Q. Are antibacterial soaps better than plain soap and water?

A. Antibacterial soaps are often promoted in advertisements as being better at preventing illness than regular soap. Many people, worried about getting sick, don't mind paying more for antibacterial soaps.

Researchers from the University of Michigan's School of Public Health reviewed 27 studies conducted between 1980 and 2006 comparing antibacterial soap to regular soap.

Results showed that in the concentrations used in home and community settings, washing hands with antibacterial soap was no more effective in preventing coughs, sore throats, congestion, diarrhea or fever than plain soap.

In fact, antibacterial soaps in the formulations sold to the public do not remove any more bacteria than plain soaps.

The active ingredient in most antibacterial soaps is called triclosan. Triclosan is available in higher concentrations in hospital formulations and therefore may be more effective at killing bacteria in these settings. They still are ineffective against viruses that cause colds and flu.

Another concern is that triclosan may cause some bacteria to become resistant to antibiotics such as amoxicillin, rendering them ineffective. Also, in lab experiments, E. coli bugs (responsible for several food-poisoning outbreaks) showed resistance when exposed to triclosan soap. This means, E. coli could survive in the concentrations used in consumer-formulated antibacterial soaps.

Some bacterial-reduction studies have shown that increased application time shows better results. Folks in these studies spent a longer amount of time washing hands or washed their hands several times in a row. This is not typical in real-world practice.

In September, the Food and Drug Administration ordered Procter and Gamble, makers of Vicks foaming sanitizer for hands, to stop advertising that this product prevents the spread of viruses that cause colds. The FDA will be scrutinizing claims from other companies selling antibacterial soaps containing triclosan as well.

Good hand-washing practices are your best defense against spreading colds and infections.

You should wash your hands for at least 20 to 30 seconds, (the amount of time it takes to sing the song "Row, Row, Row Your Boat"). Rub your hands together while washing to create friction. This helps remove dead skin and dirt that harbors germs. Rinse thoroughly and dry your hands well.

Ultimately, it is more important to wash your hands well than worry about the type of soap you use. Save your money and invest in plain soap.

Amy Tousman is a registered dietitian and certified diabetes educator with Nutrition Unlimited in Kailua. Hawai'i experts in traditional medicine, naturopathic medicine and diet take turns writing the Prescriptions column. Send your questions to: Prescriptions, Island Life, The Adverti-ser, P.O. Box 3110, Honolulu, HI 96802; islandlife@honoluluadvertiser.com; or fax 535-8170. This column is not intended to provide medical advice.