero B, Cousins RJ, eds. Modern Nutrition in Health and Disease. 11th ed. Baltimore, MD: Lippincott Williams & Wilkins; 2005:470-81.
- Paniz C, Bertinato JF, Lucena MR, et al. A daily dose of 5 mg folic acid for 90 days is associated with increased serum unmetabolized folic acid and reduced natural killer cell cytotoxicity in healthy Brazilian adults. J Nutr 2017;147:1677-85. [PubMed abstract]
- Crider KS, Bailey LB, Berry RJ. Folic acid food fortification-its history, effect, concerns, and future directions. Nutrients 2011;3:370-84. [PubMed abstract]
- Yetley EA, Pfeiffer CM, Phinney KW, et al. Biomarkers of folate status in NHANES: a roundtable summary. Am J Clin Nutr 2011;94:303S-12S. [PubMed abstract]
- Lakoff A, Fazili Z, Aufreiter S, et al. Folate is absorbed across the human colon: evidence by using enteric-coated caplets containing 13C-labeled [6S]-5-formyltetrahydrofolate. Am J Clin Nutr 2014;100:1278-86. [PubMed abstract]
- Bailey LB, Stover PJ, McNulty H, et al. Biomarkers of nutrition for development-folate review. J Nutr 2015;145:1636S-80S. [PubMed abstract]
- Green R. Indicators for assessing folate and vitamin B-12 status and for monitoring the efficacy of intervention strategies. Am J Clin Nutr 2011;94:666S-72S. [PubMed abstract]
- S. Food and Drug Administration. Food Labeling: Revision of the Nutrition and Supplement Facts Labels. external link disclaimer2016.
- S. Department of Agriculture, Agricultural Research Service. FoodData Centralexternal link disclaimer, 2019.
- S. Food and Drug Administration. Food Standards: Amendment of Standards of Identity For Enriched Grain Products to Require Addition of Folic Acid.external link disclaimer Federal Register 1996;61:8781-97.
- Choumenkovitch SF, Selhub J, Wilson PW, et al. Folic acid intake from fortification in United States exceeds predictions. J Nutr 2002;132:2792-8. [PubMed abstract]
- S. Food and Drug Administration. FDA approves folic acid fortification of corn masa flour.external link disclaimer 2016. [PubMed abstract]
- Government of Canada. Regulations amending the food and drug regulations (1066). Canada Gazette 1998;132.
- Centers for Disease Control and Prevention. CDC grand rounds: Additional opportunities to prevent neural tube defects with folic acid fortification. MMWR Morb Mortal Wkly Rep 2010;59:980-4. [PubMed abstract]
- Yeung LF, Cogswell ME, Carriquiry AL, et al. Contributions of enriched cereal-grain products, ready-to-eat cereals, and supplements to folic acid and vitamin B-12 usual intake and folate and vitamin B-12 status in US children: National Health and Nutrition Examination Survey (NHANES), 2003-2006. Am J Clin Nutr 2011;93:172-85. [PubMed abstract]
- National Institutes of Health. Dietary Supplement Label Database. 2018.
- Scaglione F, Panzavolta G. Folate, folic acid and 5-methyltetrahydrofolate are not the same thing. Xenobiotica 2014;44:480-8. [PubMed abstract]
- Greenberg JA, Bell SJ, Guan Y, et al. Folic acid supplementation and pregnancy: more than just neural tube defect prevention. Rev Obstet Gynecol 2011;4:52-9. [PubMed abstract]
- Henderson AM, Aleliunas RE, Loh SP, et al. l-5-Methyltetrahydrofolate supplementation increases blood folate concentrations to a greater extent than folic acid supplementation in Malaysian women. J Nutr 2018;148:885-90. [PubMed abstract]
- Green TJ, Liu Y, Dadgar S, et al. Wheat rolls fortified with microencapsulated L-5-methyltetrahydrofolic acid or equimolar folic acid increase blood folate concentrations to a similar extent in healthy men and women. J Nutr 2013;143:867-71. [PubMed abstract]
- Venn BJ, Green TJ, Moser R, et al. Comparison of the effect of low-dose supplementation with L-5-methyltetrahydrofolate or folic acid on plasma homocysteine: a randomized placebo-controlled study. Am J Clin Nutr 2003;77:658-62. [PubMed abstract]
- Venn BJ, Green TJ, Moser R, et al. Increases in blood folate indices are similar in women of childbearing age supplemented with [6S]-5-methyltetrahydrofolate and folic acid. J Nutr 2002;132:3353-5. [PubMed abstract]
- Lamers Y, Prinz-Langenohl R, Bramswig S, et al. Red blood cell folate concentrations increase more after supplementation with [6S]-5-methyltetrahydrofolate than with folic acid in women of childbearing age. Am J Clin Nutr 2006;84:156-61. [PubMed abstract]
- Pietrzik K, Bailey L, Shane B. Folic acid and L-5-methyltetrahydrofolate: comparison of clinical pharmacokinetics and pharmacodynamics. Clin Pharmacokinet 2010;49:535-48. [PubMed abstract]
- S. Department of Agriculture, Agricultural Research Service. What We Eat in America, 2013-2014.external link disclaimer 2017.
