Can you keep your bones strong by taking calcium supplements? Older people, particularly older women, have long been advised to get 1,200 mg of calcium daily, primarily from supplements.
Many doctors who are generally skeptical about the benefits of vitamins or other dietary supplements have been recommending calcium for decades. But research from New Zealand published in The BMJ indicates that calcium supplements don’t do much, if anything, to prevent fractures.
Calcium Data: Doubtful for Decades
An editorial in The BMJ reveals that this is not new news:
“Calcium is vital to many biological processes, and serum concentration is tightly regulated. Net calcium excretion must be replaced, but the amount of calcium needed has been debated for decades. Twenty five years ago in this journal, Kanis and Passmore concluded that calcium supplements to prevent fractures were not justified by the available evidence, [ref #1] though this view was challenged by determined opponents. According to two linked articles, [ref # 2] [ref # 3] the conclusions of Kanis and Passmore still hold true. Furthermore, there seems little to be gained from an increased consumption of calcium rich foods.”
How to Handle Heresy? Review the Data!
Most health professionals will have a hard time accepting this summary so we will provide the data and some color commentary to help understand what the results reveal.
Two studies were published in The BMJ. One was a meta-analysis of randomized controlled trials. The researchers reviewed 59 studies involving extra calcium from food or from supplements.
It found that men and women who took calcium supplements increased their bone mineral density by about 1 percent in the first year. The improvement did not persist and adding vitamin D did not make a difference. The researchers conclude:
“The small effects on BMD [bone mineral density] are unlikely to translate into clinically meaningful reductions in fractures. Therefore, for most individuals concerned about their bone density, increasing calcium intake is unlikely to be beneficial.”
Bone mineral density is only a biomarker for the the important outcome, which is avoiding fractures. That is, after all, what people really care about. The second study analyzed data from all available research on calcium intake (from food or supplements) and its relationship to broken bones.
“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.”
The researchers note:
“Collectively, these results suggest that clinicians, advocacy organisations, and health policymakers should not recommend increasing calcium intake for fracture prevention, either with calcium supplements or through dietary sources.”
Color Commentary from The People’s Pharmacy
Did you appreciate the significance of these conclusions? This means that the promise that calcium builds strong bones is not supported by scientific evidence. It is estimated that up to half of all older women in Western countries take extra calcium. That’s in large measure because of ads on television or in magazines. Their health professionals have also encouraged them to take up to 1200 mg of calcium a day. Some take even more than that. These women are not likely to achieve the results they were promised.
The Downsides of Extra Calcium:
Previous studies have shown that calcium supplements have some disadvantages. Taking extra calcium increases the possibility of kidney stones, a very painful complication (New England Journal of Medicine, Feb. 16, 2006).
People taking calcium supplements are also more likely to be hospitalized with severe abdominal discomfort due to constipation, cramping or bloating (Journal of Bone Mineral Research, March 2012).
Most seriously, those using calcium supplements have an increased risk of heart attacks (BMJ, July 29, 2010).
We know this may be a hard pill to swallow, so to speak. When you have been advised to take calcium for so long it comes as a shock to learn that 1) you may not have received much if any benefit from the pills or extra dietary calcium and 2) you may have actually done some harm.
To really get an in-depth understanding of this controversial subject we encourage you to listen to our one-hour radio interview with some amazing guests including Walter Willett, MD, DrPH, Chairman of the Department of Nutrition at Harvard University’s School of Public Health. This program will provide additional insights into this complex subject. Here is a link to Show 752: Bone Vitality. It will give you some additional suggestions about keeping bones strong beyond calcium.
Here are some reader’s comments about Show # 752:
“What a POWERFUL show today! This information needs to get out more. I can’t believe there isn’t more being done to correct one of the biggest medical falsehoods of our time.”
“I loved the information in this interview.”
“This was a very good show and I think we have learned new things about improving osteoporosis today.”
“This was one of the best public radio shows and it led to an NPR moment for my wife, who never experienced an NPR moment before. It was actually several minutes in the car while it was very hot outside.”
Find out how to download Show # 752 at this link.
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