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Nutrients Sep 2021The primary aim was to systematically review the current evidence investigating if dietary interventions rich in protein lead to improved body weight management in... (Meta-Analysis)
Meta-Analysis
Are Dietary Proteins the Key to Successful Body Weight Management? A Systematic Review and Meta-Analysis of Studies Assessing Body Weight Outcomes after Interventions with Increased Dietary Protein.
The primary aim was to systematically review the current evidence investigating if dietary interventions rich in protein lead to improved body weight management in adults with excessive body weight. The secondary aim was to investigate potential modifying effects of phenotyping. A systematic literature search in PubMed, Web of Science, and Cochrane Library identified 375 randomized controlled trials with 43 unique trials meeting the inclusion criteria. The Cochrane collaboration tool was used for a thorough risk of bias assessment. Based on 37 studies evaluating effects of dietary protein on body weight, the participants with increased protein intake (ranging from 18-59 energy percentage [E%]) were found to reduce body weight by 1.6 (1.2; 2.0) kg (mean [95% confidence interval]) compared to controls (isocaloric interventions with energy reduction introduced in certain studies). Individuals with prediabetes were found to benefit more from a diet high in protein compared to individuals with normoglycemia, as did individuals without the obesity risk allele (AA genotype) compared to individuals with the obesity risk alleles (AG and GG genotypes). Thus, diets rich in protein would seem to have a moderate beneficial effect on body weight management.
Topics: Adult; Body Mass Index; Body Weight; Diet, High-Protein; Dietary Proteins; Exercise; Female; Humans; Male; Middle Aged; Obesity; Overweight; Randomized Controlled Trials as Topic; Weight Gain; Weight Loss; Young Adult
PubMed: 34579069
DOI: 10.3390/nu13093193 -
Sports Medicine (Auckland, N.Z.) Jan 2016Dietary supplements (DSs) are commercially available products consumed as an addition to the usual diet and are frequently ingested by athletes. (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Dietary supplements (DSs) are commercially available products consumed as an addition to the usual diet and are frequently ingested by athletes.
OBJECTIVE
Our objective was to examine the prevalence of DS use by athletes.
DATA SOURCES
PubMed, Ovid MEDLINE, OVID Healthstar, and Cumulative Index to Nursing and Allied Health were searched for original research articles published up to August 2014. Search terms included specific sports, specific DSs, and other terms.
STUDY SELECTION
Studies were selected if they were written in English, involved athletes, and provided a quantitative assessment of the proportion of athletes using specific DSs. Percent of athletes using specific DSs.
SYNTHESIS OF DATA
Methodological quality of studies was assessed by three reviewers using an 8-point scale that included evaluations for sampling methods, sampling frame, sample size, measurement tools, bias, response rate, statistical presentation, and description of the participant sample. Where there were at least two investigations, meta-analysis was performed to obtain summary (pooled) prevalence estimates (SPEs) on (1) DS use prevalence by sport and sex, (2) DS use prevalence by elite versus non-elite athletic status, and (3) specific DS prevalence for all athletic groups combined. Meta-analyses included evaluations of homogeneity and publication bias.
RESULTS
A total of 159 unique studies met the review criteria. Methodological quality was generally low with an average ± standard deviation of 43 ± 16% of available rating points. There was low homogeneity for SPEs when compiled by sport, athletic status, and/or specific DSs. Contributing to the lack of homogeneity were differences in studies' objectives and types of assessments used (e.g., dietary surveys, interviews, questionnaires). Despite these limitations, the data generally indicated that elite athletes used DSs much more than their non-elite counterparts. For most DSs, use prevalence was similar for men and women except that a larger proportion of women used iron while a larger proportion of men used vitamin E, protein, and creatine. No consistent change in use over time was observed because even the earliest investigations showed relatively high use prevalence.
CONCLUSION
It was difficult to generalize regarding DS use by athletes because of the lack of homogeneity among studies. Nonetheless, the data suggested that elite athletes used dietary supplements far more than their non-elite counterparts; use was similar for men and women with a few exceptions; use appeared to change little over time; and a larger proportion of athletes used DSs compared with the general US population. Improvements in study methodology should be considered in future studies especially (1) defining DSs for participants; (2) querying for very specific DSs; (3) using a variety of reporting timeframes (e.g., daily, 2-6 times/week, 1 time/week and <1 time/week); (4) reporting the sampling frame, number of individuals solicited, and number responding; (5) reporting characteristics of volunteers (and non-volunteers, if available); and (6) using similar methods on several occasions to examine possible temporal trends among athletes.
