Calcium Supplements: Are They Safe?

In July, a meta-analysis of the effect of calcium supplementation on heart attacks was published in the British Medical Journal (1). They found that people taking calcium supplements were more likely to have a heart attack. People have asked me if I think this means vegans should not supplement with calcium.

If you look at the study (the full paper is available for free at the link in the abstract below), they found that the increased risk of heart attack was limited to people who started out with a dietary calcium intake of 700 mg/day or more. Most vegans do not get that much calcium through foods. In most of the studies they examined, the level of calcium supplementation was substantially higher than 500 mg.

This study indicates that if you are an adult who gets 700 mg of calcium from your diet (including fortified foods), you probably shouldn’t take more than about a 300 mg supplement of calcium per day.

The DRI for calcium for ages 9 to 18 is 1,300 mg. This meta-analysis was conducted on older people trying to prevent osteoporosis and is probably not applicable for teenagers, whose bones are still building.

The DRI for calcium for people over 50 is 1,200. My recommendation for people in this age group who want to meet the DRI is to get at least 700 mg per day through foods and only supplement enough to make up the difference.

It’s worth noting that some observational studies of calcium intake (from foods, not supplements) have shown higher intakes to be protective against heart disease.

1. 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.

23 Responses to “Calcium Supplements: Are They Safe?”

  1. beforewisdom Says:

    Can you really get 700mg of calcium a day from food, excluding fortified foods, on a vegan diet?

    The best sources are the green leafy vegetables, but they are also tend to be hard to digest.

    I’m sure someone could write a menu, but does anyone out there consistently….. eat …..a vegan diet with 700 mg of calcium from non-fortified foods and without digestive distress?

  2. Bettie Says:

    Well, if it was me, I’d cook those leafy greens thoroughly, adding some sauteed fresh ginger root to make the food more digestible. Also, I wonder if anybody really needs the amounts of calcium mentioned above. It would be better to ask why your body is so inefficient, why can’t it use calcium better?

  3. Jack Norris RD Says:

    Bettie, A lack of exercise could possibly be the answer.

  4. beforewisdom Says:

    I exercise hard, several times a week. I also keep a log of what I eat. I cook my leafy greens…..the kind with a significant amount of calcium thoroughly ( 8 – 20 min depending on the greens ). I am in great health. Yet, if I steadily eat 2 cups of cooked cruciferous greens for more than 2-3 days, I begin getting uncomfortable flatulence.

    I don’t think I am odd. Most people don’t eat what they think they eat. I keep a food diary. I know what I am consuming. There is no way a vegan can get 700 mg of calcium from foods, sans supplements ( & fortification ) without eating at least 2 cups of chopped cooked greens a day.

  5. Bettie Says:

    Oh, I believe every word of what you say, Beforewisdom. I guess I was mixing up two different topics. What I meant was that we are not machinery, where if you put in so much fuel you should automatically get correct results.

    Other things need to be working optimally in the first place. Like liver function, just for starters. There is a reason that older societies did liver cleansing in the spring from early childhood onward. Also I would have a look at the possibility of parasite infestation, etc. etc. I am not yet convinced that we all, across the board, need all that calcium. In some Asian lands, I have heard, people don’t consume either dairy or lots of calcium-rich foods, yet have no bone problems.

    As to exercise, I suspect that is a big factor.

  6. Jack Norris RD Says:


    My understanding is that in some Asian countries they have less hip fractures, but not less spinal fractures or better bone mineral density. It’s thought to be because they are less prone to falling and their hips are shaped in a way making them less prone to fracture. However, people of African origin have better bone mineral density with less calcium – they genetically metabolize calcium better than do Caucasians.

  7. beforewisdom Says:


    Are you a medical doctor of some kind. I ask because you said you might need to check for parasites. I live in a fairly metropolitan area of the United States. I don’t think I have parasites and I think my liver is fine.

    As to suspecting that exercise as a factor, what do you mean? As a factor in preventing osteoporosis or as a factor to getting a flatulence when eating cruciferious leafy vegetables twice a day every day for several days?

