AsianScientist (Aug. 11, 2011) – Folate, which gets its name from the Latin word “folium” (for leaf), occurs naturally in foods such as leafy green vegetables, fruits and dried beans and peas.
Crucial during periods of cellular division and growth (such as pregnancy and infancy), this water-soluble B-group vitamin is needed to make the cell building-blocks of DNA and RNA, and also to produce and maintain new cells.
A study by investigators from Vanderbilt-Ingram Cancer Center and the Shanghai Cancer Institute, published in the American Journal of Epidemiology, has shown folate to be beneficial in reducing the risk of breast cancer, and that premenopausal women who get adequate amounts of folate in their diet have a 40 percent reduced risk of developing breast cancer.
“In our study, it appears that folate is most protective of hormone negative, or what we call double negative, breast cancer,” said Martha Shrubsole, assistant professor of Medicine in the Division of Epidemiology at Vanderbilt and lead author of the paper.
“We don’t have evidence that an extremely high intake of folate protects against breast cancer, but it appears that low folate levels may increase a premenopausal woman’s risk of developing breast cancer,” she added.
Using data from the Shanghai Women’s Health Study in China, the investigators assessed the records of 72,861 women who enrolled in the study between 1997 and 2008. Of these women, researchers identified 718 who developed breast cancer during the course of the study.
When they enrolled, all of the women answered a food frequency questionnaire indicating types and quantities of foods consumed on a regular basis.
Food in Shanghai is generally not fortified with vitamins – including folic acid – and moreover, few women in this population take supplements, which helped the researchers estimate daily intake of B-group vitamins.
After studying the data, the researchers found no link between vitamins B6 or B12 and breast cancer risk. However, a clear protective effect was noticed for folate-consumption among premenopausal women, although the data doesn’t state the quantity needed for this protective effect.
Previous research on folate intake and its possible role in breast cancer risk had produced inconsistent results.
There is a lesson for those in Western societies, concludes Shrubsole, since the Asian women in the study were getting their folate from food sources rather than supplemental forms.
“The good news for American women is that we don’t necessarily need to use a vitamin supplement in order to benefit from folate. While the women in this study may not eat the same kind of diet, it is possible that naturally derived folates from food are equally, or more important than, the synthetic folic acid that is a part of our American diet,” she said.
“I think this is an important message because physiologically, the way our bodies use nutrients is similar whether you are in Tennessee or in Shanghai, China,” she said.
The researchers also found evidence that too much niacin (also known as Vitamin B3, nicotinamide, nicotinic acid, inositol hexanicotinate, or Vitamin PP) in the diet may be linked to an increased risk of hormone positive breast cancer. No other studies have found this effect, and further research has been recommended to validate these findings.
The article can be found at: Shrubsole MJ et al. (2011) Dietary B Vitamin and Methionine Intakes and Breast Cancer Risk Among Chinese Women.
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Source: Vanderbilt-Ingram Cancer Center.
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