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Spices are rich in natural antioxidants and have been shown to be potent inhibitors of lipid peroxidation during cooking of meat. Turmeric contains unique conjugated curcuminoids with strong antioxidant activity. Piperine, one of the main constituents of black pepper, is known to increase the bioavailability of curcuminoids in mouse and human studies when consumed with turmeric. We investigated whether adding black pepper to turmeric powder may further inhibit lipid peroxidation when added to meat patties prior to cooking. The addition of black pepper to turmeric significantly decreased the lipid peroxidation in hamburger meat. When investigating the antioxidant activity of the main chemical markers, we determined that piperine did not exhibit any antioxidant activity. Therefore, we conclude that other black pepper ingredients are responsible for the increased antioxidant activity of combining black pepper with turmeric powder.

Many laboratory-based studies have shown that soy can suppress breast cancer proliferation. However, given the recent controversy generated by animal experiments that soy may under certain conditions stimulate breast cancer growth, we decided to carry out a pilot clinical trial in order to elucidate any interaction(s) between short-term isoflavone supplement administration and breast cancer growth. After a core-needle biopsy established the diagnosis of breast cancer, 17 patients were administered soy isoflavone tablets for two weeks. This surgically based study provided the unique opportunity to make objective observations based on human breast cancer tissues and blood obtained prior to and after isoflavone supplement treatment in the same patient. Twenty-six historical control cases with similar characteristics to the experimental patients were selected for comparison. We observed that the apoptosis/mitosis ratios in isoflavone-treated cancer specimens were not significantly different from those of control untreated cancer specimens. Furthermore, there appeared to be a statistically nonsignificant trend towards cancer growth inhibition in the isoflavone treatment group, as manifested by higher apoptosis/mitosis ratios compared with those from the control untreated group. Ex vivo/in vitro assays using serum from breast cancer patients prior to and at the conclusion of soy treatment reveal no significant proliferative changes on both breast cancer cells and endothelial cells. We concluded that the effect of soy on breast cancer deserves further studies in larger clinical trials.

Our literature review of currently available data in the area of tea and cancer prevention demonstrated that there is more conclusive evidence for the chemopreventive effect of green tea compared with black tea. We suggest that this is due to a large variation of the flavanol content in tea, which is not taken into consideration in most of the epidemiological studies. It was the purpose of this study to determine the flavanol content of various teas and tea products and to correlate it with their radical scavenging activity. A modified oxygen radical absorbance capacity (ORAC) assay at pH 5.5 was utilized. The total flavavol content varied from 21.2 to 103.2 mg/g for regular teas and from 4.6 to 39.0 mg/g for decaffeinated teas. The ORAC value varied from 728 to 1686 trolox equivalents/g tea for regular teas and from 507 to 845 trolox equivalents/g for decaffeinated teas. There was a significant correlation of flavanol content to ORAC value (r = 0.79, P = 0.0001) for the teas and green tea extract. The large variation in flavanol content and ORAC value among various brands and types of tea provides critical information for investigators using tea in studies of nutrition and cancer prevention.

We investigated three hepatic cytochrome P‐450 isozymes and the aryl hydrocarbon (Ah) receptor in rats fed one of the following three diets for 15 months: a diet containing the AIN vitamin mixture (control), the control diet devoid of choline andfolate (CFD), or the CFD diet devoid of niacin (CFND). Hepatic tumors developed in all CFD‐and CFND‐fed rats. Western blot analyses of nontumor hepatic tissue showed that NADPH‐cytochrome P‐450 reductase (P‐450 reductase) increased significantly in the CFD and CFND groups compared with the control group. Hepatic cytochrome P‐450 2C11 (CYP2C11) was not detectable in the CFD and CFND groups compared with the control group. Ah receptor and cytochrome P‐450 1A1 (CYP1A1) were detected in higher amounts in livers of both deficient groups. CYP1A1 is an enzyme associated with bioactivation of exogenous genotoxins. To our knowledge, this is the first time it has been shown that CYP1A1 and the Ah receptor are induced by dietary deficiencies.

This study was undertaken to investigate the relationship between beta-carotene intake and biochemical indices of antioxidant status in the blood of nine premenopausal women ages 18 to 42.Nine healthy adult women were fed a low beta-carotene diet for 68 days. They were repleted with the same diet supplemented with beta-carotene (15 mg beta-carotene) for 28 days. During the last week of the study, they received an additional mixed carotenoid supplement. Indices of blood antioxidant status were measured on days 1, 29, 36, 43, 50, 64, 71, 92, and 99.We found significant increases of erythrocyte conjugated dienes between the 71st and 99th day of the study; increases of glutathione (GSH) peroxidase (GP) on day 43 and day 92 compared to a decrease on day 29; and decreases of GSH reductase throughout the treatment period. Erythrocyte catalase activities seemed to parallel GP activities. Erythrocyte oxidized glutathione (GSSG) levels were depressed both after beta-carotene depletion and repletion. beta-Carotene depletion/repletion had no effect on plasma vitamin E or GSH levels. Platelet GSH levels were depressed after beta-carotene depletion followed by elevated GSH levels after beta-carotene repletion.A diet low in beta-carotene and adequate in all other nutrients, including vitamin A, resulted in altered erythrocyte and platelet antioxidant indices; however, it had little impact on plasma GSH or vitamin E levels in young healthy women. Our results are consistent with the suggestion that carotenes may be important in the prevention of oxidative damage.