The latter observation is highly suggestive of a true cause and effect relationship between dietary folate and the risk of colorectal cancer. Dietary folate has also been related to other epithelial cancers such as those of the uterine cervix, stomach, esophagus and lung. Nevertheless, the data are clearly most compelling for the colorectum. The dose of folate necessary to convey some protection against cancer is not entirely clear but some study results suggest that as little as four times the basal requirement is enough to convey a significant amount of protection. I want to add that one has to be extremely cautious in giving large doses of folate to individuals who potentially have a colorectal neoplasm already existing.
Cancer cells are rapidly proliferating and, as such, they have high requirements for folate.
Giving large doses of folate to individuals who have existing cancers can actually accelerate the growth of those cancers. In the American diet, the fortified breakfast cereals, leafy green vegetables, orange juice and organ meats such as liver and kidney are all rich sources. Folate is a heat-liable vitamin, so overcooking can destroy its activity. Moreover, because it is a water-soluble vitamin, if you boil your vegetables in a large volume of water and then discard the water, much of the folate is discarded as well. October 1999 Email this article to a friend References 1.