Beta-carotene is a powerful antioxidant. Studies have shown that people who eat a diet high in beta-carotene — found primarily in orange vegetables and leafy greens
— have a reduced risk of cancer, particularly of the lung, colon, and stomach. Among premenopausal women, one study found that eating a lot of vegetables that include beta-carotene, folate, vitamin C, and fiber – like sweet potatoes
— reduced the risk of breast cancer by about half.