The aim of the present study was to investigate the anti-hypertensive and angiotensin-converting enzyme (ACE) inhibition effects of soyabean protein hydrolysate in spontaneously hypertensive rats (SHR). Soyabean protein hydrolysate was prepared by peptic hydrolysis and was added into the feed of SHR (0 % for the S0 group, 0·5 % for the S1 group, and 1 % for the S2 group) for 12 weeks. Systolic blood pressure and mean blood pressure of the S1 (164·3 (sem 4·7); 128·0 (sem 5·0) mmHg) and S2 (156·8 (sem 1·6); 120·8 (sem 3·4) mmHg) groups were significantly lower than those of the S0 group (199·4 (sem 5·2); 158·3 (sem 7·0) mmHg) at the end of the study. In the analysis of ACE activity, plasma and heart ACE activities of the S1 and S2 groups were significantly lower than those of the S0 group, and there were no significant differences in aorta, kidney, and lung ACE activities among all SHR. Soyabean protein hydrolysate had no significant effect on plasma lipids, electrolytes, or on left ventricular wall or aorta wall thickness. The results suggest that the long-term administration of soyabean protein hydrolysate might retard the development of hypertension in SHR by its inhibitory effect on ACEin vivo.

Green tea catechin has been proposed to have an anti-obesity effect. The aim of the present study was to investigate whether the effect of catechin-rich green tea in combination with inulin affects body weight and fat mass in obese and overweight adults. A total of thirty subjects were divided into a control group and an experimental group who received 650 ml tea or catechin-rich green tea plus inulin. A reduction of body weight ( − 1·29 (sem 0·35) kg) and fat mass (0·82 (sem 0·27) kg) in the experimental group was found after 6 weeks, and no adverse effects were observed. After refraining from consumption for 2 weeks, sustained effects on body weight and fat mass were observed. We conclude that continuous intake of catechin-rich green tea in combination with inulin for at least 3 weeks may be beneficial for weight management.

Clinical trials have shown that soya protein reduces the concentrations of some atherogenic lipids in subjects with normal renal function. The present study examined the effects of soya protein on serum lipid concentrations and lipoprotein metabolism in patients on hypercholesterolaemic haemodialysis. Twenty-six hypercholesterolaemic (total cholesterol ≥6·21mmol/l) patients on haemodialysis were studied in a randomized, double-blind, placebo-controlled clinical trial. After a 4-week run-in phase, the subjects were randomly assigned to two groups. Isolated soya protein or milk protein 30g was consumed daily as a beverage at breakfast or post-dialysis for 12 weeks. Soya protein substitution resulted in significant reductions in total cholesterol (17·2 (sd8·9)%), LDL-cholesterol (15·3 (sd12·5)), apo B (14·6 (sd12·1)%) and insulin (23·8 (sd18·7)%) concentrations. There were no significant changes in HDL-cholesterol or apo A-I. These results indicate that replacing part of the daily protein intake with soya protein has a beneficial effect on atherogenic lipids and favourably affects lipoprotein metabolism in hypercholesterolaemic patients undergoing haemodialysis.