    If the latter, what is the relationship between exercise and flatulence with just one type of food? How do you know of this relationship? I work out 3-4 times a week for about 90 min.

  8. beforewisdom Says:


    BTW, aside from getting flatulence when I eat 2 cups a day of finely chopped cooked cruciferous leafy vegetables. I have no digestive problems. In fact, my digestion is quite good with every food.

  9. beforewisdom Says:


    May I ask, do you eat 2 cups of finely chopped, cooked, green leafy vegetables every day? Are you free of the same issues?

  10. Bettie Says:

    1. I eat lots of cooked leafy greens, but not 2 cups every day. Sometimes I really want lots, and other times I stop at one medium serving. I don’t force anything down my gullet. Strangely, I rarely get gas from anything, so all I can assume is that I have a digestive system that is not prone to these kinds of reactions. My weaknesses lie elsewhere.

    2. Some people weren’t designed to eat certain foods is my opinion, no matter what other factors are (or are not) in place. At some point we have to decide that something or other is not good for us in large quantities. I recall Ed Bauman saying we should eat according to our ethnicity. If tons of greens aren’t in your background, maybe that’s it.

    3. No, of course I’m not a doctor. Just interested in health & nutrition.

    4. Living in a metropolitan area doesn’t protect you from infestation by parasites, unfortunately. Have a look if you wish at the large section on parasite infection in Paul Pitchford’s big book (3rd ed.) Healing with Whole Foods. After several years on the purest diet imaginable I was astounded to discharge a veritable ****load of worms.

    5. Re liver function. You can go for liver function tests till the cows come home, but they detect only conditons where the cells are ruptured. They don’t measure what is known in Chinese or natural medicine as “liver congestion” or “liver stagnation”. This condition is just as bad.

    6. Appropriate exercise makes everything work better. Doncha think?

    7. Jack, I didn’t know that about Asian bones and accident-proneness. Very interesting, indeed. I guess Africans would have better bone mineral density than Caucasians (not to mention such beautiful white teeth) because they live where there’s lots of sun all the time and thereby produce so much more Vitamin D (inducing much calcium uptake). I wonder if it’s too late for me to move to Africa.

  11. Jack Norris RD Says:


    > I guess Africans because they live where there’s lots of sun all the time and thereby produce so much more Vitamin D…

    This is the case for people of African descent wherever they happen to live. It’s genetic, not environmental.


  12. beforewisdom Says:

    Bettie Says:

    1. I eat lots of cooked leafy greens, but not 2 cups every day.

    That feeds in to my original point. It is one thing to say vegans should get 700 mg of calcium a day, but that is unlikely to happen given vegan food sources ( non fortified/not supplements ). I know this because I tried eating to the numbers….2 cups a day.

    I recall Ed Bauman saying we should eat according to our ethnicity.

    Is Ed Bauman a research scientist?

  13. Bettie Says:

    Then I wonder why “AfroAmericans” living in 4-season climates are, according to the experts, at risk for Vitamin D deficiency conditions and are advised to take high dosage of the supplement.

  14. Jack Norris RD Says:


    Black people are more at risk for vitamin D deficiency, but that doesn’t mean they don’t metabolize calcium better. I’m not sure if their vitamin D deficiency is less likely to cause osteoporosis than a white person’s vitamin D deficiency, but there are a lot of other disease that vitamin D protects against that aren’t affected by calcium, like autoimmune diseases and cancer.

  15. Molly Says:

    Hi beforewisdom,
    Just throwing in my two cents’, but I eat no fortified foods (only whole grains), and lots of leafy greens, and I have no trouble with digestion. I do in fact get about 700 mg calcium from my diet on average. I’m not sure what type of digestive issues you’re referring to, so perhaps some elaboration would help.

  16. Molly Says:

    Oh, sorry – for some reason, I could only see BW’s original post. Nevermind!

