A minimum serum folate concentration of 8.0 ng/ml is needed for effective reduction of colorectal cancer risk, says a new Japanese study.
In the study, blood samples from 258 men and 200 women were obtained and the folate levels compared between people with and without colorectal tumor (1). The study results showed that men with blood levels below 8.0 nanograms per milliliter were 50 percent more likely to develop a colorectal tumor (‘adenoma’) while women were 23 percent more likely. There were no differences in the incidence of adenoma when blood levels exceeded this figure.
The researchers concluded that these results would provide the first evidence-based recommendation of a minimum essential serum folate concentration level for effective reduction of the risk of colorectal adenoma. As the concentration of serum folate that increases the risk of colorectal cancer is still unknown, further studies would be required to determine the appropriate serum folate concentration level for reduced risk of colorectal adenoma and colorectal cancer. The results would have implications for other populations, suggested the researchers, since folate levels were higher for the participants of this study than for participants in the US NHANES III survey, where white men had a mean folate level of 5.8 ng/ml and white women had a level of 7.2 ng/ml.
Over recent years, some scientists suggested that folic acid – the synthetic form of folate – may promote the formation of cancers under certain circumstances where a person may already have a pre-cancerous or cancerous tumor. However, a recent analysis of data from almost 100,000 men and women from the American Cancer Society indicated that increased intakes of folic acid from fortified foods and dietary supplements are not linked to an increased risk of colorectal cancer (2).