Beneficial effects of dietary carbohydrate restriction in chronic cor pulmonale

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

BACKGROUND

Macronutrients can differently affect respiratory function markers such as VO₂ , VCO₂ , PaO₂ , PaCO₂ and respiratory quotients (RQ), but systematic appraisal of the evidence on randomized clinical trials (RCTs) is lacking.

OBJECTIVE

To compare the response of respiratory function markers to high-carbohydrate and high-fat intake in patients with lung diseases.

METHODS

Systematic review conducted according to Cochrane Collaboration recommendations, reported following PRISMA 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 GRADE, 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 COPD. High-fat intake decreased VCO₂ [MD = -35.89(95%CI -45.24; -26.21) ml/min; I²=0%], VO₂ [MD= -29.30(95% CI -40.94, -17.66) ml/min; I² = 0%], PaCO₂ [MD = -4.62(95%CI -7.67; -1.58) mmHg; I²=84%], and RQ [MD = -0.08(95%CI -0.09; -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; -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. This article is protected by copyright. All rights reserved.

Ketogenic Diet for Obese COVID-19 Patients: Is Respiratory Disease a Contraindication? A Narrative Review of the Literature on Ketogenic Diet and Respiratory Function

Morbid obese people are more likely to contract SARS-CoV-2 infection and its most severe complications, as need for mechanical ventilation. Ketogenic Diet (KD) is able to induce a fast weight loss preserving lean mass and is particularly interesting as a preventive measure in obese patients. Moreover, KD has anti-inflammatory and immune-modulating properties, which may help in preventing the cytokine storm in infected patients. Respiratory failure is actually considered a contraindication for VLCKD, a very-low calorie form of KD, but in the literature there are some data reporting beneficial effects on respiratory parameters from ketogenic and low-carbohydrate high-fat diets. KD may be helpful in reducing ventilatory requirements in respiratory patients, so it should be considered in specifically addressed clinical trials as an adjuvant therapy for obese patients infected with SARS-CoV-2.

Ketogenic Diet as a Preventive and Supportive Care for COVID-19 Patients

Severe obesity is associated with an increased risk of admission to intensive care units and need for invasive mechanical ventilation in patients with COVID-19. The association of obesity and COVID-19 prognosis may be related to many different factors, such as chronic systemic inflammation, the predisposition to severe respiratory conditions and viral infections. The ketogenic diet is an approach that can be extremely effective in reducing body weight and visceral fat in the short term, preserving the lean mass and reducing systemic inflammation. Therefore, it is a precious preventive measure for severely obese people and may be considered as an adjuvant therapy for patients with respiratory compromise.

Scientific evidence underlying contraindications to the ketogenic diet: An update

First identified as a feasible treatment for intractable epilepsy, the ketogenic diet (KD) has recently gained popularity thanks to growing evidence on applications such as weight loss, most importantly, but also NAFLD, cancer, neurologic conditions and chronic pain. As with any treatment, whether pharmacologic or not, the KD might not be an appropriate intervention for every individual, and a number of contraindications have been proposed, now deeply rooted into clinical practice, excluding de facto many patients that could benefit from its use. However, many of these concerns were expressed due to the absence of clinical studies conducted on fragile populations, and an assessment of lately emerged evidence relative to KD safety is currently lacking and much needed. We herein provide a critical revision of the literature behind each safety alert, in order to guide through the treatment options in the case of subjects with an indication to the KD and a borderline safe situation. Based on available evidence, the possible use of this diet as a therapeutic intervention should be assessed on a patient-to-patient basis by adequately skilled medical doctors, keeping in mind current recommendations, but reading them through the knowledge of the current state of the art.

Food Pyramid for Subjects with Chronic Obstructive Pulmonary Diseases

Nutritional problems are an important part of rehabilitation for chronic obstructive pulmonary disease (COPD) patients. COPD patients often present with malnutrition, sarcopenia, and osteoporosis with possible onset of cachexia, with an inadequate dietary intake and a poor quality of life. Moreover, diet plays a pivotal role in patients with COPD through three mechanisms: regulation of carbon dioxide produced/oxygen consumed, inflammation, and oxidative stress. A narrative review based on 99 eligible studies was performed to evaluate current evidence regarding optimum diet therapy for the management of COPD, and then a food pyramid was built accordingly. The food pyramid proposal will serve to guide energy and dietary intake in order to prevent and treat nutritionally related COPD complications and to manage progression and COPD-related symptoms. The nutrition pyramid described in our narrative review is hypothetical, even in light of several limitations of the present review; the main limitation is the fact that to date there are no randomized controlled trials in the literature clearly showing that improved nutrition, via the regulation of carbon dioxide produced/oxygen consumed, inflammation and oxidative stress, improves symptoms and/or progression of COPD. Even if this nutritional pyramid is hypothetical, we hope that it can serve the valuable purpose of helping researchers focus on the often-ignored possible connections between body composition, nutrition, and COPD.

Pulmonary hypertension and cardiac insufficiency in three cows with primary lung disease

Increased pulmonary arterial pressures as a result of pulmonary disease are described in two cows with chronic pneumonia and one cow with acute pneumonia. Based on clinical signs of congestive right heart failure, increased pulmonary arterial pressure, and right ventricular hypertrophy, cor pulmonale was diagnosed in one cow. Two cows had increased pulmonary arterial pressure and signs of right heart insufficiency, but right ventricular hypertrophy was not identified. Two of the cows had ventral edema and exercise intolerance. All cows had jugular venous distention and increased right atrial and pulmonary arterial pressures. Peripheral arterial PaO2 was decreased in two cows, and not measured in the third cow. Although an uncommon cause of congestive heart failure in cattle at low altitudes, pulmonary hypertension should be considered in cattle with clinical right heart failure.