Effect of black tea drinking on blood lipids, blood pressure and aspects of bowel habit.
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.
Bingham
S A
SA
Medical Research Council, Dunn Clinical Nutrition Centre, Cambridge.
Vorster
H
H
Jerling
J C
JC
Magee
E
E
Mulligan
A
A
Runswick
S A
SA
Cummings
J H
JH
D010129:4-Aminobenzoic Acid / Q000652:urine; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000652:urine; D001794:Blood Pressure; D002318:Cardiovascular Diseases / Q000517:prevention & control; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D018592:Cross-Over Studies; D005243:Feces; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood*; D008297:Male; D008875:Middle Aged; D013662:Tea; D014280:Triglycerides / Q000097:blood
D015415:Biomarkers; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D008055:Lipids; D013662:Tea; D014280:Triglycerides; D002784:Cholesterol; D010129:4-Aminobenzoic Acid