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Are calcium supplements dangerous?
Hello, my friends welcome to another episode of The Nugent Report, I’m Dr. Steve Nugent.
This episode is dedicated to calcium but it’s an entirely different approach than what you expected. For more than half a century people all over the world have been told “women need more calcium”. It is true that women need more calcium than men, however it is not universally true that women need calcium supplementation, in fact the majority of women consuming the modern diet don’t need calcium supplementation.
All of my subscribers know that the Nugent report is objective reporting about science and health and that means no bias and we don’t care about groupthink. The phrase “Everybody knows” is not science. Scientific knowledge is growing at such tremendous speed that it’s impossible for any single human being to keep up with. On the Nugent report we simply try to eat this elephant one bite at a time.
In this episode of the Nugent report you’re going to learn some things about calcium that may not only surprise you, they may shock you.
Here are just a few of the questions that we will address in this episode…
- Are you getting too much calcium?
- How is calcium absorbed and utilized?
- Is calcium just for bones?
- Are there foods rich in Calcium besides dairy?
- Do calcium supplements prevent weak bones and fractures?
- What are the risks with excess calcium supplementation?
People have been told for more than a century that you need calcium for strong healthy bones. This statement is correct. The average person however does not that healthy bones require much more than calcium, and the average person does not know that if you have too little magnesium or vitamin D that calcium will either calcified in your body or be excreted in urine which can lead to kidney stones.
Both the food and food supplement industries have been pushing the idea that women need more calcium. Once again it is true that women require more than men but only about 30% of women have a need for calcium supplementation above and beyond what’s in the modern diet. Too much calcium presents potential health problems. That’s the kind of thing that I want to convey to you. Under the heading of integrative health is a psychologist I also need to point out that human beings have a need to have virtually any topic reduced to the simplest common denominator. The one-size-fits-all approach is always more welcome than an approach that requires complex analysis. The fact is, the one-size-fits-all approach when it comes to calcium supplementation is not accurate and not a good idea.
For more details on how magnesium and vitamin D play a role in the absorption and utilization of calcium I would invite you to listen to my podcasts from my series on magnesium and vitamin D. “Science marches on” as I’m so fond of saying and things change.
When I first learned the basics of clinical nutrition it was many decades ago and unfortunately the overwhelming majority of practitioners today are still putting that decades old information and are not aware of more recent scientific study that contradicts some of what we used to believe was true.
Let’s begin with what calcium is needed for before we go on to the other questions. Calcium is an essential mineral meaning that your body must have it but cannot make it within your body, so it must be supplied to your body from an external source. The most preferable source would be food and in some cases food supplements. Science is showing us that some nutrients need to be supplemented because the modern diet supplies insufficient levels whereas with some nutrients this is not yet the case.
Even before the food industry began fortifying foods with calcium in order to sell more product to female consumers by emphasizing their food was fortified with extra calcium and then repeating the groupthink chant “women need more calcium” there is now an abundant level of calcium available in the modern diet. Some individuals are actually consuming too much calcium and don’t know it.
As the modern diet continues to change, calcium containing foods are often disproportionate in dietary choices.
Calcium is the most abundant mineral in the body. When someone says calcium in a Word Association test, the response might be bone or it might be dairy. We’ll talk about food sources in a few minutes. But understand that your body cannot function without calcium; it’s far more than just a necessity for healthy bones and teeth. You may recall from the series on magnesium and vitamin D, that magnesium is the mineral that relaxes a muscle and calcium is the mineral that contracts the muscle in order for a muscle to function it must contract and relax and repeat that cycle.
Calcium is also required for vasodilation, nerve transmission, vascular contraction, hormone secretion and intracellular signaling. Calcium is so important to the body, that the body very tightly regulates calcium balance in the blood(1). Approximately 1% of your body’s total supply of calcium is found in your blood and the other 99% is found in bones and teeth. It is true that if your body requires more calcium in the blood it will leach that calcium from the bone. This however does not mean that a calcium supplement will solve the problem.
Calcium must interact with both magnesium and vitamin D or it cannot be absorbed and utilized. So supplementing calcium without sufficient levels of magnesium and vitamin D would make calcium useless and even potentially harmful.
Remember from previous episodes that inadequate intake levels and deficiencies are two different things. An inadequate level means getting too little to maintain normal healthy function and may over time lead to a health issue, whereas a deficiency will almost certainly lead to a significant health problem. Depending on whether using the term in adequate or deficient anywhere between 30% and 42% of the population are getting insufficient levels of vitamin D from diet alone. More than 70% of people are getting inadequate levels of magnesium from diet alone. For decades people have been told that they need a two to one ratio of calcium to magnesium and so they look for this on dietary supplement labels. However, when you begin to calculate the amount of calcium in the modern diet it now throws that ratio off completely. As an example, because my diet is very high in calcium containing foods, I take 1170 mg daily of magnesium in the form of a bisglycinate chelate. Clearly the most efficient and effective form of magnesium available today. In a few moments I’ll give you some examples of calcium amounts in various foods and I know you’ll be surprised.
