Plasma Carotenoids, Vitamin C, Tocopherols, and Retinol and the Risk of Breast Cancer in the European Prospective Investigation into Cancer and Nutrition Cohort

Authors: Bakker M. et. al.

Source: Am J Clin Nutr 2016;103:454-464.

www.ncbi.nlm.nih.gov/pubmed/26791185

This group noted that, while fruits and vegetables purportedly decrease cancer risk, current studies show weak associations between a plant-based diet and breast cancer. They note that the way the studies were conducted may have blunted the observed results. The European Prospective Investigation in Cancer (EPIC) cohort is an ongoing study of women across the continent.  This cohort provided a way for the group to very objectively evaluate the effects of carotenoids, vitamin C, tocopherols and retinol on breast cancer risk. Their impression was that their study would have a more accurate association between these dietary factors and breast cancer risks.

The EPIC cohort provided over 3000 women for the study. The group was almost evenly split between women who did and did not develop breast cancer. The blood samples each woman provided at entry into the EPIC study were tested for the nutrients in question. Other demographic information included details such as age, menopausal status, body mass index (BMI) and smoking history. The study was designed to have an overrepresentation of premenopausal and estrogen receptor negative (ER-) cancer cases.

The investigators found that elevated blood levels of ?-carotene and ?-carotene were associated with a 39-59% reduction of ER- breast cancer risk. They also found that vitamin C had a protective effect against estrogen receptor positive (ER+) breast cancers.

Foods rich in ?-carotene and ?-carotene include carrots and leafy green vegetables. The investigators conclude that, while consumption of these foods may have benefits for breast health, other dietary and lifestyle choices must be kept in mind. All daily habits may collaborate to exert individual effects on each woman’s breast health.