Increasing the intake of calcium and vitamin D supplements is apparently of no use in reducing the risk of breast cancer, according to new results from the Women's Health Initiative study. Previous research had suggested that vitamin D played a role in decreasing the cancer risk.
'We can't yet make a general recommendation about how much calcium and vitamin D individuals should take each day as supplements,' said Dr. Rowan Chlebowski, the study's lead author. These results were based on findings in 36,282 U.S. post-menopausal women in the study.
The researchers measured the incidence of breast cancer among 18,176 women randomly assigned to take 1000 milligrams of calcium carbonate and 400 international units of vitamin D daily. These cases were compared to a control group of 18,106 women.
After seven years there was no difference in the breast cancer incidents in either group. But Dr. Walter Willett, an epidemiologist and nutritionist at Harvard said that the study was flawed since all of the women were allowed to continue using calcium and vitamin D supplements routinely.
The study findings were presented at the annual meeting of the American Society of Clinical Oncology.