Submitted to: Journal of Nutrition
Publication Type: Proceedings
Publication Acceptance Date: 5/1/2008
Publication Date: 8/1/2008
Citation: Arab, L., Blumberg, J. 2008. Introduction to the Proceedings of the Fourth International Scientific Symposium on Tea and Human Health. Journal of Nutrition. 1526S-1528S.
Technical Abstract: This article provides an introduction to the Fourth International Scientific Symposium on Tea and Human Health. Recent observational studies support a reduction in risk of cardiovascular disease among tea drinkers but a critical evaluation of this work raises the challenge of conducting long-term randomized clinical trials on the effects of diet and lifestyle, and suggests the need for continued refinement of prospective cohort studies to improve the precision of the exposure assessment. Basic research and clinical trials support the hypothesis that tea polyphenols increase the availability of nitric oxide and its actions to affect vasodilation and related physiological functions. A systemic review of the evidence indicates a significantly lower risk of lung cancer associated with a high intake of tea, specifically among never smokers. Some of the confounding in studies of tea intake and cancer risk might be better understood through new investigations of susceptibility and repair genotypes in these cohorts. Preliminary evidence suggests a beneficial effect of tea on glucoregulatory control as determined via biomarkers such as fasting insulin and glucose, fructosamine, hemoglobin A1c, and homeostasis model assessment of insulin resistance. With observational evidence that tea consumption is inversely associated with the incidence of age-related dementias, in vitro and animal model investigations of tea polyphenols reveal they are bioavailable to the brain and can act via antioxidant, iron-chelation, signal transduction modulation, and other mechanisms to effect neuroprotective and/or neurorescue actions. Electroencephalographic recordings paired with cognitive task performance demonstrate that L-theanine from tea plays a role in attentional processing in synergy with caffeine. Dietary intake data from NHANES reveal that differences in total flavonoid intake among subgroups are principally due to the percent of tea consumers and their prevalence of tea consumption.