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Clinical Nutrition ESPEN Jun 2020Clinical evidence which investigated the effects of l-carnitine, a vitamin-like substance, on weight loss had led to inconsistent results. This study therefore aimed to... (Meta-Analysis)
Meta-Analysis Review
Effects of l-carnitine supplementation on weight loss and body composition: A systematic review and meta-analysis of 37 randomized controlled clinical trials with dose-response analysis.
BACKGROUND AND AIM
Clinical evidence which investigated the effects of l-carnitine, a vitamin-like substance, on weight loss had led to inconsistent results. This study therefore aimed to examine the effect of l-carnitine supplementation on body weight and composition by including the maximum number of randomized controlled trials (RCTs) and to conduct a dose-response analysis, for the first time.
METHODS AND RESULTS
Online databases were searched up to January 2019. In total, 37 RCTs (with 2292 participants) were eligible. Meta-analysis showed that l-carnitine supplementation significantly decreased body weight [Weighted mean difference (WMD) = -1.21 kg, 95% confidence interval (CI): -1.73, -0.68; P < 0.001], body mass index (BMI) (WMD = -0.24 kg/m, 95% CI: -0.37, -0.10; P = 0.001), and fat mass (WMD = -2.08 kg, 95% CI: -3.44, -0.72; P = 0.003). No significant effect was seen for waist circumference (WC) and body fat percent. The meta-analysis of high-quality RCTs only confirmed the effect on body weight. A non-linear dose-response association was seen between l-carnitine supplementation and body weight reduction (P < 0.001) suggesting that ingestion of 2000 mg l-carnitine per day provides the maximum effect in adults. This association was not seen for BMI, WC and body fat percent.
CONCLUSIONS
l-carnitine supplementation provides a modest reducing effect on body weight, BMI and fat mass, especially among adults with overweight/obesity.
Topics: Adult; Body Composition; Body Weight; Carnitine; Dietary Supplements; Humans; Randomized Controlled Trials as Topic; Weight Loss
PubMed: 32359762
DOI: 10.1016/j.clnesp.2020.03.008 -
BMJ (Clinical Research Ed.) Aug 2016To quantify the dose-response associations between total physical activity and risk of breast cancer, colon cancer, diabetes, ischemic heart disease, and ischemic... (Meta-Analysis)
Meta-Analysis Review
Physical activity and risk of breast cancer, colon cancer, diabetes, ischemic heart disease, and ischemic stroke events: systematic review and dose-response meta-analysis for the Global Burden of Disease Study 2013.
OBJECTIVE
To quantify the dose-response associations between total physical activity and risk of breast cancer, colon cancer, diabetes, ischemic heart disease, and ischemic stroke events.
DESIGN
Systematic review and Bayesian dose-response meta-analysis.
DATA SOURCES
PubMed and Embase from 1980 to 27 February 2016, and references from relevant systematic reviews. Data from the Study on Global AGEing and Adult Health conducted in China, Ghana, India, Mexico, Russia, and South Africa from 2007 to 2010 and the US National Health and Nutrition Examination Surveys from 1999 to 2011 were used to map domain specific physical activity (reported in included studies) to total activity.
ELIGIBILITY CRITERIA FOR SELECTING STUDIES
Prospective cohort studies examining the associations between physical activity (any domain) and at least one of the five diseases studied.
