Studies have not established the effect of oranges on breast cancer
Oranges contain substances that have been shown to be antiproliferative and antioxidant. Studies have also found that oranges inhibit breast cancer in mice and have proapoptic effects on breast cancer cells.
Breast cancer-related effects of eating oranges
Oranges and orange peels contain polymethoxyflavones (a type of flavonoid) that have been shown to have antiproliferative and proapoptotic effects on breast cancer cells. Dietary flavonoids are also believed to aid the body's antioxidant defenses against free radicals (the major antioxidant component of orange juice is vitamin C). Oranges also contain hesperetin and limonoids, which appear to possess substantial anticancer activity. Orange juice has been shown to reduce the extent of DNA damage caused by certain mutagens. Although initial studies concerning the chemopreventive properties of oranges are very promising, they have been conducted primarily with in vitro cell culture and animal models. However, one Korean study found an association between orange juice consumption and lower incidence of breast cancer.