Potential Link Between Shampoo and Brain Development

Ivanhoe Newswire
Monday, August 7, 2006; 12:00 AM

(Ivanhoe Newswire) -- An ingredient commonly found in shampoo interferes with normal brain development in baby mice when applied to the skin of pregnant mice, according to a new study from the University of North Carolina at Chapel Hill.

In the past, the ingredient, diethanolamine (DEA), has been tested for its potential effects as a cancer-causing agent. This new study is the first of its kind to explore the compound's effect on brain development.

DEA appears to block the body's ability to absorb the essential nutrient choline, which is thought to be essential for normal brain development. A pregnant woman requires extra amounts of choline as the baby grows inside her.

When DEA was applied to the skin of pregnant mice, the fetuses showed inhibited cell growth and increased cell death in the hippocampus -- an area of the brain responsible for memory. At very high doses, DEA treatment in pregnant mice resulted in spontaneous miscarriage. Researchers witnessed smaller and smaller litters as they increased the dosage of DEA.

However, according to researchers, the dose of DEA a person might get from shampooing is at least 10 times lower than the dose found to interfere with brain development.

Steven Zeisel, M.D., Ph.D., is professor of nutrition and associate dean of research in the School of Public Health at UNC and author of the study. "I don't believe any woman who's been using these products needs to have a sleepless night about having caused her child harm," reports Dr. Zeisel. "At this point it is a caution, but it would probably be prudent to look at labels and try to limit exposure until we know for sure."

Researchers are now doing more research to find out the lowest dose that would harm a fetus in mice, a process that could take about a year.

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SOURCE: The Federation of American Societies for Experimental Biology, 2006;20:1635-1640