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ARS Home » Plains Area » Grand Forks, North Dakota » Grand Forks Human Nutrition Research Center » Healthy Body Weight Research » Research » Publications at this Location » Publication #297009

Title: Effect of black tea intake on blood cholesterol concentrations in individuals with mild hypercholesterolemia: A diet-controlled randomized trial

Author
item Troup, Rasa - University Of Minnesota
item Hayes, Jennifer - Maryland Department Of Health And Mental Hygiene
item Raatz, Susan
item Thyagarajan, Bharat - University Of Minnesota
item Khaliq, Waseem - Johns Hopkins University School Of Medicine
item Jacobs, David - University Of Minnesota
item Key, Nigel - University Of North Carolina
item Morawski, Bozena - University Of Minnesota
item Kaiser, Daniel - Greatbatch, Inc
item Bank, Alan - United Heart And Vascular Clinic
item Gross, Myron - University Of Minnesota

Submitted to: Journal of the Academy of Nutrition and Dietetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/7/2014
Publication Date: 2/2/2015
Publication URL: http://handle.nal.usda.gov/10113/60292
Citation: Troup, R., Hayes, J.H., Raatz, S.K., Thyagarajan, B., Khaliq, W., Jacobs, D.R., Key, N.S., Morawski, B.M., Kaiser, D., Bank, A.J., Gross, M. 2015. Effect of black tea intake on blood cholesterol concentrations in individuals with mild hypercholesterolemia: A diet-controlled randomized trial. Journal of the Academy of Nutrition and Dietetics. 115(2) 264-271.

Interpretive Summary: Habitual intake of black tea has been associated with lower serum cholesterol concentrations in observational studies. However, clinical trials have had inconsistent results. We studied the effect of black tea on cholesterol concentrations in 57 (32 men and 25 women) mildly hypercholesterolemic under controlled conditions. Participants completed a 15-week, double blind, randomized crossover trial, during which they consumed a controlled low-flavonoid diet plus 5 cups of black tea or a tea-like placebo over two 4-week treatment periods. At the end of the trial period, no differences were statistically or clinically significant in cholesterol, HDL or LDL. Thus, the intake of 5 cups of black tea in combination with a low-flavonoid, typical American diet did not significantly alter the lipid profile of mildly hypercholesterolemic subjects.

Technical Abstract: Habitual intake of black tea has predominantly been associated with relatively lower serum cholesterol concentrations in observational studies. However, clinical trials evaluating the potential effects of black tea on serum cholesterol have had inconsistent results. These mixed results could be explained by several factors, in particular, uncontrolled confounding caused by lifestyle factors e.g. self-selected diets. The diet-controlled clinical trial presented herein provides estimates of the effect of black tea consumption on cholesterol concentrations in 57 (32 men and 25 women) mildly hypercholesterolemic individuals (total cholesterol concentrations between 4.9 and 6.7 mmol/L, 190 and 260 mg/dl), under tightly controlled conditions that minimize possible confounding. Participants completed a 15-week, double blind, randomized crossover trial, during which they consumed a controlled low-flavonoid diet plus 5 cups of black tea or a tea-like placebo over two 4-week treatment periods. The caffeinated placebo drink matched the color and taste of the tea, and did not contain any flavonoids. At the end of the trial period, differences in cholesterol concentrations between tea and placebo treatments were +1.64% for total cholesterol, -0.77% for low-density lipoprotein cholesterol (LDL-C), +1.40% for high-density lipoprotein cholesterol (HDL-C), +7.81% for triglycerides, -0.23% for LDL plus HDL cholesterol fraction, and -3.08% for LCL-C/HDL-C ratio. None of these differences were statistically or clinically significant. Thus, the intake of 5 cups of black tea in combination with a low-flavonoid, typical American diet did not significantly alter the lipid profile of mildly hypercholesterolemic subjects.