Effect of Dietary Strategies on Respiratory Quotient and Its Association with Clinical Parameters and Organ Fat Loss: A Randomized Controlled Trial.

Ariela Goldenshluger,Nir Goldstein,Yoash Chassidim,Dan Schwarzfuchs,Hila Zelicha,Yftach Gepner,Ilan Shelef,Keren Constantini,Anat Yaskolka Meir,Gal Tsaban

doi:10.3390/nu13072230

Abstract

The relation between changes in respiratory quotient (RQ) following dietary interventions and clinical parameters and body fat pools remains unknown. In this randomized controlled trial, participants with moderate abdominal obesity or/and dyslipidemia (n = 159) were randomly assigned to a Mediterranean/low carbohydrate (MED/LC, n = 80) or a low fat (LF, n = 79) isocaloric weight loss diet and completed a metabolic assessment. Changes in RQ (measured by indirect calorimeter), adipose-tissue pools (MRI), and clinical measurements were assessed at baseline and after 6 months of intervention. An elevated RQ at baseline was significantly associated with increased visceral adipose tissue, hepatic fat, higher levels of insulin and homeostatic insulin resistance. After 6 months, body weight had decreased similarly between the diet groups (−6 ± 6 kg). However, the MED/LC diet, which greatly improved metabolic health, decreased RQ significantly more than the LF diet (−0.022 ± 0.007 vs. −0.002 ± 0.008, p = 0.005). Total cholesterol and diastolic blood pressure were independently associated with RQ changes (p = 0.045). RQ was positively associated with increased superficial subcutaneous-adipose-tissue but decreased renal sinus, pancreatic, and intramuscular fats after adjusting for confounders. Fasting RQ may reflect differences in metabolic characteristics between subjects affecting their potential individual response to the diet.

Highlights

Obesity is related to metabolic [1,2] and cardiovascular risks [3,4] through excessive weight and adiposity [1]
A Mediterranean diet was found to be more strongly associated with health benefits, including cardiovascular disease risk reduction [10,11,12,13,14], and prevention of type 2 diabetes [15], than other regimes, such as a low fat diet [11], the dietary approach to stop hypertension (DASH) diet, or the Paleolithic, or Nordic diets [12,13]
Baseline associations for the 277 participants revealed that respiratory quotient (RQ) was positively associated with visceral adipose tissue (VAT) area (β = 0.163, p < 0.0001), hepatic fat content (β = 0.107, p = 0.049, Figure 2a) and higher insulin

Summary

Introduction

Obesity is related to metabolic [1,2] and cardiovascular risks [3,4] through excessive weight and adiposity [1]. Visceral adipose tissue (VAT) has been associated with obesity-related health risks [1]. Previous reports have suggested that dietary intervention, either alone [5] or combined with exercise [2,6], can benefit health, irrespective of weight loss per se, by reducing VAT [2,5,7,8], hepatic fat [5,7], and intrapericardial fat [5], and by mobilizing additional internal stored fat [5,7,8,9]. Some evidence suggests that the health benefits of the Mediterranean diet are mediated by a limitation in carbohydrate intake [18], especially when it is replaced by unsaturated fats and by polyunsaturated fats [18,19]

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Conclusion