  17. Laura Says:

    It’s becoming increasingly harder to remain vegan. I’m sick at heart that my college-aged daughter is thinking of reverting to becoming vegetarian, not only because of issues like the one discussed on this forum, but because of the scarcity of affordable vegan items on food shelves. No need to reply, I just had to say something to someone.

  18. Jack Norris RD Says:


    Your daughter should try Trader Joe’s if she lives near one. They have a lot of affordable vegan products. But, you don’t really need fake meats and such to be vegan – there was a time when there were almost no foods like that and we got by on much cheaper (and probably healthier in large amounts) staples like beans, potatoes, rice, peanut butter, bread, pasta, etc.

    As for the calcium supplement issue, the advice to limit supplements to 300 mg per day is fairly cautious and for people who are trying to really tweek their diets for the best health possible. But, I’m not sure what you are referring to exactly in saying it’s increasingly harder to remain vegan.

  19. Laura Says:

    Thank you Jack for your reply. My 20-year old daughter needs to bring 3 meals a day, plus snacks, with her on a daily basis because of extended school and work schedules. The time and cost involved in purchasing and preparing wholesome vegan meals is getting out of hand and I think the options of minimally processed foods are still narrow. I’m doing OK, although spending a lot of time cooking, but she’s missing foods she used to eat while a vegetarian. If she is experiencing this, then she is probably not alone. Then we learn about supplements like calcium, B12, and now creatine and sustainable algea as mentioned in today’s e-mail. It’s just a bit overwhelming. If I/we could relieve suffering by eating a pill, I’d give up the comforts of food.

  20. Jack Norris RD Says:


    I don’t know many people who have to pack 3 meals a day – that’s a lot.

    Creatine is totally optional and probably not even desirable for most vegans. The DHA from algae is also pretty optional, but for older vegans it might be more important as the ability to make DHA decreases with age. But even so, many vegans live just fine for many years without it. It’s not clear that all vegans need it.

    B12 is important for everyone, and so is calcium if you don’t eat a lot of collards, kale, and broccoli every day. But both can be obtained from a fortified soymilk. That said, it’s good to get B12 twice a day if you’re only getting it from fortified foods, but a cheap multivitamin would work, or another fortified food at a different point in the day. Or a second glass of soymilk.

  21. Molly Says:

    Hi Laura,
    I’m in the same situation as your daughter – I bring 3-4 meals and a snack with me daily, am vegan, and also deal with several health issues that restrict my diet even more. I spend a lot of time in the kitchen planning and preparing my food. I eat affordably by shopping the grocery store weekly sales, and mainly buying lots of fresh produce, dry beans, whole grains, and staying away from most packaged convenience items. I will still buy veggie burgers here and there, and a few other things (bread and crackers are too much work to make myself!), but I try to keep mostly to fresh and homemade items, for the sake of my health.

    In my opinion, it is easier now to be vegan than ever before. Companies are becoming more aware and more willing to offer animal-free options, and restaurants are more accommodating than ever. The whole-food movement is taking off like no other.

    Yes, non-processed fresh food may sometimes be expensive, but with experience it is possible to eat well on a smaller budget. I don’t eat cheaply, but I don’t break the bank, either. I would be really happy to give some tips or swap ideas with your daughter if she’s interested. I’ve been navigating the grocery store minefield for many years, and have learned quite a bit about what is and is not worth your dollars. If you think she’d be interested, post a reply and I’ll figure out a way to send you my email address. Either way, I wish her the best of luck.

  22. Matt Says:


    from what I remember, the worry here was that calcium was released into the system too quickly when it is in the form of a supplement, leading to calcification of the arteries, this would, I assume, occur in foods with added calcium.

    Does the fact the people in the study were already consuming 700mg of calcium have relevance if the aforementioned reason was the problem, not the amount of calcium?


  23. Jack Norris RD Says:


    I doubt it’s a matter of how quickly the calcium enters the blood, but rather how much enters the blood. That’s just a guess, I’ve never seen research on the issue of how quickly calcium is entering the blood and what impact that might have.

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