Folate and Cancer Risk: What the Research Shows
A review published in Current Opinion in Obstetrics and Gynecology (2004; 16(1):19–25) evaluated multiple studies examining folate intake and breast cancer. The authors concluded that folate appears to play an important role in breast cancer prevention, especially in women who consume alcohol. They also noted that some evidence suggests a protective role for vitamin D, though the effect was smaller.
Another line of research has explored folate’s impact on precancerous lesions. In the June 12, 2006 online edition of Cancer, Italian researchers reported that folic acid supplementation helped prevent the progression of laryngeal leukoplakia — a precancerous condition. The study included 43 subjects, each with low blood folate levels. Participants took 5 mg of folic acid every eight hours, a dose well above the standard RDA of 800 mcg.
After six months:
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None of the leukoplakia lesions progressed to cancer
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28% of lesions disappeared entirely
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44% showed measurable improvement
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Homocysteine levels declined significantly
Folate is required for DNA repair and methylation reactions, and low folate can elevate homocysteine, an amino acid linked with cardiovascular disease, cancer risk, and other chronic conditions.
Dietary folate may play a broader protective role as well. Research in the Journal of the National Cancer Institute (March 15, 2006) showed that folate from food—not supplements—was associated with a lower incidence of pancreatic cancer. The authors noted consistency with earlier studies suggesting folate may help reduce risk of colorectal and breast cancers.
Together, these findings highlight the potential importance of maintaining adequate folate intake through a diet rich in leafy greens, vegetables, and other folate-containing foods.
