Caffeine, CYP1A2 Genotype, and Exercise Performance: A Systematic Review and Meta-analysis.

PURPOSE: This study aimed to summarize and meta-analyze existing evidence regarding the influence of CYP1A2 genotypes on the acute effects of caffeine for exercise performance and to investigate the interaction between genotype, dosage, and timing of caffeine supplementation. METHODS: Six databases were searched for studies determining the effect of caffeine (except mouth rinsing) on exercise performance between CYP1A2 genotypes. Three-level meta-analyses were performed using standardized mean differences (SMD; Hedge's g ) to determine the effect of caffeine on exercise outcomes within and between CYP1A2 genotypes (AA, AC, and CC). Meta-regressions were performed for dose, timing, and presence of reported conflict of interests (RCOI). A meta-analysis was also performed with placebo values to assess for imbalances between genotypes. RESULTS: Thirteen studies, totaling 119 outcomes and 440 participants, were included (233 AA, 175 AC, ad 34 CC). Caffeine improved performance for AA (SMD = 0.30, 95% confidence interval [CI] = 0.21-0.39, P < 0.0001) and AC (SMD = 0.16, 95% CI = 0.06-0.25, P = 0.022) but worsened performance for CC (SMD = -0.22, 95% CI = -0.44 to -0.01, P < 0.0001). Dose affected only CC, with greater doses generating more positive SMD (CC-dose estimate: +0.19/1 mg·kg -1 body mass, 95% CI = 0.04-0.33, P = 0.01). Timing influenced only CC, with better performance with later onset of exercise after supplementation (CC-timing estimate: +0.01/min, 95% CI = 0.00-0.02, P = 0.02). RCOI only affected SMD of CC (CC-RCOI estimate: -0.57, 95% CI = -1.02 to -0.12, P = 0.01). After excluding studies with RCOI, no influence of genotype was seen (all P ≥ 0.19). Small, nonsignificant differences were seen in placebo between genotypes (SMD AA vs CC: -0.13; AA vs AC: -0.12; AC vs CC: -0.05; all P ≥ 0.26). CONCLUSIONS: Caffeine improved performance for AA and AC but worsened performance for CC. Dose and timing moderated the efficacy of caffeine for CC only. Caution is advised because baseline differences and studies with RCOI could have influenced these results.

Impaired cardiorespiratory fitness and endothelial function after SARS-CoV-2 infection in a sample of mainly immunocompromised youth.

This study aimed to compare cardiopulmonary fitness and endothelial function 6 months after hospital diagnosis in a sample mainly comprising immunocompromised patients with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection versus noninfected controls. Youth (n = 30; age: 14 yr; 60% females) with confirmed SARS-CoV-2 seen in a tertiary hospital of Sao Paulo, Brazil, were matched by propensity score based on BMI, age, sex, and pre-existing diseases with a control group who had not been tested positive for SARS-CoV-2 infection (n = 30; age: 15 yr; 50% females). Cardiopulmonary fitness (by means of a cardiopulmonary exercise test: CPET) and brachial flow-mediated dilation (%b-FMD) were assessed 3-6 mo after diagnosis. Patients were matched by propensity score based on BMI, age, sex and pre-existing diseases, if any, with a control group who had not been tested positive for SARS-CoV-2. Compared with controls, patients with COVID-19 showed reduced ventilatory anaerobic threshold (VAT) and peak exercise time and minute ventilation/maximum voluntary ventilation (V̇e/MVV) (all P < 0.01). Brachial endothelial function variables were all adjusted for body surface area (BSA). Patients with COVID-19 had decreased %b-FMD (3.6 vs. 5.4; P = 0.03) mean and positive flow (P = 0.02 and P = 0.03, respectively) versus controls. Adjusted linear regression models exploring associations between CPET variables, %b-FMD and the potential predictors post-COVID-19 syndrome, number of symptoms, hospitalization, and COVID severity did not detect significant associations, except for total shear rate in hospitalization (coefficient: -65.07 [95%CI -119.5;-10.5], P = 0.02). Immunocompromised and previously healthy children and adolescents with COVID-19 presented with impaired exercise capacity and endothelial dysfunction when compared with their noninfected counterparts, but the mechanisms remain unknown.NEW & NOTEWORTHY COVID-19 appeared to impair recovery of exercise capacity and endothelial function in a sample mainly comprising immunocompromised patients, but the mechanisms are unknown. These findings support the need for preventive measures against COVID-19 in this vulnerable population and suggest the necessity of proper monitoring and treatment for these patients.

