Researchers studied more than 1700 women in 1993 with high blood levels of folate. Ten years later, the women with the highest amount of blood folate levels were at a 70% higher risk of breast tumors that respond to estrogen or progesterone than those with the lowest levels. It is also believed that folate actually "feeds the tumor."
What to do? Until more studies are done, play it safe. If you take a multivitamin:
- Watch your cereals. Many breakfast/energy bars and cereals are fortified with folate or folic acid. If you typically eat more than one serving (about 1/2 - 1 cup) watch for cereals that contain 25 or 50% of the daily value for folic acid.
- Go whole grain. White pasta, rice, and breads are fortified with 100 to 130 mcg of folic acid per cup. Whole grain bread, pasta and brown rice are not.
- Don't worry about naturally occuring folate. The folate in orange juice, vegetables, beans and other foods isn't absorbed as well as the folic acid in fortified foods, so it's not a problem.
~ American Journal of Clinical Nutrition~