According to the US National Institutes of Health: “Frank calcium deficiencies are uncommon”. There is simply a lot more calcium in the modern diet then you knew. At this point you might be having what I call a “yeah but moment”. That’s when you hear something which is totally different from what you’ve been told, totally different from the groupthink and then you say to yourself, “yeah but I heard that, so-and-so said that, my favorite talking head in the news media said that, etc. my subscribers know to control themselves when they have a yeah but moment. If you’re having one now, then get a grip, get over it and pay close attention, the Nugent report is an objective learning experience.
Let’s momentarily go back to the idea of cofactors for absorption and utilization of calcium. It is not uncommon these days for physicians to do blood tests on their patients and then recommend not just hundreds but even thousands of units of vitamin D. Prior to the availability of patient testing for blood levels of vitamin D all physicians were taught and most followed the government recommendation which said that 400 IU (or 10 µg) per day was the daily requirement.
10 µg daily is now the recommended daily allowance for an infant between the ages of 0 and 12 months. As is the case with many nutrients, requirements vary by age and/or gender. Currently, the required daily allowance of vitamin D for both males and females between the ages of one and 70 years is 600 IU daily or 15 µg. Males and females above the age of 70 are recommended to have a minimum of 800 IU or 20 µg. As is the case with most nutrients, vitamin D performs more than one task so although it is essential for the processing and absorption of calcium it has many other functions as well.
According to the 2015–2016 National Health and Nutrition Examination Survey (NHANES) which is the most recent national survey available, most people in the United States consume less than recommended amounts of vitamin D. “An analysis of data found that average daily vitamin D intakes from foods and beverages were 5.1 mcg (204 IU) in men, 4.2 mcg (168 IU) in women, and 4.9 mcg (196 IU) in children aged 2–19 years” [40]. The 2013–2016 NHANES data revealed that that 92% of men, more than 97% of women, and 94% of people aged 1 year and older ingested less than the EAR of 10 mcg (400 IU) in their daily diet.[41].
I realize all the federal abbreviations can get confusing and it’s possible that not every subscriber has listened to every podcast. In a previous podcast I did explain all of the government abbreviations that relate to nutrition, but I’ll explain EAR just in case you’re new here. EAR is the Estimated Average Requirement: that is the Average daily level of intake estimated to meet the requirements of 50% of healthy individuals; usually used to assess the nutrient intakes of groups of people and to plan nutritionally adequate diets for them; can also be used to assess the nutrient intakes of individuals.(41) So let’s regroup to make sense of this. According to the latest science, more than 90% of the population at all ages and both genders are getting less than 50% of what’s required for healthy individuals.(41)
I suggested in my podcasts series on magnesium and vitamin D is that often what appears to be a deficiency of one nutrient is actually and in adequate intake of the cofactors to allow for the absorption of that nutrient.
In the future I’ll be doing a podcast on muscle loss as well as one on bone loss as we age. There is insufficient time to cover that in this podcast. For now, understand that as we age many cells in the body break down at a faster rate than they are replaced that is 1 Simple Way of defining the aging process. We begin to experience muscle loss on average around the age of 40, this is more significant for men than for women. In my 50s I began to increase my protein intake as well as digestive enzymes so that I could process this increase of protein and profit by it. The older I get the more protein I am supplementing in my diet to fight the reality of aging and accompanying muscle loss. There is more to that story than simply eating protein of course. Many of the protein foods I consume are very high in calcium but offer almost no magnesium or vitamin D. This is why I take so much additional magnesium in the form of a bisglycinate and why also supplement significant levels of vitamin D. As you learn more on the Nugent report you will be able to better tailor your personal nutrition program.
Let’s take a look at some foods that are high in calcium and you will find the food charts or links to those charts on Dr. Nugent.com which hosts the Nugent report. For those of you listening on the audio only podcast the URL for that site is drnugent.com DR Nugent as one word lowercase no hyphens were periods.
For more details on this, I would refer you to my podcasts on vitamin D and magnesium.
In most modern countries there is the equivalent of a milk producers Association or dairy Association in the US there is even one in each of the 50 states. These associations around the world have done a fantastic job in convincing people that they need to consume milk for calcium in fact they’ve done such a good job that there are many people who think that dairy is the only source of calcium. I know this from decades of interacting with women who were concerned about their bone health.
The fact is, calcium is essential to the life of virtually every animal that a person might consume and it’s found in significant levels in many vegetable products and even some fruits.
Collard greens contain 360 mg per 8 ounces for those listening or watching who live outside of the US 8 US ounces is approximately 227 g. In the US a common serving size is 8 ounces. The Chinese cabbage known as bok choy is 160 mg of calcium per every 8 ounces or approximately 227 g. An 8 ounce serving of kale has 180 g of calcium. 8 ounces of soybeans contains 175 mg of calcium. Even an orange has 55 mg of calcium. Only 3 US ounces or 85 grams of sardines provides 325 mg of calcium, 3 ounces of salmon provides 180 mg calcium and 3 ounces of shrimp, commonly referred to outside of the US as prawn, provides 125 mg of calcium. That’s a lot of calcium and I haven’t even talked about dairy yet. Milk cheese and yogurt are very high in calcium. A 6 ounce serving of plain yogurt provides 310 mg of calcium. An 8 ounce glass of milk regardless of fat content provides about 310 mg of calcium. Eight US fluid ounces is equivalent to approximately 236 ML for my subscribers outside of the US. Only 1 ounce of cheese mozzarella, which is a common size for string cheese snacks in the US provides 210 mg of calcium. 1 ounce of cheddar provides 205 mg, only 4 US ounces of cottage cheese known in some countries as curds and whey provides 125 mg, 4 ounces of Feta cheese has 140 mgs. of calcium.
