Thursday, January 6, 2011 (Last Updated: 01/10/2011)
THURSDAY, Jan. 6 (HealthDay News) -- Higher blood levels of folate may result in the methylation of two tumor-suppressing genes in colorectal tissue, according to research published in the December issue of Cancer Prevention Research.
Kristin Wallace, Ph.D., of Dartmouth Medical School in Hanover, N.H., and colleagues collected demographic, lifestyle, and dietary data and compared methylation of two tumor-suppressing genes between two colonoscopies three years apart in 781 subjects. The purpose of the study was to assess the effect of folate intake, diet, and lifestyle on DNA methylation in normal colorectal tissue.
With each 10-year increase in age, the researchers found a 1.7 and 2.9 percent increase in methylation level for ERα and SFRP1, respectively, and a significantly lower methylation level for the two genes in African-Americans than in Caucasians and Hispanics. Higher levels of red blood cell folate were associated with higher methylation levels in both genes.
"Our results suggest that CpG Island methylation in normal colorectal mucosa is related to advancing age, race, rectal location, and red blood cell folate levels. These data have important implications regarding the safety of supplementary folate administration in healthy adults, given the hypothesis that methylation in normal mucosa may predispose to colorectal neoplasia," the authors write.
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