Los Angeles Times — Adding folic acid to flours, pastas and rice has reduced the rate of spina bifida and anencephaly in the United States, sparing 1,000 babies each year from these devastating birth defects. But a recent study suggests those health gains may have come at a cost: an extra 15,000 cases of colon cancer annually.
The report, from Tufts University, is the latest to raise a cautionary note about a public-health policy that has been largely viewed as a success.
"Have we done more harm than benefit?" said Dr. John Potter, a colon cancer expert at the Fred Hutchinson Cancer Center in Seattle, who was not connected to the latest research.
Writing last month in the journal Cancer Epidemiology Biomarkers and Prevention, scientists reported that colon cancer cases in the United States spiked after manufacturers began fortifying cereal grains with folic acid in the late 1990s. They saw a similar trend in Canada, which began fortification around the same time.
The pattern was surprising, researchers said, because colon cancer rates had been steadily dropping since the mid-1980s. Greater consumption of folic acid looked like the explanation.
Joel Mason, lead author and professor of nutrition science and policy at Tufts, said the report does not prove that extra dietary folic acid causes colon cancer but does suggest fortification may have unforeseen trade-offs. Nutritionists have long known that younger women need 400 micrograms of folic acid daily to reduce their chances of giving birth to infants with neural tube defects, caused by the failure of the fetal spinal column to fully close. Although rare, such defects are devastating.
Since 1998, U.S. food manufacturers have been required to add 140 micrograms of folic acid to each 100 grams of cereal grains that are labeled "enriched." Breads, cereals and other grain-based foods shipped across state lines are all fortified with folic acid, a B vitamin naturally found in green leafy vegetables, fruits, dried beans and nuts.
In only a few years, the rate of neural tube defects in the United States fell, from 10.6 per 10,000 births in 1996, before fortification, to 7.6 per 10,000 births in 2000. Canada also saw a sharp decline. Those results deepened the desires of some scientists and health advocates for even greater improvements.
