29/06/2007 – Low intake of vitamin B6 may increase a man’s risk of colorectal cancer by 31 per cent, suggests a study from Japan.
The study, published in this month’s Journal of Nutrition, evaluated the intake of range of B-vitamins among 81,184 subjects taking part in the Japan Public Health Center-based Prospective Study.
The results also appeared to show that men with higher alcohol intake also benefited from the potentially protective effects of vitamin B6
“Our results support previous evidence that low vitamin B-6 intake is associated with an increased risk of colorectal cancer. In particular, a higher intake of vitamin B-6 appears beneficial in men with higher alcohol intake,” wrote lead author Junko Ishihara from Japan’s National Cancer Center in collaboration with researchers from Gunma University Graduate School of Medicine.
There are 363,000 new cases of colorectal cancer every year in Europe, with an estimated 945,000 globally. About 492,000 deaths occur from the cancer each year.
Ishihara and co-workers used a 138-item self-administered food frequency questionnaire (FFQ) to quantify the intakes of folate
By the end of 2002, 526 cases of colorectal cancer (335 men, 191 women) had been diagnosed amongst the cohort.
Only increased vitamin B6 intake was found to impart a statistically significant benefit on male participants, with the highest intakes associated with a 31 per cent reduction in colorectal cancer risk, compared to the lowest intakes.
“Men who consumed 150 g/wk alcohol or more had twice the risk of colorectal cancer of those who drank less in the lowest [intake group] of vitamin B-6 intake, but risk due to alcohol intake was not higher in the [intake group] of vitamin B-6 intake,” added the researchers.
No benefits were observed for women, or for either sex with respect to folate and methionine, while vitamin B12 was associated with a small increased risk of the disease in men.
More research is needed to further investigate these associations, particularly mechanistic studies, which did not form part of this study, and randomised trials.
Last year, increase vitamin B intake was associated with protective effects against Parkinson’s disease. Researchers from the Erasmus Medical Center in Rotterdam recruited 5,289 people over the age of 55 and found that people who had daily vitamin B6 intakes of 230.9 micrograms or more had an associated risk of developing Parkinson’s disease 54 per cent lower than people who had average daily intakes lower than 185.1 micrograms.
Source: Journal of Nutrition
July 2007, Volume 137, Pages 1808-1814
“Low Intake of Vitamin B-6 Is Associated with Increased Risk of Colorectal Cancer in Japanese Men”
Authors: J. Ishihara, T. Otani, M. Inoue, M. Iwasaki, S. Sasazuki, S. Tsugane and for the Japan Public Health Center-based Prospective Study Group, vitamin B-6, vitamin B-12, and methionine among 38,107 men and 43,077 women. The participants were followed from 1995-1998.