Avocados Contain Potent Liver Protectants

The weeklong scientific meeting, held once every five years, is hosted by the American Chemical Society, in conjunction with its counterparts in Australia, Canada, Japan and New Zealand.

To evaluate the protective activity of food against liver injury, the researchers fed 22 different fruits to a group of rats with liver damage caused by galactosamine, a powerful liver toxin. As measured by changes in the levels of specific liver enzymes, the avocado showed the most potent activity among these fruits in slowing liver damage, according to the lead researchers, Hirokazu Kawagishi, Ph.D., and Kimio Sugiyama, Ph.D., professors at Shizuoka University in Shizuoka, Japan.

"Besides offering taste and nutrition, avocados seem to improve liver health," says Kawagishi. "People should eat more of them."

Five compounds appear to be active in reducing liver damage. Each was tested in rats with chemically induced liver injuries. The injuries resembled those caused by viruses, suggesting that avocado extracts may be especially promising for the treatment of viral hepatitis, according to the researchers.

The investigators do not know whether the results from the rat studies will translate into liver protection among humans, how much avocado extract it will take to have a beneficial effect, or how the active chemicals work. Further studies are needed, they say.

The leading producer of avocados worldwide is Mexico. In the United States, California is the leader, followed by Florida and Hawaii.

The study adds to a growing body of evidence supporting the many health benefits of the avocado, a popular addition to salads, sandwiches and California rolls. In addition to benefiting the liver, the green-skinned fruits are rich in vitamins E and C, high in fiber and potassium, and contain large amounts of folate, a vitamin that helps reduce birth defects in pregnant women.

While avocados are high in fat, much of the fat is of the monounsaturated variety, which has been shown to reduce cholesterol levels.

The study was funded by Monbu-syo (the Ministry of Education in Japan) and by Kagome Co., Ltd., a major food and beverage manufacturer in Japan. Kagome plans to patent the avocado extract and test it on humans in the near future, the researchers say.

More than 8,000 research papers will be presented during this year's International Chemical Congress, which is sponsored jointly by the American Chemical Society, the Chemical Society of Japan, the Canadian Society of Chemistry, the Royal Australian Chemical Institute and the New Zealand Institute of Chemistry.

Hirokazu Kawagishi and Kimio Sugiyama are both professors in the department of applied biological chemistry at Shizuoka University in Shizuoka, Japan.