- Bailey RL, Dodd KW, Gahche JJ, et al. Total folate and folic acid intake from foods and dietary supplements in the United States: 2003-2006. Am J Clin Nutr 2010;91:231-7. [PubMed abstract]
- Bailey RL, McDowell MA, Dodd KW, et al. Total folate and folic acid intakes from foods and dietary supplements of US children aged 1-13 y. Am J Clin Nutr 2010;92:353-8. [PubMed abstract]
- Yang Q, Cogswell ME, Hamner HC, et al. Folic acid source, usual intake, and folate and vitamin B-12 status in US adults: National Health and Nutrition Examination Survey (NHANES) 2003-2006. Am J Clin Nutr 2010;91:64-72. [PubMed abstract]
- Ho RC, Cheung MW, Fu E, et al. Is high homocysteine level a risk factor for cognitive decline in elderly? A systematic review, meta-analysis, and meta-regression. Am J Geriatr Psychiatry 2011;19:607-17. [PubMed abstract]
- Scholl TO, Johnson WG. Folic acid: influence on the outcome of pregnancy. Am J Clin Nutr 2000;71:1295S-303S. [PubMed abstract]
- Gloria L, Cravo M, Camilo ME, et al. Nutritional deficiencies in chronic alcoholics: relation to dietary intake and alcohol consumption. Am J Gastroenterol 1997;92:485-9. [PubMed abstract]
- Gibson A, Woodside JV, Young IS, et al. Alcohol increases homocysteine and reduces B vitamin concentration in healthy male volunteers–a randomized, crossover intervention study. QJM 2008;101:881-7. [PubMed abstract]
- Centers for Disease Control and Prevention. Folic acid 2012.external link disclaimer
- S. Preventive Services Task Force, Bibbins-Domingo K, Grossman DC, et al. Folic acid supplementation for the prevention of neural tube defects: US Preventive Services Task Force recommendation statement. JAMA 2017;317:183-9. [PubMed abstract]
- American College of Obstetricians and Gynecologists. Frequently Asked Questions, FAQ001, Pregnancy, Nutrition During Pregnancy.external link disclaimer 2018.
- Rossi RE, Whyand T, Murray CD, et al. The role of dietary supplements in inflammatory bowel disease: a systematic review. Eur J Gastroenterol Hepatol 2016;28:1357-64. [PubMed abstract]
- Molloy AM, Pangilinan F, Brody LC. Genetic risk factors for folate-responsive neural tube defects. Annu Rev Nutr 2017;37:269-91. [PubMed abstract]
- National Institute of Mental Health. Autism spectrum disorder. 2018.