The food industry has learned that they can sell more to female consumers if they fortify the product with extra calcium. Most people don’t think about a glass of orange juice as containing calcium. There is natural calcium which occurs in an orange anyway as I mentioned previously but for US ounces of commonly fortified orange juice provides 150 mg of calcium per glass. Many tofu products are fortified with additional calcium delivering as much is 205 mg per 4 ounces. For those who wish to avoid dairy and purchase almond milk rice milk or soy milk, the typical product is fortified with about 300 mg of calcium per 8 ounce glass. Even tofu products are often fortified with calcium with an average of about 205 mg per 4 ounces. Even breakfast cereals are frequently fortified with calcium and may offer an additional 100 to even as much as 1000 mg of calcium per 8 ounce serving.
The point is, there’s a lot more calcium in the modern diet than you thought there was. These fortified foods are typically not fortified with extra magnesium or vitamin D and in the rare cases that they are fortified with D they are rarely fortified in the right ratio to the calcium.
Does Calcium supplementation prevent bone fractures?
A review published in the British medical Journal which examined 97 papers and found 44 qualified for review on calcium intake and bone fractures concluded that, “Dietary calcium intake is not associated with risk of fracture, and there is no clinical trial evidence that increasing calcium intake from dietary sources prevents fractures. Evidence that calcium supplements prevent fractures is weak and inconsistent. Another review paper of 59 randomize eligible studies drew a similar conclusion. These are not the only reviews that have arrived at the same conclusion. There isn’t time a single podcast to address them all.
Objectively speaking it’s important to note what these various studies were studying and how they were designed. As I stressed previously, without sufficient levels of magnesium and vitamin D, the calcium will be useless or even potentially harmful. Many of the studies were done with calcium alone, some of the studies were done with calcium from food only or calcium from dietary supplements only a few were done with adding vitamin D to the calcium but none with adding magnesium. There is also the consideration of ratios which often was not followed in the studies. So, to be fully objective, I strongly believe that calcium from food is well absorbed and can increase bone mineral density if it is in the presence of adequate levels of magnesium and vitamin D at the same time. I believe this is also true with dietary supplements. As is frequently said at the end of the scientific study, “more study is needed”. So, I’m not saying that calcium supplements are dangerous, or useless on their face, simply that not everyone requires calcium supplementation because of the very significant levels of calcium in the modern diet and if you’re going to supplement you have to ensure that you have adequate levels of vitamin D and magnesium. With the amount of calcium that I consume in food personally, I would personally choose a dietary supplement that contains magnesium and vitamin D but not calcium because of the balance of these nutrients that naturally occur in food and my personal choices as well as the choices of many in modern society in terms of diet.
If your physician detects low blood levels of calcium that may mean that you need to increase your calcium or it may mean that you need to increase your levels of magnesium and or vitamin D. If you go through a scan such as a DEXA scan and find that your bone mineral density is declining, it may mean that you need more calcium, or once again, it may mean that you need one of the cofactors for the absorption and utilization of calcium or one of the cofactors that help to hold calcium in your bone. It’s just not as simple as saying all women should take more calcium.
What are the risks of taking too much calcium?
If you have excessively high levels of calcium in your blood it is known as hypercalcemia. This condition can cause calcification in your soft tissue renal insufficiency and kidney stones just for starters.[1].
I have spoken with several women who have given birth, survived gallstones and also had kidney stones and each of them told me that kidney stones were far more painful than childbirth and gallstones combined. The one thing you don’t want to do is form kidney stones because you’re not following the latest science on calcium intake.
Calcium also has a tendency to tighten your stool and in fact may result in constipation. As I’ve mentioned in previous podcasts, various minerals interact with each other, some in a positive way and some not. Balance is wellness, it is essential to maintain healthy balance of nutrients in your blood. Too much calcium as an example can block the absorption of zinc and iron. This of course can have very serious consequences.(1). Several scientific sources have confirmed that excessive calcium intake from dietary supplements versus excessive calcium intake from food increases your risk of kidney stones (1,2,3). Another surprise for many may be the scientific evidence that indicates that high levels of calcium intake increases the risk of prostate cancer. (1). I need to emphasize that at this stage of research science does not exactly understand how and why this is. There are also at least six different studies that link high calcium intake, particularly from supplements, with increased risk of cardiovascular disease (4-7,8,9).
I hope this episode on calcium proves to be beneficial for you. I’m almost certain that most everyone was surprised with much of this information.
Thanks for listening to the Nugent report and until next time, this is Dr. Steve Nugent urging you to stay safe, be sensible and be objective.
| Table 2: Recommended Dietary Allowances (RDAs) for Vitamin D [1] | ||||
| Age | Male | Female | Pregnancy | Lactation |
| 0-12 months* | 10 mcg (400 IU) |
10 mcg (400 IU) |
||
| 1–13 years | 15 mcg (600 IU) |
15 mcg (600 IU) |
||
| 14–18 years | 15 mcg (600 IU) |
15 mcg (600 IU) |
15 mcg (600 IU) |
15 mcg (600 IU) |
| 19–50 years | 15 mcg (600 IU) |
15 mcg (600 IU) |
15 mcg (600 IU) |
15 mcg (600 IU) |
| 51–70 years | 15 mcg (600 IU) |
15 mcg (600 IU) |
||
| >70 years | 20 mcg (800 IU) |
20 mcg (800 IU) |
||
*Adequate Intake (AI)
According to the most recent data it appears that people are also getting far too little magnesium from diet alone.
