Biotech Corn Reduces Serious Birth Defects, Study Shows

Published February 1, 2005

In the early 1990s, Hispanic women in the Rio Grande Valley of Texas gave birth to babies with neural tube defects (NTDs)–including spina bifida, hydrocephalus, and anencephaly–at a rate of 33 per 10,000 live births, approximately six times the U.S. national average for non-Hispanic women.

Help may be on the way, however, as recent research shows that by switching to genetically modified corn, women can significantly lower the odds of giving birth to children with such defects.

Ground-Corn-Related Deaths

Most unborn children affected by NTDs do not even survive to birth, and those who do are usually severely disabled. One hundred eighty-four Mexican-American women and their babies suffered these conditions during the early 1990s.

The precise cause for the increased rate of NTDs in Texas remained a mystery until recent research shed light on a surprising cause. Studies from China, Guatemala, South Africa, and the United States show a clear link between diets containing unprocessed corn (known as maize in most of the world) and NTDs.

Unprocessed corn is found in tortillas and other products that contain whole ground corn. Research in Guatemala showed that in four rural departments (regions similar to U.S. states) the children of women who ate unprocessed corn as a significant part of their diet had a rate of NTDs (34.29 per 10,000 live births) at least six times the world average rate.

What connection could exist between unprocessed corn in the diet and children being born with NTDs? Fumonisin, a deadly mycotoxin found in unprocessed corn, is the likely culprit, according to research published in the April 2004 issue of the Journal of Nutrition.

At the time that the Hispanic women of the Rio Grande valley suffered the high rate of NTDs in their babies, the fumonisin level in corn in the Rio Grande Valley was two to three times the normal level. The women also reported much higher than average dietary consumption of homemade tortillas prepared from unprocessed corn.

Mycotoxins such as fumonisin are highly toxic chemicals produced by molds and fungi. When corn is attacked by insects, a mold called fusarium can grow at the site of insect damage and produce fumonisin. Poor storage conditions can promote post-harvest growth of molds on grain as well.

The Journal of Nutrition research made another important connection. Researchers learned that fumonisin interferes with the cellular uptake of folic acid. Folic acid in the diet, provided either directly from foods eaten or through food fortification and dietary supplements, is known to reduce the incidence of NTDs in developing fetuses. Because fumonisin prevents folic acid from being absorbed by cells, women eating a diet of unprocessed corn contaminated with fumonisin are at higher risk of giving birth to babies with NTDs, even when their diet contains an adequate amount of folic acid.

Safe Biotech Corn

There is a way to limit toxic mold infestation in corn. Researchers in Argentina, France, Italy, Spain, Turkey, and the United States have clearly established that planting corn seeds genetically engineered to be resistant to corn borers and similar insect pests results in the harvesting of corn with much lower levels of fumonisin.

The insect-protected corn varieties contain a protein found in a common soil bacterium called bacillus thuringiensis. In nature, this bacteria kills certain insect larvae but is harmless to all other insect species, as well as humans and animals.

Such biological preparations have been used safely for years in agriculture and are one of few insect control methods used in organic agriculture: bacillus thuringiensis was first used as a commercial insecticide in France in 1938, and then in the United States in the 1950s.

Scientists have engineered corn that can produce the protein itself, in the hopes of making insect-protected corn plants. This genetically improved corn, dubbed Bt corn, usually has dramatically lower levels of fumonisin. It is not unusual for Bt corn to have one-tenth to one-twentieth the amount of fumonisin found on organic and conventional corn varieties.

The U.S. Food and Drug Administration and the U.K. Food Safety Agency have established guidelines for recommended maximum fumonisin levels in food and feed products made from corn. Even before the connection between fumonisin and NTDs was discovered, food safety agencies recognized fumonisin as a highly toxic carcinogen.

Although highly processed cornstarch and corn oil are unlikely to be contaminated with fumonisin, unprocessed corn or lightly processed corn (such as cornmeal) can have fumonisin levels that exceed recommended levels.

Organic Corn Contamination

The U.K. Food Safety Agency tested six organic cornmeal products and 20 conventional cornmeal products for fumonisin contamination in September 2003. The six organic cornmeals had fumonisin levels nine to 40 times the recommended levels for human health. All six organic cornmeal products were voluntarily withdrawn from grocery stores.

Genetically improved Bt corn kernels were less often damaged by insects, which greatly reduced the chance of fumonisin contamination and its harmful effects.

This health benefit adds to the benefits Bt corn already has brought to farmers and consumers. Farmers have found Bt corn improves yields and lowers labor costs. Bt corn also reduces pesticide use. Improved yields and reduced costs mean grain prices are kept low.

Bruce Chassy ([email protected]) is professor of food microbiology and nutritional sciences and executive associate director of the Biotechnology Center, University of Illinois, Urbana-Champaign. Drew Kershen ([email protected]) is Earl Sneed Centennial professor of law, University of Oklahoma College of Law, Norman, Oklahoma. This article was published by Truth about Trade & Technology ( and is reprinted with permission.