Green tea, garlic, onions, fruits and vegetables might help prevent cancer, cardiovascular diseases, Parkinson's and Alzheimer's, for they contain antioxidants that neutralize DNA damage, which is often linked to these diseases, a Clemson study has found.

DNA damage occurs when metal ions in the body such as iron and copper produce reactive oxygen compounds that damage human cells.

As part of the study, Julia Brumaghim and colleagues showed the new mechanism for antioxidant activity, as the antioxidants bind to naturally present iron and copper in the body to prevent formation of reactive oxygen compounds that damage DNA.

"Our studies have shown that antioxidants even at low concentrations found in these foods bind to iron and copper and prevent DNA damage," Brumaghim said.

"This goes a long way in understanding how antioxidant supplements might help treat or even prevent these debilitating illnesses", she said.