Effects of dietary lipids on renin-angiotensin system (RAS) and hypertension: A systemic review for basic studies

Abstract

Background: The Renin-Angiotensin System (RAS) has been proposed to mediate obesity-related hypertension. However, the contribution of a high-fat diet (HFD) directly to RAS and hypertension remains to be investigated. The aim of this study was to systematically review the effects of dietary lipids, either administrated as lipid-based diets or as supplements on RAS and hypertension in basic studies. Methods: Literature search was performed using Embase, Medline, Scopus, Web of Science, PubMed and google scholar database for preclinical studies on the effect of lipid-base diets/supplements on RAS and hypertension. The articles had to be published between 1960 and 2014 written in English. Results: From the initial 3392 hits, 31 studies were included in the review. HFD (45% high saturated fat) increased systolic blood pressure (SBP) and increased both systemic and local RAS activation in hypertensive rats while the effect of a HFD in normotensive models (rats and mice) was less clear. Conjugated linoleic acid and γ-linolenic acid-rich oils reduced SBP in hypertensive, normotensive and obese rats; the former also decreased adipose RAS activation in diabetic and hypertensive obese rats. In contrast, repeatedly heated oils increased SBP and plasma angiotensin converting enzyme activity after 6-month supplementation in normotensive rats. Conclusion: Dietary lipids significantly affected SBP and regulated both systemic and local RAS activation, which might underlie the involvement of lipid-rich diets in hypertension. However, the data are still limited.