RESULTS
174 articles were identified: 35 for breast cancer, 19 for colon cancer, 55 for diabetes, 43 for ischemic heart disease, and 26 for ischemic stroke (some articles included multiple outcomes). Although higher levels of total physical activity were significantly associated with lower risk for all outcomes, major gains occurred at lower levels of activity (up to 3000-4000 metabolic equivalent (MET) minutes/week). For example, individuals with a total activity level of 600 MET minutes/week (the minimum recommended level) had a 2% lower risk of diabetes compared with those reporting no physical activity. An increase from 600 to 3600 MET minutes/week reduced the risk by an additional 19%. The same amount of increase yielded much smaller returns at higher levels of activity: an increase of total activity from 9000 to 12 000 MET minutes/week reduced the risk of diabetes by only 0.6%. Compared with insufficiently active individuals (total activity <600 MET minutes/week), the risk reduction for those in the highly active category (≥8000 MET minutes/week) was 14% (relative risk 0.863, 95% uncertainty interval 0.829 to 0.900) for breast cancer; 21% (0.789, 0.735 to 0.850) for colon cancer; 28% (0.722, 0.678 to 0.768) for diabetes; 25% (0.754, 0.704 to 0.809) for ischemic heart disease; and 26% (0.736, 0.659 to 0.811) for ischemic stroke.
CONCLUSIONS
People who achieve total physical activity levels several times higher than the current recommended minimum level have a significant reduction in the risk of the five diseases studied. More studies with detailed quantification of total physical activity will help to find more precise relative risk estimates for different levels of activity.
Topics: Breast Neoplasms; China; Colonic Neoplasms; Diabetes Mellitus; Exercise; Ghana; Global Burden of Disease; Humans; India; Metabolic Equivalent; Mexico; Myocardial Ischemia; Risk Factors; Russia; South Africa; Stroke; Time Factors
PubMed: 27510511
DOI: 10.1136/bmj.i3857 -
Theranostics 2023Metabolic reprogramming is one of the most important hallmarks of malignant tumors. Specifically, lipid metabolic reprogramming has marked impacts on cancer progression... (Review)
Review
Metabolic reprogramming is one of the most important hallmarks of malignant tumors. Specifically, lipid metabolic reprogramming has marked impacts on cancer progression and therapeutic response by remodeling the tumor microenvironment (TME). In the past few decades, immunotherapy has revolutionized the treatment landscape for advanced cancers. Lipid metabolic reprogramming plays pivotal role in regulating the immune microenvironment and response to cancer immunotherapy. Here, we systematically reviewed the characteristics, mechanism, and role of lipid metabolic reprogramming in tumor and immune cells in the TME, appraised the effects of various cell death modes (specifically ferroptosis) on lipid metabolism, and summarized the antitumor therapies targeting lipid metabolism. Overall, lipid metabolic reprogramming has profound effects on cancer immunotherapy by regulating the immune microenvironment; therefore, targeting lipid metabolic reprogramming may lead to the development of innovative clinical applications including sensitizing immunotherapy.
Topics: Humans; Tumor Microenvironment; Lipid Metabolism; Immunotherapy; Cell Death; Lipids; Neoplasms
PubMed: 37064872
DOI: 10.7150/thno.82920 -
Nutrients Jan 2021Although creatine has been mostly studied as an ergogenic aid for exercise, training, and sport, several health and potential therapeutic benefits have been reported....
Although creatine has been mostly studied as an ergogenic aid for exercise, training, and sport, several health and potential therapeutic benefits have been reported. This is because creatine plays a critical role in cellular metabolism, particularly during metabolically stressed states, and limitations in the ability to transport and/or store creatine can impair metabolism. Moreover, increasing availability of creatine in tissue may enhance cellular metabolism and thereby lessen the severity of injury and/or disease conditions, particularly when oxygen availability is compromised. This systematic review assesses the peer-reviewed scientific and medical evidence related to creatine's role in promoting general health as we age and how creatine supplementation has been used as a nutritional strategy to help individuals recover from injury and/or manage chronic disease. Additionally, it provides reasonable conclusions about the role of creatine on health and disease based on current scientific evidence. Based on this analysis, it can be concluded that creatine supplementation has several health and therapeutic benefits throughout the lifespan.
