Markers of respiratory function response to high‐carbohydrate and high‐fat intake in patients with lung diseases: a systematic review with meta‐analysis of randomized clinical trials

Abstract

Background Macronutrients can differently affect respiratory function markers such as VO2, VCO2, PaO2, PaCO2, and respiratory quotients (RQs), but systematic appraisal of the evidence on randomized clinical trials (RCTs) is lacking. Objective The objective of this work is to compare the response of respiratory function markers with high‐carbohydrate and high‐fat intake in patients with lung diseases. Methods Systematic review conducted according to Cochrane Collaboration recommendations, reported following Preferred Reporting Items for Systematic Reviews and Meta‐Analysis for pairwise systematic reviews of interventions 2020. PubMed, EMBASE, Scopus, and Cochrane CENTRAL were searched up to July 2021. Two reviewers selected the RCTs and extracted the data. Risk of bias and the certainty of evidence were assessed by RoB 2 and Grading of Recommendations Assessment, Development, and Evaluation System criteria, respectively. Statistical and graphical data guided the publication bias investigation. Meta‐analyses were conducted. Results We included 14 RCTs (362 participants), four of which were parallel. Most studies included patients with chronic obstructive pulmonary disease. High‐fat intake decreased VCO2 (mean difference [MD] = −35.89 ml/min [95% confidence interval (CI), −45.24 to −26.21]); I² = 0%), VO2 (MD = −29.30 ml/min [95% CI, −40.94 to −17.66]; I² = 0%), PaCO2 mm Hg (MD = −4.62 [95% CI, −7.67 to −1.58]; I² = 84%), and RQ (MD = −0.08 [95% CI, −0.09 to −0.06]; I² = 0%) in the subset of parallel RCTs. In crossover RCTs, there was generally no evidence of effect except for a greater decrease in RQ (MD = −0.09 [95% CI, −0.12 to −0.02]; I² = 96%) in favor of high‐fat intake. Conclusion High‐fat intake resulted in greater reductions of VCO2, VO2, PaCO2, and RQ in adult patients with lung diseases. The certainty of the evidence is very low/low, and it precludes a specific recommendation on macronutrients contribution to energy intake of these patients.

An Ontology-Based Decision Support System for Tailored Clinical Nutrition Recommendations for Patients With Chronic Obstructive Pulmonary Disease: Development and Acceptability Study

“…Regarding dietary fiber, it was decided that providing a lower indication than that provided by the Livelli di Assunzione di Riferimento di Nutrienti ed energia (LARN; National Recommended Energy and Nutrient Intake Levels) was preferred to encourage the intake of energy and protein foods, especially considering the difficulties met by patients with COPD in feeding and the early sense of satiety as a result of high-fiber food intake. Compared to the LARN, a higher intake of lipids was recommended, especially for phenotypes presenting with a partial pressure of carbon dioxide of >50 mm Hg, a measure of carbon dioxide in arterial or venous blood [ 53 ]. For saturated fats, a maximum intake of 10% of total daily calories was suggested according to LARN guidelines.…”

Mirtazapine as Appetite Stimulant in Patients With Non–Small Cell Lung Cancer and Anorexia

“…High fat intake has been associated with significantly improved of respirator function markers (reduction of VCO 2 , VO 2 , PaCO 2 , and respiratory quotients [RQs]) in patients with lung cancer. 14 Although all patients received personalized nutritional advice, only the mirtazapine group achieved a significant improvement in fat source of energy at 8 weeks compared with placebo.…”

“…In this double-blind randomized clinical trial, there was no difference in appetite scores in patients who received mirtazapine or placebo, but only the mirtazapine group registered a significant increase in energy intake through the 4 weeks of follow-up, and was maintained after 8 weeks, mainly in fat intake, which is a better and crucial source of energy. High fat intake has been associated with significantly improved of respirator function markers (reduction of VCO 2 , VO 2 , PaCO 2 , and respiratory quotients [RQs]) in patients with lung cancer . Although all patients received personalized nutritional advice, only the mirtazapine group achieved a significant improvement in fat source of energy at 8 weeks compared with placebo.…”

Ketogenic diet acutely improves gas exchange and sleep apnoea in obesity hypoventilation syndrome: A non‐randomized crossover study

“…1 Mechanisms by which KD improves OHS theoretically include (1) lower V ̇CO 2 , (2) the stimulatory effects of ketone bodies on 12 In this study, KD lowered RQ from 0.81 to 0.75, and P v CO 2 was linearly related to RQ. Prior studies have demonstrated that altering macronutrient composition affects CO 2 homeostasis in respiratory disorders 13 with high carbohydrates intake compromising functional outcomes. [14][15][16][17] A caloric deficit in its own right also reduces V ̇CO 2.…”