Topics: Athletes; Creatine; Dietary Proteins; Dietary Supplements; Humans; Iron, Dietary; Sex Factors; Vitamin E
PubMed: 26442916
DOI: 10.1007/s40279-015-0387-7 -
The American Journal of Clinical... Mar 2013There is evidence that reducing blood glucose concentrations, inducing weight loss, and improving the lipid profile reduces cardiovascular risk in people with type 2... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
There is evidence that reducing blood glucose concentrations, inducing weight loss, and improving the lipid profile reduces cardiovascular risk in people with type 2 diabetes.
OBJECTIVE
We assessed the effect of various diets on glycemic control, lipids, and weight loss.
DESIGN
We conducted searches of PubMed, Embase, and Google Scholar to August 2011. We included randomized controlled trials (RCTs) with interventions that lasted ≥6 mo that compared low-carbohydrate, vegetarian, vegan, low-glycemic index (GI), high-fiber, Mediterranean, and high-protein diets with control diets including low-fat, high-GI, American Diabetes Association, European Association for the Study of Diabetes, and low-protein diets.
RESULTS
A total of 20 RCTs were included (n = 3073 included in final analyses across 3460 randomly assigned individuals). The low-carbohydrate, low-GI, Mediterranean, and high-protein diets all led to a greater improvement in glycemic control [glycated hemoglobin reductions of -0.12% (P = 0.04), -0.14% (P = 0.008), -0.47% (P < 0.00001), and -0.28% (P < 0.00001), respectively] compared with their respective control diets, with the largest effect size seen in the Mediterranean diet. Low-carbohydrate and Mediterranean diets led to greater weight loss [-0.69 kg (P = 0.21) and -1.84 kg (P < 0.00001), respectively], with an increase in HDL seen in all diets except the high-protein diet.
CONCLUSION
Low-carbohydrate, low-GI, Mediterranean, and high-protein diets are effective in improving various markers of cardiovascular risk in people with diabetes and should be considered in the overall strategy of diabetes management.
Topics: Blood Glucose; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Diet, Carbohydrate-Restricted; Diet, Fat-Restricted; Diet, Mediterranean; Diet, Protein-Restricted; Diet, Vegetarian; Dietary Carbohydrates; Dietary Fats; Dietary Fiber; Dietary Proteins; Energy Intake; Glycemic Index; Humans; Lipids; Randomized Controlled Trials as Topic; Risk Factors; Weight Loss
PubMed: 23364002
DOI: 10.3945/ajcn.112.042457 -
Nutrients Dec 2021Health authorities increasingly recommend a more plant-based diet, rich in fruits, vegetables, pulses, whole grains and nuts, low in red meat and moderate in dairy,...
Health authorities increasingly recommend a more plant-based diet, rich in fruits, vegetables, pulses, whole grains and nuts, low in red meat and moderate in dairy, eggs, poultry and fish which will be beneficial for both health and the environment. A systematic review of observational and intervention studies published between 2000 and January 2020 was conducted to assess nutrient intake and status in adult populations consuming plant-based diets (mainly vegetarian and vegan) with that of meat-eaters. Mean intake of nutrients were calculated and benchmarked to dietary reference values. For micronutrient status, mean concentrations of biomarkers were calculated and compared across diet groups. A total of 141 studies were included, mostly from Europe, South/East Asia, and North America. Protein intake was lower in people following plant-based diets compared to meat-eaters, but well within recommended intake levels. While fiber, polyunsaturated fatty acids (PUFA), folate, vitamin C, E and magnesium intake was higher, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake was lower in vegetarians and vegans as compared to meat-eaters. Intake and status of vitamin B12, vitamin D, iron, zinc, iodine, calcium and bone turnover markers were generally lower in plant-based dietary patterns compared to meat-eaters. Vegans had the lowest vitamin B12, calcium and iodine intake, and also lower iodine status and lower bone mineral density. Meat-eaters were at risk of inadequate intakes of fiber, PUFA, α-linolenic acid (ALA), folate, vitamin D, E, calcium and magnesium. There were nutrient inadequacies across all dietary patterns, including vegan, vegetarian and meat-based diets. As plant-based diets are generally better for health and the environment, public health strategies should facilitate the transition to a balanced diet with more diverse nutrient-dense plant foods through consumer education, food fortification and possibly supplementation.
