Effect of black tea drinking on blood lipids, blood pressure and aspects of bowel habit

• Published in: British journal of nutrition Vol. 78; no. 1; pp. 41 - 55
• Main Authors: Bingham, S. A., Vorster, H., Jerling, J. C., Magee, E., Mulligan, A., Runswick, S. A., Cummings, J. H.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01-07-1997
• Subjects: 4-Aminobenzoic Acid - urine; Adult; Aged; Biological and medical sciences; Biomarkers - urine; Blood lipids; Blood Pressure; Cardiovascular disease; Cardiovascular Diseases - prevention & control; Cholesterol - blood; Cholesterol, HDL - blood; Cholesterol, LDL - blood; Cross-Over Studies; Feces; Female; Human and Clinical Nutrition; Human physiology applied to population studies and life conditions. Human ecophysiology; Humans; Lipids - blood; Male; Medical sciences; Middle Aged; Nutritional survey. Food supply and nutritional requirement; Tea; Triglycerides - blood; Tea; Cardiovascular disease; Blood lipids; Consumption; Human; Lipemia; Food habit; Blood pressure; Cholesterol
• ISSN: 0007-1145; 1475-2662
• DOI: 10.1079/BJN19970117

Thirty-one men (47 (SD 14) years) and thirty-four women (35 (SD 13) years) took part in a 4-week randomized cross-over trial to compare the effect of six mugs of black tea daily v. placebo (water, caffeine, milk and sugar) on blood lipids, bowel habit and blood pressure, measured during a run-in period and at the end of weeks 2, 3 and 4 of the test periods. Compliance was established by adding a known amount of p–aminobenzoic acid (PABA) to selected tea bags, and then measuring its excretion in urine. Mean serum cholesterol values during run-in, placebo and on tea drinking were 5·67 (SD 1·05), 5·76 (SD 1·11) and 5·69 (SD 1·09)mmol/l (P=0·16). There were also no significant changes in diet, LDL-cholesterol, HDL-cholesterol, triacylglycerols, and blood pressure in the tea intervention period compared with placebo. Compared with placebo, stool consistency was softened with tea (P=0·04), and no other differences were found in bowel habit. Results were unchanged when fifteen ‘non-compliers’, whose PABA excretion indicated that fewer than six tea bags had been used, were excluded from the analysis, and when differences between run-in and tea periods were considered separately for those who were given tea first or second.