Table 1: Recommended Dietary Allowances (RDAs) for Magnesium [1]
Age Male Female Pregnancy Lactation
Birth to 6 months 30 mg* 30 mg*
7–12 months 75 mg* 75 mg*
1–3 years 80 mg 80 mg
4–8 years 130 mg 130 mg
9–13 years 240 mg 240 mg
14–18 years 410 mg 360 mg 400 mg 360 mg
19–30 years 400 mg 310 mg 350 mg 310 mg
31–50 years 420 mg 320 mg 360 mg 320 mg
51+ years 420 mg 320 mg
Table 3: Tolerable Upper Intake Levels (ULs) for Calcium [1]
Age Male Female Pregnant Lactating
0–6 months 1,000 mg 1,000 mg
7–12 months 1,500 mg 1,500 mg
1–8 years 2,500 mg 2,500 mg
9–18 years 3,000 mg 3,000 mg 3,000 mg 3,000 mg
19–50 years 2,500 mg 2,500 mg 2,500 mg 2,500 mg
51+ years 2,000 mg 2,000 mg
References
- Committee to Review Dietary Reference Intakes for Vitamin D and Calcium, Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: National Academy Press, 2010.
- Tranquilli AL, Dekker G, Magee L, Roberts J, Sibai BM, Steyn W, et al. The classification, diagnosis and management of the hypertensive disorders of pregnancy: A revised statement from the ISSHP. Pregnancy Hypertens. 2014;4:97-104. [PubMed abstract]
- Lowe SA, Bowyer L, Lust K, McMahon LP, Morton M, North RA, et al. SOMANZ guidelines for the management of hypertensive disorders of pregnancy 2014. Aust N Z J Obstet Gynaecol. 2015;55:e1-29. [PubMed abstract]
- Michaelsson K, Melhus H, Warensjo Lemming E, Wold A, Byberg L. Long term calcium intake and rates of all cause and cardiovascular mortality: community based prospective longitudinal cohort study. BMJ 2013;12;346:f228. [PubMed abstract]
- Bolland MJ, Avenell A, Baron JA, Grey A, MacLennan GS, Gamble GD, Reid IR.Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis. BMJ. 2010 Jul 29;341:c3691. [PubMed abstract]
- Bolland MJ, Barber PA, Doughty RN, Mason B, Horne A, Ames R, Gamble GD, Grey A, Reid IR. Vascular events in healthy older women receiving calcium supplementation: randomised controlled trial. BMJ 2008; 2;336:262-6. [PubMed abstract]
- Li K, Kaaks R, Linseisen J, Rohrmann S. Associations of dietary calcium intake and calcium supplementation with myocardial infarction and stroke risk and overall cardiovascular mortality in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition study (EPIC-Heidelberg). Heart 2012;98:920-5. [PubMed abstract]
- Xiao Q, Murphy RA, Houston DK, Harris TB, Chow WH, Park Y. Dietary and Supplemental Calcium Intake and Cardiovascular Disease Mortality: The National Institutes of Health-AARP Diet and Health Study. JAMA Intern Med. 2013 Feb 4:1-8. [PubMed abstract]
- Bolland MJ, Grey A, Avenell A, Gamble GD, Reid IR. Calcium supplements with or without vitamin D and risk of cardiovascular events: reanalysis of the Women’s Health Initiative limited access dataset and meta-analysis. BMJ. 2011 Apr 19;342:d2040. [PubMed abstract]
- Bailey RL, Dodd KW, Goldman JA, Gahche JJ, Dwyer JT, Moshfegh AJ, Sempos CT, Picciano MF. Estimation of total usual calcium and vitamin D intakes in the United States. J Nutr. 2010 Apr;140(4):817-22. [PubMed abstract]
| Table 1: Selected Food Sources of Calcium | ||
| Food | Milligrams (mg) per serving |
Percent DV* |
| Yogurt, plain, low fat, 8 ounces | 415 | 32 |
| Orange juice, calcium fortified, 1 cup | 349 | 27 |
| Mozzarella, part skim, 1.5 ounces | 333 | 26 |
| Sardines, canned in oil, with bones, 3 ounces | 325 | 25 |
| Cheddar cheese, 1.5 ounces | 307 | 24 |
| Milk, nonfat, 1 cup** | 299 | 23 |
| Soymilk, calcium fortified, 1 cup | 299 | 23 |
| Milk, reduced fat (2% milk fat), 1 cup | 293 | 23 |
| Milk, buttermilk, lowfat, 1 cup | 284 | 22 |
| Milk, whole (3.25% milk fat), 1 cup | 276 | 21 |
| Yogurt, fruit, low fat, 6 ounces | 258 | 20 |
| Tofu, firm, made with calcium sulfate, ½ cup*** | 253 | 19 |
| Salmon, pink, canned, solids with bone, 3 ounces | 181 | 14 |
| Cottage cheese, 1% milk fat, 1 cup | 138 | 11 |
| Tofu, soft, made with calcium sulfate, ½ cup*** | 138 | 11 |
| Breakfast cereals, fortified with 10% of the DV for calcium, 1 seving | 130 | 10 |
| Frozen yogurt, vanilla, soft serve, ½ cup | 103 | 8 |
| Turnip greens, fresh, boiled, ½ cup | 99 | 8 |
| Kale, fresh, cooked, 1 cup | 94 | 7 |
| Ice cream, vanilla, ½ cup | 84 | 6 |
| Chia seeds, 1 tablespoon | 76 | 6 |
| Chinese cabbage (bok choi), raw, shredded, 1 cup | 74 | 6 |
| Bread, white, 1 slice | 73 | 6 |
| Tortilla, corn, one, 6” diameter | 46 | 4 |
| Tortilla, flour, one, 6” diameter | 32 | 2 |
| Sour cream, reduced fat, 2 tablespoons | 31 | 2 |
| Bread, whole-wheat, 1 slice | 30 | 2 |
| Kale, raw, chopped, 1 cup | 24 | 2 |
| Broccoli, raw, ½ cup | 21 | 2 |
| Cream cheese, regular, 1 tablespoon | 14 | 1 |
The U.S. Department of Agriculture’s (USDA’s) FoodData Central lists the nutrient content of many foods and provides a comprehensive list of foods containing calcium arranged by nutrient content and by food name.
