Folate, a B vitamin, is found in foods such as green leafy vegetables. Martha J. Shrubsole, from Vanderbilt Epidemiology Center (Tennessee, USA), and colleagues analyzed data collected from the Shanghai Women's Health Study, involving 72,861 participants, ages 40 to 70 years.  The team assessed for potential relationships between intakes of folate, niacin, and vitamin B6 and B12 and incidence of breast cancer.  During the course of the study 718 cases of breast cancer were diagnosed. While the researchers found no link between vitamin B6 and B12 intakes and the risk of breast cancer in both pre- and post-menopausal women, they did observe that folate intake was associated with a reduced risk of breast cancer – with the effect limited to premenopausal women. Specifically, average intakes of 404 micrograms per day were associated with a 42% reduction in the risk of breast cancer, as compared with average intakes of 194 micrograms per day.  The team concludes that: “For premenopausal women, higher intake of folate was associated with decreased breast cancer risk.”