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Author Russell, Robert M.
Source CiteSeerX
Content type Text
File Format PDF
Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science
Subject Keyword Case Study ♦ High Dose Supplement Use ♦ Beta-carotene Supplement ♦ High Dose Beta-carotene Supplement ♦ Lung Tissue ♦ Lung Cancer ♦ Contradictory Evidence ♦ C-fos Gene ♦ Tumor Suppressor Gene ♦ Retinoic Acid ♦ Cell Proliferation ♦ Current Smoker ♦ Elevated Expression ♦ Asbestos-exposed Worker ♦ 20-30 Mg ♦ Animal Model ♦ Rar Beta Gene Expression ♦ Serum Beta-carotene ♦ Human Intervention Study ♦ Large Body ♦ Carotene Supplement ♦ Squamous Metaplasia ♦ Second Study ♦ Observational Epidemiologic Study ♦ United State ♦ Male Physician ♦ Proliferative Response
Abstract A large body of observational epidemiologic studies has demonstrated that individuals who eat more fruits and vegetables rich in carotenoids and/or who have higher levels of serum beta-carotene have a lower risk of cancer, particularly lung cancer. However, contradictory evidence has arisen from human intervention studies using beta-carotene supplements (20-30 mg per day). An increase in risk of lung cancer among smokers who took beta-carotene supplements was reported in two trials conducted among smokers and/or asbestos-exposed workers, but not among male physicians in the United States (only 11 % of whom were current smokers). We have used an animal model to study whether β-carotene supplements predispose to lung carcinogenesis and the mechanisms that are involved. When ferrets were given high dose beta-carotene supplements and exposed to cigarette smoke for 6 months, a proliferative response in lung tissue and squamous metaplasia were observed. These animals also had statistically significant lower concentrations of retinoic acid in lung tissues as well as reductions in RAR beta gene expression (a tumor suppressor gene) as compared to controls. Finally, in ferrets given high dose beta-carotene supplements and exposed to smoke, there also were elevated expressions of C-jun and C-fos genes, which are involved in cell proliferation. In a second study where ferrets
Educational Role Student ♦ Teacher
Age Range above 22 year
Educational Use Research
Education Level UG and PG ♦ Career/Technical Study
Publisher Institution Tufts Unive Sity