DIETARY-COMPONENTS MODIFY THE ABILITY OF GARLIC TO SUPPRESS 7,12-DIMETHYLBENZ(A)ANTHCACENE-INDUCED MAMMARY DNA-ADDUCTS

Various dietary components were evaluated as factors influencing garli c's ability to depress rat mammary cell DNA adducts resulting from 7,1 2-dimethylbenz(a)anthracene (DMBA) treatment. Diets with or without ga rlic powder (20 g/kg) were provided for 2 wk before DMBA treatment (25 mg/kg body weight). Rats fed diets containing 36 g casein/100 g diet had 31% fewer (P < 0.05) mammary cell DNA adducts than those fed 12 g/ 100 g. Garlic supplementation significantly (P < 0.05) reduced DNA add ucts in rats fed either 12 or 36 g casein/100 g by 35 and 32%, respect ively. In the absence of dietary garlic, DNA adducts were 23% lower (P < 0.05) in rats provided a diet containing supplemental L-methionine at 0.9 9/100 g than at 0.3 g/100 g. However, adduct inhibition by garl ic supplementation was greater in rats fed the lower (P < 0.05) amount of methionine (54 vs. 26% inhibition). Adduct levels in rats fed diet s with 20 g corn oil/100 g were twice those occurring in rats fed 5 g/ 100 g (P < 0.05), regardless of adjustment for energy density. Garlic supplementation prevented the increase in DNA adducts caused by increa sing dietary corn oil. Combining dietary supplements of garlic, seleni te (0.5 mg/kg diet) and retinyl acetate (328 mg/kg diet) inhibited the occurrence of DNA adducts to a greater degree than when each was supp lied individually. These studies demonstrate that while dietary garlic can reduce DNA adduct formation in mammary tissue caused by DMBA, thi s protection is influenced by several dietary components.