Early epidemiological studies and limited measurements of blood retinol seemed to support an inverse relationship between vitamin A intake and cancer, and/or blood retinol and cancer, and/or P-carotene intake and cancer in humans (reviewed in References 32 and 33). The current body of knowledge, however, does not support such conclusions. First, as pointed out above, serum retinol is a poor indicator of vitamin A status and of vitamin A and carotenoid intake. Second, retinol in serum samples can be adversely affected easily by storage and handling, producing misleading results. Third, many of the epidemiological studies concluding that an inverse relationship existed between vitamin A and cancer, based their conclusions on an inverse relationship between colored vegetable intake and cancer. As mentioned above, color is not a reliable indicator of the vitamin A value of vegetables; in addition, each type of vegetable can contain up to 10,000 different phytochemicals. Certain of these phytochemicals seem to have potent anticancer activity. Lately, a focused study on bladder cancer (the Netherlands Cohort Study of >120,000 persons >6 years) has further uncoupled supplementation with dietary vitamin A and carotenoids with reducing cancer risk.34
Was this article helpful?
Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.