Dietary olive oil intake induces female-specific hepatic lipid accumulation without metabolic impairment in mice.

Olive oil is one of the most widely researched Mediterranean diet components in both experimental models and clinical studies. However, the relationship between dietary olive oil intake and liver function in a healthy state of the body remains unclear. Because men are at a greater risk of developing hepatic diseases than women, and because hepatic metabolism is regulated by sex hormones, we hypothesized that olive oil-induced changes in hepatic metabolism would differ by sex. To test our hypothesis, 12-week-old C57BL/6JJcl male and female mice were fed an olive oil diet for 4 weeks. Blood was collected and serum biochemical components were analyzed. Hepatic lipid accumulation was determined via histological analysis using Sudan III staining. Finally, transcript expression levels of hepatic metabolism-related genes were analyzed using quantitative polymerase chain reaction. We observed significant increased hepatic lipid droplet accumulation in olive oil-fed female mice. Serum biochemical and liver messenger RNA expression analyses revealed that the hepatic lipid accumulation was nonpathological and did not involve inflammation. Moreover, the expression of genes related to triacylglycerol and fatty acid synthesis (Dgat1, Dgat2, Agpat3, and Fasn) was significantly upregulated in the liver of olive oil-fed female mice compared with control female mice. Our study demonstrates female-specific hepatic lipid accumulation without liver impairment in a dietary olive oil-fed mouse model. These findings provide a deeper mechanistic understanding of sex-dependent hepatic lipid metabolism of dietary oils.

Edible insect Locusta migratoria shows intestinal protein digestibility and improves plasma and hepatic lipid metabolism in male rats.

Although edible insect migratory locusts are considered sustainable food resources with proteins and n-3 lipids, their physiological effects on lipid metabolism are not clarified. Here, we clarified the amino acid (AA) value of the edible migratory locust powder (MLP), protein digestibility, and dietary effects of MLP on growth and lipid metabolism in rats. The AA score was 63, which was low score due to the limiting AA (Trp). MLP protein digestibility was resistant to gut pepsin but digestible to intestinal trypsin and chymotrypsin. Dietary MLP represented favorable growth and enhanced intestinal condition and lipid metabolism in rats, particularly, low-density lipoprotein metabolism and arteriosclerosis-related fatty acid profiles. Liver triglyceride accumulation and fatty acid desaturation indices were increased by activating lipids uptake into the liver, while lipogenic protein expression and enzyme activities and liver function indices were reduced by MLP. Conclusively, intestinal digestible MLP is a nutraceutical for the prevention of dyslipidemia.

Dietary Olive Oil Intake Improves Running Endurance with Intramuscular Triacylglycerol Accumulation in Mice.

Olive oil is a functional food shown to have a variety of bioactive effects. Therefore, we expect it to be a novel functional food with an exercise-mimetic effect on skeletal muscles. This study aimed to investigate the effect of olive oil on the endurance capacity and muscle metabolism in mice. Mice fed a 7% (w/w) olive oil diet for eight weeks showed improved treadmill running endurance and increased intramuscular triacylglycerol (IMTG) accumulation in the gastrocnemius muscle compared to soybean oil diet-fed controls. The increase in running endurance with olive oil intake was independent of the muscle fiber type. To elucidate underlying the mechanism of elevated IMTG levels, we examined the expression levels of the genes related to lipid metabolism. We found that the expression of diacylglycerol O-acyltransferase1 (DGAT1) was significantly upregulated in the muscle of olive oil diet-fed mice. In addition, the olive oil diet-fed mice showed no metabolic impairment or differences in growth profiles compared to the controls. These results suggest that dietary olive oil intake affects muscle metabolism and muscle endurance by increasing energy accumulation.