Resveratrol, the antioxidant found in abundance in red grapes, has been studied for its potential anti-cancer properties. It may help slow the growth of cancer cells and reduce the spread of certain types of cancer, including breast and colon cancer. While more research is needed, red grapes can be a valuable part of an anti-cancer diet. Red grapes are a good source of vitamin C, which plays a crucial role in strengthening the immune system. A strong immune system helps the body fight off infections, viruses, and other illnesses. Consuming red grapes regularly can help keep your immune system in top shape.