Bolland MJ, Leung W, Tai V, et al. Calcium intake and risk of fracture: systematic review. BMJ. 2015;351:h4580. Published 2015 Sep 29. doi:10.1136/bmj.h4580
Bolland MJ, Leung W, Tai V, et al. Calcium intake and risk of fracture: systematic review. BMJ. 2015;351:h4580. Published 2015 Sep 29. doi:10.1136/bmj.h4580
Tai V, Leung W, Grey A, Reid IR, Bolland MJ. Calcium intake and bone mineral density: systematic review and meta-analysis. BMJ. 2015 Sep 29;351:h4183. doi: 10.1136/bmj.h4183. PMID: 26420598; PMCID: PMC4784773.
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[Dr. Nugent报告 – 第14期 – 钙质]
[录制视频片头部分]
简介： Dr. Nugent报告，以科学方式分析健康与营养。欢迎收看本期“Dr. Nugent报告”，本节目由Dr. Steve Nugent主讲，为您提供健康和营养方面的优质客观信息。
Dr. Steve Nugent是著名的心理学家、作家、公共演说家，也是科学、健康、保健和营养方面的专家。请访问我们的网站DrNugent.com，并在Facebook、Twitter和Instagram上关注@TheNugentreport。
Dr. Nugent： 钙质补充剂危险吗？观众朋友们大家好，欢迎收看新一期的Dr. Nugent报告。我是Dr. Steve Nugent。本期节目将专门讨论钙质，但讨论的方式可能会比较特别。半个多世纪以来，全世界的人都以为女性需要更多钙质。
与男性相比，女性确实需要更多钙质。但是，并不是所有女性都需要钙质补充剂。实际上，根据最新的科学研究，从现在摄入的饮食来看，多数女性根本不需要钙质补充剂。这可能已经让你有些惊讶。
关注我的人都知道，Dr. Nugent报告以客观方式报道科学与健康。这意味着，我们不存在偏见，不在意群体思维。众所周知不代表科学。科学知识飞速发展，不可能每个人都能及时获取。
Dr. Nugent报告尝试逐一分解难题。本期Dr. Nugent报告呈现的知识可能会让你大吃一惊，甚至会颠覆你的认知。本期节目将涉及以下几个问题。你摄入的钙质是不是太多了？人体如何吸收和利用钙质？钙质只作用于骨骼吗？除奶制品之外，还有哪些食物富含钙质？钙质补充剂能预防骨质脆弱和骨折吗？摄入过多钙质补充剂有什么风险？
半个多世纪以来，人们一直被灌输这样的观念：强壮健康的骨骼离不开钙质。事实也是这样。这种表述没有问题。但大家不知道的是，健康骨骼需要的不仅是钙质。
大家也不知道，如果镁或维生素D含量过少，钙质会在体内钙化，或者通过尿液排出，这可能会导致肾结石。几十年以来，食品及膳食补充剂行业一直在灌输这样的理念：女性需要更多钙质。
再说一遍，跟男性相比，女性确实需要更多钙质，但是仅有30%的女性需要钙质补充剂。钙质过多会导致潜在的健康问题，这也是我想通过“整体健康”这个概念向大家传递的信息。
但是，作为一名心理学家，我也要指出，人们总倾向于把所有问题都简化成最简单的集体认识。一刀切的方法总是比需要细致分析的方法更受欢迎。而事实是，在钙质补充剂的问题上，一刀切的方法有失准确，也不够好——通过这期节目，你会了解这一点。
关于镁和维生素D在钙质吸收和利用方面的作用，可以去听我主讲的镁及维生素D播客系列。正如我常说的一句话，“科学不断前进”。我们十年前、二十年前，对我来说是四十多年前学到的东西，现在已经不再适用。现在距离我第一次学习临床营养基本知识已经几十年了。
不幸的是，今天的大多数从事人员依然使用着几十年前的信息，他们没有意识到，最近的科学研究驳斥了他们深信的多数信息。在我们讨论其他问题之前，先来看一下钙质的作用。
钙质是一种必需矿物，这意味着人体需要但不能自己产生钙质，所以，需要从外部来源获取。最佳的获取来源是食物。在很多情况下，如有必要，也可通过补充剂获取。科学显示，因为现代饮食中的含量不够，很多营养成分需要补充，而另外一些营养成分则不是这种情况。
