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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” . 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..
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..
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 |
|0-12 months*||10 mcg
|1–13 years||15 mcg
|14–18 years||15 mcg
|19–50 years||15 mcg
|51–70 years||15 mcg
|>70 years||20 mcg
*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 
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 
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
- 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|
|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]
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。
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？
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。