Only Specific Carotenoids Seem To Be Protective Against Colon Cancer
Numerous recent studies have demonstrated a protective effect of the carotenoid family against the development of certain types of cancer. The carotenoids, though, are a diverse group of compounds and studies have not yet definitively determined which members of this chemical family are most active in cancer protection. However, a recent study published in the February 2000 edition of the American Journal of Clinical Nutrition may shed some light on this subject.
This study, conducted at the Univeristy of Utah Medical School, examined 1993 patients with their first primary colon cancer to a population of 2410 control subjects without colon cancer. Subsequently, data were obtained from a specific dietary questionnaire administered to both groups of patients. These data were then assigned nutrient values and were analyzed on the basis of dietary intake of alpha-carotene, beta-carotene, lycopene, lutein, zeaxanthin and beta-cryptotoxanthin.
Results demonstrated that the only carotenoid associated with a statistically significant inverse relationship with colon cancer was lutein. Moreover, this inverse relationship was more prominent in patients diagnosed at a young age and in patients with tumors located proximally within the colon.
The principal dietary sources of lutein in patients analyzed in this study were carrots, celery, spinach, broccoli, lettuce and tomatoes. As a result, researchers concluded that increased dietary intake of these foods may be beneficial in reducing colon cancer risk. Although this is compelling observational evidence, the definitive answer will not be available until a good, randomized, placebo controlled trial is conducted. Until then, it is certainly not a bad idea to consume the high-carotene foods, as they are generally healthy in many other ways.