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Calcium, vitamin D, and fractures

When I saw the headlines about this recently published study on bone health saying “Vitamin D and calcium supplements may not lower fracture risk” I thought: Wait, that’s news? I think I remember seeing that headline a few years ago.

Indeed, in 2015, this very blog reported on similar studies of calcium supplements, noting that calcium supplements have risks and side effects, and are not likely indicated for most healthy community-dwelling adults over 50. These folks are not in a high-risk category for vitamin deficiencies, osteoporosis, and fractures, and we usually advise them to get their calcium from food. Dietary sources of calcium are everywhere, including milk and yogurt, but also include green leafy veggies like collard greens, legumes like black-eyed peas, tofu, almonds, orange juice… the list goes on.

What’s new with this most recent study?

This research found that taking vitamin D supplements did not protect against fractures in people over 50. The authors examined 33 research studies including over 50,000 people for their analysis. However, and it’s a big however, study investigators note several times that their research included only healthy people out in the community, and that their findings do not apply to elderly people living in nursing homes who may have a poorer diet, less sun exposure and mobility, and who are at particularly high risk for fractures. Indeed, the original recommendations for calcium supplementation were based on a study of elderly, nursing-home bound women with vitamin deficiencies and low bone density, for whom calcium and vitamin D supplements did significantly reduce fracture risk.

What is the takeaway?

Well, simply, not much has changed. My advice to my healthy patients is still to get calcium from foods, and the best diet for this is a Mediterranean-style diet rich in colorful plants, plenty of legumes, and fish. This plus high-protein, low-fat, and low-sugar dairy (yogurt is ideal) can supply plenty of calcium. As far as vitamin D, well, vitamin D supplementation continues to be a topic of lively and livid debate among everyone, including competing guideline-authoring endocrine experts (see my Harvard Health Blog post on this). I hesitate to wander into that minefield again. But here goes…

The scoop on vitamin D deficiency

There is a large group of people who are likely to be deficient in vitamin D. It includes people with eating disorders; people who have had gastric bypass surgeries; those with malabsorption syndromes like celiac sprue; pregnant and lactating women; people who have dark skin; and those who wear total skin covering (and thus absorb less sunlight). In addition, people with or at risk for low bone density (perimenopausal and postmenopausal women, people diagnosed with other skeletal disorders, or who take certain medications), should discuss whether they need supplements and to have blood levels of vitamin D monitored.

Many New England-dwelling (and Northern hemisphere) residents are at risk for a dip in vitamin D levels during the long, dark winter months. In my own practice I do consider that a risk factor, and I advise a vitamin D supplement of 1,000 IUs daily. For people who would rather avoid a supplement but may need a boost of vitamin D, it is also found in some common foods, including sardines, salmon, tuna, cheese, egg yolks, and vitamin-fortified milk. I will add that, for those who fall into the “healthy community-dwelling adult” category, a supplement of anywhere from 400 to 2,000 IUs of vitamin D daily is not likely to cause harm. Yes, vitamin D toxicity is a thing, usually seen at levels above 80 ng/ml, which causes excessive calcium to be released into the bloodstream. This is rare, but I have seen it in patients who took high-dose vitamin D supplementation of 50,000 IUs weekly over a long period of time.

Other important and effective ways to protect your bones

There are other methods that may be more effective at maintaining bone health and reducing fracture risk. One that we can likely all agree on is regular physical activity. Weight-bearing exercise like walking, jogging, tennis, and aerobics definitely strengthens bones. Core exercises like yoga and Pilates can improve balance. All of this can help reduce falls and fracture risk.
And so, in the end, I am recommending what I always end up recommending: a Mediterranean-style diet rich in colorful plants, plenty of legumes, fish, plus low-sugar, low-fat dairy and plenty of varied physical activity throughout your entire life… and maybe calcium and/or vitamin D supplementation for certain people, following a discussion with their doctors.
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