Grapes, apples and their juices can prevent the development of atherosclerosis in hamsters eating a high-fat, high-cholesterol diet, French researchers have found.

Fruit juices had a more powerful anti-atherosclerotic effect than the fruit itself, Dr. Kelly Decorde of the Universite Montpellier and colleagues found, showing for the first time that processing fruit can have a “major impact” on its health benefits.

Most of the fruit people eat is processed, the researchers say, but information on the nutritional composition of a fruit is typically limited to its raw form.

To investigate how juicing might affect the content of phenolic compounds, which are powerful antioxidants contained in fruits, the researchers fed hamsters grapes, grape juice, apples, apple juice or water, along with a diet designed to promote atherosclerosis - the buildup of fatty plaque deposits in the arteries that can lead to heart attacks or strokes. A control group of animals ate normal chow.

The amount of fruit the hamsters consumed was equivalent to three apples or three bunches of grapes daily for a human. Hamsters given juice drank the equivalent of four glasses daily for a person weighing 70 kilograms (154 pounds).

The apples and grapes had about the same phenol content, while the purple grape juice had 2.5 times more phenols than apple juice.

Compared with animals given water, those given fruit or fruit juice had lower cholesterol levels, less oxidative stress, and less fat accumulation in their aorta, the main vessel supplying oxygenated blood to the body. Purple grape juice had the strongest effect, followed by purple grapes, apple juice and apples.

The findings suggest that the amount of phenols contained in a food have a direct effect on its antioxidant properties, the researchers write. Other antioxidant compounds in the fruits, such as vitamin C and carotenoids, could also contribute to their effects.

The results, Decorde’s team writes, “provide encouragement that fruit and fruit juices may have a significant clinical and public health relevance.”

SOURCE: Molecular Nutrition and Food Research, April 2008.