Calcium rich foods are an important part of a healthy diet.  BUT, as always, balance is important.  Too much of a good thing is not always a good thing.  And when it comes to calcium, research is showing that too much (especially when it comes from supplements) may actually be harmful.

When I was in medical school and residency I was always told to encourage women to drink milk and eat yogurt and if they didn’t do that daily to advise a calcium supplement. The recommended doses at that time were 1000mg for pre-menapausal women and 1500mg for post-menopausal women.   In many conferences and lectures we were encouraged to just given women 1000- 1500mg of calcium in supplements to be sure they were getting enough.

I went along with that for a long time. Interestingly, in noticed that my patients often took less than I prescribed. Perhaps these women had an intuitive sense that too much calcium from supplements might be unnecessary or even potentially harmful.  I will outline some of the potential risks in this blog today.

But what about the “potential benefits?  Every pill or supplement you take into your body will offer you both potential risk and potential benefit.  It is wise to keep this in mind and to be sure you are fully aware of both sides of the equation before deciding if something will be part of your regular routine.

Let’s start with the benefits…..

1) BONE HEALTH:
Calcium is an important mineral to the body.  It is largely stored in the bones and does contribute to bone strength.  In fact 98% of the calcium in your body is located in your bones.  The rest is divided between your teeth (1%) and your blood (1%).

In women who have a low intake of dietary calcium, research has shown the taking 500mg a day of calcium citrate does improve the strength of bones in the femur, spine, and wrist.   Other research has made it clear that adding vitamin D to the calcium supplement is needed to show definite benefit in decreasing the risk of osteoporosis in post menopausal women.  The reason you need to take the vitamin D is because you need adequate vitamin D in your body or else the calcium will not be properly absorbed.

A 2010 report from the Institute of Medicine (IOM) found that most Americans get more then enough calcium from diet to maintain healthy bones.  The only group who did not seem to be taking enough in through diet was girls aged 9 through 18.  This may be why research published in 2011 in Osteoporsis Int showed improved bone strength in a group of girls aged 9 through 13 who took calcium 800mg  PLUS vitamin D  (400mg) for 6months.

In contrast, many post-menopausal women may be taking too much calcium if they take high dose supplements.

2) OTHER  POTENTIAL BENEFITS:

Other potential benefits of calcium supplementation include: reducing PMS,  slightly lowering blood pressure, slightly improving cholesterol levels, and possibly preventing polyps in the colon.  Some favorable research does exist for each of these conditions.

There was a time when calcium was reported to aid in weight loss but follow up research proved that was not true.

3) DEATH AND HEART DISEASE:
There was a study with white, postmenopausal women published in the Archives of Internal Medicine in 2011 that showed a 3.8% reduction in risk of death over a 22 year period in the women who took up to (but not over) 900mg per day in supplements.

Another recent study published in the Journal of the American Medical Assn this year followed a large group of men and women for 12 years and showed a decreased risk of death from heart disease with increased calcium intake (from all sources combined), up to a total of  about 1200mg per day.

Remember that is 1200mg from BOTH food and supplements.  Taking 1000mg a day in supplements is very likely to put you well over this and into a much higher range of calcium intake.  This is important to realize because excessive calcium intake appears to carry with it some pretty concerning risks.  Read on to learn more….

The Risks of calcium supplementation: 

1) HEART DISEASE:
In addition to the findings that some calcium intake may be protective to the heart research is showing that too much calcium (especially from supplements) may be doing just the opposite.

In recent years medical research has certainly shown that we have good reason to be cautious.  In 2010 a study in the British Medical Journal showed an increase in heart attacks in women taking high doses of calcium.  Interestingly this risk was NOT seen when the women took both calcium and vitamin D.  So there are still a lot of questions about what is really going on here.

Still that same study mentioned above, the one published this year in JAMA, showed that in men taking more than 1000mg a day of calcium in supplement form, there was a significantly increased risk for death from heart attack over the 12 year period studied.    This finding was not seen in the women in that study but other studies have shown some association between heart disease in calcium supplementation for both men and  women if  they  were already taking in more than 805 mg of calcium from foods.  Fortunately there was NO association between dietary calcium and an increased risk for heart attack.  The problem seemed to come from combining a moderate to high amount of dietary calcium along with the supplements.

More recently the British Medical Journal published a 19-year study conducted in Sweden that showed a significantly higher risk of Death in women with high calcium intake (especially if it came from supplements).  Women in the group taking >1400mg of calcium per day (from diet and supplements) were 40% more likely to die during the trial period compared to women in the group taking in 600mg to 1000mg per day(Michaelsson, BMJ 2013).

Some experts have theorized that there is a high spike of calcium in the blood following ingestion of a supplement and speculate that this “burst” of calcium may increase the risk for the calcium to deposit in the arteries leading to increased risk of developing plaques/ blockages in those arteries.  We still don’t know.  But there are enough questions re: safety to make it clear that more is not better when it comes to your calcium pills.

