Scientific Presentation

THE HEBREW UNIVERSITY OF JERUSALEMRobert H. Smith Faculty of Agriculture, Food and Environment The Division for External StudiesThe Effect of Black Tea on Blood Cholesterol Lecturer: Dr. Natalie Avital-Cohen Presented by: Yared Hailu 05/01/2016

INTRODUCTIONBlack tea, which is the most commonly consumed beverage in the world after water, is rich inpolyphenolic flavonoids that possess; * anti-oxidant * anti-mutagenic * anti-inflammatory and * anti-allergenic properties  These flavonoids believed be hypocholesterolemic agentMany research done at different time  Seven observational studies reported  black tea consumption is correlated with lower Total Cholesterol in humans  Another six studies found  no association between tea drinking and total cholesterol.• Problem• The results evaluating the effect of black tea on serum cholesterol have been inconsistent because of uncontrolled confounding caused by lifestyle factors (eg, diet).

OBJECTIVE• Examining the effect of black tea beverage intake on serum lipid concentrations using a standardized tea treatment in completely controlled cofounding variables.

MATERIAL and MEHODS• Participants• Between April 2002 and April 2004, 1,500 individuals were recruited via television, radio, and print advertisements in Minneapolis and St Paul, MN. TC= Total Cholesterol, HDL-C= high-density lipoprotein cholesterol, TG= triglyceride Source: Rosa Troup, Effect of black tea intake on blood cholesterol concentrations

STUDY DESIGN and INTERVETION Double-blind, randomized crossover study design used  Key conditions were tightly controlled to minimize possible confounding  Research team members, participants and analysts remained blinded until the final analysis The intervention consisted of 5 cups per day of black tea or tea-like placebo for 8 weeks Participants were to consume the entire controlled low-flavonoid diet and daily water-soluble vitamin supplements The products were coded with randomly generated numbers that linked their content to the treatment assignment in a blinded fashion.Table 1. Ingredient description of black tea treatment and placebo used in a study to examine the efficacy of 5 cups per day of black tea on serum cholesterol concentrationsIngredient (g/pouch) Black tea PlaceboFlavonoid 3.9 0Malto base 3.5 3.5Aspartame 0.08 0.07Malic acid 0.09 0.09Caffeine 0.048 0.048Lemon or apple fruit flavor 0.084 0.084Source: Rosa Troup, Effect of black tea intake on blood cholesterol concentrations

Time 57 participant were met all entry criteria Participants Randomized Initiated of consumption low flavonoid diet prepared by study team. Baseline data for weight, blood pressure, and serum lipids Blood draw on day 6 at a.m and p.m 57 participants were block-randomized by sex to initial consumption of either 5 cups per day of black tea or placebo. Why 5 cups? Because;  The selection of 5 cups of tea per day was based on its therapeutic potential and that, if therapeutic, this volume could be reasonably incorporated into a patient’s daily routine Morning measurement at Day 1:a.m of the first tea/placebo Days 7, 14, 21, 28 a.m and Day 21:p.m Blood was collected in 2.5ml serum separation tubes, and the resulting serum sample was analyzed for TC, HDL-C and TG. 28 days, why?  Significant effects on plasma cholesterol concentration, platelet aggregation, brachial artery reactivity, and oxidative damage, given response times, could occur within a 1-month period of tea intake, hence the 28-day treatment period. Wash-out period, why? The washout period duration allowed  for removing of substances from the body OR  re-equilibration of parent and metabolite concentrations or Day 6: a.m and p.m Day 1: a.m Days 7, 14,21,28:a.m and Day 21:p.m Source: Rosa Troup, Effect of black tea intake on blood cholesterol concentrations

RESULTS and DISCUSSION Table 2. Baseline characteristics by primary treatment assignment of participants in a study to examine the effect of 5 cups per day of black tea on serum cholesterol concentrations (n¼57) dHDL-C=high-density lipoprotein cholesterol. gLDL-C= low-density lipoprotein cholesterol hVLDL-C=very low-density lipoprotein cholesterol. iTG¼triglyceride. kAST=Aspartate aminotransferase. *P<0.05Source: Rosa Troup, Effect of black tea intake on blood cholesterol concentrations

Conti……. Results were considered statistically significant at an a level of .05. Mean baseline characteristic values was analyzed using one-way analysis of variance to ensure that important covariates were equally distributed across randomization groups. A paired t-test was used to evaluate treatment carryover effects between baseline and day-1 lipid concentrations. Differences in lipid concentrations across treatment groups were calculated using the day-28 serum measurement taken at the end of each treatment period. The effect of tea consumption on each lipid concentration was analyzed as a repeated measures regression using the PROC MIXED pro-cedure in SAS software Analyses were adjusted for treatment period via the inclusion of a period covariate. Treatment-period interactions were also tested.

Conti…….Source: Rosa Troup, Effect of black tea intake on blood cholesterol concentrations

CONCLUSION No results were statistically or clinically significant The intake of 5 cups of black tea per day did not alter the lipid profile of borderline hypercholesterolemic subjects significantly.• Additional research is needed to explore other tea- consumption related mechanisms of potential importance in cardiovascular disease etiology

LIMITATION Inability to test for dose response relationships between tea and lipid concentrations Inability to evaluate the effects of tea consumption against different background diets.

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