食品行业往食物内添加钙质，并强调这一点，意在向女性消费者销售更多产品。然后重复群体思维的咒语：女性需要更多钙质。在现代饮食中，钙质含量十分充足。
很多人实际上摄入了过多钙质并且对此一无所知。现代饮食不断变化，含钙食物常常比例失衡。钙质是人体内含量最多的矿物质，身体健康的情况下，应当是这样。
在词语关联性测试中，如果一个人说了“钙质”，对应联想应该是骨骼或者奶制品。我们之后会讲到食物来源。但要明白，没有钙质，身体就不能运转。它的作用远远超过确保骨骼与牙齿健康。
你们可能还记得，有期节目讲到，镁和维生素D可以舒张肌肉，钙质可以收缩肌肉。肌肉要想正常运作，必须重复进行收缩舒张这个规律动作。血管扩张、神经传递、血管收缩、激素分泌，甚至细胞内信号传递都需要钙。
钙质对人体至关重要，人体会极力平衡钙质在血液中的含量。人体中约有1%的总钙质存在于血液中，其余99%存在于骨骼和牙齿中。如果血液需要更多钙质，会吸取骨骼中的钙质。
但这并不意味，钙质补充剂可以解决这个问题。钙质需要与镁和维生素D发生反应，否则将不能被吸收或利用。因此，只补钙，但体内镁和维生素D含量却不够的话，钙质就会变得一无所用，甚至带来潜在的危害。前面几期节目讲过，摄入水平不足和缺乏是两种不同概念。
血液内水平不足意味着水平低下，不足以维持正常的健康功能，长久之后可能会导致健康问题。而缺乏是必然会导致严重的健康问题。大约有30%-42%的人无法单靠饮食获取足量的维生素D，从而导致钙质不足或缺乏。
而70%以上的人无法单靠饮食获取足量的镁。几十年以来，人们一直以为需要将钙镁比控制在2:1。他们试图通过膳食补充剂实现这点。
但是，计算一下现代饮食中的钙质含量，会发现这个比例已经彻底失衡。以我自己为例，我的个人饮食中包含大量含钙食物。我每日摄入双甘氨酸酯螯合物，补充1170毫克的镁元素。显然，这是最有效、最便捷的科学补镁方式。
之后，我会举例告诉大家各种食物中的钙含量。你们将会大吃一惊。按照美国国家卫生研究院的说法，“单纯的钙质缺乏并不常见。”你认识不到现代饮食中含有的钙质有多充足。
现在，你可能会说“虽然…但是…”。这个时候，我需要告诉你一些事实，挑战那些你们自以为正确的观念。你会想，虽然如此，但那个谁说过…，我最喜欢的某某在电视上说过…。虽然如此，但我的医生说…。大家不要再执着于“虽然…但是…”，仔细听一下我们的观点。Dr. Nugent报告可以为你提供一次客观的学习经历。
我们暂时回到影响钙质吸收和利用的其他因素。现在，医生常常会给病人做血液检查，然后建议他们补充数千单位的维生素D。
在可以做血液维生素D检查之前，医生们都是遵照政府建议，也就是400国际单位，这相当于每天摄入10微克。很多医生相信这个建议，他们认为超过400国际单位可能会导致中毒。我知道这些，因为我职业生涯早期接触过很多这种情况。
今天，随着“科学的不断前进”，每天10微克的标准仅适用于0-12月的婴儿。很多营养成分都是这样，不同的年龄和性别有着不同的要求，而现在，1-70岁男女人群的每日维生素D摄入标准是600国际单位，也就是15微克。
70岁以上的人群每日至少需要800国际单位也就是20微克。跟多数营养成分一样，维生素D肩负多种任务。钙质的分解和吸收离不开维生素D，它还有很多其他作用。请收听由我主讲的与镁和维生素D有关的播客。
根据2015-2016国家健康与营养调查，这是最新的全国性调查。多数美国人的维生素D摄入量未达到建议水平。通过分析数据得出，男性平均每日从饮食中获取的最少维生素D含量为5.1微克，也就是204国际单位。女性的数据为4.2微克，也就是168国际单位，2-9岁的儿童为4.9微克，也就是196国际单位。
2013-2016研究数据显示，92%的男性，97%以上的女性，94%的1岁以上人群每日从饮食中摄入的量未达到10微克，即400国际单位的平均需要量。好，我明白，这些单位可能有点让人费解，有的听众可能没听过之前的节目。在之前的播客中，我讲过跟营养相关的单位。现在我重新讲解一下。
平均需要量是预估的平均需求量。也就是50%健康人群预计所需的平均每日摄入量。它通常用于评估人群的营养摄入，并为这些人群设计营养充足的饮食。
我们现在重新梳理一下，尝试去理解。根据最新的科学研究，90%以上各年龄段各性别的人群摄入的维生素D水平都不足。提醒一下，人体需要维生素D来分解钙质。如果缺乏维生素D，钙质补充剂于事无补。实际上，它们可能会起反作用。