- Berry RJ, Crider KS, Yeargin-Allsopp M. Periconceptional folic acid and risk of autism spectrum disorders. JAMA 2013;309:611-3. [PubMed abstract]
- Bjork M, Riedel B, Spigset O, et al. Association of folic acid supplementation during pregnancy with the risk of autistic traits in children exposed to antiepileptic drugs in utero. JAMA Neurol 2018;75:160-8. [PubMed abstract]
- Schmidt RJ, Kogan V, Shelton JF, et al. Combined prenatal pesticide exposure and folic acid intake in relation to autism spectrum disorder. Environ Health Perspect 2017;125:097007. [PubMed abstract]
- Goodrich AJ, Volk HE, Tancredi DJ, et al. Joint effects of prenatal air pollutant exposure and maternal folic acid supplementation on risk of autism spectrum disorder. Autism Res 2018;11:69-80. [PubMed abstract]
- Roffman JL. Neuroprotective effects of prenatal folic acid supplementation: why timing matters. JAMA Psychiatry 2018;75:747-8. [PubMed abstract]
- Caffrey A, Irwin RE, McNulty H, et al. Gene-specific DNA methylation in newborns in response to folic acid supplementation during the second and third trimesters of pregnancy: epigenetic analysis from a randomized controlled trial. Am J Clin Nutr 2018;107:566-75. [PubMed abstract]
- DeVilbiss EA, Gardner RM, Newschaffer CJ, et al. Maternal folate status as a risk factor for autism spectrum disorders: a review of existing evidence. Br J Nutr 2015;114:663-72. [PubMed abstract]
- Suren P, Roth C, Bresnahan M, et al. Association between maternal use of folic acid supplements and risk of autism spectrum disorders in children. JAMA 2013;309:570-7. [PubMed abstract]
- Schmidt RJ, Tancredi DJ, Ozonoff S, et al. Maternal periconceptional folic acid intake and risk of autism spectrum disorders and developmental delay in the CHARGE (CHildhood Autism Risks from Genetics and Environment) case-control study. Am J Clin Nutr 2012;96:80-9. [PubMed abstract]
- Levine SZ, Kodesh A, Viktorin A, et al. Association of maternal use of folic acid and multivitamin supplements in the periods before and during pregnancy with the risk of autism spectrum disorder in offspring. JAMA Psychiatry 2018;75:176-84. [PubMed abstract]
- Virk J, Liew Z, Olsen J, et al. Preconceptional and prenatal supplementary folic acid and multivitamin intake and autism spectrum disorders. Autism 2016;20:710-8. [PubMed abstract]
- He H, Shui B. Folate intake and risk of bladder cancer: a meta-analysis of epidemiological studies. Int J Food Sci Nutr 2014;65:286-92. [PubMed abstract]
- Kim YI. Will mandatory folic acid fortification prevent or promote cancer? Am J Clin Nutr 2004;80:1123-8. [PubMed abstract]
- Kim YI. Folate and carcinogenesis: evidence, mechanisms, and implications. J Nutr Biochem 1999;10:66-88. [PubMed abstract]
- Kim YI. Folate and cancer: a tale of Dr. Jekyll and Mr. Hyde? Am J Clin Nutr 2018;107:139-42. [PubMed abstract]
- Andreeva VA, Touvier M, Kesse-Guyot E, et al. B vitamin and/or omega-3 fatty acid supplementation and cancer: ancillary findings from the supplementation with folate, vitamins B6 and B12, and/or omega-3 fatty acids (SU.FOL.OM3) randomized trial. Arch Intern Med 2012;172:540-7. [PubMed abstract]
- Ebbing M, Bonaa KH, Nygard O, et al. Cancer incidence and mortality after treatment with folic acid and vitamin B12. JAMA 2009;302:2119-26. [PubMed abstract]
- Mason JB. Unraveling the complex relationship between folate and cancer risk. Biofactors 2011;37:253-60. [PubMed abstract]
- Giovannucci E, Stampfer MJ, Colditz GA, et al. Folate, methionine, and alcohol intake and risk of colorectal adenoma. J Natl Cancer Inst 1993;85:875-84. [PubMed abstract]
- Gibson TM, Weinstein SJ, Pfeiffer RM, et al. Pre- and postfortification intake of folate and risk of colorectal cancer in a large prospective cohort study in the United States. Am J Clin Nutr 2011;94:1053-62. [PubMed abstract]
- Sanjoaquin MA, Allen N, Couto E, et al. Folate intake and colorectal cancer risk: a meta-analytical approach. Int J Cancer 2005;113:825-8. [PubMed abstract]
