What happened? A new study reports that supplements containing calcium and vitamin D provide only modest protection from bone fractures in women.

In the study of more than 36,000 middle-aged and elderly women, daily calcium and vitamin D supplements slightly reduced bone thinning and reduced the risk of hip fractures. But the results weren't as promising as researchers had anticipated.

After an average of seven years, women who took the supplements scored only 1 percent higher on hipbone density tests than did women who took a placebo. The supplements reduced the risk of hip fractures by 12 percent, but offered no protection from spine or wrist fractures. For women age 60 and older — those most likely to experience hip fractures — the supplements reduced the risk of hip fractures by 21 percent.

Aside from the impact on bone health, calcium supplements were found to slightly increase the risk of kidney stones.

In a related study, researchers found no link between calcium supplements and a reduced risk of colon cancer, as earlier research had suggested they might.

What does this mean to you? The findings from this study may be called into question because calcium intake from diet and other sources — in addition to the supplements given as part of the study — were not accounted for. This may have affected the study results.

According to Todd Nippoldt, M.D., an endocrinologist at Mayo Clinic, Rochester, Minn., "Calcium continues to play an important role in bone health," and it seems reasonable to recommend that women consume the recommended daily levels of calcium and vitamin D through diet, supplements or both. Although calcium supplements alone may not provide adequate protection against osteoporosis, calcium remains an important part of a healthy diet for many women.

"As a general rule, we still recommend a daily intake of 1,500 milligrams of elemental calcium and 400 international units of vitamin D from diet and supplements," says Dr. Nippoldt. "However, these recommendations may vary depending on individual circumstances." You and your doctor can determine the appropriate intake of calcium and vitamin D in your specific situation.