28 research outputs found
Effect of body fat distribution on the transcription response to dietary fat interventions
Combination of decreased energy expenditure and increased food intake results in fat accumulation either in the abdominal site (upper body obesity, UBO) or on the hips (lower body obesity, LBO). In this study, we used microarray gene expression profiling of adipose tissue biopsies to investigate the effect of body fat distribution on the physiological response to two dietary fat interventions. Mildly obese UBO and LBO male subjects (n = 12, waist-to-hip ratio range 0.93–1.12) were subjected to consumption of diets containing predominantly either long-chain fatty acids (PUFA) or medium-chain fatty acids (MCT). The results revealed (1) a large variation in transcription response to MCT and PUFA diets between UBO and LBO subjects, (2) higher sensitivity of UBO subjects to MCT/PUFA dietary intervention and (3) the upregulation of immune and apoptotic pathways and downregulation of metabolic pathways (oxidative, lipid, carbohydrate and amino acid metabolism) in UBO subjects when consuming MCT compared with PUFA diet. In conclusion, we report that despite the recommendation of MCT-based diet for improving obesity phenotype, this diet may have adverse effect on inflammatory and metabolic status of UBO subjects. The body fat distribution is, therefore, an important parameter to consider when providing personalized dietary recommendation
The effect of fatty acid chain length on energy metabolism in healthy women /
The effect of fatty acids on energy metabolism has been shown to be dependent on their acyl structure. In humans, following short term feeding, medium chain triglycerides (MCT) have been shown to increase the thermic effect of food and fat oxidation as compared to long chain triglycerides (LCT). Short term results in animals have been comparable. In longer term, animal studies, MCT vs. LCT have resulted in less weight gain during overfeeding or refeeding after weight loss. However, observations of the longer term effects of MCT in humans beyond 7 days are sparse and inconclusive. Hence, the objective of the thesis was to examine the effects of MCT vs. LCT on total energy expenditure, its components basal metabolic rate and thermic effect of food, and on substrate oxidation, including both exogenous and endogenous fat oxidation for a period of one week, following one week of prefeeding. Twelve healthy college aged women were fed eucaloric 14 days diets enriched with either MCT or LCT in a randomized cross over design, with a two week washout period. Doubly labelled water, respiratory gas exchange analysis, and 1-13C labelled myristic, palmitic, and stearic acids were used to measure total energy expenditure, components of energy expenditure, and endogenous long chain fatty acid oxidation, respectively. The presence of MCT in the diet significantly increased endogenous oxidation of labelled long chain fatty acids following 14 days of feeding, while the presence of LCT did not. Respiratory gas exchange analysis showed significantly increased basal metabolic rate on day 7 of MCT vs. LCT feeding, but this effect of diet was reduced to a trend by day 14. Dietary treatment did not result in significant differences in total energy expenditure during the second week of feeding. These results suggest that, after two weeks of feeding, MCT continue to affect energy metabolism through increased endogenous fat oxidation and a suggestion of heightened basal metabolic rate, bu
Consumption of an Oil Composed of Medium Chain Triacyglycerols, Phytosterols, and N-3 Fatty Acids Improves Cardiovascular Risk Profile in Overweight Women
Medium chain triacylglycerols (MCT) have been suggested as efficacious in weight management because they possess greater thermogenic qualities relative to long chain triacylglycerols; however, MCT may also increase circulating lipid concentrations, possibly increasing risk of cardiovascular disease (CVD). The present objective was to examine the effect of a diet supplemented with a functional oil (FctO) composed of energy expenditure-enhancing MCT (50% of fat), cholesterollowering phytosterols (22 mg/kg body weight), and triacylglycerol-suppressing n-3 fatty acids (5% of fat), versus a beef tallow-based diet (BT), on plasma lipid and aminothiol concentrations. In a randomized, single-blind, crossover design, partially-inpatient trial, 17 overweight women consumed each oil as part of a controlled, supervised, targeted energy balance diet for 27 days, with 4 or 8 weeks of washout between phases. Mean plasma total cholesterol concentration was lower (P < .0001), by 9.1%, on FctO (4.37 ؎ 0.20 mmol/L) versus BT (4.80 ؎ 0.20 mmol/L). Mean plasma low-density lipoprotein (LDL) cholesterol was also lower (P < .0001) following FctO (2.39 ؎ 0.15 mmol/L) versus BT (2.86 ؎ 0.16 mmol/L), representing a 16.0% difference between diets. High-density lipoprotein (HDL) cholesterol and circulating triacylglycerol concentrations remained unaffected by treatment. Ratios of HDL:LDL and HDL:total cholesterol were higher (P < .01) by 22.0% and 11.0%, respectively, on FctO versus BT. Plasma total homocysteine remained unchanged with FctO, but decreased (P < .05) with control, hence higher (P < .05) end points were observed with FctO (6.95 ؎ 0.33 mol/L) versus BT (6.27 ؎ 0.28 mol/L). Plasma glutathione increased (P < .05) by 0.44 mol/L with FctO supplementation. In conclusion, despite equivocal effects on homocysteine levels, consumption of a functional oil composed of MCT, phytosterols, and n-3 fatty acids for 27 days improves the overall cardiovascular risk profile of overweight women