- Kennedy DA, Stern SJ, Moretti M, et al. Folate intake and the risk of colorectal cancer: a systematic review and meta-analysis. Cancer Epidemiol 2011;35:2-10. [PubMed abstract]
- Bassett JK, Severi G, Hodge AM, et al. Dietary intake of B vitamins and methionine and colorectal cancer risk. Nutr Cancer 2013;65:659-67. [PubMed abstract]
- de Vogel S, Dindore V, van Engeland M, et al. Dietary folate, methionine, riboflavin, and vitamin B-6 and risk of sporadic colorectal cancer. J Nutr 2008;138:2372-8. [PubMed abstract]
- Neuhouser ML, Cheng TY, Beresford SA, et al. Red blood cell folate and plasma folate are not associated with risk of incident colorectal cancer in the Women’s Health Initiative observational study. Int J Cancer 2015;137:930-9. [PubMed abstract]
- Chuang SC, Rota M, Gunter MJ, et al. Quantifying the dose-response relationship between circulating folate concentrations and colorectal cancer in cohort studies: a meta-analysis based on a flexible meta-regression model. Am J Epidemiol 2013;178:1028-37. [PubMed abstract]
- Song Y, Manson JE, Lee IM, et al. Effect of combined folic acid, vitamin B(6), and vitamin B(12) on colorectal adenoma. J Natl Cancer Inst 2012;104:1562-75. [PubMed abstract]
- Figueiredo JC, Mott LA, Giovannucci E, et al. Folic acid and prevention of colorectal adenomas: a combined analysis of randomized clinical trials. Int J Cancer 2011;129:192-203. [PubMed abstract]
- Cole BF, Baron JA, Sandler RS, et al. Folic acid for the prevention of colorectal adenomas: a randomized clinical trial. JAMA 2007;297:2351-9. [PubMed abstract]
- Vollset SE, Clarke R, Lewington S, et al. Effects of folic acid supplementation on overall and site-specific cancer incidence during the randomised trials: meta-analyses of data on 50,000 individuals. Lancet 2013;381:1029-36. [PubMed abstract]
- van Wijngaarden JP, Swart KM, Enneman AW, et al. Effect of daily vitamin B-12 and folic acid supplementation on fracture incidence in elderly individuals with an elevated plasma homocysteine concentration: B-PROOF, a randomized controlled trial. Am J Clin Nutr 2014;100:1578-86. [PubMed abstract]
- Tu H, Dinney CP, Ye Y, et al. Is folic acid safe for non-muscle-invasive bladder cancer patients? An evidence-based cohort study. Am J Clin Nutr 2018;107:208-16. [PubMed abstract]
- Kim SJ, Zuchniak A, Sohn KJ, et al. Plasma folate, vitamin B-6, and vitamin B-12 and breast cancer risk in BRCA1- and BRCA2-mutation carriers: a prospective study. Am J Clin Nutr 2016;104:671-7. [PubMed abstract]
- Figueiredo JC, Grau MV, Haile RW, et al. Folic acid and risk of prostate cancer: results from a randomized clinical trial. J Natl Cancer Inst 2009;101:432-5. [PubMed abstract]
- Tomaszewski JJ, Cummings JL, Parwani AV, et al. Increased cancer cell proliferation in prostate cancer patients with high levels of serum folate. Prostate 2011;71:1287-93. [PubMed abstract]
- Wien TN, Pike E, Wisloff T, et al. Cancer risk with folic acid supplements: a systematic review and meta-analysis. BMJ Open 2012;2:e000653. [PubMed abstract]
- Kim S, Choi BY, Nam JH, et al. Cognitive impairment is associated with elevated serum homocysteine levels among older adults. Eur J Nutr 2018. [PubMed abstract]
- Kim YI. Folate: a magic bullet or a double edged sword for colorectal cancer prevention? Gut 2006;55:1387-9. [PubMed abstract]
- Ulrich CM, Potter JD. Folate supplementation: too much of a good thing? Cancer Epidemiol Biomarkers Prev 2006;15:189-93. [PubMed abstract]
- Mason JB, Tang SY. Folate status and colorectal cancer risk: a 2016 update. Mol Aspects Med 2017;53:73-9. [PubMed abstract]
- Lee JE, Willett WC, Fuchs CS, et al. Folate intake and risk of colorectal cancer and adenoma: modification by time. Am J Clin Nutr 2011;93:817-25. [PubMed abstract]
- National Toxicology Program. NTP monograph: identifying research needs for assessing safe use of high intakes of folic acid. National Toxicology Program, 2015.
