Ten grapes have only 15 calories and they have the lowest sugar content of most fruits. This is according to a recent USDA publication. They also contain high amounts of boron that is thought to be essential in building healthy bones.
Grapes also contain high amounts of quercetin.
According to Terence Leighton, Ph.D., Professor of Biochemistry at the University of California at Berkeley, quercetin is one of the strongest anti-cancer agents known. Quercetin is effective against cancer because it blocks cell changes that initiate cancer, and stops the spread of malignant cells that group together to become tumors. This was published in Better Nutrition , January 1990.