Carotenoids and human health

RESUMO

After the discovery of vitamin A in 1913, the yellow pigments of fruits and vegetables were soon implicated as compounds with similar nutritional affects B-carotene was shown to be converted intro vitamin A by moore in 1929, and chemical structures of both vitamin A and ß-carotone were determined two years later. Thus, the sole function of ß-carotene in human health was considered to be its conversion into vitamin A. On the basis of observational epidemiologic studies, conducted in the mid-1970s, however, carotenoids were implicated as protective agents, firts against lung cancer and then against a variety of other chronic diseases. Intervention trials employing ß-carotene, however, either have shown no preventive effect or indeed, in two cases, have echanced the incidence of lung cancer in middle-aged male smokers and asbestos workers. The possible protective action of carotenoids can be attributed to their properties as singlet oxygen quenchers and antioxidants, whereas their cancer-enchancing actions in lung can be ascribed to the prooxidant action of carotenoid free radicals in damaged cells. Apart from chronic disease, ß-carotene has shown significant therapeutic value in individuals suffering from photosensitivity disorders and provides temporary relief to persons afflicted with leukoplakia. Apart from a medical contex, the colored carotenoids found in many living organisms and in many foods delight both the eye and the palate. Thus, human health and the enjoyment of life are greatly benefited by the presence of these interesing pigments in nature, whether or not they ultimately prove to have more specific protective affects againts chronic diseases