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# Vitamin D cuts breast cancer risk
- URL: https://www.foodconsumer.org/vitamin_d_cuts_breast_cancer_risk_0613110712/
- Published: 2011-06-13T20:12:00.000Z
- Updated: 2026-09-22T15:55:03.000Z
- Description: Laura Anderson of Cancer Care Ontario and colleagues report that women who spent 21 or more hours a week outdoors as adolescents were 29 percent less likely to develop breast cancer than those spending six hours, with reductions of 26 to 50 percent for time outdoors at later ages.
- Author: Food Consumer
- Tags: Vitamins, Nutrition, Breast Cancer, Vitamin D, #vivvo-import

By David Liu, Ph.D. and editing by Elizabeth Hutchinson

Monday June 13, 2011 (foodconsumer.org) -- A new study in the June 9, 2011 issue of the American Journal of Epidemiology suggests that vitamin D may have a preventative effect against breast cancer.

The population-based case-control study led by Laura N. Anderson of Prevention and Cancer Control, Cancer Care Ontario in Canada and colleagues, showed that women who spent more time outdoors during adolescence and adulthood were less likely to be diagnosed with breast cancer.

Epidemiological studies have shown an association between vitamin D intake and exposure to sunlight and a reduced risk of breast cancer, suggesting that vitamin D deficiency may play a role in the pathology of breast cancer.

Compared with women who spent six hours per week outdoors, those who spent 21 hours or more per week during adolescence were 29 percent less likely to develop breast cancer. The reduction in risk was 26 percent, 39 percent, and 50 percent when the subjects were in their 20s to 30s, 40s to 50s, and 60s to 74 years, respectively.

Sun protection and exposure to ultraviolet rays were not correlated with breast cancer risk. A combined source of vitamin D was associated with reduced risk of breast cancer, though.

The researchers concluded that "This study suggests that factors suggestive of increased cutaneous production of vitamin D are associated with reduced breast cancer risk."