Antioxidants vs Carotenoids:  Inhibitors or Promoters of Experimental Colorectal Cancers

Thomas A. Colacchio, MD; Vincent A. Memoli, MD; Laurie Hildebrandt
Arch Surg. 1989;124(2):217-221. doi:10.1001/archsurg.1989.01410020091014.
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• The organospecific, 1,2-dimethylhydrazine-induced murine tumor model was used to test the effects on tumor formation of the following dietary supplements: (1) ascorbic acid, 7% per weight; (2) alpha tocopherol, 1% per weight; (3) beta carotene, 1% per weight; and (4) canthazanthin, 1% per weight. Following a four-week dietary acclimation, a 16-week 1,2-dimethylhydrazine induction, and a four-week hiatus, the animals were killed, underwent autopsies, and tumor formation was recorded. The antioxidant supplements of ascorbic acid and alpha tocopherol resulted in a significant decrease in tumor formation when compared with control groups. In contrast, the beta carotene group showed no difference in tumor formation, and canthazanthin, a non-provitamin A carotenoid, resulted in an increase in tumor formation when compared with controls. In addition, the K-gel powder control diet (a carrier medium for alpha tocopherol acetate) had a significantly higher rate of tumor formation than the regular chow and placebo beadlet control diets. In sum, ascorbic acid and alpha tocopherol demonstrated a clear chemopreventive effect, whereas beta carotene had no effect, and canthazanthin appeared to function as a promoter in this organospecific tumor model.

(Arch Surg 1989;124:217-221)


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