In 1996 and 1998, there were abrupt reversals in the 15-year downward trends in colorectal cancer rates in the United States and Canada, respectively. Since peaking in 1998 in the United States and in 2000 in Canada, the rates have not returned to their earlier levels. Although folic acid fortification of enriched grains including bread, cereal, flour, rice, and pasta did not become mandatory until 1998, large food companies began voluntary fortification in 1996, first in the United States and later in Canada.
Folic acid is the synthetic form of folate, a B vitamin that is essential for cell growth. After intestinal absorption, folic acid is converted to methyltetrahydrofolate, found naturally in foods such as leafy green vegetables, legumes and citrus fruits. The body's response to folic acid appears to be complex, says Mason. While fortification of the food supply is clearly beneficial for women of child-bearing age and their offspring, it is possible that it may, coincidentally, be linked to the increase in colorectal cancer rates. Our report is intended to create a foundation upon which to further explore that possibility.
As Mason and colleagues note, there is a compelling body of scientific evidence suggesting that habitually high intakes of dietary folate are protective against colorectal cancer. Mason explains, however, that There are several reasons why we may have inadvertently created the opposite effect with folic acid fortification. First, folates pivotal role in DNA synthesis also makes it a potential growth factor for cancerous or pre-cancerous cells, and when administered in large quantities to individuals who unknowingly harbor cancer cells, it could paradoxically enhance cancer development. The addition of substantial quantities of folic acid into the foodstream may have f
Contact: Siobhan Gallagher
Tufts University, Health Sciences