Impact of Methyl-Donor Micronutrient Supplementation on DNA Methylation Patterns: A Systematic Review and Meta-Analysis of in vitro, Animal, and Human Studies.

BACKGROUND: DNA methylation patterns are directly associated with diverse metabolic disorders. The status of methyl-donor micronutrients has been associated with DNA methylation levels, and altered ingestion of folate, choline, betaine, B vitamins and methionine may impact genes both globally and at the level of promoter regions. Despite this, the role of methyl-donor micronutrient supplementation on DNA methylation profiles is currently unclear. OBJECTIVES: The aims of this systematic review and meta-analysis were to identify and synthesize the evidence about methyl-donor nutrient supplementation on DNA methylation. METHODS: A systematic literature search was performed in Medline, Embase, Scopus, and Web of Science databases with a combination of terms related to DNA methylation assessment, supplementation, and methyl-donor nutrients. Studies (in vitro, animal models, or human clinical trials) were included if DNA methylation levels after any kind of methyl-donor micronutrient supplementation or treatment was investigated. Studies were assessed for bias using Revised Cochrane risk-of-bias tool for randomized trials, risk-of-bias in Non-randomized Studies of Interventions or Systematic Review Centre for Laboratory Animal Experimentation tools. Data were extracted from studies measuring DNA methylation levels in any sample or tissue, following any kind of methyl-donor micronutrient supplementation or treatment. Separate random-effects meta-analyses were performed for animal model studies and human clinical trials that examined the effects of folic acid supplementation on DNA methylation. RESULTS: Fifty-seven studies were included in this systematic review: 18 human clinical trials, 35 in animal model, and 4 in vitro studies. Concerning overall risk of bias, most of the studies were classified as "high risk" or "some concerns." Meta-analysis with meta-regression from studies in animal models showed that folic acid dose significantly affected DNA methylation and that high and very high doses showed increases in DNA methylation when compared to low doses. However, meta-analysis of human clinical trials showed that folic acid supplementation did not promote significant changes in DNA methylation when compared to placebo. CONCLUSION: Folic acid supplementation may change global DNA methylation levels in animals supplemented with high, as compared to low, doses. Heterogeneity in studies and supplementation protocols make it difficult to establish clinical recommendations. However, these effects, even if small, might be of clinical importance in the management of patients with diseases related to DNA hypomethylation.

Variability in variability: does variation in morphological and physiological traits differ between men and women?

Many researchers presume greater variability between female participants than between males due to the menstrual cycle. This view has encouraged a sex bias in health and medical research, resulting in considerable knowledge gaps with important clinical implications. Yet in another field-evolutionary biology-the received wisdom is the reverse: that men are more variable, possibly due to male heterogamety. To test these competing hypotheses, we compared variance between the sexes for 50 morphological and physiological traits, analysing data from the NHANES database. Nearly half the traits did not exhibit sexual dimorphism in variation, while 18 exhibited greater female variation (GFV), indicating GFV does not dominate human characteristics. Only eight traits exhibited greater male variation (GMV), indicating GMV also does not dominate, and in turn offering scant support for the heterogamety hypothesis. When our analysis was filtered to include only women with regular menstrual cycles (and men of equivalent age), the number of traits with GFV and GMV were low and not statistically different, suggesting that the menstrual cycle does not typically explain GFV when it occurs. In practical terms, health and medical researchers should no longer simply assume that female participants will induce additional variation in the traits of interest.

Food consumption based on processing level (according to Nova system) during the COVID-19 pandemic among adolescents with immunocompromised conditions: a case-control study.

The COVID-19 pandemic impacts on eating habits among adolescents may be more relevant in pediatric patients with immunocompromised chronic diseases. This case-control study conducted between June and October 2020 aimed to: (i) describe dietary patterns of adolescents with chronic conditions compared to healthy controls and (ii) determine associations between food consumption, health-related quality of life (HRQL) and sleep quality during the COVID-19 pandemic. Participants (184 immunocompromised and 58 healthy adolescents, aged 14.3 [SD 2.5]) responded to HRQL and sleep validated instruments (PedsQL and PSQI) and three 24 h food recalls via online software. Adjusted linear and logistic regressions were used to assess differences in dietary patterns and associations between food consumption (according to Nova classification) and HRQL and sleep quality. Adolescents with gastrohepatic, rheumatic, and kidney diseases had an improved dietary pattern vs. their healthy peers, showing greater consumption of unprocessed and minimally processed foods (unstandardized coefficient (b) = 7.35%[95%CI 1.59; 13.1]; b = 15.10%[95%CI 7.00; 23.1]; and b = 11.2%[95%CI 5.68; 16.8]), and lower consumption of ultraprocessed foods (b = -7.53%[95%CI-12.90; -2.18]; b = -11.4%[95%CI-18.90; -3.94]; b = -10.8%[95%CI-16.00; -5.68]). Consumption of culinary ingredients was associated with reduced psychological HRQL in controls (standardized coefficient (ß) = -0.26[95%CI-0.52; -0.004]), and processed food consumption was associated with improved sleep latency in immunocompromised participants (ß = 0.16[95%CI 0.01; 0.31]). These findings suggest diet quality may play a role in HRQL and sleep quality in this population, and may be relevant for clinical practitioners and policy makers when considering the importance of dietary quality in immunocompromised youths.

