Dietary calcium best protection against osteoporosis
Calcium is important in the fight against osteoporosis, but dietary calcium creates healthier bones than supplements, say scientists.
Bone density can decline if the body has too little calcium and can increase the risk of osteoporosis.
Scientists asked 183 postmenopausal women to detail their calcium intake for a week and assumed this would be representative of the women's long-term diet.
Women were divided into three groups: the "supplement group" who obtained 70% of their daily calcium from tablets; the "diet group" who got 70% of calcium from dairy products and food; and the "diet plus supplement group" who obtained calcium from both sources.
Women who got most of their calcium from food took in the least calcium but had the highest bone density in their spines and hipbones.
Scientists say dietary calcium shifts estrogen metabolism in favour of active estrogen production.
Calcium supplements, however, may take longer to induce active estrogen production because they sometimes take longer to absorb.
"Only about 35% of the calcium in most supplements ends up being absorbed by the body," says Reina Armamento-Villareal at Washington University School of Medicine.
"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."