Could washing your hair make you stupid?

05:49 PM PDT on Wednesday, May 12, 2004

NBC News

New research in animals suggests your shampoo may be washing away more than dirt. Researchers have uncovered evidence that suggests an ingredient found in some soaps and shampoos might affect memory.

The research centers around an ingredient found in shampoos, soaps and other products we use to keep clean. It's called DEA, the stuff that helps makes soap and shampoo soft and bubbly, but there's also some research that shows DEA may rob the brains ability to make memory cells.

Dr. Steven Zeisel of the UNC School of Public Health has uncovered evidence in mice that suggests DEA, and a similar ingredient, TEA, seep through the skin and block the brain's ability to absorb choline, a key nutrient that plays a crucial role in the memory cell-making process in the developing brain.  "And what we found for example, is that low choline causes half as many cells to be divided as when you give extra choline, so that's a huge change," said Dr. Zeisel.

Earlier research by Dr. Zeisel showed that mice that were deprived of choline in the womb weren't as sharp as the animals whose mothers were fed a choline rich diet.

Now they want to see if the choline blocking effect found in DEA and TEA will have the same memory robbing impact.

"And our hypothesis is that they will, and we'll be able to show that doses of this compound administered frequently will cause abnormal brain development in the baby and they'll perform as if their mothers were eating too little choline in the diet," said Dr. Zeisel.

The bottom line is the animals won't be as smart. But what could all this mouse research mean for people?

Zeisel says if the DEA hypothesis holds true, the memory impact would probably be minimal in adults but could have a bigger effect on the developing brain during pregnancy and the first few years of life. "I would never have thought that washing my hair could harm my baby - and again our research might not show that, but that's the reason we're putting the effort in put together a team funding from NIH try to find out for sure for people," said Dr. Zeisel.

The findings could have us all taking a second look at what's inside those bubbles that keep us squeaky-clean. The UNC research is using the same amounts of DEA that most of us would get if we shampooed our hair a couple of times a week.

Zeisel and his team of researchers are also testing to see if adding extra choline to the diet can make up for the brain cell deficiency caused by DEA. Choline is a nutrient that is found in many of the foods we eat. High doses of choline are found in eggs and peanuts.

DEA stands for diethanolamine, a chemical that is used in shampoos, lotions, creams and other cosmetics. DEA is used widely because it provides a rich lather in shampoos and keeps a favorable consistency in lotions and creams. TEA, the other ingredient being tested is similar and stands for triethanolamine.  For more information on products that contain diethanolamine DEA and triethanolamine, TEA, log onto the national institute's of health household product database.