- Clarke R, Halsey J, Lewington S, et al. Effects of lowering homocysteine levels with B vitamins on cardiovascular disease, cancer, and cause-specific mortality: Meta-analysis of 8 randomized trials involving 37 485 individuals. Arch Intern Med 2010;170:1622-31. [PubMed abstract]
- Huang T, Chen Y, Yang B, et al. Meta-analysis of B vitamin supplementation on plasma homocysteine, cardiovascular and all-cause mortality. Clin Nutr 2012;31:448-54. [PubMed abstract]
- Toole JF, Malinow MR, Chambless LE, et al. Lowering homocysteine in patients with ischemic stroke to prevent recurrent stroke, myocardial infarction, and death: the Vitamin Intervention for Stroke Prevention (VISP) randomized controlled trial. JAMA 2004;291:565-75. [PubMed abstract]
- Lonn E, Yusuf S, Arnold MJ, et al. Homocysteine lowering with folic acid and B vitamins in vascular disease. N Engl J Med 2006;354:1567-77. [PubMed abstract]
- Albert CM, Cook NR, Gaziano JM, et al. Effect of folic acid and B vitamins on risk of cardiovascular events and total mortality among women at high risk for cardiovascular disease: a randomized trial. JAMA 2008;299:2027-36. [PubMed abstract]
- Ebbing M, Bleie O, Ueland PM, et al. Mortality and cardiovascular events in patients treated with homocysteine-lowering B vitamins after coronary angiography: a randomized controlled trial. JAMA 2008;300:795-804. [PubMed abstract]
- Christen WG, Cook NR, Van Denburgh M, et al. Effect of combined treatment with folic acid, vitamin B6, and vitamin B12 on plasma biomarkers of inflammation and endothelial dysfunction in women. J Am Heart Assoc 2018;7. [PubMed abstract]
- Huo Y, Li J, Qin X, et al. Efficacy of folic acid therapy in primary prevention of stroke among adults with hypertension in China: the CSPPT randomized clinical trial. JAMA 2015;313:1325-35. [PubMed abstract]
- Study of the Effectiveness of Additional Reductions in Cholesterol Homocysteine Collaborative Group, Armitage JM, Bowman L, et al. Effects of homocysteine-lowering with folic acid plus vitamin B12 vs placebo on mortality and major morbidity in myocardial infarction survivors: a randomized trial. JAMA 2010;303:2486-94. [PubMed abstract]
- Huo Y, Qin X, Wang J, et al. Efficacy of folic acid supplementation in stroke prevention: new insight from a meta-analysis. Int J Clin Pract 2012;66:544-51. [PubMed abstract]
- Kong X, Huang X, Zhao M, et al. Platelet count affects efficacy of folic acid in preventing first stroke. J Am Coll Cardiol 2018;71:2136-46. [PubMed abstract]
- Stampfer M, Willett W. Folate supplements for stroke prevention: targeted trial trumps the rest. JAMA 2015;313:1321-2. [PubMed abstract]
- Marti-Carvajal AJ, Sola I, Lathyris D, et al. Homocysteine-lowering interventions for preventing cardiovascular events. Cochrane Database Syst Rev 2017;8:CD006612. [PubMed abstract]
- Jenkins DJA, Spence JD, Giovannucci EL, et al. Supplemental Vitamins and minerals for CVD prevention and treatment. J Am Coll Cardiol 2018;71:2570-84. [PubMed abstract]
- Tian T, Yang KQ, Cui JG, et al. Folic acid supplementation for stroke prevention in patients with cardiovascular disease. Am J Med Sci 2017;354:379-87. [PubMed abstract]
- Seshadri S, Beiser A, Selhub J, et al. Plasma homocysteine as a risk factor for dementia and Alzheimer’s disease. N Engl J Med 2002;346:476-83. [PubMed abstract]
- Ravaglia G, Forti P, Maioli F, et al. Homocysteine and folate as risk factors for dementia and Alzheimer disease. Am J Clin Nutr 2005;82:636-43. [PubMed abstract]
- Clarke R. B-vitamins and prevention of dementia. Proc Nutr Soc 2008;67:75-81. [PubMed abstract]
- Smith AD, Refsum H. Homocysteine, B vitamins, and cognitive impairment. Annu Rev Nutr 2016;36:211-39. [PubMed abstract]
- Smith AD, Refsum H, Bottiglieri T, et al. Homocysteine and dementia: an international consensus statement. J Alzheimers Dis 2018;62:561-70. [PubMed abstract]
- Hooshmand B, Solomon A, Kareholt I, et al. Associations between serum homocysteine, holotranscobalamin, folate and cognition in the elderly: a longitudinal study. J Intern Med 2012;271:204-12. [PubMed abstract]
- Eussen SJ, de Groot LC, Joosten LW, et al. Effect of oral vitamin B-12 with or without folic acid on cognitive function in older people with mild vitamin B-12 deficiency: a randomized, placebo-controlled trial. Am J Clin Nutr 2006;84:361-70. [PubMed abstract]
