Short chain fatty acids in obesity metabolic phenotypes: associations with dietetic consumption, body composition and components of energy and glycemic homeostasis

Author(s)

Isabela Solar

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Aplicadas
• Defense date: 2020-07-17

Examining board members

Ana Carolina Junqueira Vasques; Patrícia de Oliveira Prada; Ana Carolina Franco de Moraes

• Advisor: Ana Carolina Junqueira Vasques; Bruno Geloneze Neto

Abstract

Introduction: Obesity is a chronic disease, characterized by excessive accumulation of fat tissue, which presents itself under several phenotypes. There are individuals metabolically healthy obese - MHO, metabolically unhealthy obese - MUO and metabolically unhealthy normal weight - MUNW. The pathophysiological mechanisms underlying the development of each phenotype are partially elucidated. Evidence suggests that the intestinal microbiota modulates the energy and glycemic homeostasis via the production of short-chain fatty acids (SCFA), produced through the fermentation of dietary fibers by the intestinal microbiota. Objective: Compare the fecal concentrations of SCFA between the phenotypes MHO, MUO, MUNW and a metabolically healthy normal weight group, and investigate the association of AGCC with body adiposity, components of energy and glycemic homeostasis and food consumption. Methods: A cross-sectional study, part of the Nutritionists' Health Study, with 111 women of fertile age, distributed among the four metabolic phenotypes. Women with BMI < 25 kg/m² were classified as normal weight and ? 25 kg/m² as obese/overweight. The definition of metabolic health took into account the absence of changes in blood pressure levels, glycemic, lipemic and cardiovascular disease. The evaluation of body composition was performed by DEXA. The components of energy homeostasis (resting energy expenditure, metabolic flexibility and substrate oxidation rate) and glycemic (insulin resistance, insulin secretion and GLP-1) were evaluated in the standard mixed-meal tolerance test associated with indirect calorimetry with 180-minute protocol. The food consumption (energy, macronutrients and fibers) was evaluated by a food frequency questionnaire. The SCFA were quantified in the feces by gas chromatography coupled to the mass spectrometer. Results: The participants had on average 28 ± 5 years and 25.6 ± 5.0 BMI and the frequency of phenotypes was 33.9% normal metabolically healthy weight, 15.3% MUNW, 25.4% MHO and 25.4% MUO. SCFA concentrations did not differ between the four phenotypes. There was an inverse association between the concentrations of propionate and butyrate and the levels of BMI and central adiposity. Propionate and acetate were inversely associated with AUC of glycemia; propionate correlated positively with the insulinogenic index and AUC of GLP-1. Total SCFA and acetate correlated positively with resting energy expenditure (REE); and propionate and butyrate correlated positively with GER adjusted for body weight. Propionate correlated inversely with the oxidation rate of carbohydrates in fasting, and total SCFA, propionate and fecal butyrate obtained positive correlation with the oxidation rate of lipids 60 minutes after the consumption of the standard mixed-meal. There was no association between food consumption and SCFA. Conclusion: The findings do not support that the determination of SCFA in feces helps to differentiate metabolic phenotypes. However, higher concentrations of fecal SCFA were associated with lower accumulation of mainly central body adiposity, higher rates of REE and lipid oxidation and levels of GLP-1 in the postprandial period, in parallel with a better beta cell function, and lower glycemic incursion after oral stimulation (AU)

• FAPESP's process: 17/24578-2 - Short chain fatty acids in metabolic phenotypes of obesity: associations with dietary consumption, body composition and components of energy and glycemic homeostasis
• Grantee: Isabela Solar
• Support Opportunities: Scholarships in Brazil - Master