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Could corn, a seemingly innocuous food rich in potassium, fiber and vitamins B and C, be bad for you?
The crunchy yellow kernels gained a questionable reputation this month after researchers said a toxin in a fungus that grows on corn could cause fatal birth defects.
Part of the evidence is a survey of Hispanic women in southern Texas. Those who ate many corn tortillas early in their pregnancies were 2 1/2 times more likely to have babies with neural-tube defects, mainly anencephaly and spina bifida.
But while the threat could be significant in parts of Asia, Africa and Central and South America where people consume great quantities of corn --- and in pockets of the United States such as southern Texas --- most Americans don't face much of a danger because they eat relatively little corn, the researchers say.
And health officials say all people can greatly reduce the toxin's effect --- and the risk of neural-tube defects from any cause --- with a simple step: getting at least 400 micrograms of folates or folic acid a day. The main sources of naturally occurring folates are leafy green vegetables, legumes and citrus fruits, while many cereals and other grain products are fortified with folic acid, and most vitamin pills include it.
The bottom line for worriers: Focus more on eating a balanced diet or popping a daily vitamin pill than thinking about whether corn will harm a mom or her baby.
The researchers reported in this month's Journal of Nutrition that the toxin, fumonisin, may be linked to neural-tube defects. Anencephaly is a fatal condition involving an undeveloped brain, and spina bifida, an improperly closed spine, can be mild or severely disabling. Together, the conditions occur in about six of every 10,000 births, though rates are somewhat higher for Hispanics.
In addition to the Texas survey that suggests a link, the researchers said mouse studies also found a connection, and lab studies showed that fumonisin can inhibit the metabolism of folic acid, which has been proven to prevent neural-tube defects.
"It's much more of a problem internationally," said Vicky Stevens of the Atlanta-based American Cancer Society, an author of the report, also compiled by researchers at Georgia Tech and a U.S. Department of Agriculture lab in Athens, among other institutions.
"In the U.S., it's not really a big problem, though it may be a little more for people who consume a lot of corn, such as Hispanics," Stevens said.
According to the March of Dimes, the birth defects prevention organization that funded some of the research, it's too early to say women who may become pregnant should cut back on corn.
"We need to study the issue more," said spokeswoman Michele Kling. "If you're worried about a certain food, stay away from it. Just be sure you get your multivitamin every day."
It's unclear how much corn contains fumonisin and in what amounts. Weather conditions and other factors affect the growth of the fungus containing fumonisin, called fusarium, so levels of the toxin may vary from year to year and place to place, said Ron Riley, a USDA toxicologist.
The Food and Drug Administration issued fumonisin guidelines to the corn industry in 2001, suggesting maximum levels for corn products, but there are no requirements.
Some corn bread, grits and muffins may contain small amounts of fumonisin, the FDA says, with even less in corn flakes and other cereals, and virtually none in corn syrups and sweeteners. The more processed a product is, the less fumonisin it likely has, said Riley of the USDA.
Two other developments related to folic acid could help put women of childbearing age at ease: > The maker of Maseca, a corn flour brand popular among Hispanics, said it may begin fortifying the product with folic acid in the United States. Azteca Milling of Irving, Texas, has been adding the vitamin to Maseca sold in Mexico for a few years, said Don Schleppegrell, vice president of sales.
Since 1998, the FDA has required that most grains sold in this country contain folic acid, but only if they claim to be enriched, which U.S.-marketed Maseca does not. > A new prescription prenatal vitamin by First Horizon Pharmaceutical Corp. of Alpharetta contains a new type of folic acid the company says is better for the one in eight women who unknowingly has a genetic mutation that interferes with folic acid metabolism.
Dr. Godfrey Oakley, an Emory University epidemiology professor and former director of the division of birth defects and disability at the Centers for Disease Control and Prevention, counters that women with the mutation don't need the new product, Prenate Elite, if they get enough folates or regular folic acid. But the pill could encourage more women to get at least some form of the vitamin, which would be good, he said.
Oakley's advice to women is to wipe out birth-defect worries every morning with breakfast.
"Take a multivitamin or eat a cereal that has 400 micrograms of folic acid per serving," he said. "Those are two very easy ways to get enough."
Copyright 2004 The Atlanta Journal-Constitution