Vitamin B6 is involved in approximately 100 reactions in the body, including protein and red blood cell metabolism. The nervous and immune systems also need it to function efficiently. In addition, vitamin B6 is important for the synthesis and maintenance of DNA – two processes that are likely involved in the development of colorectal cancer. Researchers from Brigham and Women’s Hospital (BWH), in a first-ever study on the relationship between plasma levels of vitamin B6 and colorectal cancer in women, found that the vitamin may actually help reduce colorectal cancer risk. Details of this research are published in the May 4 issue of the Journal of the National Cancer Institute.
In addition to dietary supplements as the main source, vitamin B6 is also found in a wide variety of foods including fortified cereals, beans, meat, poultry, fish, and some fruits and vegetables.
According to lead researcher, BWH’s Esther K. Wei, “Our results demonstrate that vitamin B6 could possibly help reduce the incidence of colorectal cancer; however, other studies are needed to support and confirm these results.”
For this study, researchers analyzed blood samples, provided in 1989, from 32,826 female participants in the Nurses’ Health Study. Researchers analyzed these samples for levels of PLP (pyridoxal 5′-phosphate) – the main active form of vitamin B6 in the blood. From 1989 to 2000 (1998 for adenoma), a total of 194 colorectal cancer cases and 410 colorectal adenoma (polyps) cases were documented. Researchers observed that over the follow-up period, women with higher levels of PLP in their blood samples had a lower incidence of colorectal cancer than women with lower levels of PLP. More specifically, researchers observed 59 cases of colorectal cancer among the 25 percent of women (approximately 8,200) with the lowest PLP concentrations compared with 33 cases of colorectal cancer in the 25 percent of women with the highest PLP levels. Among these women, dietary intake of vitamin B6 was also inversely associated with colorectal cancer risk. The inverse associations of plasma and dietary vitamin B6 with future risk of colorectal cancer were independent of other known risk factors. A similar association was also observed for colorectal adenoma (polyps), a precursor of colorectal cancer, though the magnitude of the association was weaker.
Colorectal cancer is the second leading cause of cancer-related death in the United States. According to the American Cancer Society (ACS), approximately 56,730 Americans will die of colorectal cancer this year despite the availability of effective screening tests. In addition to screening, colorectal cancer risk can be reduced by a balanced diet containing adequate amounts of vegetables, fruits, and whole grain foods, and limited amounts of high-saturated-fat foods. Lifestyle recommendations include maintaining a healthy body weight, not smoking, and engaging in daily physical activity.