A diet high in α-linolenic acid and monounsaturated fatty acids attenuates hepatic steatosis and alters hepatic phospholipid fatty acid profile in diet-induced obese rats.

This study investigated the efficacy of the plant-based n-3 fatty acid, α-linolenic acid (ALA), a dietary precursor of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), for modulating hepatic steatosis. Rats were fed high fat (55% energy) diets containing high oleic canola oil, canola oil, a canola/flax oil blend (C/F, 3:1), safflower oil, soybean oil, or lard. After 12 weeks, C/F and weight-matched (WM) groups had 20% less liver lipid. Body mass, liver weight, glucose and lipid metabolism, inflammation and molecular markers of fatty acid oxidation, synthesis, desaturation and elongation did not account for this effect. The C/F group had the highest total n-3 and EPA in hepatic phospholipids (PL), as well as one of the highest DHA and lowest arachidonic acid (n-6) concentrations. In conclusion, the C/F diet with the highest content of the plant-based n-3 ALA attenuated hepatic steatosis and altered the hepatic PL fatty acid profile.

Dietary supplementation of trans-11-vaccenic acid reduces adipocyte size but neither aggravates nor attenuates obesity-mediated metabolic abnormalities in fa/fa Zucker rats.

Conjugated linoleic acid (CLA) present in dairy and ruminant fat has beneficial effects on metabolic syndrome characteristics in humans and some rodent models. Production practices to increase the milk content of CLA are also substantially elevating trans-11-vaccenic acid (VA). Questions are being raised whether VA has the same beneficial actions as CLA or has adverse biological effects similar to industrially produced trans-fatty acids. The present study examined the effects of dietary supplementation of either 0 or 1·5 % (w/w) VA for 8 weeks on lipidaemia, glycaemia, blood pressure, hepatic steatosis, adipocyte size and molecular markers of inflammation and insulin signalling in fa/fa Zucker rats. Dietary supplementation of VA did not alter feed intake, weight gain, blood pressure or organ:body weight (BW) ratios, except the epididymal fat:BW ratio which was lower in the VA group compared with the control group. The total liver lipid concentration as an indicator of hepatic steatosis was not different between the groups. Likewise, there were no changes in fasting lipidaemia, glycaemia or oral glucose tolerance. Although there were no physiological differences observed between the groups, animals supplemented with VA had smaller adipocytes (approximately 7 % smaller than the controls). The VA group also had higher adipophilin and IL-10 protein levels in epididymal adipose tissue (1·7- and 1·4-fold higher than the controls, respectively); however, there were no changes observed in critical nodes of insulin signalling. The present study provides evidence that supplementation with VA, a naturally produced trans-fat, has some positive effects on adipose tissue and did not exacerbate obesity-mediated metabolic abnormalities.