Effects of tea on plasma lipids

ABSTRACT

To find out the possible association between levels of cholesterol and tea consumption in the general population known to consume large amount of tea in a day. The study was conducted in the periphery areas of Multan district from 1990 to 1993. The data was obtained on 550 [300 [20-40 years] male subjects and 250 older age group [41-65 years] male subjects. Information collected on each subject included detailed demographic data, personal habits including smoking, frequency of participation in leisure time, physical activity, a detailed history of daily tea intake and weekly egg consumption. They were also questioned about medication and special dietary intake [such a low salt, low cholesterol, low saturated fat or weight reducing diets].Height and weight were measured. Relative weight was defined by Quetelet index [weight in g] / [height in cm2]. Blood samples, obtained by venepuncture, were drawn in vacuum tubes without additive, with the subject su pine and after fasting for between 9 and 10h. Serum was separated from the whole blood within 2h of being drawn. Sera separated from the whole blood were frozen at -70°C until analyzed. Total cholesterol [TC] was estimated by enzymes assay [Boehringer Knoll kit, Mannheim, FRG]. HDL-cholesterol [HDL-C] was measured after precipitation with heparin and manganese chloride. Triglycerides were estimated by enzyme assay [Boehringer Knoll kit, Mannheim, FRG]. Serum low density lipoproteins cholesterol [LDL-C] was estimated. Quality control methods were employed throughout all the analyses. The data presented here are for the those subjects who were not an any special diet, medication or suffering from any endocrine disease. The association between tea intake and other dietary variables were tested using the Chi square test. An analysis of covariance was used to examine the association between tea intake and lipid levels. Separate analyses of covariance were carried out in each of two age groups 20-40 years and 41- 65 years. A negative association between drinking of tea and TC levels were found in both age groups studied. The difference was found to be entirely due to a difference in LDL-cholesterol levels. The negative association between tea consumption and TC levels was significant in heavy drinkers of tea with or without smoking