Surprising foods that boost bone health

cropped photo of a woman's hands holding a bowl of prunes

Maintaining a varied diet may mean eating some foods purely for fun and others for function. Prunes often fall into the latter camp, widely regarded as a gastronomic tool to stay regular. But new evidence suggests these dried plums are more than a one-trick pony, boosting not only digestion but bone strength as well.

The study, published in the October 2022 issue of The American Journal of Clinical Nutrition, found that eating five or six prunes a day helped women past menopause to preserve bone mineral density in their hips, which could translate to fewer bone breaks. The researchers, who tracked 235 older women for a year, speculated that the daily handful of prunes lowered inflammatory chemicals that contribute to bone breakdown.

After menopause, women tend to lose bone density quickly and are far more likely than men to develop bone-weakening osteoporosis. About three-quarters of all broken hips happen to women; that injury dramatically increases the odds of losing your independence and dying earlier. Additionally, half of all women over 50 will fracture their hip, wrist, or spine during their lifetime, according to the National Institutes of Health.

"Even if prunes didn't work that well for bones, you'd need a very low bar to recommend eating them" because of their other benefits, says Dr. Harold Rosen, director of the Osteoporosis Prevention and Treatment Center at Harvard-affiliated Beth Israel Deaconess Medical Center.

But prunes aren't alone on the list of surprising foods that boast bone benefits.

To safely strengthen bones, stick to low-impact exercise

Foods rich in calcium and vitamin D go a long way toward maintaining bone strength. But exercise — especially activities that make you move your own body weight against gravity — also stimulates bones to get stronger and stay that way.

That said, older adults at higher risk of bone-eroding osteoporosis should probably ignore trendy advice to engage in so-called jump training or high-impact activities requiring you to pound the ground, says Dr. Harold Rosen, director of the Osteoporosis Prevention and Treatment Center at Beth Israel Deaconess Medical Center.

"I don't like the idea of pounding," Dr. Rosen says. "While it makes some sense, it could also lead to injuries. A lot of older people also have shoulder or knee problems — I don't think they help themselves by pounding on their bones."

Low-impact alternatives can also keep bones strong — and more safely, he says. These include

walking briskly outdoors or on a treadmill
climbing stairs on a machine
doing gentle aerobics
using elliptical training machines.

Dynamic duo

Unlike prunes, most foods and drinks notable for bolstering bone health do the trick with calcium, a major component of bones. The mineral works best when paired with vitamin D, which helps the body absorb calcium.

It's normal for bone to break down and rebuild itself in a continuous process called remodeling. As the bones release stored calcium into the bloodstream to carry out body functions ranging from blood clotting to muscle contractions and more, we replenish the supply with the calcium we eat and drink.

Our bone mass reaches its peak when we're around age 30, and it remains steady for about the next two decades. But after menopause, we lose bone more quickly than our bodies can replace it. And aging in general can prompt our body to leach calcium from bones.

It's well known that top sources for calcium include dairy products such as milk, yogurt, and cheese, along with dark leafy greens such as collards, kale, Swiss chard, and broccoli. Breakfast cereals and fruit juices are often fortified with the mineral as well.

But you might not be aware of these other foods that pack a calcium punch.

Dried figs. Two figs contain about 65 milligrams (mg) of calcium. Like prunes (and perhaps even tastier than their cousin), figs can be sliced over oatmeal or blended into smoothies. They also work well paired with cheese and even as a pizza topping.

Canned salmon. A 3-ounce serving has 180 mg of calcium. It's so rich in the mineral because canned salmon includes tiny, soft bones that you likely won't even notice, Dr. Rosen says. "A regular salmon filet has only 36 mg of calcium, which I wouldn't call a strong source," he adds. It's easy to mix canned salmon with mayonnaise to make a sandwich spread (as you would with tuna) or whip it up into a dip.

Plant milks. We automatically think of cow's milk as a solid calcium source, and with good reason. But milk made from almonds, rice, or soy is typically fortified to reach a calcium level similar to its dairy counterpart: 8 ounces contains 350 to 400 mg. Check labels, and also watch out for sugar that might be added to plant milk.

Tofu. This soy-based mainstay of Asian cuisine boasts 430 mg of calcium in a 4-ounce serving, while calcium-enriched versions often have double that amount. Soy foods, which include edamame, are generally high in calcium, Dr. Rosen says, as well as an important source of protein — also important to bone health.

Almonds and almond butter. Known for their heart-health benefits, almonds are easy to love (though calorie-dense). A half-cup of the nuts alone has 190 mg of calcium, while 2 tablespoons of almond butter contains 111 mg of calcium.

White canned beans. Each cup of these soup- and chili-enriching legumes — which encompass navy, cannellini, great northern, and lima beans — contains about 190 mg of calcium. Beans are a smart source of protein as well, Dr. Rosen says.

Detect osteoporosis before you break a bone

Osteoporosis, a disease in which bones become weak and brittle, strikes four times as many older women as men, a disparity due in part to our loss of bone-protecting estrogen after menopause. But while you may shrink a bit in height or develop a slightly stooped posture as you age — hints that osteoporosis is lurking — the condition typically doesn't announce itself until you break a bone.

One weapon can stave off that painful scenario, however: bone density testing. The x-ray technology, known as a DEXA scan, measures the density of calcium and other minerals in bones. It can detect osteoporosis before a dangerous fracture happens. DEXA can also predict your risk for a future bone break or determine how well osteoporosis medication is working.

Bone density testing is recommended for all women starting at age 65 and every two years thereafter. Women 50 to 64 should also begin regular testing if they have certain risk factors for osteoporosis, such as low body weight, a past fracture, a parent who broke a hip, a disease linked to bone loss, or medication use known to thin the bones.

How is DEXA scanning done? Over a 15-minute period, you'll lie on your back on a padded table. One x-ray device will pass over your hips and lower spine, while another passes underneath. As with other x-ray testing, you'll be asked to stay still and hold your breath at certain points.

The test will generate two scores. One compares your bone density to that of a healthy young adult. The second compares it to peers of the same age, gender, and ethnic background. The higher your score, the denser your bones. While current guidelines help your doctor decide when to treat low bone density, further research is needed to determine whether the guidelines related to ethnicity are accurate.

Tackling shortfalls

Adding a few lower-profile calcium-rich foods to your diet can enhance bone benefits beyond what you get from daily basics such as dairy products and dark greens. How much calcium should you aim for? The National Academy of Medicine recommends 1,000 mg daily for women 50 and under and 1,200 mg each day for women 51 and older. To maximize its impact, complement calcium intake by consuming 800 international units (IU) of vitamin D each day, particularly if you live in a part of the world where daylight is not plentiful.

Read product labels to help you tally just how much calcium and vitamin D you're getting on an average day through diet, Dr. Rosen says. "Assess your nutrition first," he says. "Once you've added up the numbers, you can make up the difference between the recommended and actual amounts using supplements."

But don't go overboard. Strong evidence suggests women taking calcium–vitamin D combination supplements have a higher risk of developing kidney stones. "People used to keep aiming higher and higher for daily calcium intake, but I don't think that's a good idea," Dr. Rosen says.

Also, be wary of other supplements that claim to have bone benefits. In particular, the heavy metal strontium is often marketed for this use, he says, but research has shown it "only makes bone look denser on scans."