Dietary Carotenoids For Reduction Of Cancer Risk

Abstract The consumption of fruits and vegetables is related to reduced incidence of cancer risk, such relation is supported by retrospective and prospective epidemiological studies. In particular, carotenoids and other plant micronutrients have been studied as cancer-preventive agents. Carotenoids are tetraterpenoids formed by multiple conjugated double bonds that have an important role as natural antioxidant pigments (e.g., red, orange, and yellow color) and photoprotectors. Several studies reported the relation of carotenoids (lycopene, β-carotene, α-carotene, lycopene, lutein, zeaxanthin, β-cryptoxanthin, fucoxanthin, canthaxanthin, and astaxanthin) found in food over reduction of cancer risk, which figure among the main death causes in 2012, accounting for 8.2 million registered cases. The suggested action mechanisms of carotenoids anticancer activity are related to direct inhibition of specific cellular processes (e.g., growth factor signaling) and cell cycle progression, although carotenoids can also regulate several transcription systems. The structure activity relationship plays an important role on cancer prevention, wherein lycopene displays a higher effect on modulation of electrophile/antioxidant response element than other carotenoids. In addition, oxidation products of lycopene and a few other carotenoids generate compounds with potential to promote apoptosis on cancer cells. Although the carotenoid anticancer activity showed promising results in vitro, in vivo, and epidemiological studies, some ambiguous data in literature do not indicate association between the consumption of plant food–rich diet and reduction on cancer risk, especially in animal tests.