Topics: Adult; Aged; Aged, 80 and over; Animals; Asia; Diet, Vegan; Diet, Vegetarian; Dietary Fiber; Dietary Proteins; Eating; Energy Intake; Europe; Feeding Behavior; Female; Humans; Male; Meat; Micronutrients; Middle Aged; North America; Nutrients; Nutritional Status; Vitamins
PubMed: 35010904
DOI: 10.3390/nu14010029 -
BMJ (Clinical Research Ed.) Jul 2020To examine and quantify the potential dose-response relation between intake of total, animal, and plant protein and the risk of mortality from all causes, cardiovascular... (Meta-Analysis)
Meta-Analysis
Dietary intake of total, animal, and plant proteins and risk of all cause, cardiovascular, and cancer mortality: systematic review and dose-response meta-analysis of prospective cohort studies.
OBJECTIVE
To examine and quantify the potential dose-response relation between intake of total, animal, and plant protein and the risk of mortality from all causes, cardiovascular disease, and cancer.
DESIGN
Systematic review and meta-analysis of prospective cohort studies.
DATA SOURCES
PubMed, Scopus, and ISI Web of Science until December 2019, and references of retrieved relevant articles.
STUDY SELECTION
Prospective cohort studies that reported the risk estimates for all cause, cardiovascular, and cancer mortality in adults aged 18 or older.
DATA SYNTHESIS
Random effects models were used to calculate pooled effect sizes and 95% confidence intervals for the highest versus lowest categories of protein intake and to incorporate variation between studies. Linear and non-linear dose-response analyses were done to evaluate the dose-response relations between protein intake and mortality.
RESULTS
32 prospective cohort studies were included in the systematic review and 31 in the meta-analysis. During the follow-up period of 3.5 to 32 years, 113 039 deaths (16 429 from cardiovascular disease and 22 303 from cancer) occurred among 715 128 participants. Intake of total protein was associated with a lower risk of all cause mortality (pooled effect size 0.94, 95% confidence interval 0.89 to 0.99, I=58.4%, P<0.001). Intake of plant protein was significantly associated with a lower risk of all cause mortality (pooled effect size 0.92, 95% confidence interval 0.87 to 0.97, I=57.5%, P=0.003) and cardiovascular disease mortality (pooled hazard ratio 0.88, 95% confidence interval 0.80 to 0.96, I=63.7%, P=0.001), but not with cancer mortality. Intake of total and animal protein was not significantly associated with risk of cardiovascular disease and cancer mortality. A dose-response analysis showed a significant inverse dose-response association between intake of plant protein and all cause mortality (P=0.05 for non-linearity). An additional 3% energy from plant proteins a day was associated with a 5% lower risk of death from all causes.
CONCLUSIONS
Higher intake of total protein was associated with a lower risk of all cause mortality, and intake of plant protein was associated with a lower risk of all cause and cardiovascular disease mortality. Replacement of foods high in animal protein with plant protein sources could be associated with longevity.
Topics: Adult; Aged; Aged, 80 and over; Animal Proteins, Dietary; Cardiovascular Diseases; Cause of Death; Diet; Female; Follow-Up Studies; Humans; Male; Middle Aged; Neoplasms; Plant Proteins; Prospective Studies; Risk Factors
PubMed: 32699048
DOI: 10.1136/bmj.m2412 -
The American Journal of Gastroenterology Apr 2011The incidence of inflammatory bowel disease (IBD) is increasing. Dietary factors such as the spread of the "Western" diet, high in fat and protein but low in fruits and... (Review)
Review
OBJECTIVES
The incidence of inflammatory bowel disease (IBD) is increasing. Dietary factors such as the spread of the "Western" diet, high in fat and protein but low in fruits and vegetables, may be associated with the increase. Although many studies have evaluated the association between diet and IBD risk, there has been no systematic review.
METHODS
We performed a systematic review using guideline-recommended methodology to evaluate the association between pre-illness intake of nutrients (fats, carbohydrates, protein) and food groups (fruits, vegetables, meats) and the risk of subsequent IBD diagnosis. Eligible studies were identified via structured keyword searches in PubMed and Google Scholar and manual searches.
RESULTS
Nineteen studies were included, encompassing 2,609 IBD patients (1,269 Crohn's disease (CD) and 1,340 ulcerative colitis (UC) patients) and over 4,000 controls. Studies reported a positive association between high intake of saturated fats, monounsaturated fatty acids, total polyunsaturated fatty acids (PUFAs), total omega-3 fatty acids, omega-6 fatty acids, mono- and disaccharides, and meat and increased subsequent CD risk. Studies reported a negative association between dietary fiber and fruits and subsequent CD risk. High intakes of total fats, total PUFAs, omega-6 fatty acids, and meat were associated with an increased risk of UC. High vegetable intake was associated with a decreased risk of UC.
CONCLUSIONS
High dietary intakes of total fats, PUFAs, omega-6 fatty acids, and meat were associated with an increased risk of CD and UC. High fiber and fruit intakes were associated with decreased CD risk, and high vegetable intake was associated with decreased UC risk.