未来，我会做几期有关伴随人体衰老，肌肉和骨骼流失的节目。人口老龄化越来越严重。这个问题会一直存在，当然，除非科学找到了防止衰老的办法。当下，衰老是不可避免的。我没有办法在一期播客中探讨所有问题。
但大家应当知道，在40岁左右，我们的肌肉会大量流失。因此，我们必须要从饮食中摄入更多蛋白质，并增加锻炼。我们必须要锻炼肌肉，摄入蛋白质，才能保持原来的肌肉水平，若要加强肌肉，还需做更多努力。我50多岁了，开始大量增加蛋白质摄入，也开始服用消化酶。
因为如果蛋白质超过常规摄入量的话，应当同时增加消化酶摄入。因为蛋白质很难消化，一份食物中多了几盎司或几克，这当然很难。除了蛋白质摄入之外，这个例子也说明了很多问题。
但我的意思是，我的个人饮食中包含大量蛋白质。我选择的蛋白食物中，很多都含有大量钙质。但却不含镁或维生素D。所以我通过双甘氨酸酯来大量补镁。
再说一次，我建议大家去听有关这些话题的往期播客。我们来看一下富含钙质的食物，你会在drnugent.com这个网站上发现很多食物图表，顺便说一下，如果你在听这期播客，不是观看的话，这是一个小写单词，不带点和连字符，这个单词是Dr. Nugent报告主持人的名字。
再说一下，如果想获取更详细的讲解，请回顾收听我推出的有关镁和维生素D的播客。在很多现代国家，会有牛奶生产协会或类似机构。事实上，在美国，我们不仅有全国性协会，每个州也有一个此类协会。
在全世界范围内，这些协会极力说服人们他们需要喝更多牛奶，需要补钙。事实上，我在职业生涯中跟很多人进行过对话，他们都以为牛奶是唯一的钙质来源。如果他们向我展示骨骼扫描光片，说自己的骨骼矿物质密度在下降，他们开口说的第一句话是，我不喝牛奶，还能怎么办呢？还是那句话，我会简短地讲一下食物来源。
你会发现食物中其实含有大量的钙质。很多营养成分不能通过当代饮食摄入，我建议大家通过补充剂进行补充。钙质对地球上的所有动物而言都是不可或缺的。
所以，如果你是杂食主义者，什么都吃。杂食主义饮食是普通人的饮食，我现在不想争论什么素食主义；现在顾不上这个。如果你选择素食或纯素饮食，选择得当的话，你也可以摄入足量的钙质，是的，你可以。
我们回到正常人选择的杂食主义饮食，这种饮食包含动物蛋白。每种动物都有肌肉；如果含有钙质的话，所有肌肉都可以收缩。神经系统，还有很多人体部分，都需要钙质。摄入动物制品，就等于摄入了钙质。你没必要成杯成杯地喝牛奶，你还能怎么做呢？
有许多植物，包括很多蔬菜和水果都含钙质。现在，大家听好了；这是一个播客，所以大家可以反复回放。不想做笔记也没有关系。
但是要仔细听，我会给你们一个食物清单，你们应该会觉得惊奇。每8盎司羽衣甘蓝含有360毫克钙质，美国之外的听众或观众可能不知道，8美盎司相当于227克。
这是固体美盎司，跟液体美盎司不同。在美国，很多情况下，一份食物和饮料的常规量是8盎司。每8盎司大白菜含有160毫克钙质。这也相当于227克。
8盎司甘蓝含有180毫克钙质。8盎司大豆含有175毫克钙质。即使是橙子，一颗橙子中也含有55毫克钙质。重量相当于3美盎司，也就是约85克。所以，3盎司沙丁鱼含有325毫克钙质。仅仅85克，3盎司。竟然含325毫克钙质！3盎司三文鱼中含有180毫克钙质。
3盎司虾中，含有125毫克钙质，这个量很大。我还没提到奶制品。牛奶、奶酪和酸奶中都富含钙质。6盎司原味酸奶含有310毫克钙质，只是一份哦！
不管脂肪成分，一杯8盎司的牛奶——有人可能会说，是不是低脂，是不是2%含量？——我们不管脂肪含量，8盎司牛奶中含有310毫克钙质。8液体美盎司，大概相当于236毫升。1盎司马苏里拉奶酪竟然含有210毫克钙质，只1盎司！
1盎司切达奶酪含有205毫克钙质，4盎司农家干酪就含有125毫克。4盎司羊奶干酪含有140毫克钙质。我还没提到加钙食品。食品行业深知，往产品中添加钙质可以吸引更多女性消费者。
多数人不知道橙汁中含有钙质。当然了，他们也是刚刚才知道橙子含有钙质。但是，现在的加钙橙汁产品每4盎司含有150毫克钙质。当然了，如果杯子大的话，8盎司橙汁中含有的钙质会翻倍。
很多豆腐制品添加了钙质，每4盎司就含有205毫克钙质。很多人不摄入奶制品，可以购买杏仁露、大米露或豆奶。常规产品中，8盎司容积的包装瓶里添加了300毫克钙质。
食物中添加的钙质已经够多了。早餐麦片常常添加钙，可以额外提供100毫克钙质，有些麦片甚至每8盎司添加1000毫克钙质。我的意思是，现代饮食中含有很多钙质；跟镁和维生素D不同，钙质无处不在。这些加钙食物通常不加镁和维生素D，即使少数食品加入了这两种元素，它们与钙质的比例也不合理。好的，我们来探讨一下科学。
