Effect of dietary interventions on markers of type 2 inflammation in asthma: A systematic review.

INTRODUCTION: Type 2 (T2) inflammation is a key mechanism in the pathophysiology of asthma. Diet may have immunomodulatory effects, and a role for diet in T2 inflammation has been suggested in the literature. Indeed, diet and food allergies play a role in children with atopic asthma, but less is known about diet in relation to adult asthma, which is often non-atopic. OBJECTIVE: To review the effect of dietary interventions on markers of T2 inflammation in adults with asthma. METHODS: The databases PubMed, Embase, Cochrane Library, and CINAHL were searched for eligible studies until December 2022. We included studies of all types of foods, nutrients, diets or supplements, either as an exposure or as an intervention, in adults and adolescents with asthma. Outcomes of interest included the T2 biomarkers FeNO, eosinophils, IL-4, IL-5, IL-13, eosinophil cationic protein and eosinophil peroxidase. The methodological quality of eligible studies was systematically evaluated, and the results were summarised according to dietary clusters. RESULTS: The systematic search identified studies on the dietary clusters antioxidants (n = 14), fatty acids, (n = 14), Mediterranean-style diets (n = 5), phytotherapy (n = 7), prebiotics & probiotics (n = 8), vitamin D (n = 7), and other dietary factors (n = 5). Studies within the phytotherapy and omega-3 poly-unsaturated fatty acids (PUFA) clusters showed possible improvements in T2 inflammation. Furthermore, we found little evidence for an effect of antioxidants, prebiotics & probiotics, and Mediterranean-style diets on T2 inflammation. However, heterogeneity in study protocols, methodological shortcomings and limited power of almost all studies make it difficult to fully determine the impact of different dietary approaches on T2 inflammation in asthma. CONCLUSIONS: Overall, the current evidence does not support a specific dietary intervention to improve T2 inflammation in asthma. Interventions involving phytotherapy and omega-3 PUFA currently have the best evidence and warrant further evaluation in well-designed and adequately powered studies, while taking into account T2-high phenotypes of asthma.

The association of low muscle mass with prevalence and incidence of type 2 diabetes in different BMI classes.

OBJECTIVE: The aim of this study is to investigate whether muscle mass is associated with the prevalence and incidence of type 2 diabetes and whether this association differs within men and women of normal weight, overweight or obesity. METHODS: Adult participants were included from the Lifelines cohort study. Low muscle mass was defined as < -1SD of the gender-stratified creatinine excretion rate (CER). Multivariate logistic regression analysis was used to assess the association between muscle mass and the prevalence and incidence of type 2 diabetes. RESULTS: Muscle mass was associated with the prevalence of type 2 diabetes both in men and in women (OR 1.51 [95 %CI 1.32-1.72]; P < 0.001 and OR 1.53 [1.36 - 1.73]; P < 0.001). Incident type 2 diabetes was associated with a decreased muscle mass for both men and women (male; OR 1.22 [1.05 - 1.43]; P = 0.01 and female; OR 1.36 [1.17 - 1.59]; P < 0.001), and remained significant after adjustments in normal weight women (OR 1.77 [1.16-2.70]; P = 0.008). CONCLUSIONS: Both a low muscle mass and loss of muscle mass are associated with the prevalence and incidence of diabetes in the general population. This association is strongest in people with normal weight, and weakens in people within higher BMI subgroups.

Measuring Muscle Mass and Strength in Obesity: a Review of Various Methods.

Lower muscle mass in populations with obesity is associated obesity-related diseases like hypertension and type 2 diabetes mellitus. Bariatric surgery leads to sustained weight loss. During the weight reduction, loss of muscle should be minimized. Thus reliable quantification of muscle mass is much needed and therefore the also the need for validated methods. Imaging methods, magnetic resonance imaging and computed tomography scan, have been the gold standard for many years. However, these methods are costly and have limitations such as the maximum weight. Dual-energy X-ray absorptiometry is currently the most used alternative. Other, less expensive methods are very limited in their validation in populations with morbid obesity. This narrative review summarizes the current knowledge regarding measuring muscle mass and strength in obesity.