Calcium Supplements: The risks of calcium supplements | Chris Kresser

Why You Should Think Twice about Taking Calcium Supplements


Last updated on

These dairy products, bone-in fish, and leafy greens can eliminate the need for calcium supplements.
Eating foods rich in calcium, like dairy products, leafy greens, and bone-in fish, can help you avoid the risks of calcium supplements. iStock/piotr_malczyk

I’ve made the argument before that some supplements may be necessary to prevent a nutrient deficiency even if you’re nourishing your body with a nutrient-dense, whole-foods diet. Some nutrients are challenging to get through food alone, especially if you’re not digesting food optimally or you’re struggling with a chronic disease that increases your need for particular nutrients. I recommend wise supplementation for many of my patients, and I have seen the benefits of supplementation in my own life as well.

That said, there are several supplements that are commonly recommended by conventional doctors and healthcare practitioners that are unneeded at best, and potentially harmful at worst. Calcium supplements are a prime example of this.

Do Calcium Supplements Work?

Calcium has become extremely popular to supplement with, especially among aging women, in the hope that it will prevent fractures and protect against osteoporosis.

We’ve all seen the products on the market aimed at the “worried well,” such as Viactiv and Caltrate, suggesting that supplementing with calcium can help maintain bone health and prevent osteoporosis. Osteoporosis is a serious concern in women’s health, and it affects at least 10 percent of American women. (1) Yet the evidence that calcium supplementation strengthens the bones and teeth was never strong to begin with, and it has grown weaker with new research published in the past few years.

Are you taking a common supplement that may increase the risk of heart disease, stroke, and death? Read this article to find out.

A 2012 analysis found that consuming a high intake of calcium beyond recommended dietary guidelines, typically from supplementation, provided no benefit for hip or lumbar vertebral bone mineral density in older adults. (2) A 2007 study published in The American Journal of Clinical Nutrition found that calcium supplements don’t reduce fracture rates in postmenopausal women and may even increase the rate of hip fractures. (3)

Are Calcium Supplements Safe?

Beyond being ineffective for bone health, calcium supplements are associated with some pretty serious health risks.

Heart Disease Risk

Studies on the relationship between calcium and cardiovascular disease (CVD) suggest that dietary intake of calcium protects against heart disease, but supplemental calcium may increase the risk. A 2012 study of 24,000 men and women aged 35 to 64 years published in the British Medical Journal (BMJ) found that those who used calcium supplements had a 139 percent greater risk of heart attack during the 11-year study period, while intake of food calcium did not increase the risk. (4) A meta-analysis of studies involving more than 12,000 people also published in the BMJ found that calcium supplementation increases the risk of:

  • Heart attack by 31 percent
  • Stroke by 20 percent
  • Death from all causes by 9 percent (5)

An analysis involving 12,000 men published in JAMA Internal Medicine found that intakes of over 1,000 mg of supplemental calcium per day—from multivitamins or individual supplements—were associated with a 20 percent increase in the risk of death from CVD. (6) Researchers suspect that the increase of calcium in the blood that occurs after supplementation may facilitate the calcification of arteries, whereas calcium obtained from food is absorbed at slower rates and in smaller quantities than from supplements. (7) It is also suspected that extra calcium intake above one’s requirements is not absorbed by the bones, but is excreted in the urine, increasing the risk of calcium kidney stones. The excess calcium could also be circulated in the blood, where it might attach to atherosclerotic plaques in arteries or heart valves. (8)

Cancer, Kidney Stones, and Other Health Risks

The Office of Dietary Supplements at the National Institutes of Health has compiled a comprehensive review of the health risks associated with excess calcium, particularly from supplementation. (9)

For example, daily supplementation of calcium at 1,000 mg is associated with increased prostate cancer risk and an increase in kidney stones. (10)

Additionally, a recent Swedish study reported a 40 percent higher risk of death among women with high calcium intakes (1,400 mg and above), and a 157 percent higher risk of death if those women were taking a 500-mg calcium supplement daily. Those rates were compared to women with moderate daily calcium intakes between 600 and 1,000 mg. (11) A Consumer Lab analysis found that many of the calcium supplements they analyzed failed quality testing for reasons including lead contamination and mislabeled contents. (12)

Other Forms of Calcium Supplementation

Even if you’re not popping a calcium pill every morning, that doesn’t mean you’re not consuming supplemental calcium. Many commonly consumed foods in the United States are fortified with supplemental forms of calcium, including:

  • Orange juice
  • Breakfast cereals
  • Non-dairy milk
  • Bread
  • Instant oatmeal
  • Graham crackers
  • Other staples of the Standard American Diet

While these foods are typically eliminated on a whole-foods or Paleo diet, it’s important to pay attention to whether some of your fridge staples, such as commercial almond, coconut, or other varieties of non-dairy milk, are fortified with calcium. You may be consuming more supplemental calcium than you realize.

