Research Accomplishment Reports 2010

Antioxidant Nutrients, Reactive Oxygen Species and Oxidative Stress

C.K. Chow
Department of Human Environmental Sciences

 

Non-Technical Summary

Antioxidant inadequacy and environmental agents cause oxidative stress, which contribute to the pathogenesis of many degenerative diseases. This project examines if antioxidant nutrients, individually or in combination, protect against oxidative damage resulting from environmental stress.

2010 Project Description

Nitrites, important antimicrobial and flavoring/coloring agents widely-used in meat products, may cause fatal methemoglobinemia and other adversary effects. However, the mechanism by which nitrite exerts its adversary effect is not yet clear.

Sprague-Dawley rats fed a nutrient adequate diet are rather resistant to the adversary effect of 2000 ppm sodium nitrite in drinking water. However, when nitrite-treated rats were fed a vitamin E-deficient and low selenium diet, over 40% were dead or moribund in nine weeks, while no mortality resulted from those supplemented with either vitamin E or selenium. All nitrite-treated rats fed the vitamin E-deficient and low selenium diet developed massive liver necrosis, mild to markedly muscular degeneration, tubular nephrosis and eosinophilic enteritis. No pathological lesions were observed in nitrite-treated rats supplemented with either selenium or vitamin E.

Studies have shown that nitrites are both oxidation product and precursor of nitric oxide (NO.), which may react with superoxide to form highly reactive peroxynitrite (ONOO-). Also, vitamin E may mediate the generation and availability of superoxide, and seleno-proteins may reduce ONOO-. Results obtained have been reported in the professional meeting and in the process of being published

2010 Impact

Findings suggest that increased formation of ONOO- in nitrite-treated rats receiving low vitamin E and selenium may lead to tissue lesions and subsequent mortality, and that vitamin E and selenium may protect against the adverse effects of nitrites by reducing reactive ONOO-. Information obtained from the study supports the hypothesis that nutritional status of affected subjects may alter their cellular susceptibility to environmental agents.

2010 Publications

Chow, C.K. Association of fruit and vegetables consumption and colorectal cancer risk: a role of cigarette smoking. Am. J. Clin. Nutr. 91: 238-238, 2010.

Chow, C.K. Dietary fat intake and subsequent weight change in adults. Am. J. Clin. Nutr. 92: 463-464, 2010.

Chow, C.K. Dietary intake of menaquinones and risk of cancer incidence and mortality. Am. J. Clin. Nutr. 92: 1533-1534, 2010.

Chow, C.K. and C.B. Hong. Effect of dietary vitamin E and selenium on nitrite toxicity. Proc. 3rd Int. Conf. Sci. Tech., Penang, in press, 2010.