A diet containing soybean oil heated for three hours increases adipose tissue weight but decreases body weight in C57BL/6 J mice

Abstract

BackgroundOur previous work showed that dietary oxidized linoleic acid given, as a single fatty acid, to LDL receptor knockout mice decreased weight gain as compared to control mice. Other studies have also reported that animals fed oils heated for 24 h or greater showed reduced weight gain. These observations, while important, have limited significance since fried foods in the typical human diet do not contain the extreme levels of oxidized lipids used in these studies. The main goal of this study was to investigate the effects of a diet containing soybean oil heated for 3 h on weight gain and fat pad mass in mice. Additionally, because PPARγ and UCP-1 mediate adipocyte differentiation and thermogenesis, respectively, the effect of this diet on these proteins was also examined.FindingsFour to six week old male C57BL/6 J mice were randomly divided into three groups and given either a low fat diet with heated soybean oil (HSO) or unheated soybean oil (USO) or pair fed for 16 weeks. Weight and food intake were monitored and fat pads were harvested upon the study’s termination. Mice consuming the HSO diet had significantly increased fat pad mass but gained less weight as compared to mice in the USO group despite a similar caloric intake and similar levels of PPARγ and UCP1.ConclusionThis is the first study to show that a diet containing soybean oil heated for a short time increases fat mass despite a decreased weight gain in C57BL/6 J mice. The subsequent metabolic consequences of this increased fat mass merits further investigation.

Effects of Polar Compounds Generated from the Deep-Frying Process of Palm Oil on Lipid Metabolism and Glucose Tolerance in Kunming Mice

“…Heated or fried oils have been claimed to have adverse effects on health in in vivo studies, − including disorder of lipid metabolism and liver functions. Moreover, glucose intolerance and oxidative stress have been observed in subjects after the consumption of oxidized oils. − ,− However, the mechanism of the adverse effects of frying oils remains unknown.…”

The Effects of Heated Oils Used in Fast Food Restaurants on Metabolic, Inflammatory and Oxidative Stress Markers, Blood Pressure, and Liver Histology in Sprague-Dawley Rats

“…Consistent with the results of this study, Bautista et al (21) showed that although food intake in the group of rats that had consumed a diet containing 10 times heated oil was more than the other groups, yet no difference in weight gain was observed between groups after 10 weeks of intervention. Also, Penumetcha et al (7) reported that a diet containing soybean oil heated for 3 hours increased adipose tissue weight yet decreased body weight in mice. The reduction that was seen in the energy and weight gain of rats on week 7 of this study was likely due to the effect of blood sampling at the end of week 6, which caused death of some animals.…”

“…Similarly, heating soybean oil at 180°C for 8 hours/day for 4 days elevated oxidative stress without elevation of blood pressure (15). Likewise, heating soybean oil for 3 hours increased fat mass while it reduced body weight of mice (7). Also, 8-week ingestion of high oxidized frying oil (205°C for four 6-hour periods) deteriorated insulin secretion from pancreatic islets (11).…”