Topics: Colitis, Ulcerative; Crohn Disease; Diet; Dietary Carbohydrates; Dietary Fats; Dietary Fiber; Dietary Proteins; Fatty Acids, Omega-6; Fatty Acids, Unsaturated; Fruit; Humans; Inflammatory Bowel Diseases; Meat; Risk Assessment; Vegetables
PubMed: 21468064
DOI: 10.1038/ajg.2011.44 -
Nutrients Feb 2021Although animal protein is usually considered to be a more potent stimulator of muscle protein synthesis than plant protein, the effect of protein source on lean mass... (Meta-Analysis)
Meta-Analysis
Although animal protein is usually considered to be a more potent stimulator of muscle protein synthesis than plant protein, the effect of protein source on lean mass and muscle strength needs to be systematically reviewed. This study aimed to examine potential differences in the effect of animal vs. plant protein on lean mass and muscle strength, and the possible influence of resistance exercise training (RET) and age. The following databases were searched: PubMed, Embase, Scopus and CINAHL Plus with Full Text, and 3081 articles were screened. A total of 18 articles were selected for systematic review, of which, 16 were used for meta-analysis. Total protein intakes were generally above the recommended dietary allowance at the baseline and end of intervention. Results from the meta-analyses demonstrated that protein source did not affect changes in absolute lean mass or muscle strength. However, there was a favoring effect of animal protein on percent lean mass. RET had no influence on the results, while younger adults (<50 years) were found to gain absolute and percent lean mass with animal protein intake (weighted mean difference (WMD), 0.41 kg; 95% confidence interval (CI) 0.08 to 0.74; WMD 0.50%; 95% CI 0.00 to 1.01). Collectively, animal protein tends to be more beneficial for lean mass than plant protein, especially in younger adults.
Topics: Adult; Age Factors; Aged; Animal Proteins, Dietary; Female; Humans; Male; Middle Aged; Muscle Strength; Muscle, Skeletal; Nutritional Physiological Phenomena; Plant Proteins, Dietary; Randomized Controlled Trials as Topic; Resistance Training
PubMed: 33670701
DOI: 10.3390/nu13020661 -
International Journal of Sport... Apr 2014Caloric restriction occurs when athletes attempt to reduce body fat or make weight. There is evidence that protein needs increase when athletes restrict calories or have... (Review)
Review
UNLABELLED
Caloric restriction occurs when athletes attempt to reduce body fat or make weight. There is evidence that protein needs increase when athletes restrict calories or have low body fat.
PURPOSE
The aims of this review were to evaluate the effects of dietary protein on body composition in energy-restricted resistance-trained athletes and to provide protein recommendations for these athletes.
METHODS
Database searches were performed from earliest record to July 2013 using the terms protein, and intake, or diet, and weight, or train, or restrict, or energy, or strength, and athlete. Studies (N = 6) needed to use adult (≥ 18 yrs), energy-restricted, resistance-trained (> 6 months) humans of lower body fat (males ≤ 23% and females ≤ 35%) performing resistance training. Protein intake, fat free mass (FFM) and body fat had to be reported.
RESULTS
Body fat percentage decreased (0.5-6.6%) in all study groups (N = 13) and FFM decreased (0.3-2.7kg) in nine of 13. Six groups gained, did not lose, or lost nonsignificant amounts of FFM. Five out of these six groups were among the highest in body fat, lowest in caloric restriction, or underwent novel resistance training stimuli. However, the one group that was not high in body fat that underwent substantial caloric restriction, without novel training stimuli, consumed the highest protein intake out of all the groups in this review (2.5-2.6g/kg).
CONCLUSIONS
Protein needs for energy-restricted resistance-trained athletes are likely 2.3-3.1g/kg of FFM scaled upwards with severity of caloric restriction and leanness.
Topics: Adipose Tissue; Athletes; Body Composition; Body Fluid Compartments; Body Weight; Caloric Restriction; Dietary Proteins; Energy Intake; Female; Humans; Male; Nutritional Requirements; Resistance Training; Sports; Sports Nutritional Physiological Phenomena
PubMed: 24092765
DOI: 10.1123/ijsnem.2013-0054 -
Osteoporosis International : a Journal... Jun 2017This systematic review summarizes the effect of combined exercise and nutrition intervention on muscle mass and muscle function. A total of 37 RCTs were identified.... (Review)
Review
UNLABELLED
This systematic review summarizes the effect of combined exercise and nutrition intervention on muscle mass and muscle function. A total of 37 RCTs were identified. Results indicate that physical exercise has a positive impact on muscle mass and muscle function in subjects aged 65 years and older. However, any interactive effect of dietary supplementation appears to be limited.
