Carotenoids constitute a ubiquitous group of
isoprenoid pigments. They are very efficient physical quenchers of
singlet oxygen and scavengers of other
reactive oxygen species.
Carotenoids can also act as chemical quenchers undergoing irreversible oxygenation. The molecular mechanisms underlying these reactions are still not fully understood, especially in the context of the anti- and
pro-oxidant activity of
carotenoids, which, although not synthesized by humans and animals, are also present in their blood and tissues, contributing to a number of biochemical processes. The
antioxidant potential of
carotenoids is of particular significance to human health, due to the fact that losing
antioxidant-
reactive oxygen species balance results in "oxidative stress", a critical factor of the pathogenic processes of various chronic disorders. Data coming from epidemiological studies and clinical trials strongly support the observation that adequate
carotenoid supplementation may significantly reduce the risk of several disorders mediated by
reactive oxygen species. Here, we would like to highlight the beneficial (protective) effects of dietary
carotenoid intake in exemplary widespread modern civilization diseases, i.e.,
cancer, cardiovascular or
photosensitivity disorders, in the context of
carotenoids' unique antioxidative properties.