2) PROSTATE CANCER:  Here’s a quote from the Harvard School of Public Health on this issue:

“A diet high in calcium has been implicated as a probable risk factor for prostate cancer. (17) In a Harvard study of male health professionals, men who drank two or more glasses of milk a day were almost twice as likely to develop advanced prostate cancer as those who didn’t drink milk at all. (18) The association appears to be with calcium itself, rather than with dairy products in general: A more recent analysis of the Harvard study participants found that men with the highest calcium intake—at least 2,000 milligrams a day—had nearly double the risk of developing fatal prostate cancer as those who had the lowest intake (less than 500 milligrams per day). (19)”

More research is needed.  But until that time it seems wise for men to limit their calcium intake.  Most experts agree it is best for men to get their calcium from food and to keep their total intake to <2000mg per day.  If a man does take a supplement most experts advise to keep it to 500mg or less.

3) KIDNEY STONES:   Research has shown that there can be an increased risk of kidney stones from calcium supplementation, especially with doses 1000mg or over.  Fortunately there has not been any problem found from dietary calcium so if you have a history of  kidney stones you can still feel safe to get your calcium from food.

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OTHER FACTORS TO CONSIDER IN CALCIUM BALANCE:

So the question remains, is there benefit to taking calcium supplements?  The answer depends on you.  Do you follow a very acid diet?  Is your dietary intake of calcium low?

The calcium in your bones does play a role in keeping your bones strong but it also has another function.  It is critical to maintaining a healthy acid-base balance in the blood.  Your blood must keep within a very narrow pH range.  Going just a little bit too high or too low will lead to dire health consequences.   If your pH begins to drift out too much into an “acid” range then the bones release calcium into the blood to buffer the excess acids.

This is key to understand because the standard American diet is one that drives the body toward an acid state.  In fact the amount of calcium you take in may not be the only thing we need to focus on when it comes to bone health.  Equally important is reducing the amount of high acid foods and getting enough alkaline foods.  Acid forming foods include: Soda (regular AND diet),  meat,  dairy (yes, dairy!), white sugar, processed foods, trans-fats.  Alkaline foods include: fruits and vegetables, beans, herbs).  High salt intake can also trigger the kidneys to excrete calcium and lead to weakening of bones (http://www.jacn.org/content/25/suppl_3/271S.full)

Loss of calcium through the urine goes UP when diets are high in protein and sodium.  In fact it has been shown that vegans (people who eat no animal protein) have low excretion of calcium in their urine and vegetarians lose less than omnivores. (Breslau, J. of Clincal Endocrinology and Metabolism. 1988)

Furthermore, calcium absorption will be increased and excess loss decreased by:

–Keeping your vitamin D level in the normal range

–Avoiding excess animal protein (have some vegetarian meals if you can)

–Limit your intake of sodium to less than 2400mg per day (read labels!)

–Eat more fruits and vegetables, they help keep the blood more alkaline.  (aim for 7-9 servings/day)

–Avoid excessive caffeine and alcohol (both have been linked to accelerated bone loss)

–Avoid white sugar and simple carbohydrates (they push the blood in the acid direction)

Also there may be foods that are particularly protective.  One researcher looking into this and according to the textbook on Integrative Medicine:

“Muhlbauer described 25 plant foods as bone resorption inhibitory food items (BRIFI). These include garlic, rosemary, Italian parsley, sage, thyme, parsley, dill, onion, arugula, prune, fennel, orange, leek, yellow boletus, wild garlic, field agaric, red cabbage, celeriac, red wine, and lettuce.^[51] In addition to effects on acid-base balance, the benefits of plant foods also appear to be related to the pharmacologically active compounds they contain. Certain specific monoterpenes,^[52] flavonoids, and phenols^[53] may be responsible for the observed beneficial effects on bone.”

Keeping these foods in your diet will likely slow your loss of calcium and therefore decrease your need for supplementation.

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GETTING CALCIUM FROM FOOD:

And of course including plenty of dietary sources of calcium helps, too.  I’m going to include a link to a table here to guide you but bear in mind adding up the “millgrams” of each of these is only part of what will keep your bones healthy.

Some foods may be more “bioavailable” meaning that the body is better able to absorb the calcium they contain (this is likely true for dark greens).  Also some people may be better able to absorb calcium.  Pregnant women have been shown to be better able to absorb and maintain calcium in their systems during this time.  They still need to take in calcium but they don’t need to take in more than their non-pregnant peers.

For those who like hard numbers the following recommendations currently exist:

For those ages 1-3: 700mg/day, ages 4-8: 1000mg/day,  ages 9-18:  1300mg /day,  ages 19-50:  1000mg/day,  ages 51- 70: 1000mg/ day for men and 1200mg/day for women, ages >71: 1200mg.

Here’s that link that lists the specific calcium content in foods:

http://www.ucsfhealth.org/education/calcium_content_of_selected_foods/index.html

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CALCIUM FROM SUPPLEMENTS:

If you do take supplements then bear the following in mind:

–Do not take more than 900mg/day in supplements.  Looking at the research suggests that a max of 500mg is  enough.

–Be sure to take vitamin D with your calcium so it can be absorbed

–Calcium citrate is better absorbed and can be taken with or without food.  This type of calcium may be a better choice for people with low stomach acid.  Calcium carbonate is less expensive but less easily absorbed so it is better to take with meals.

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Additional References:

Naturadatabase.com Calcium monograph

Rakel, David MD.  Integartive Medicine, 3rd ed

Harvard school of public health web site:  http://www.hsph.harvard.edu/nutritionsource/calcium-full-story/#calcium-from-milk

consumerlab.com : product review of calcium supplements