Fourth International Conference on Prevention of Human Cancer:
Nutrition and Chemoprevention Controversies.
June 3-6, 1992, Tucson, AZ, A16, 1992. (1992)
Retinoids or carotenoids: can I have another choice? (Meeting abstract)
Dartmouth Medical Sch. Hanover. NH
Both retinoids and carotenoids have been shown to decrease cancer occurrence in selected animal models of carcinogenesis, but the retinoids appear to have more potent activity against a wider variety of tumors. Future use of retinoids for cancer prevention is likely to be limited, however, because of their toxic effects on bone and skin (among other organs). In contrast to retinoids, carotenoids seem to be free of important toxicity, and this fact makes them much more promising for use in the general adult population. The problem with carotenoids is that there is only circumstantial evidence for their having a cancer-preventive effect in humans, since the data come almost entirely from epidemiological studies of diet and serum. The lower risk of cancer observed in these studies among people who eat more carotenoid-rich fruits and vegetables (and who consequently have higher blood levels of carotenoids) could be due to substances other than carotenoids in these foods, or even to nondietary factors (such as not smoking).... Pressed to choose between retinoids, with their clear toxicity and uncertain efficacy, and carotenoids, which thus far appear to be as ineffective as they are safe, a person might reasonably ask for a third option. For now, the most rational and prudent choice would be to consume a diet high in fruits and vegetables and not to take either supplemental carotenoids or retinoids until there is better evidence of their efficacy and safety.
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