Almost 15,000 people took part in the study, which reported that increased blood levels of the vitamin’s active form, pyridoxal 5'-phosphate (PLP), were significantly associated with a reduced risk of colorectal cancer, according to findings published in the journal Cancer Epidemiology Biomarkers & Prevention.
The study follows similar findings from Scotland-based researchers published in the same journal last year. Researchers from the University of Edinburgh, Western General Hospital (Edinburgh) and the University of Aberdeen, reported that increased intakes of vitamin B6 from dietary and supplements may reduce the risk of colorectal cancer by over 20 per cent (Cancer Epidemiol Biomarkers Prev., Vol. 17, pp. 171-182).
There are 363,000 new cases of colorectal cancer every year in Europe, with an estimated 945,000 globally. There are about 492,000 deaths from the cancer each year. Only about five per cent of colorectal adenomas are thought to become malignant, and this process could take between five and ten years.
Jung Eun Lee from Brigham and Women's Hospital and Harvard Medical School, collaborated with scientists from Harvard School of Public Health, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, and GlaxoSmithKline R&D on the study.
The researchers prospectively evaluated the link between blood PLP levels and risk of colorectal cancer amongst 14,916 men. During the course of the study, 197 incident cases of colorectal cancer were documented, and these cases were then compared to 371 healthy.
Lee and his co-workers report that PLP levels were positively correlated with blood levels of folate and vitamin B12. PLP levels were also slightly inversely correlated blood levels of homocysteine, and the inflammatory markers C-reactive protein (CRP), tumor necrosis factor-alpha receptor 2, and interleukin-6 (IL-6).
Regarding the incidence of colorectal cancer, plasma PLP levels were inversely linked with risk of colorectal cancer, said the researchers. Indeed, when increasing levels were found to decrease the risk by 8, 58, and 51 per cent, they sad.
“In conclusion, vitamin B6 may protect against colorectal cancer independent of other one-carbon metabolites and inflammatory biomarkers,” they concluded.
Source: Cancer Epidemiology, Biomarkers & Prevention 2009, Volume 18, Pages 1197-1202 doi: 10.1158/1055-9965.EPI-08-1001“Prospective Study of Plasma Vitamin B6 and Risk of Colorectal Cancer in Men” Authors: J.E. Lee, H. Li, E. Giovannucci, I.-M. Lee, J. Selhub, M. Stampfer, J. Ma