A study published in Gastroenterology found that high folate intake is associated with a reduced risk of colorectal cancer, which is consistent with most previous epidemiologic studies, according to the researchers.1
Although recent studies suggested that consumption of very high levels of folate through supplements and a folate-fortified diet may increase the risk of some cancers, this study found that folate intake may benefit colorectal cancer prevention. However, at least one other study found that folate had no effect on recurrence of colorectal adenomas.
The study in Gastroenterology, which was led by Victoria Stevens, PhD, strategic director of laboratory services at the ACS, is the first to look at the association of folate and colorectal cancer risk with follow-up entirely after the mandatory fortification of the US diet with folate. In addition, it is the first study to distinguish between forms of folate found naturally and folic acid, which is used for fortification and in supplements.
Researchers investigated the link between folate consumption and colorectal cancer among 99,523 participants in the Cancer Prevention Study II Nutrition Cohort. They found that between 1999 and 2007, a period entirely after folate fortification began, a total of 1023 people were diagnosed with colorectal cancer. The researchers did not observe any higher or lower risk during the first 2 years of follow-up, but from 2002 to 2007, high folate intake was associated with a reduced risk of colorectal cancer.
Dr. Stevens notes that because 1 randomized trial did not show a link between folate supplementation and reduced risk of adenomas, researchers need to continue to investigate the impact of folate on cancer development in high-risk populations as well as differences between the natural and synthetic forms of the vitamin.