现在，特别是女性，我的意思是大家都听过，但女性听到的更多，你们需要钙质添加剂，因为它们可以确保骨骼健康，可以防止骨折，对不对？我了解了相关科学研究；我没时间去看所有报纸，报纸太多了，根本看不完。我在这里举一个例子。
英国医学期刊上发表了一篇报告，综述了44份优质论文。我说的优质是指，写作综述论文时，你需要考量所有的研究参数，因为如果它不符合某些参数，它就不具备综述资格。
共有44份论文，这44份论文都探讨了通过食物或/和钙质补充剂来补充钙质，与骨折风险的关联。这里是一个直接引用，“膳食性钙质摄入跟骨折风险不存在关联，没有临床试验证据表明，增加膳食性钙质摄入可以预防骨质。支持钙质补充剂防止骨质的证据不足且不连贯”。
另一份针对59份优质随机研究的综述论文得出类似结论，类似的综述论文还有很多。一个简单的事实是，科学说明，这里要抛弃集体思维。科学说明，骨质疏松不是钙质缺乏疾病！我知道，世界上的所有人都以为是，但这是错误的。
最新的科学证实，骨质疏松的导致因素更有可能是维生素D缺乏，而不是钙质缺乏。当然，如果维生素D和镁的含量不足，骨质疏松的可能性会更大。这跟钙质无关，而是跟维生素D和镁有关。
客观来说，我们需要了解这些研究的研究内容以及研究方式。正如我之前强调的，体内镁和维生素D含量不够的话，钙质就会变得一无所用，甚至带来潜在的危害。很多研究只研究了钙质；一些研究只研究了膳食性钙质，或只研究了膳食补充剂，或结合研究了两者。有些研究在一次的量中加入过多钙质。所以，如果你在一次的量中加入500毫克，身体无法一次吸收这多余的500毫克，人体科学研究也表明了这一点。
很多研究一次就加入了1000甚至1200毫克的量，这当然会导致数据偏差。我想告诉大家这些，是因为这是客观分析，不带任何目的。也要考虑到比例，这些研究也没有考虑到这一点。
所以，完全客观地说，我认为，膳食性钙质可以被人体很好地吸收，可以增加骨骼矿物质的密度。我认为有这方面的证据。如果镁和维生素含量能同时达到充足水平的话。我相信，膳食补充剂同样也是如此。
正如每个科学研究结束时所说的那样，未来还需要更多研究。因此，我不会直接说钙质补充剂危险而无用，我只会说不是所有人都需要钙质补充剂。因为现代饮食中已经含有大量钙质。如果你需要补充，你需要确保体内的维生素D和镁元素充足。
从通过食物摄入的钙质来看，我会选择含有镁和维生素D、但不含钙质的膳食补充剂。这是因为食物和我的个人选择会实现营养物质的均衡。
关于饮食，现代社会中很多人也会做这种选择。如果医生发现你血液中缺乏钙质，这意味着你需要补钙。这也可能意味着你需要镁和补维生素D。
如果通过骨质密度测试发现骨骼矿物密度正在下降，这可能意味着你需要补钙。也可能意味着你需要补充影响钙质吸收和利用的其中一个元素。或者是帮助锁住骨骼钙质的其中一个元素。不能简单地说所有女性都应该补钙。
好吧，说了这么多，我们已经确立一个基础。摄入过多钙质有什么风险？如果血液中的钙水平过高，会导致高钙血症。这种病症是由软组织中的钙化导致的。它会导致肾功能不全和肾结石，这还只是小问题。
我跟既生过孩子也得过胆结石和肾结石的女性们聊过。她们说，肾结石比生孩子和胆结石加起来还痛苦。你绝对不想无视有关钙摄入的最新科学发现，最后得上肾结石。钙质还会让粪便变硬，最后导致便秘。
正如在之前的播客中提到的那样，很多矿物质会相互作用。有些相互作用是有益的，有些则不是。平衡就是健康；我们需要实现血液中的营养物质平衡。钙质过多会抑制锌的吸收。也会抑制铁的吸收。这些当然都是严重的问题。
很多科学来源证实，通过膳食补充剂或食物摄入过多钙质，最终会使肾结石增加。更加令人吃惊的是，科学证据表明，高水平的钙摄入会增加前列腺癌的风险。我需要强调，目前的研究尚不能说明其中的原因。
另外，至少有六个研究认为，大量的钙摄入，特别是通过膳食补充剂的摄入，会增加心血管疾病的风险。我希望这期关于钙质的节目可以让你受益。
我相信，这期节目的很多信息会让大多数人大吃一惊。感谢收听Dr. Nugent报告，下次再见，我是Dr. Steve Nugent，向你传递安全、理性、客观的理念。
结语： 感谢收听本期Dr. Nugent报告。访问DrNugent.com，获取更多有关健康与营养的事实性信息。如有问题或反馈意见，可发送邮件至info@drnugent.com。请在Facebook、Twitter和Instagram上关注@TheNugentreport。收听Dr. Nugent报告，获取事实性信息，资讯先人一步。
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