Topics: Aging; Biological Availability; Chronic Disease; Creatine; Dietary Supplements; Humans; Wounds and Injuries
PubMed: 33572884
DOI: 10.3390/nu13020447 -
British Journal of Sports Medicine Aug 2023To determine and compare the dose-response effects of exercise and caloric restriction on visceral adipose tissue in overweight and obese adults, while controlling for... (Meta-Analysis)
Meta-Analysis Review
Dose-response effects of exercise and caloric restriction on visceral adiposity in overweight and obese adults: a systematic review and meta-analysis of randomised controlled trials.
OBJECTIVE
To determine and compare the dose-response effects of exercise and caloric restriction on visceral adipose tissue in overweight and obese adults, while controlling for the weekly energy deficit induced by the interventions.
METHODS
PubMed, Embase, CINAHL and Web of Science were searched for randomised controlled trials comparing exercise or caloric restriction against eucaloric controls in overweight or obese adults. The primary outcome was the change in visceral fat measured by CT or MRI. Meta-analyses and meta-regressions were performed to determine the overall effect size (ES) and the dose-dependent relationship of exercise and caloric restriction on visceral fat. Heterogeneity, risk of bias and the certainty of evidence were also assessed.
RESULTS
Forty randomised controlled trials involving 2190 participants were included. Overall, exercise (ES -0.28 (-0.37 to -0.19); p<0.001; I=25%) and caloric restriction (ES -0.53 (-0.71 to -0.35); p<0.001; I=33%) reduced visceral fat compared with the controls. Exercise demonstrated a dose-response effect of -0.15 ((-0.23 to -0.07); p<0.001) per 1000 calories deficit per week, whereas the effect of caloric restriction was not dose-dependent (ES 0.03 (-0.12 to 0.18); p=0.64). Most of the studies showed a moderate risk of bias.
CONCLUSIONS
These findings support the dose-dependent effects of exercise to reduce visceral fat in overweight and obese adults. Caloric restriction did not demonstrate a dose-response relationship, although this may be attributed to the smaller number of studies available for analysis, compared with exercise studies.
PROSPERO REGISTRATION NUMBER
CRD42020210096.
Topics: Adult; Humans; Overweight; Adiposity; Obesity; Exercise; Intra-Abdominal Fat; Randomized Controlled Trials as Topic
PubMed: 36669870
DOI: 10.1136/bjsports-2022-106304 -
Nutrients Aug 2021A low-carbohydrate, high-fat (LCHF) diet has been proposed to enhance the fat utilization of muscle and the aerobic capacity of endurance athletes, thereby improving... (Meta-Analysis)
Meta-Analysis
A low-carbohydrate, high-fat (LCHF) diet has been proposed to enhance the fat utilization of muscle and the aerobic capacity of endurance athletes, thereby improving their exercise performance. However, it remains uncertain how the macronutrient intake shift from carbohydrate to fat affects endurance exercise training and performance. This study performed a systematic review and meta-analysis to explore the effects of a ketogenic low-carbohydrate, high-fat (K-LCHF) diet on aerobic capacity and exercise performance among endurance athletes. Searches were carried out in five electronic databases, and we followed the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. The search included studies using an LCHF diet as an intervention protocol and compared data on factors such as maximum oxygen uptake (VOmax) and rating of perceived exertion (RPE) from the graded exercise test. In this case, 10 studies met the criteria and were included in the meta-analysis. We did not find a significant effect of K-LCHF diet interventions on VOmax, time to exhaustion, HRmax or RPE. However, a significant overall effect in the substrate oxidation response to respiratory exchange rate was observed. The meta-analysis showed that K-LCHF diets did not affect aerobic capacity and exercise performance. Therefore, high-quality interventions of a K-LCHF diet are needed to illustrate its effect on various endurance training programs.
Topics: Adult; Athletes; Diet, Ketogenic; Exercise Tolerance; Female; Hemodynamics; Humans; Male; Middle Aged; Nutritive Value; Oxygen Consumption; Physical Conditioning, Human; Physical Endurance; Respiratory Mechanics; Young Adult
PubMed: 34445057
DOI: 10.3390/nu13082896 -
Diabetes Research and Clinical Practice May 2017Postprandial hyperglycemia plays a decisive role in the development of chronic metabolic disorders. The effect of vinegar intake with a meal on postprandial glucose has... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
Postprandial hyperglycemia plays a decisive role in the development of chronic metabolic disorders. The effect of vinegar intake with a meal on postprandial glucose has been studied in several trials with conflicting results.
