An investigation into the effects of green tea consumption on body composition and cardiovascular health in a healthy population

Background: Obesity is a preventable condition which contributes to the development of many diseases leading to morbidity and early mortality in the Scottish population. Scottish diets are low in fruit and vegetables and consequently polyphenols. Polyphenols are a form of antioxidant which have been linked to longer life and a lower incidence of disease. Waist to height ratio is a measure of obesity used to discern a patient's chance of developing obesity related disease. It has been shown that green tea can decrease waist circumference, thus improving waist to height ratio. Methods to increase the consumption of polyphenols in the Scottish population would be beneficial to reduce obesity, specifically visceral obesity and lower the incidence of obesity related disease. Objective: To investigate the effects of short-term consumption of green tea on body composition and cardiovascular health in a healthy population. Methods: 10 healthy subjects were recruited. Participants consumed three cups of caffeinated green tea daily (600mls) for three weeks. Anthropometric measures, body composition and blood pressure, dietary intake, thirst perception, physical activity, urine and bowel frequency were assessed prior to the intervention and after. Compliance was assessed through the completion of an end of intervention questionnaire. Prior to this, the test beverage was analysed to determine total antioxidant and polyphenol capacity. Results: No significant changes observed in body composition, anthropometric measures, blood pressure, thirst perception or urination frequency after three weeks (p>0.05). A significant increase in the reported frequency of bowel movements observed, increasing from 1.49 &plusmn 0.31 to 1.80 &plusmn 0.28 over three weeks. No significant differences observed from the dietary analysis and physical activity questions. Conclusion: The results suggest that regular green tea consumption has little effect on the body composition of healthy adults. A significant increase was seen in the frequency of bowel movements, suggesting that green tea may have a potential laxative effect. Further investigation is needed as such therapeutic interventions which increase polyphenol intake across Scottish populations could be used to improve health.msc_pubheaunpub2166_ethesesunpu