- van der Zwaluw NL, Dhonukshe-Rutten RA, van Wijngaarden JP, et al. Results of 2-year vitamin B treatment on cognitive performance: secondary data from an RCT. Neurology 2014;83:2158-66. [PubMed abstract]
- Kang JH, Cook N, Manson J, et al. A trial of B vitamins and cognitive function among women at high risk of cardiovascular disease. Am J Clin Nutr 2008;88:1602-10. [PubMed abstract]
- Aisen PS, Schneider LS, Sano M, et al. High-dose B vitamin supplementation and cognitive decline in Alzheimer disease: a randomized controlled trial. JAMA 2008;300:1774-83. [PubMed abstract]
- Walker JG, Batterham PJ, Mackinnon AJ, et al. Oral folic acid and vitamin B-12 supplementation to prevent cognitive decline in community-dwelling older adults with depressive symptoms–the Beyond Ageing Project: a randomized controlled trial. Am J Clin Nutr 2012;95:194-203. [PubMed abstract]
- Clarke R, Bennett D, Parish S, et al. Effects of homocysteine lowering with B vitamins on cognitive aging: meta-analysis of 11 trials with cognitive data on 22,000 individuals. Am J Clin Nutr 2014;100:657-66. [PubMed abstract]
- Balk EM, Raman G, Tatsioni A, et al. Vitamin B6, B12, and folic acid supplementation and cognitive function: a systematic review of randomized trials. Arch Intern Med 2007;167:21-30. [PubMed abstract]
- Malouf R, Grimley Evans J. Folic acid with or without vitamin B12 for the prevention and treatment of healthy elderly and demented people. Cochrane Database Syst Rev 2008:CD004514. [PubMed abstract]
- Dangour AD, Whitehouse PJ, Rafferty K, et al. B-vitamins and fatty acids in the prevention and treatment of Alzheimer’s disease and dementia: a systematic review. J Alzheimers Dis 2010;22:205-24. [PubMed abstract]
- Ford AH, Almeida OP. Effect of homocysteine lowering treatment on cognitive function: a systematic review and meta-analysis of randomized controlled trials. J Alzheimers Dis 2012;29:133-49. [PubMed abstract]
- Durga J, van Boxtel MP, Schouten EG, et al. Effect of 3-year folic acid supplementation on cognitive function in older adults in the FACIT trial: a randomised, double blind, controlled trial. Lancet 2007;369:208-16. [PubMed abstract]
- Huang X, Fan Y, Han X, et al. Association between serum vitamin levels and depression in U.S. adults 20 years or older based on National Health and Nutrition Examination Survey 2005-2006. Int J Environ Res Public Health 2018;15. [PubMed abstract]
- Gougeon L, Payette H, Morais JA, et al. Intakes of folate, vitamin B6 and B12 and risk of depression in community-dwelling older adults: the Quebec Longitudinal Study on Nutrition and Aging. Eur J Clin Nutr 2016;70:380-5. [PubMed abstract]
- Morris MS, Fava M, Jacques PF, et al. Depression and folate status in the US population. Psychother Psychosom 2003;72:80-7. [PubMed abstract]
- Papakostas GI, Petersen T, Mischoulon D, et al. Serum folate, vitamin B12, and homocysteine in major depressive disorder, Part 1: predictors of clinical response in fluoxetine-resistant depression. J Clin Psychiatry 2004;65:1090-5. [PubMed abstract]
- Trujillo J, Vieira MC, Lepsch J, et al. A systematic review of the associations between maternal nutritional biomarkers and depression and/or anxiety during pregnancy and postpartum. J Affect Disord 2018;232:185-203. [PubMed abstract]
- Chong MF, Wong JX, Colega M, et al. Relationships of maternal folate and vitamin B12 status during pregnancy with perinatal depression: The GUSTO study. J Psychiatr Res 2014;55:110-6. [PubMed abstract]
- Blunden CH, Inskip HM, Robinson SM, et al. Postpartum depressive symptoms: the B-vitamin link. Ment Health Fam Med 2012;9:5-13. [PubMed abstract]
- Yan J, Liu Y, Cao L, et al. Association between duration of folic acid supplementation during pregnancy and risk of postpartum depression. Nutrients 2017;9. [PubMed abstract]
- Coppen A, Bailey J. Enhancement of the antidepressant action of fluoxetine by folic acid: a randomised, placebo controlled trial. J Affect Disord 2000;60:121-30. [PubMed abstract]
- Bedson E, Bell D, Carr D, et al. Folate Augmentation of Treatment–Evaluation for Depression (FolATED): randomised trial and economic evaluation. Health Technol Assess 2014;18:vii-viii, 1-159. [PubMed abstract]