RESEARCH METHODS AND PROCEDURES
The purpose of the current study was to systematically review control trials that report on the effect of vinegar intake on postprandial glucose response. Postprandial insulin response was considered as secondary outcome.
RESULTS
The pooled analysis of studies revealed a significant mean glucose and insulin area under the curve (AUC) reduction in participants who consumed vinegar compared with the control group (standard mean difference=-0.60, 95%CI -1.08 to -0.11, p=0.01 and -1.30, 95%CI -1.98 to -0.62, p<0.001, respectively).
CONCLUSIONS
The findings suggest that vinegar can be effective in reducing postprandial glucose and insulin levels, indicating it could be considered as an adjunctive tool for improving glycemic control.
Topics: Acetic Acid; Blood Glucose; Cross-Over Studies; Female; Humans; Hyperglycemia; Insulin; Male; Postprandial Period
PubMed: 28292654
DOI: 10.1016/j.diabres.2017.01.021 -
Sports Medicine (Auckland, N.Z.) Feb 2022Body-fluid loss during prolonged continuous exercise can impair cardiovascular function, harming performance. Delta percent plasma volume (dPV) represents the change in... (Meta-Analysis)
Meta-Analysis
The Hydrating Effects of Hypertonic, Isotonic and Hypotonic Sports Drinks and Waters on Central Hydration During Continuous Exercise: A Systematic Meta-Analysis and Perspective.
BACKGROUND
Body-fluid loss during prolonged continuous exercise can impair cardiovascular function, harming performance. Delta percent plasma volume (dPV) represents the change in central and circulatory body-water volume and therefore hydration during exercise; however, the effect of carbohydrate-electrolyte drinks and water on the dPV response is unclear.
OBJECTIVE
To determine by meta-analysis the effects of ingested hypertonic (> 300 mOsmol kg), isotonic (275-300 mOsmol kg) and hypotonic (< 275 mOsmol kg) drinks containing carbohydrate and electrolyte ([Na] < 50 mmol L), and non-carbohydrate drinks/water (< 40 mOsmol kg) on dPV during continuous exercise.
METHODS
A systematic review produced 28 qualifying studies and 68 drink treatment effects. Random-effects meta-analyses with repeated measures provided estimates of effects and probability of superiority (p) during 0-180 min of exercise, adjusted for drink osmolality, ingestion rate, metabolic rate and a weakly informative Bayesian prior.
RESULTS
Mean drink effects on dPV were: hypertonic - 7.4% [90% compatibility limits (CL) - 8.5, - 6.3], isotonic - 8.7% (90% CL - 10.1, - 7.4), hypotonic - 6.3% (90% CL - 7.4, - 5.3) and water - 7.5% (90% CL - 8.5, - 6.4). Posterior contrast estimates relative to the smallest important effect (dPV = 0.75%) were: hypertonic-isotonic 1.2% (90% CL - 0.1, 2.6; p = 0.74), hypotonic-isotonic 2.3% (90% CL 1.1, 3.5; p = 0.984), water-isotonic 1.3% (90% CL 0.0, 2.5; p = 0.76), hypotonic-hypertonic 1.1% (90% CL 0.1, 2.1; p = 0.71), hypertonic-water 0.1% (90% CL - 0.8, 1.0; p = 0.12) and hypotonic-water 1.1% (90% CL 0.1, 2.0; p = 0.72). Thus, hypotonic drinks were very likely superior to isotonic and likely superior to hypertonic and water. Metabolic rate, ingestion rate, carbohydrate characteristics and electrolyte concentration were generally substantial modifiers of dPV.
