ascorbic-acid and Respiratory-Tract-Neoplasms

We examined the association between whole-grain intake and incident upper aerodigestive tract cancer in a cohort of 34,651 postmenopausal, initially cancer-free women. We also studied established risk factors for upper aerodigestive cancers, including fruit and vegetable intake, smoking and alcohol intake. A mailed questionnaire at baseline in 1986 included a food-frequency questionnaire and assessment of other cancer risk factors. During the 14-year follow-up period, 169 women developed cancer of the upper aerodigestive tract. For all upper aerodigestive cancers together, significant inverse associations were observed for the highest compared to the lowest tertile of whole grains [relative risk (RR) = 0.53, 95% confidence interval (CI) 0.34-0.81] and yellow/orange vegetables (RR = 0.58, 95% CI 0.39-0.87). In addition, those in the highest compared to lowest tertile of fiber intake from whole grain were less likely to develop upper aerodigestive tract cancer (RR = 0.56, 95% CI 0.37-0.84); fiber intake from refined grain was not significantly associated with upper aerodigestive tract cancer. Findings were generally similar for oropharyngeal (n = 53), laryngeal (n = 21), nasopharyngeal/salivary (n = 18), esophageal (n = 21) and gastric (n = 56) cancers, though numbers of cases were too small for statistical testing within individual cancers. These findings confirm previous observations that high intake of fruits and vegetables and that intake of whole grains and the fiber derived from them may reduce risk of upper aerodigestive tract cancers.

Topics: Aged; Alcohol Drinking; Ascorbic Acid; Carotenoids; Diet; Diet Records; Dietary Fiber; Digestive System Neoplasms; Edible Grain; Energy Intake; Female; Fruit; Humans; Middle Aged; Postmenopause; Respiratory Tract Neoplasms; Risk Factors; Surveys and Questionnaires; Vegetables; Vitamin A; Vitamin E

We investigated whether the consumption of fruit and vegetables lowered cancer mortality in a cohort of 2112 Welsh men ages 45-69 years (The Caerphilly Study), which was followed-up for 13.8 years. At baseline (between 1979 and 1983), participants completed a 56-item food frequency questionnaire from which the consumption of fruit and vegetables was calculated. Relative risks (RR) were estimated with Cox proportional hazard analysis, with death from various types of cancer as a dependent variable, and fruit, vegetables, vitamin C, beta-carotene, dietary fiber, and potential confounders as independent variables. Mean consumption of vegetables and fruit at baseline was 118 g/day and 83 g/day, respectively. During follow-up 114 men died from cancer, including 51 men who died from respiratory tract cancer and 45 men who died from digestive tract cancer. Fruit consumption and the intake of dietary fiber were inversely related to respiratory tract cancer, but after adjustment for potential confounders including age, smoking, and social class, the association with fruit consumption became nonsignificant. Vegetable and fruit consumption was, independently from other risk factors, inversely related to mortality from cancer of the digestive tract (P for trend = 0.021), mainly due to an inverse association with fruit consumption (RR for the highest quartile versus the lowest was 0.3; 95% CI, 0.1-0.8). Vitamin C, beta-carotene, and dietary fiber were not significantly associated with cancers of the digestive tract. Vegetable and fruit consumption was also inversely related to all-cause cancer mortality, and the strongest association was observed for fruit consumption (RR in the highest versus lowest quartile was 0.5; 95% CI, 0.3-1.0). Consumption of vegetables and particularly the consumption of fruit could considerably lower the risk of dying from cancer in middle-aged men.

Topics: Age Factors; Antioxidants; Ascorbic Acid; beta Carotene; Cause of Death; Cohort Studies; Confounding Factors, Epidemiologic; Diet; Dietary Fiber; Digestive System Neoplasms; Feeding Behavior; Follow-Up Studies; Fruit; Humans; Longitudinal Studies; Male; Middle Aged; Neoplasms; Proportional Hazards Models; Respiratory Tract Neoplasms; Risk Factors; Smoking; Social Class; Vegetables; Wales

A large dietary supplement (1%) of vitamin C was given to male Syrian hamsters exposed to cigarette smoke and receiving 12 weekly subcutaneous injections of diethylnitrosamine (DEN) to determine whether or not high doses of vitamin C can prevent the development of tumors by DEN in the respiratory tract. Treatment with DEN developed various types of tumors in the respiratory tract of hamsters and cigarette smoke exposure potentiated the tumor development in the nasal cavity, larynx and trachea. In comparison with the smoke-exposed hamsters treated with DEN, the vitamin C-supplemented hamsters showed significantly lower incidence of nasal cavity tumors and exhibited significantly earlier appearance of tracheal tumors. In addition, the laryngeal tumors also tended to develop earlier in the vitamin C-supplemented hamsters. The results indicate that high doses of vitamin C may inhibit tumor induction by DEN and exposure to cigarette smoke in the nasal cavity, but the development of laryngeal and tracheal tumors appeared to be accelerated by vitamin C supplement.

Topics: Animals; Ascorbic Acid; Cricetinae; Diethylnitrosamine; Male; Mesocricetus; Mouth Mucosa; Nicotiana; Nitrosamines; Plants, Toxic; Respiratory Tract Neoplasms; Smoke