Apolipoprotein E genotype modulates the effect of black tea drinking on blood lipids and blood coagulation factors: a pilot study

Abstract

Apolipoprotein E (ApoE) genotype was determined in sixty-five subjects who had taken part in a 4-week randomized crossover trial to compare the effect of six mugs of black tea per dayv. placebo on blood lipids and blood coagulation factors. Four ApoE genotype variants (seven E2/E3, forty-five E3/E3, twelve E3/E4 and one E4/E4) were found. ApoE allele frequency was within the range typical for Caucasian populations (ApoE-E2 5·4 %; ApoE-E3 83·8 %; ApoE-E4 10·8 %). Individuals bearing at least one E4 allele had substantially higher levels of serum total cholesterol, LDL cholesterol and triacylglycerols. Mean plasminogen activator inhibitor (PAI-1) activity was higher in ApoE-E4 allele-bearing individuals (E3/E4 + E4/E4, 11·89 (SE 1·27) U/ml; E3/E3, 9·19 (SE 0·80) U/ml; E2/E3, 7·21 (SE 1·04) U/ml,Pvalues of E4-group v. E3 and E2 being respectively 0·093 and 0·030). These unexpected findings imply that elevated PAI-1 activity may be a hitherto unrecognized additional factor involved in the increased cardiovascular disease risk associated with apoE-E4 allele. The interactions between tea drinking and genotype were also examined. In the E3/E3 homozygotes, HDL-cholesterol was significantly reduced in the tea period (mean placebo 1·54 mmol/lv. mean tea 1·50 mmol/l,P= 0·027). In the E2/E3 group, triacylglycerol concentration was significantly reduced (mean placebo 1·18 mmol/lv. mean tea 1·09 mmol/l,P= 0·039). Tea also caused a significant decrease of PAI-1 activity in the subjects with E2/E3 genotype (mean placebo 7·21 U/mlv. mean tea 5.88 U/ml,P= 0·007). In the other two genotype groups, there was no significant effect of tea. The results indicate that tea drinking has a beneficial effect on some cardiovascular disease risk-associated factors, especially in E2 allele-bearing individuals. Dietary intervention may be particularly effective in population groups with certain genetic characteristics.