Vascular dilatory functions of ovo-lactovegetarians compared with omnivores

Vegetarians have lower blood pressure and lower cardiovascular mortality. V egetarian diets may have lower cardiovascular risks through positive influe nce on endothelium-dependent relaxation and related functions. The objectiv e,, of this study were to assess the differences of vascular dilatory funct ions between middle-aged vegetarians and sex and age-matched omnivores befo re they develop any clinical manifestations of atherosclerosis. Twenty heal thy vegetarians over the age of 50 and 20 healthy omnivores over the age of 50 were recruited for this study. Subjects with known risk factors for ath erosclerosis such as hypertension, diabetes, obesity, hypercholesteremia, c igarette smoking, family history of vascular diseases, or taking any regula r medication were excluded. Medical history, body weight, height, and durat ion of vegetarian diet were recorded. Baseline CBC, urinalysis and biochemi cal data such as fasting blood glucose, thyroid function, blood urea nitrog en, creatinine, serum electrolytes (sodium, potassium, chloride, calcium an d magnesium), lipid profiles [total cholesterol, triglycerides, high densit y lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol] were obtained after a 14 h fast. Blood pressures and heart rate were recor ded in supine position. Vascular dilatory functions, both flow-mediated (en dothelium-dependent) and nitroglycerin-induced (endothelium-independent), w ere evaluated by using a non-invasive ultrasonographic method. The results show that there were no significant differences in the baseline characteris tic between the vegetarians and the omnivores. There were also no significa nt differences in serum glucose, lipid profiles and thyroid function betwee n these two groups. However, vasodilatation responses (both flow-mediated a nd nitroglycerin-induced) were significantly better in the vegetarian group and the degree of vasodilatation appeared to be correlated with years on v egetarian diets. Our findings suggest that vegetarian diets, by themselves, have a direct beneficial effect on vascular endothelial and smooth muscle function and may help to account for the lower incidence of atherosclerosis and cardiovascular mortality. (C) 2001 Elsevier Science Ireland Ltd. All r ights reserved.