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Asking 'is milk good for your bones?' feels like a weird question. Milk has been billed as a mighty bone-bolsterer since well before the days of the celebrity milk mustache. Bones are made up mostly of calcium and research shows that getting plenty of this nutrient early in life builds bone mass. "So of course you'd think, keep eating calcium as an adult for strong bones—and, in turn, prevent fractures," says Walter Willett, M.D., a professor of epidemiology and nutrition at Harvard T.H. Chan School of Public Health in Boston.
However, recent research has turned this conventional wisdom on its head—at least when it comes to adults—and caused a lot of public confusion. A study published in the British Medical Journal found that every serving of milk a day increased the risk of a fracture by nine percent. And a 2017 meta-analysis in the Journal of the American Medical Association concluded that calcium supplements also did nothing to reduce the risk of breaking a bone. What gives?
First, the BMJ study showed only that people who drank more milk had more fractures. What it didn't prove? That the dairy caused those fractures, rather than some other factor. Even the researchers say that women who have osteoporosis—which means they already have an increased risk of breaks—may be seeking out more milk for its bone health reputation, not that the milk itself weakened their bones.
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If drinking milk doesn't cause fractures, will it help prevent them?
"That's a little complicated," says Shivani Sahni, Ph.D., director of nutrition at the Hinda and Arthur Marcus Institute for Aging Research in Boston, who studies diet and osteoporosis. "The calcium you get from dairy is essential for building bone mass through your early 20s. It also helps prevent bone loss later in life. But the association between dairy consumption and a lower risk of fracture isn't well established. There haven't been enough studies." And some studies show it can reduce breaks, while others say it can't. The research has been just as inconclusive about calcium supplements. But last year, the U.S. Preventive Services Task Force, an independent panel of experts, reviewed all the data and concluded that there's not enough evidence to recommend women take calcium supplements to stave off bone breaks.
So, how can calcium help prevent bone loss, but possibly have no influence on fracture risk?
Again: it's complicated. Your personal risk of breaks involves a lot more than just one mineral. "Hormonal changes after menopause, low physical activity, low muscle mass, balance issues—all of these factors greatly influence your odds of fracture," says Willett. Also, Sahni says to think about it like this: If you have osteoporosis, your goal is fracture prevention. And if you don't, then you want to prevent osteoporosis—and to do that you should, among other things, consume calcium.
The USDA recommends that most adults get 1,000 mg of the mineral a day. Aside from dairy, good sources of calcium include soybeans, salmon and leafy greens. The bulk of your calcium should be coming from your diet, says Sahni, because when you focus on food, you garner other benefits. "Lean protein, vitamin C, carotenoids, magnesium and other nutrients are all needed for bone health," she says.
A study published in the European Journal of Nutrition found that people following a Mediterranean-style diet, filled with produce, nuts, fish and whole grains, had a 21 percent lower risk of hip fracture than those who ate a lot of sugar, refined grains and red meat. So, consume a variety of calcium-rich foods. If you want to talk to your doctor about a supplement, that's fine—just think of it as a safety net, not a primary calcium source. Also, make vitamin D a priority—it helps your body absorb calcium.
Although calcium gets much of the attention when it comes to bone health (despite lingering questions), it's far from the only solution. Regular exercise may be even more important. No controversy there. "The proof is amazingly consistent: physical activity, like resistance training and weight-bearing exercise, is very good for preventing fractures," says Willett. "It's probably the most important thing you can do to keep your bones healthy."