Saturday May 31, 2014 (foodconsumer.org) -- Eating foods fortified with synthetic folate (vitamin B9) may increase risk of breast cancer in European American women, a study in the International Journal of Cancer suggests.

Folate is added to processed foods in the same of preventing pregnant women from having babies with birth defects.  Evidence has recently emerged to suggest that high intake of fortified (synthetic folate) in wheat flour and processed foods may boost risk of breast cancer.

The study shows that European American women who had highest intake of synthetic folate were 53% more likely than those who had lowest intake of synthetic folate to be diagnosed with breast cancer.

Researchers analyzed data from 1582 African American women with 749  diagnosed with breast cancer and 1434 European American women with 744 diagnosed with breast cancer and found the link between intake of synthetic folate and elevated risk of breast cancer.

The study was intended to examine the effect of folate, which may potentially attribute to the cancer development, on the risk of breast cancer in African American women and European American women because observational studies show that the former are more likely than the latter to develop breast cancer.

Although high intake of synthetic folate was linked to elevated risk of breast cancer, high intake of folate from natural foods was associated with 43% and 42% reduced risk of breast cancer and ER-positive tumors, respectively, in Black American women.

The study suggests that fortification of folate in wheat flour and processed foods may boost the risk of breast cancer in European American women, if not all women.

Synthetic folate is present not only in wheat flour and processed foods, but also used in many folate supplements.

Natural folate is found high in plant-based foods including beans, lentils, spinach, asparagus, lettuce, avocado, broccoli, and oranges.  No evidence suggests that high intake of natural folate causes any harm. (David Liu, PHD)

Reference

Zhihong Gong, Christine B. Ambrosone, Susan E. McCann, Gary Zirpoli, Urmila Chandran, Chi-Chen Hong, Dana H. Bovbjerg, Lina Jandorf, Gregory Ciupak1, Karen Pawlish, Quanjun Lu, Helena Hwang, Thaer Khoury, Bshara Wiam and Elisa V. Bandera, Associations of dietary folate, Vitamins B6 and B12 and methionine intake with risk of breast cancer among African American and European American women, International Journal of Cancer, Volume 134, Issue 6, pages 1422–1435, 15 March 2014