Vitamin C

Grapefruit is bursting with vitamin C; a mere half of a grapefruit provides 46.86 mg, or 78.1 percent, of the recommended daily value. Grapefruit is an excellent source of this antioxidant, which supports cardiovascular health by preventing the oxidation of cholesterol. In addition, consuming vitamin Crich foods supports the immune system, and leads to reduced risk of death from heart disease, cancer and stroke, says the site.