------------ 出典 American Journal of Clinical Nutrition, Vol. 85, No. 2, 504-510, February 2007 http://www.ajcn.org/cgi/content/abstract/85/2/504
Watercress supplementation in diet reduces lymphocyte DNA damage and alters blood antioxidant status in healthy adults1,2,3 Chris IR Gill, Sumanto Haldar, Lindsay A Boyd, Richard Bennett, Joy Whiteford, Michelle Butler, Jenny R Pearson, Ian Bradbury and Ian R Rowland 1 From the Northern Ireland Centre for Food and Health, Centre for Molecular Biosciences, University of Ulster, Coleraine, N Ireland, United Kingdom (CIRG, SH, LAB, JW, MB, JRP, IB, and IRR), and the Institute of Food Research, Norwich Research Park, Colney, Norwich, United Kingdom (RB)
Background: Cruciferous vegetable (CV) consumption is associated with a reduced risk of several cancers in epidemiologic studies.
Objective: The aim of this study was to determine the effects of watercress (a CV) supplementation on biomarkers related to cancer risk in healthy adults.
Design: A single-blind, randomized, crossover study was conducted in 30 men and 30 women (30 smokers and 30 nonsmokers) with a mean age of 33 y (range: 19–55 y). The subjects were fed 85 g raw watercress daily for 8 wk in addition to their habitual diet. The effect of supplementation was measured on a range of endpoints, including DNA damage in lymphocytes (with the comet assay), activity of detoxifying enzymes (glutathione peroxidase and superoxide dismutase) in erythrocytes, plasma antioxidants (retinol, ascorbic acid, -tocopherol, lutein, and ß-carotene), plasma total antioxidant status with the use of the ferric reducing ability of plasma assay, and plasma lipid profile.
Results: Watercress supplementation (active compared with control phase) was associated with reductions in basal DNA damage (by 17%; P = 0.03), in basal plus oxidative purine DNA damage (by 23.9%; P = 0.002), and in basal DNA damage in response to ex vivo hydrogen peroxide challenge (by 9.4%; P = 0.07). Beneficial changes seen after watercress intervention were greater and more significant in smokers than in nonsmokers. Plasma lutein and ß-carotene increased significantly by 100% and 33% (P < 0.001), respectively, after watercress supplementation.
Conclusion: The results support the theory that consumption of watercress can be linked to a reduced risk of cancer via decreased damage to DNA and possible modulation of antioxidant status by increasing carotenoid concentrations.
Key Words: Watercress • cruciferous vegetables • DNA damage • antioxidants • humans • cancer biomarkers
--------------- 出典 American Journal of Clinical Nutrition, Vol. 85, No. 2, 497-503, February 2007 http://www.ajcn.org/cgi/content/abstract/85/2/497
Vitamin A, retinol, and carotenoids and the risk of gastric cancer: a prospective cohort study1,2,3 Susanna C Larsson, Leif Bergkvist, Ingmar Näslund, Jörgen Rutegård and Alicja Wolk 1 From the Division of Nutritional Epidemiology, The National Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden (SCL and AW); the Department of Surgery and Centre for Clinical Research, Central Hospital, Västerås, Sweden (LB); the Department of Surgery, Örebro University Hospital, Örebro, Sweden (IN); and the Department of Surgery, Section of Colorectal Surgery, University Hospital, Örebro, Sweden (JR)
Background: Vitamin A may influence gastric carcinogenesis through its essential role in controlling cell proliferation and differentiation. However, epidemiologic studies of vitamin A, retinol (preformed vitamin A), and provitamin A carotenoids in relation to the risk of gastric cancer have documented inconsistent results.
Objective: The objective of the study was to examine the associations between intakes of vitamin A, retinol, and specific carotenoids and the risk of gastric cancer in a prospective population-based cohort study of Swedish adults.
Design: The study cohort consisted of 82 002 Swedish adults aged 45–83 y who had completed a food-frequency questionnaire in 1997. The participants were followed through June 2005.
Results: During a mean 7.2-y follow-up, 139 incident cases of gastric cancer were diagnosed. High intakes of vitamin A and retinol from foods only (dietary intake) and from foods and supplements combined (total intake) and of dietary -carotene and ß-carotene were associated with a lower risk of gastric cancer. The multivariate relative risks for the highest versus lowest quartiles of intake were 0.53 (95% CI: 0.32, 0.89; P for trend = 0.02) for total vitamin A, 0.56 (95% CI: 0.33, 0.95; P for trend = 0.05) for total retinol, 0.50 (95% CI: 0.30, 0.83; P for trend = 0.03) for -carotene, and 0.55 (95% CI: 0.32, 0.94; P for trend = 0.07) for ß-carotene. No significant associations were found for ß-cryptoxanthin, lutein and zeaxanthin, or lycopene intake.
Conclusion: High intakes of vitamin A, retinol, and provitamin A carotenoids may reduce the risk of gastric cancer.
Key Words: Carotenoids • gastric cancer • prospective cohort studies • retinol • vitamin A