- Roberts E, Carter B, Young AH. Caveat emptor: Folate in unipolar depressive illness, a systematic review and meta-analysis. J Psychopharmacol 2018;32:377-84. [PubMed abstract]
- Sarris J, Murphy J, Mischoulon D, et al. Adjunctive nutraceuticals for depression: A systematic review and meta-analyses. Am J Psychiatry 2016;173:575-87. [PubMed abstract]
- Cleare A, Pariante CM, Young AH, et al. Evidence-based guidelines for treating depressive disorders with antidepressants: a revision of the 2008 British Association for Psychopharmacology guidelines. J Psychopharmacol 2015;29:459-525. [PubMed abstract]
- Ravindran AV, Balneaves LG, Faulkner G, et al. Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 clinical guidelines for the management of adults with major depressive disorder: Section 5. Complementary and Alternative medicine treatments. Can J Psychiatry 2016;61:576-87. [PubMed abstract]
- Papakostas GI, Shelton RC, Zajecka JM, et al. L-methylfolate as adjunctive therapy for SSRI-resistant major depression: results of two randomized, double-blind, parallel-sequential trials. Am J Psychiatry 2012;169:1267-74. [PubMed abstract]
- Wilson RD, Genetics C, Motherisk. Pre-conceptional vitamin/folic acid supplementation 2007: the use of folic acid in combination with a multivitamin supplement for the prevention of neural tube defects and other congenital anomalies. J Obstet Gynaecol Can 2007;29:1003-13. [PubMed abstract]
- Pitkin RM. Folate and neural tube defects. Am J Clin Nutr 2007;85:285S-8S. [PubMed abstract]
- Williams J, Mai CT, Mulinare J, et al. Updated estimates of neural tube defects prevented by mandatory folic Acid fortification – United States, 1995-2011. MMWR Morb Mortal Wkly Rep 2015;64:1-5. [PubMed abstract]
- Lamers Y. Folate recommendations for pregnancy, lactation, and infancy. Ann Nutr Metab 2011;59:32-7. [PubMed abstract]
- Scott JM. Evidence of folic acid and folate in the prevention of neural tube defects. Bibl Nutr Dieta 2001:192-5. [PubMed abstract]
- Molloy AM, Kirke PN, Brody LC, et al. Effects of folate and vitamin B12 deficiencies during pregnancy on fetal, infant, and child development. Food Nutr Bull 2008;29:S101-11; discussion S12-5. [PubMed abstract]
- Williams LJ, Rasmussen SA, Flores A, et al. Decline in the prevalence of spina bifida and anencephaly by race/ethnicity: 1995-2002. Pediatrics 2005;116:580-6. [PubMed abstract]
- Rader JI, Schneeman BO. Prevalence of neural tube defects, folate status, and folate fortification of enriched cereal-grain products in the United States. Pediatrics 2006;117:1394-9. [PubMed abstract]
- Dary O. Nutritional interpretation of folic acid interventions. Nutr Rev 2009;67:235-44. [PubMed abstract]
- Shane B. Folate-responsive birth defects: of mice and women. Am J Clin Nutr 2012;95:1-2. [PubMed abstract]
- Viswanathan M, Treiman KA, Kish-Doto J, et al. Folic acid supplementation for the prevention of neural tube defects: an updated evidence report and systematic review for the US Preventive Services Task Force. JAMA 2017;317:190-203. [PubMed abstract]
- Centers for Disease Control and Prevention. Use of folic acid for prevention of spina bifida and other neural tube defects–1983-1991. MMWR Morb Mortal Wkly Rep 1991;40:513-6. [PubMed abstract]
- Czeizel AE, Puho EH, Langmar Z, et al. Possible association of folic acid supplementation during pregnancy with reduction of preterm birth: a population-based study. Eur J Obstet Gynecol Reprod Biol 2010;148:135-40. [PubMed abstract]
- Liu S, Joseph KS, Luo W, et al. Effect of folic acid food fortification in Canada on congenital heart disease subtypes. Circulation 2016;134:647-55. [PubMed abstract]
- Botto LD, Mulinare J, Erickson JD. Occurrence of congenital heart defects in relation to maternal mulitivitamin use. Am J Epidemiol 2000;151:878-84. [PubMed abstract]
- Shaw GM, O’Malley CD, Wasserman CR, et al. Maternal periconceptional use of multivitamins and reduced risk for conotruncal heart defects and limb deficiencies among offspring. Am J Med Genet 1995;59:536-45. [PubMed abstract]
- Johnson MA. If high folic acid aggravates vitamin B12 deficiency what should be done about it? Nutr Rev 2007;65:451-8. [PubMed abstract]
- Morris MS, Jacques PF, Rosenberg IH,et al. Folate and vitamin B-12 status in relation to anemia, macrocytosis, and cognitive impairment in older Americans in the age of folic acid fortification. Am J Clin Nutr 2007;85:193-200. [PubMed abstract]