Disordered Eating Attitudes and Food Choice Motives Among Individuals Who Follow a Vegan Diet in Brazil.

Importance: It remains controversial whether adhering to a vegan diet may be associated with a higher prevalence of disordered eating. Also, main food choice motives and their association with disordered eating in this population are still unknown. Objective: To determine the association between disordered eating attitudes and food choice motives of individuals who follow a vegan diet. Design, Setting, and Participants: This is a cross-sectional online survey conducted between September 2021 and January 2023. Individuals of both sexes, aged 18 years or older, following a vegan diet for at least 6 months, currently living in Brazil were recruited through advertisements on social media. Exposure: Adherence to a vegan diet and food choice motives. Main Outcomes and Measures: Disordered eating attitudes and food choice motives. Results: Nine hundred seventy-one participants completed the online survey. Median (IQR) age and BMI of participants was 29 (24-36) years and 22.6 (20.3-24.9), respectively, and 800 participants (82.4%) were female. Most participants (908 respondents [94%]) were categorized with the lowest level of disturbed eating attitudes. "Need and hunger," "liking," "health," "habits," and "natural concerns" were the most important food choice motives in this population, while "affect regulation," "social norms," and "social image" were the less important ones. Adjusted models showed that "liking," "need and hunger," and "health" were associated with lower levels of disordered eating attitudes, while "price," "pleasure," "sociability," "traditional eating," "visual appeal," "social norms," "social image," "weight control," and "affect regulation" were associated with higher levels of disordered eating attitudes. Conclusions and Relevance: In this cross-sectional study, as opposed to previous suggestions, levels of disordered eating were very low among vegans, although certain food choice motives were associated with disordered eating attitudes. Understanding the motivations of adhering to diets that may impose restrictions, which include vegan diets, may help tailor interventions focused on promoting healthy eating and preventing or treating disordered eating.

Use of factor analysis to model relationships between bone mass and physical, dietary, and metabolic factors in frail and pre-frail older adults.

Bone mass and quality decline with age, and can culminate in osteoporosis and increased fracture risk. This investigation modeled associations between bone and physical, dietary, and metabolic factors in a group of 200 pre-frail/frail older adults using factor analysis and structural equation modeling (SEM). Exploratory (EFA) and confirmatory factor analysis (CFA) were conducted to compose factors and to assess their robustness. SEM was used to quantify associations between bone and the other factors. Factors arising from EFA and CFA were: bone (whole body, lumbar and femur bone mineral density, and trabecular bone score; good fit), body composition - lean (lean mass, body mass, vastus lateralis, and femoral cross-sectional area; good fit), body composition - fat (total fat mass, gynoid, android, and visceral fat; acceptable fit), strength (bench and leg press, handgrip, and knee extension peak torque; good fit), dietary intake (kilocalories, carbohydrate, protein, and fat; acceptable fit), and metabolic status (cortisol, insulin-like growth factor 1 (IGF-1), growth hormone (GH), and free testosterone; poor fit). SEM using isolated factors showed that body composition (lean) (ß = 0.66, P < 0.001), body composition (fat) (ß = 0.36, P < 0.001), and strength (ß = 0.74, P < 0.001) positively associated with bone. Dietary intake relative to body mass negatively associated with bone (ß = -0.28, P = 0.001), whereas in absolute terms, it showed no association (ß = 0.01, P = 0.911). In a multivariable model, only strength (ß = 0.38, P = 0.023) and body composition (lean) (ß = 0.34, P = 0.045) associated with bone. Resistance training programs that focus on improving lean mass and strength in older individuals may benefit bone in this population.NEW & NOTEWORTHY We used factor analysis and structural equation modeling, which are rarely used in nutrition or exercise science, but constitute powerful tools that may overcome limitations of traditional analyses, combining individual related variables into factors or constructs of interest. Our investigation represents a starting point on this progressive pathway, providing useful insight and a working model for researchers and practitioners who wish to tackle complex problems such as the multifactorial causes of bone loss in older adults.

