Vitamin D supplements may cut breast cancer risk

Although vitamin D and calcium absorbed from food and total combined intake from food and supplements do not seem to influence breast cancer risk, vitamin D supplement intake greater than 10 mcg/d (400 IU/d) compared with no intake reduces the risk of breast cancer by about 25% (adjusted odds ratio [OR], 0.76; 95% confidence interval [CI], 0.59-0.98), according to the results of a recent population-based, case-control study from Canada.

The study included about 6,500 women between the ages of 25 and 74 years, about half of whom were diagnosed with breast cancer and about half of whom served as controls.

No categories of calcium supplement intake significantly influenced breast cancer risk, but researchers observed a significant inverse trend (P=.04). The researchers noted no significant interactions involving vitamin D, calcium, or menopausal status. They reported that the mean intake of vitamin D in study participants was low to begin with.