- Selhub J, Morris MS, Jacques PF. In vitamin B12 deficiency, higher serum folate is associated with increased total homocysteine and methylmalonic acid concentrations. Proc Natl Acad Sci U S A 2007;104:19995-20000. [PubMed abstract]
- Selhub J, Morris MS, Jacques PF, et al. Folate-vitamin B-12 interaction in relation to cognitive impairment, anemia, and biochemical indicators of vitamin B-12 deficiency. Am J Clin Nutr 2009;89:702S-6S. [PubMed abstract]
- Berry RJ, Carter HK, Yang Q. Cognitive impairment in older Americans in the age of folic acid fortification. Am J Clin Nutr 2007;86:265-7; author reply 7-9. [PubMed abstract]
- Carmel R. Does high folic acid intake affect unrecognized cobalamin deficiency, and how will we know it if we see it? Am J Clin Nutr 2009;90:1449-50. [PubMed abstract]
- Valera-Gran D, Navarrete-Munoz EM, Garcia de la Hera M, Fernandez-Somoano A, Tardon A, Ibarluzea J, et al. Effect of maternal high dosages of folic acid supplements on neurocognitive development in children at 4-5 y of age: the prospective birth cohort Infancia y Medio Ambiente (INMA) study. Am J Clin Nutr 2017;106:878-87. [PubMed abstract]
- Troen AM, Mitchell B, Sorensen B, et al. Unmetabolized folic acid in plasma is associated with reduced natural killer cell cytotoxicity among postmenopausal women. J Nutr 2006;136:189-94. [PubMed abstract]
- Morris MS, Jacques PF, Rosenberg IH, Selhub J. Circulating unbetabolied folic acid and 5-methyltetrahydrofolate in relation to anemia, macrocytosis, and cognitive test performance in American seniors. Am J Clin Nutr. 2010 Jun;91(6):1733-44. [PubMed abstract]
- Pfeiffer CM, Sternberg MR, Fazili Z, et al. Unmetabolized folic acid is detected in nearly all serum samples from US children, adolescents, and adults. J Nutr 2015;145:520-31. [PubMed abstract]
- Stamm RA, March KM, Karakochuk CD, et al. Lactating Canadian women consuming 1000 µg folic acid daily have high circulating serum folic acid above a threshold concentration of serum total folate. J Nutr 2018;148:1103-8. [PubMed abstract]
- Page R, Robichaud A, Arbuckle TE, et al. Total folate and unmetabolized folic acid in the breast milk of a cross-section of Canadian women. Am J Clin Nutr 2017;105:1101-9. [PubMed abstract]
- Obeid R, Kasoha M, Kirsch SH, et al. Concentrations of unmetabolized folic acid and primary folate forms in pregnant women at delivery and in umbilical cord blood. Am J Clin Nutr 2010;92:1416-22. [PubMed abstract]
- Plumptre L, Masih SP, Ly A, et al. High concentrations of folate and unmetabolized folic acid in a cohort of pregnant Canadian women and umbilical cord blood. Am J Clin Nutr 2015;102:848-57. [PubMed abstract]
- Sweeney MR, McPartlin J, Scott J. Folic acid fortification and public health: report on threshold doses above which unmetabolised folic acid appear in serum. BMC Public Health 2007;7:41. [PubMed abstract]
- Kelly P, McPartlin J, Goggins M, et al. Unmetabolized folic acid in serum: acute studies in subjects consuming fortified food and supplements. Am J Clin Nutr 1997;65:1790-5. [PubMed abstract]
- Sweeney MR, McPartlin J, Weir DG, et al. Postprandial serum folic acid response to multiple doses of folic acid in fortified bread. Br J Nutr 2006;95:145-51. [PubMed abstract]
- S. Food and Drug Administration. Guidance for Industry: A Food Labeling Guide external link disclaimer(14. Appendix F: Calculate the Percent Daily Value for the Appropriate Nutrients). 2013.
- Natural Medicines. Folate.external link disclaimer 2018.
- Duhra P. Treatment of gastrointestinal symptoms associated with methotrexate therapy for psoriasis. J Am Acad Dermatol 1993;28:466-9. [PubMed abstract]
- Ortiz Z, Shea B, Suarez Almazor M, et al. Folic acid and folinic acid for reducing side effects in patients receiving methotrexate for rheumatoid arthritis. Cochrane Database Syst Rev 2000:CD000951. [PubMed abstract]
- Linnebank M, Moskau S, Semmler A, et al. Antiepileptic drugs interact with folate and vitamin B12 serum levels. Ann Neurol 2011;69:352-9. [PubMed abstract]
- Halsted CH, Gandhi G, Tamura T. Sulfasalazine inhibits the absorption of folates in ulcerative colitis. N Engl J Med 1981;305:1513-7. [PubMed abstract]