In addition, many multivitamins contain significant amounts of calcium, so be sure to check the label if you’re taking one. This is one reason I advise you to throw away your multivitamins in most cases: they contain too little of the right nutrients and too much of the wrong ones.

Natural dairy products like yogurt, cheese, and milk contain dietary calcium—but clearly they wouldn’t be a good fit for someone who has trouble digesting dairy. Weight-bearing exercises can help improve bone health, but for someone who has experienced injuries in the past, these could be worrisome.

Situations like these are a big part of why I believe so strongly in collaborative healthcare. A person who needs to increase their calcium levels and improve their bone health—without supplementation—could work with a Functional Medicine practitioner to develop a diet plan, a personal trainer to establish safe weight-bearing exercises, and a health coach to implement those changes.

We provide an in-depth education into Functional Health in the ADAPT Health Coach Training Program. I believe that health coaches who have an understanding of Functional Health concepts will be better prepared to offer powerful emotional support to their clients—and they’ll be able to partner with Functional and integrative medicine practitioners as part of a collaborative healthcare team.

Want to learn more about the role Functional Health coaches play in collaborative healthcare? Click here for more on the ADAPT Health Coach Training Program.

The Safest Ways to Get Enough Calcium

If you’re concerned about keeping your bones healthy, you’re better off getting your calcium from food sources like:

  • Dairy products
  • Canned, bone-in fish (e.g., sardines, salmon, etc.)
  • Dark, leafy greens
  • Seeds (especially poppy and sesame)
  • Almonds

The Recommended Dietary Allowance (RDA) for calcium for adult men and women is 1,000 mg—or approximately three servings of dairy products or bone-in fish per day. Pregnant and lactating women, and adults 70 and older, need 1,200 mg per day.

If you’re not able to meet your daily needs for calcium with diet alone, there is one calcium supplement that is unlikely to cause the problems that are associated with most other forms of supplemental calcium: whole bone calcium.

Whole bone calcium is a natural, bone-derived calcium complex that contains not only calcium, but also collagen, growth factors, trace minerals, and all of the other elements that are present in healthy bone tissue. It would be expected to affect the body more like dietary calcium than like a calcium supplement, and for this reason I think it’s a good option for those that can’t get enough calcium from the diet.

Unfortunately, it’s difficult to find whole bone calcium supplements in local stores. I recommend Free-Range Pasture-Fed Whole Bone Calcium from Traditional Foods Market online to my patients. It’s made from free-range, pasture-fed cows from New Zealand.

Healthy bone formation also depends on vitamin D and vitamin K2, both of which regulate calcium metabolism. There are also other minerals besides calcium involved in supporting bone health, such as silica and magnesium. If you have adequate levels of these nutrients and regularly perform weight-bearing exercise, there is no need for calcium supplementation, which will likely do more harm than good. (13)


Join the conversation

  1. In my thyroidectomy they had to get red of one of my parathyroids there was too much calcium levels in my blood .. I was told to take 2000 mg calcium and vitamin D till the rest of my parathyroids wakes up that was 6 months ago … what should someone like me do ????

  2. In the just the past 2 years, I have gone from mildsevere osteopenia to severe generalized osteopenia, in spite of being a huge milk drinker and dairy consumer since childhood. I have metastatic neuroendocrine cancer which has spread to my bones. My dietary intake of calcium is still good. My doctors recommend a calcium supplement, as well as Xgeva once monthly. I’ve been reading that the supplements are ineffective and that drugs like Xgeva and Prolia have many dangerous side effects. I’m not sure what to do. I am 69 years old.

    • Maybe you’re not absorbing it, When I got on the 60 trace minerals, suddenly I didn’t have to take enormous amounts of vitamin C anymore, (8 grams daily). Suddenly, I had to rely only on the C in the liquid multiple. (the other change I made)

  3. The best way to get more calcium is from your diet. You probably already know that dairy products — such as milk, cheese, and yogurt — provide calcium.