INTRODUCTION
In 2013, Denison et al. conducted a systematic review including 17 randomized controlled trials (RCTs) to explore the effect of combined exercise and nutrition intervention to improve muscle mass, muscle strength, or physical performance in older people. They concluded that further studies were needed to provide evidence upon which public health and clinical recommendations could be based. The purpose of the present work was to update the prior systematic review and include studies published up to October 2015.
METHODS
Using the electronic databases MEDLINE and EMBASE, we identified RCTs which assessed the combined effect of exercise training and nutritional supplementation on muscle strength, muscle mass, or physical performance in subjects aged 60 years and over. Study selection and data extraction were performed by two independent reviewers.
RESULTS
The search strategy identified 21 additional RCTs giving a total of 37 RCTs. Studies were heterogeneous in terms of protocols for physical exercise and dietary supplementation (proteins, essential amino acids, creatine, β-hydroxy-β-methylbuthyrate, vitamin D, multi-nutrients, or other). In 79% of the studies (27/34 RCTs), muscle mass increased with exercise but an additional effect of nutrition was only found in 8 RCTs (23.5%). Muscle strength increased in 82.8% of the studies (29/35 RCTs) following exercise intervention, and dietary supplementation showed additional benefits in only a small number of studies (8/35 RCTS, 22.8%). Finally, the majority of studies showed an increase of physical performance following exercise intervention (26/28 RCTs, 92.8%) but interaction with nutrition supplementation was only found in 14.3% of these studies (4/28 RCTs).
CONCLUSION
Physical exercise has a positive impact on muscle mass and muscle function in healthy subjects aged 60 years and older. The biggest effect of exercise intervention, of any type, has been seen on physical performance (gait speed, chair rising test, balance, SPPB test, etc.). We observed huge variations in regard to the dietary supplementation protocols. Based on the included studies, mainly performed on well-nourished subjects, the interactive effect of dietary supplementation on muscle function appears limited.
Topics: Amino Acids, Essential; Creatine; Dietary Proteins; Dietary Supplements; Exercise; Exercise Therapy; Humans; Muscle Strength; Sarcopenia; Valerates; Vitamin D
PubMed: 28251287
DOI: 10.1007/s00198-017-3980-9 -
The British Journal of Nutrition Mar 2023Low-grade inflammation is a mediator of muscle proteostasis. This study aimed to investigate the effects of isolated whey and soy proteins on inflammatory markers. (Meta-Analysis)
Meta-Analysis Review
BACKGROUND AND AIMS
Low-grade inflammation is a mediator of muscle proteostasis. This study aimed to investigate the effects of isolated whey and soy proteins on inflammatory markers.
METHODS
We conducted a systematic literature search of randomised controlled trials (RCT) through MEDLINE, Web of Science, Scopus and Cochrane Library databases from inception until September 2021. To determine the effectiveness of isolated proteins on circulating levels of C-reactive protein (CRP), IL-6 and TNF-α, a meta-analysis using a random-effects model was used to calculate the pooled effects (CRD42021252603).
RESULTS
Thirty-one RCT met the inclusion criteria and were included in the systematic review and meta-analysis. A significant reduction of circulating IL-6 levels following whey protein [Mean Difference (MD): -0·79, 95 % CI: -1·15, -0·42, I = 96 %] and TNF-α levels following soy protein supplementation (MD: -0·16, 95 % CI: -0·26, -0·05, I = 68 %) was observed. The addition of soy isoflavones exerted a further decline in circulating TNF-α levels (MD: -0·20, 95 % CI: -0·31, -0·08, I = 34 %). According to subgroup analysis, whey protein led to a statistically significant decrease in circulating IL-6 levels in individuals with sarcopenia and pre-frailty (MD: -0·98, 95 % CI: -1·56, -0·39, I = 0 %). These findings may be dependent on participant characteristics and treatment duration.
CONCLUSIONS
These data support that whey and soy protein supplementation elicit anti-inflammatory effects by reducing circulating IL-6 and TNF-α levels, respectively. This effect may be enhanced by soy isoflavones and may be more prominent in individuals with sarcopenia.
Topics: Humans; Aged; Soybean Proteins; Whey Proteins; Cytokines; Whey; Tumor Necrosis Factor-alpha; Interleukin-6; Sarcopenia; C-Reactive Protein; Inflammation; Dietary Supplements; Isoflavones
PubMed: 35706399
DOI: 10.1017/S0007114522001787