Forgoing that glass of milk in favor of that calcium tablet might not be the best way to protect your bones.
A new study shows women who eat a diet high in calcium-rich foods — such as milk, cheese, and other dairy products — actually have higher bone density on standard bone scans than women who rely on calcium supplements to provide the calcium they need.
The study compared three groups of women: those in one group got most of their calcium from food, those in a second group got most of their calcium from tablets, and those in the third group fell somewhere in-between, getting some calcium from food and some from tablets.
While the food group consumed only 830 milligrams of calcium per day, they had higher bone density of the hip and spine than women in the tablet group, who consumed about 1,030 milligrams per day.
Women in the food/tablet group had the highest calcium intake — about 1,620 milligrams per day — and also had the highest bone density seen in the study.
The investigators believe the outcomes may have been better for those getting more calcium from food because dietary calcium affects metabolism of the female hormone estrogen, which is known to play a role in bone health.
However, they also note the findings could have been influenced by the type of calcium women were taking, and when they took it. For example, calcium carbonate must be taken with food to achieve full benefits, while calcium citrate can be taken at any time.
“Our results suggest that the type of calcium source may be an important determinant of estrogen metabolism, and the consumption of dietary calcium may have more positive effects on bone metabolism than does the consumption of calcium supplements and should be encouraged in patients at risk of bone loss,” write the investigators.
SOURCE: American Journal of Clinical Nutrition, 2007;85:1428-1433