    • I apologize but your conception of calcium intake is fundimentally incorrect. Man was designed to intake only plant based vitamins. Big pharma and little vita producers want you to believe that animal, metal/rock and synthetic vitamins are what your body needs but those type of vitamins are proematic at best and will lead you to sickness just like the information from all the other no knowledge medical pill popping drugest and physicians that are practicing right now. Check out real plant based vitamins, from real plant and the ALPHA plant Moringa. Good luck, have a great life. Start searching for playing based nutrients.

      • No, sorry , if man was designed to intake only plant nutrients then why can’t we make our own vitamin K2 from vitamin K1? Hmmmmm? Animals can do that, and put it in their eggs and milk and fat and skin. If we could do that, we would be quite yellow. My green eating animals have yellow milk and fat and orange eggs, and yellow fat and skin. Neon yellow.

        Also why do vegans have to take vitamin B12? Herbivorous animals don’t have to do that.

  4. While I agree with parts of this article it falls short of telling the whole story. If one follows the recommendations of the “experts” in the field, there is significant benefit to taking a “quality” calcium supplement, especially in regards to bone density as well as things like restless leg syndrome or muscle cramps. So, what is “quality” calcium. First, it needs to be a blended source of calcium, one with multiple different types of calcium present. 75% of calcium sales in this country are single source calcium carbonate, which is 3-6% absorbable until the age of bone fusion (early 20’s), and then 1-3% thereafter. So you take 1000mg of a calcium carbonate supplement only 30 mg does you any good. And that is not going to cut it. Also the best calcium supplements in the marketplace are from “condensed, freeze-dried, whole food. Two companies out there among the best are Standard Process and Nutri-West.

    • While I agree we need calcium and in a proper form, in all likelihood we already receive too much in our daily intake that can be highly problematic leading to arthritis, kidney stones, osteoporosis and calcification of the arteries, additionally towards heart conditions and cardiovascular disease.”

      When we analyzed our calcium intake and recognized the detrimental effects when we did not properly have the components like magnesium, Vitamin D3, Boron in particular, we experienced ‘bone loss’, agitation, muscle cramping, etc. When we flipped the ‘traditional medicine’s’ 2:1 Calcium to magnesium ratio upside down or at least to a 1:1 ratio, our health greatly improved, including improved bone density. My wife was at one time diagnosed with osteopenia and now she has reversed that diagnosis and she’s 58; so the claim you’ll only get worse as you get older is a flat out lie. One needs to take charge of their health.

      Another good article ‘Calcified with Calcium & Vitamin D’

      Additionally, magnesium is a natural relaxer, whereas calcium contracts. When we leaned on an increase of magnesium in our diet we experienced a more calming effect unlike when we upped our calcium intake that often increased tension, stress levels. Balance is key.

      • I thought I got plenty of calcium from milk, and have supplemented with magnesium (1-2 grams) , D, boron, K2, copper/zinc (copper deficient animals get swayback), and many other things until I was researching insomnia and ran across Joel Wallach’s wallach wisdom encyclopedia (compiled from his talks) and decided to try the cheap limestone to start and my arthritis was much relieved in 2 hours. So I am a calcium supplement convert- but again, there is a whole team including real vitamin A, and I’m finding more and more members of that team , like Lysine, vanadium, …I have converted to bone meal as they are more bioavailable. And I know a lot of natural good docs downplay the calcium supplements, but they are still not including other details that the “studies” supposedly proved- ( they are silent on the other team members).
        I know that with all the other supplements, I still had horrible leg cramps until I added Calcium. (This peaked while working 12 hour shifts at night, emphasis on night, I do better on 12 hour day shift). I still sometimes get freaked out when folks as smart and careful as Dr. Mercola and Chris Kresser discourage Calcium supplements, but they likewise left out mention of magnesium, D, K2, copper/zinc, boron, Vit A, etc. I just can’t bear the cramps enough to cut out the calcium now.

  5. Dermessence has most essential nutrients that this formula has and that act directly and indirectly in combating again signs from the inside out.

  6. It is possible to be deficient in both Ca and Mg if diet is poor or your needs are great (such as in pregnancy and nursing). Why doesn’t someone mention that?

  7. Hello I know that Bone Broth is an excellent source of calcium, but I was curious if bone broth still gives a bio available form of MCHC (Microcrystalline Hydroxyapatite) ? Or any at all since it has been heated ? Thank you

[if lte IE 8]
[if lte IE 8]