Folate is a water-soluble B-vitamin that occurs naturally in food. The new study found that all forms and sources of folate were linked to a lower risk of colorectal cancer. The strongest association came via total folate — a measurement that includes naturally occurring food folate and folic acid added to fortified foods and in supplements.
The study included 99,523 participants in the Cancer Prevention Study II Nutrition Cohort. Just over 1,000 were diagnosed with colorectal cancer between 1999 and 2007, a period after the folate fortification began. In the first two years, there was no change in risk. But there was a major form of protection seen in the subsequent five years, from 2002 to 2007.
This adds to the weight of evidence that high folate intake could reduce colorectal cancer incidence. This study was different than others in finding that it didn’t matter where you got the B-vitamin — natural foods, fortified foods, supplements — it still worked to lower the risk.
The study also addressed concerns that the high levels of folate frequently consumed in the U.S. may actually increase risk of cancer. They found no increased risk of colorectal cancer for the highest intake levels. So that idea appears not to be correct.
Folate is an essential nutrient needed to make components used for functions required for normal cell growth, including DNA synthesis and repair. Because these processes are critical for cell growth and differentiation, the relationship between folate intake and cancer development has been investigated in several cancers, and most extensively in colorectal cancer.