According to an article recently published in the Journal of the National Cancer Institute, high blood levels of folate may help protect women who drink alcohol from developing breast cancer.
Breast cancer is the second leading cause of cancer death in women in the United States, with approximately 200,000 cases diagnosed each year. Several studies have suggested that women who drink alcohol are at increased risk for developing breast cancer. Research, however, has suggested that folate may reduce this risk.
Folate, also known as folic acid, is a B-complex vitamin that is crucial for the synthesis and repair of DNA. Folate is naturally occurring in many foods, and is particularly abundant in dark, leafy greens such as spinach, turnip, beet and mustard greens. Folate is also available in asparagus, Brussels sprouts, brewer’s yeast, root vegetables, dry beans and peas, citrus fruits and juices, wheat bran, wheat germ, and other whole grains, beef liver, avocado and milk.
Despite its widespread availability in food, folate deficiency is the most common vitamin deficiency in the world. Folate deficiencies can be very dangerous, causing neural tube defects, anemia and may lead to cancer. The newest standard for the U.S. Recommended Daily Allowance (RDA) of dietary folate equivalents (DFEs) was established in 1998. DFEs are 400mcg for men and women 19 years and older, 600 mcg for pregnant women and 500mcg for lactating women. Six daily servings of fruit or vegetables are roughly equivalent to 400mcg/day.
Scientists evaluated data on 32,826 women participating in the Nurses’ Health Study between 1989 and 1990. Women answered questionnaires on food consumption patterns, including alcohol intake. In addition, blood samples taken at the beginning of the study were analyzed for levels of B vitamins, including folate. These lab results for 712 women diagnosed with breast cancer by 1996 were compared to those for 712 individually-matched women who did not develop breast cancer. The study reported that women with the highest folate blood levels who consumed approximately one or more alcoholic drink(s) a day (at least 15 grams of alcohol) were 89% less likely to develop breast cancer than women drinking the same amount of alcohol who had the lowest folate levels. The study also suggested that vitamins B6 and B12 may lower the risk of developing breast cancer in women consuming less than 15 grams of alcohol a day, but not in women who drink more. Premenopausal women with higher vitamin B12 blood levels also appeared less likely to develop breast cancer, whereas vitamin B12 did not appear to affect risk of breast cancer in postmenopausal women.
These researchers concluded that higher blood levels of folate may reduce the risk of developing breast cancer, particularly for women at higher risk due to alcohol consumption. Women who drink alcohol may wish to discuss these findings with their physician.
References: Zhang SM, Willett WC, Selhub J, et al. Plasma folate, vitamin b(6), vitamin b(12), homocysteine, and risk of breast cancer.
Journal of the National Cancer Institute. 2003;95:373-80.