Avaliação do efeito de ácido linoléico conjugado proveniente de fonte natural e sintética sobre a composição corporal, sensibilidade à insulina e perfil de lipídeos séricos em ratos wistar

Abstract

The prevalence of overweight and obesity is increasing at an alarming rate. These conditions are a major risk for chronic diseases, including type 2 diabetes. In this context, conjugated linoleic acid (CLA) has attracted considerable attention, mainly due to its anti-obesity and anti-diabetic properties. The present study aimed to independently evaluate the effects of CLA from natural and synthetic sources on obesity risk, insulin sensibility and profile of serum lipids. Fifty male Wistar rats were assigned to the following dietary treatments (n=10/group), for 60 days: Normolipidic Control (CN): diet containing 4.0% soybean oil (SO); Control Butter (MC): diet containing 21.7% standard butter and 2.3% SO; and CLA enriched Butter (M-CLA): diet containing 21.7% cis-9, trans-11 CLA-enriched butter and 2.3% SO; Hyperlipidic Control (CH), diet containing 24.0% SO; Synthetic CLA (S-CLA), diet containing 1.5% of an isomeric CLA mixture (Luta-CLA 60) and 22.5% SO. M-CLA-fed rats had lower serum insulin levels at fasting than those fed with the MC diet, while the PPARγ protein levels in adipose tissue was increased in M-CLA-fed rats compared to MCfed rats. Furthermore, R-QUICK was lower in MC than in CN group, while no differences in R-QUICK were observed among CN and M-CLA. Serum HDL cholesterol and triacylglycerol levels were higher in M-CLA-fed rat. Thus, feeding rats on a high-fat diet containing butter naturally enriched in cis-9, trans-11 CLA prevented hyperinsulinemia, increased HDL cholesterol levels and caused hypertriglyceridemia. The S-CLA diet had no effect on dietary intake and body composition. S-CLA-fed rats had lower levels of PPARγ protein in adipose tissue, hyperinsulinemia, hyperglycemia, increased HOMA index and higher levels of serum HDL cholesterol. Therefore, caution should be taken before synthetic supplements containing cis-9, trans-11 and trans-10, cis-12 CLA are recommended.