The Influence of n-3PUFA Supplementation on Muscle Strength, Mass, and Function: A Systematic Review and Meta-Analysis.

The effects of omega 3 polyunsaturated fatty acids (n-3PUFA) supplementation on skeletal muscle are currently unclear. The purpose of this systematic review was to synthesize all available evidence regarding the influence of n-3PUFA supplementation on muscle mass, strength, and function in healthy young and older adults. Four databases were searched (Medline, Embase, Cochrane CENTRAL, and SportDiscus). Predefined eligibility criteria were determined according to Population, Intervention, Comparator, Outcomes, and Study Design. Only peer-reviewed studies were included. The Cochrane RoB2 Tool and the NutriGrade approach were used to access risk of bias and certainty in evidence. Effect sizes were calculated using pre-post scores and analyzed using a three-level, random-effects meta-analysis. When sufficient studies were available, subanalyses were performed in the muscle mass, strength, and function outcomes according to participant's age (<60 or ≥60 years), supplementation dosage (<2 or ≥2 g/day), and training intervention ("resistance training" vs. "none or other"). Overall, 14 individual studies were included, total 1443 participants (913 females; 520 males) and 52 outcomes measures. Studies had high overall risk of bias and consideration of all NutriGrade elements resulted in a certainty assessment of moderate meta-evidence for all outcomes. n-3PUFA supplementation had no significant effect on muscle mass (standard mean difference [SMD] = 0.07 [95% CI: -0.02, 0.17], P = 0.11) and muscle function (SMD = 0.03 [95% CI: -0.09, 0.15], P = 0.58), but it showed a very small albeit significant positive effect on muscle strength (SMD = 0.12 [95% CI: 0.006, 0.24], P = 0.04) in participants when compared with placebo. Subgroup analyses showed that age, supplementation dose, or cosupplementation alongside resistance training did not influence these responses. In conclusion, our analyses indicated that n-3PUFA supplementation may lead to very small increases in muscle strength but did not impact muscle mass and function in healthy young and older adults. To our knowledge, this is the first review and meta-analysis investigating whether n-3PUFA supplementation can lead to increases in muscle strength, mass, and function in healthy adults. Registered protocol: doi.org/10.17605/OSF.IO/2FWQT.

Nutritional recommendations for patients undergoing prolonged glucocorticoid therapy.

Glucocorticoid (GC) therapy is a common treatment used in rheumatic and autoimmune diseases, owing to its anti-inflammatory and immunosuppressive effects. However, GC therapy can also induce a number of adverse effects, including muscle and bone loss, hypertension, metabolic perturbations and increased visceral adiposity. We review available evidence in this area and provide nutritional recommendations that might ameliorate these adverse effects. Briefly, optimizing calcium, vitamin D, sodium and protein intake and increasing consumption of unprocessed and minimally processed foods, while decreasing the consumption of ultra-processed foods, might counteract some of the specific challenges faced by these patients. Importantly, we identify a dearth of empirical data on how nutritional intervention might impact health-related outcomes in this population. Further research is required to investigate the clinical and therapeutic efficacy of these theory-based recommendations.

Influence of Adherence to Social Distancing Due to the COVID-19 Pandemic on Physical Activity Level in Post-bariatric Patients.

We assessed physical activity using accelerometers and a questionnaire in 33 post-bariatric patients who reported to be adherent (n = 15) or not (n = 18) to social distancing due to the COVID-19 pandemic. Patients adherent to social distancing spent more time in sedentary behavior (1.1 h/day, 0.1, 2.2; p = 0.045) and less time in moderate-to-vigorous physical activity (- 12.2 min/day, - 23.8, - 0.6; p = 0.040) vs. non-adherent ones. Bland-Altman analysis comparing objective and subjective physical activity estimates showed a bias for time spent in sedentary behavior and moderate-to-vigorous activity of 2.8 h/day and 8.5 min/day. In conclusion, post-bariatric patients who were adherent to social distancing measures were more inactive and sedentary than non-adherent ones. Strategies to increase physical activity in post-bariatric patients exposed to social distancing are necessary during the COVID-19 pandemic.