Researchers at Washington University School of Medicine have found that women who get most of their daily calcium from food have healthier bones than women whose calcium comes mainly from supplemental tablets.
Adequate calcium is important to prevent osteoporosis, which affects an estimated 8 million American women and 2 million American men. Another 34 million Americans have low bone mass, placing them at increased risk for osteoporosis. Calcium consumption can help maintain bone density by preventing the body from stealing the calcium it needs from the bones.
The researchers found that the women could be divided into three groups: one group, called the “supplement group,” got at least 70 percent of their daily calcium from tablets or pills; another, the “diet group,” got at least 70 percent of their calcium from dairy products and other foods; and a third, the “diet plus supplement group,” consisted of those whose calcium-source percentages fell somewhere in between these ranges.
The “diet group” took in the least calcium, an average of 830 milligrams per day. Yet this group had higher bone density in their spines and hipbones than women in the “supplement group,” who consumed about 1,030 milligrams per day. Women in the “diet plus supplement group” tended to have the highest bone mineral density as well as the highest calcium intake at 1,620 milligrams per day.
Calcium supplements differ in how well their calcium can be absorbed, and this also could play a role in the study’s findings, according to its authors. For example, calcium carbonate tablets need to be taken with a meal so that stomach acid can facilitate absorption, but calcium citrate tablets don’t have this limitation. If the study participants taking calcium carbonate weren’t conscientious about the timing of their supplements, they might not have received the highest benefit from them.
“Only about 35 percent of the calcium in most supplements ends up being absorbed by the body,” Armamento-Villareal says. “Calcium from the diet is generally better absorbed, and this could be another reason that women who got a high percentage of calcium in their food had higher bone densities.”