Eating the right apple a day should keep the doctor and other diseases away, according to Canadian scientists.

Food researchers with Agriculture Canada, working at the University of Guelph in Ontario, say the Northern Spy or Red Delicious varieties have natural antioxidant chemicals.

Antioxidants help the body defend against cancer, heart disease, high blood pressure and other diseases of aging.

Antioxidants curb oxidation in the body, preventing cell and tissue damage.

Rong Tsao, one of the scientists, says the key is in eating the peel. Levels of antioxidants are five times higher in the skin of Red Delicious apples than in its flesh and three times higher for Spy skin compared to its flesh.

Here is a rating of the eight varieties tested for antioxidants in the peel:

1. Red Delicious
2. Northern Spy
3. Idared
4. Courtland
5. Golden Delicious
6. McIntosh
7. Mutsu
8. Empire

Researchers say they want to study how the apple antioxidants act in people.

Studies on human cancer cells at Cornell University in New York made some surprising discoveries. Antioxidant chemicals extracted from Red Delicious apples stopped the growth of colon cancer and liver cancer cells by one- to two-thirds.

Greg Poushinsky, director of the federal food research program at Guelph, says his unit would like to develop an economical way of getting the antioxidant chemicals out of apple waste.