CONCLUSION
Hypotonic carbohydrate-electrolyte drinks ingested continuously during exercise provide the greatest benefit to hydration.
Topics: Bayes Theorem; Dehydration; Exercise; Humans; Osmolar Concentration; Sodium; Water-Electrolyte Balance
PubMed: 34716905
DOI: 10.1007/s40279-021-01558-y -
International Journal of Sport... Mar 2021CrossFit® is a high-intensity functional training method consisting of daily workouts called "workouts of the day." No nutritional recommendations exist for CrossFit®...
CrossFit® is a high-intensity functional training method consisting of daily workouts called "workouts of the day." No nutritional recommendations exist for CrossFit® that are supported by scientific evidence regarding the energetic demands of this type of activity or dietary and supplement interventions. This systematic review performed in accordance with PRISMA guidelines aimed to identify studies that determined (a) the physiological and metabolic demands of CrossFit® and (b) the effects of nutritional strategies on CrossFit® performance to guide nutritional recommendations for optimal recovery, adaptations, and performance for CrossFit® athletes and direct future research in this emerging area. Three databases were searched for studies that investigated physiological responses to CrossFit® and dietary or supplementation interventions on CrossFit® performance. Various physiological measures revealed the intense nature of all CrossFit® workouts of the day, reflected in substantial muscle fatigue and damage. Dietary and supplementation studies provided an unclear insight into effective strategies to improve performance and enhance adaptations and recovery due to methodological shortcomings across studies. This systematic review showed that CrossFit® is a high-intensity sport with fairly homogenous anaerobic and aerobic characteristics, resulting in substantial metabolic stress, leading to metabolite accumulation (e.g., lactate and hydrogen ions) and increased markers of muscle damage and muscle fatigue. Limited interventional data exist on dietary and supplementation strategies to optimize CrossFit® performance, and most are moderate to very low quality with some critical methodological limitations, precluding solid conclusions on their efficacy. High-quality work is needed to confirm the ideal dietary and supplemental strategies for optimal performance and recovery for CrossFit® athletes and is an exciting avenue for further research.
Topics: Athletic Performance; Biomedical Research; Diet; Dietary Supplements; Energy Metabolism; Forecasting; Heart Rate; Humans; Lactic Acid; Muscle Fatigue; Myalgia; Oxygen Consumption; Physical Conditioning, Human
PubMed: 33513565
DOI: 10.1123/ijsnem.2020-0223 -
Oxidative Medicine and Cellular... 2017Endometriosis is one of the most common gynaecologic diseases in women of reproductive age. It is characterized by the presence of endometrial tissue outside the uterine... (Review)
Review
Endometriosis is one of the most common gynaecologic diseases in women of reproductive age. It is characterized by the presence of endometrial tissue outside the uterine cavity. The women affected suffer from pelvic pain and infertility. The complex etiology is still unclear and it is based on three main theories: retrograde menstruation, coelomic metaplasia, and induction theory. Genetics and epigenetics also play a role in the development of endometriosis. Recent studies have put the attention on the role of oxidative stress, defined as an imbalance between reactive oxygen species (ROS) and antioxidants, which may be implicated in the pathophysiology of endometriosis causing a general inflammatory response in the peritoneal cavity. Reactive oxygen species are intermediaries produced by normal oxygen metabolism and are inflammatory mediators known to modulate cell proliferation and to have deleterious effects. A systematic review was performed in order to clarify the different roles of oxidative stress and its role in the development of endometriosis. Several issues have been investigated: iron metabolism, oxidative stress markers (in the serum, peritoneal fluid, follicular fluid, peritoneal environment, ovarian cortex, and eutopic and ectopic endometrial tissue), genes involved in oxidative stress, endometriosis-associated infertility, and cancer development.
Topics: Endometriosis; Female; Humans; Oxidative Stress
PubMed: 29057034
DOI: 10.1155/2017/7265238