Diet and weight loss: Their effect on norepinephrine renin and aldosterone levels

The effect of low caloric diet on blood pressure, catecholamines, plasma renin activity (PRA) and aldosterone was examined in 22 obese subjects (19 hypertensives and 3 borderline hypertensives). A significant decrease in blood pressure (P < 0.05) was observed in all patients after 10 days on the diet. Twenty subjects showed a significant decrease in norepinephrine (NE) levels (P < 0.05) and two patients showed an extreme increase in NE level. On reexamination six months later these two patients presented with high NE levels and prediet blood pressure levels despite having lost 15 and 18 kg respectively. The study group showed a significant decrease in mean PRA (P < 0.05). A correlation was observed between changes in NE levels and PRA (r = 0.42, P < 0.05) and between changes in PRA and aldosterone (r = 0.54, P < 0.05). The reduction in blood pressure associated with caloric restriction in these obese patients may be a result of reduced sympathetic nervous system activity.