Abstract
BackgroundExcess consumption of energy-dense, high-fat Western diets contributes to the development of obesity and obesity-related disorders, such as fatty liver disease. However, not only the quantity but also the composition of dietary fat may play a role in the development of liver steatosis. The aim of this study was to determine the effects of low-stearate palm oil and high-stearate lard high-fat diets on in vivo liver lipid metabolism.MethodsWistar rats were fed with either normal chow (CON), a high-fat diet based on palm oil (HFP), or a high-fat diet based on lard (HFL). After 10 weeks of diet, magnetic resonance spectroscopy was applied for the in vivo determination of intrahepatocellular lipid content and the uptake and turnover of dietary fat after oral administration of 13C-labeled lipids. Derangements in liver lipid metabolism were further assessed by measuring hepatic very-low density lipoprotein (VLDL) secretion and ex vivo respiratory capacity of liver mitochondria using fat-derived substrates. In addition, whole-body and hepatic glucose tolerance were determined with an intraperitoneal glucose tolerance test.ResultsBoth high-fat diets induced liver lipid accumulation (p < 0.001), which was accompanied by a delayed uptake and/or slower turnover of dietary fat in the liver (p < 0.01), but without any change in VLDL secretion rates. Surprisingly, liver lipid content was higher in HFP than in HFL (p < 0.05), despite the increased fatty acid oxidative capacity in isolated liver mitochondria of HFP animals (p < 0.05). In contrast, while both high-fat diets induced whole-body glucose intolerance, only HFL impaired hepatic glucose tolerance.ConclusionHigh-fat diets based on palm oil and lard similarly impair the handling of dietary lipids in the liver, but only the high-fat lard diet induces hepatic glucose intolerance.
Highlights
Excess consumption of energy-dense, high-fat Western diets contributes to the development of obesity and obesity-related disorders, such as fatty liver disease
Mice receiving a high-fat diet based on lard developed both hepatic and peripheral insulin resistance, whereas mice fed with a high-fat diet based on palm oil developed peripheral insulin resistance only [25]
All rats received the diet for a period of weeks, after which each dietary group was divided into two subgroups: one group (n = 9 per diet group) for magnetic resonance spectroscopy (MRS) measurements and oxygen consumption measurements of isolated liver mitochondria, and one group (n = per diet group) for intraperitoneal glucose tolerance tests with deuterated glucose and determination of hepatic very-low density lipoprotein (VLDL)-TG secretion rates
Summary
Excess consumption of energy-dense, high-fat Western diets contributes to the development of obesity and obesity-related disorders, such as fatty liver disease. The aim of this study was to determine the effects of low-stearate palm oil and high-stearate lard high-fat diets on in vivo liver lipid metabolism. A sedentary lifestyle and excess consumption of energydense Western diets contribute to the development of obesity and obesity-related disorders, such as insulin resistance and type 2 diabetes, dyslipidaemia, hypertension, cardiovascular disease, and fatty liver disease [1,2,3]. Dietary fats with different fatty acid compositions may differentially affect hepatic lipid metabolism. Because of the low efficiency for oxidation and secretion, diets rich in stearate may more rapidly induce hepatic steatosis as compared with palmitate, which could contribute to hepatic insulin resistance through lipidinduced mechanisms [26]. The exact effects of stearate versus palmitate on hepatic lipid metabolism are currently not known
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