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The Journal of Nutrition Jun 2020Increased protein intake has been suggested to improve gains in muscle mass and strength in adults. Furthermore, the timing of protein intake has been discussed as a... (Meta-Analysis)
Meta-Analysis
The Role of Protein Intake and its Timing on Body Composition and Muscle Function in Healthy Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
BACKGROUND
Increased protein intake has been suggested to improve gains in muscle mass and strength in adults. Furthermore, the timing of protein intake has been discussed as a margin of opportunity for improved prevention measures.
OBJECTIVE
This systematic review investigated the effect of protein supplementation on body composition and muscle function (strength and synthesis) in healthy adults, with an emphasis on the timing of protein intake.
METHODS
Randomized controlled trials were identified using PubMed, Web of Science, CINAHL, and Embase, up to March 2019. For meta-analyses, data on lean body mass (LBM), handgrip strength, and leg press strength were pooled by age group (mean age 18-55 or >55 y) and timing of protein intake. The quality of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluations approach.
RESULTS
Data from 65 studies with 2907 participants (1514 men and 1380 women, 13 unknown sex) were included in the review. Twenty-six, 8, and 24 studies were used for meta-analysis on LBM, handgrip strength, and leg press strength, respectively. The protein supplementation was effective in improving (mean difference; 95% CI) LBM in adults (0.62 kg; 0.36, 0.88) and older adults (0.46 kg; 0.23, 0.70), but not handgrip strength (older adults: 0.26 kg; -0.51, 1.04) and leg press strength (adults: 5.80 kg; -0.33, 11.93; older adults: 1.97 kg; -2.78, 6.72). Sensitivity analyses removing studies without exercise training had no impact on the outcomes. Data regarding muscle synthesis were scarce and inconclusive. Subgroup analyses showed no beneficial effect of a specific timing of protein intake on LBM, handgrip strength, and leg press strength.
CONCLUSION
Overall, the results support the positive impact of protein supplementation on LBM of adults and older adults, independently of intake timing. Effects on muscle strength and synthesis are less clear and need further investigation. This systematic review was registered on PROSPERO as CRD42019126742.
Topics: Adolescent; Adult; Body Composition; Dietary Proteins; Female; Humans; Male; Middle Aged; Muscle, Skeletal; Randomized Controlled Trials as Topic; Resistance Training; Young Adult
PubMed: 32232404
DOI: 10.1093/jn/nxaa049 -
Nutrients Dec 2022The purpose of this systematic review was to evaluate the impact of saturated fatty acid chain lengths on the development of cardiovascular disease (CVD). The importance... (Review)
Review
The purpose of this systematic review was to evaluate the impact of saturated fatty acid chain lengths on the development of cardiovascular disease (CVD). The importance of replacement macronutrients is also discussed. PubMed, CINAHL, and Cochrane library were searched for relevant prospective cohort studies that measured SFA chain length via diet analysis through October of 2020. A second updated PubMed search was conducted from October 2020 to 7 August 2022. Five prospective cohort studies were added. All studies used food frequency questionnaires to assess dietary intake. For all five added studies, the main sources of saturated fat were palmitic and steric acid from meat and cheese. Most studies discovered an association with increased risk of CVD and long-chain saturated fatty acid intake, as well as a neutral (potentially beneficial) association with short- and medium-chain saturated fatty acids. Isocaloric substitutions were associated with a higher risk for CVD when saturated fats were replaced with refined carbohydrates and protein from meat, but a reduced or neutral impact when relaced with plant-based protein, unsaturated fat, or complex carbohydrates. When examining the impact of diet on CVD risk, it is critical to consider the macronutrient replacing saturated fat as well as the saturated fat chain length, whole foods, and diet patterns on CVD risk. The studies included in this review suggest that LCSFA (C12-18) may increase the risk for CVD development, while SCFA and MCFA (C4--C10) may be more beneficial or neutral.
Topics: Humans; Cardiovascular Diseases; Fatty Acids; Dietary Fats; Prospective Studies; Carbohydrates; Risk Factors
PubMed: 36615688
DOI: 10.3390/nu15010030 -
Advances in Nutrition (Bethesda, Md.) Jan 2019Sarcopenia is an age-related condition associated with a progressive loss of muscle mass and strength. Insufficient protein intake is a risk factor for sarcopenia.... (Meta-Analysis)
Meta-Analysis
The Impact of Dairy Protein Intake on Muscle Mass, Muscle Strength, and Physical Performance in Middle-Aged to Older Adults with or without Existing Sarcopenia: A Systematic Review and Meta-Analysis.
Sarcopenia is an age-related condition associated with a progressive loss of muscle mass and strength. Insufficient protein intake is a risk factor for sarcopenia. Protein supplementation is suggested to improve muscle anabolism and function in younger and older adults. Dairy products are a good source of high-quality proteins. This review evaluates the effectiveness of dairy proteins on functions associated with sarcopenia in middle-aged and older adults. Randomized controlled trials were identified using PubMed, CINAHL/EBSCO, and Web of Science databases (last search: 10 May 2017) and were quality assessed. The results of appendicular muscle mass and muscle strength of handgrip and leg press were pooled using a random-effects model. The analysis of the Short Physical Performance Battery is presented in narrative form. Adverse events and tolerability of dairy protein supplementation were considered as secondary outcomes. Fourteen studies involving 1424 participants aged between 61 and 81 y met the inclusion criteria. Dairy protein significantly increased appendicular muscle mass (0.13 kg; 95% CI: 0.01, 0.26 kg; P = 0.04); however, it had no effect on improvement in handgrip (0.84 kg; 95% CI: -0.24, 1.93 kg; P = 0.13) or leg press (0.37 kg; 95% CI: -4.79, 5.53 kg; P = 0.89). The effect of dairy protein on the Short Physical Performance Battery was inconclusive. Nine studies reported the dairy protein to be well tolerated with no serious adverse events. Although future high-quality research is required to establish the optimal type of dairy protein, the present systematic review provides evidence of the beneficial effect of dairy protein as a potential nutrition strategy to improve appendicular muscle mass in middle-aged and older adults.
Topics: Aged; Aged, 80 and over; Dairy Products; Dietary Supplements; Female; Geriatric Assessment; Hand Strength; Humans; Male; Middle Aged; Milk Proteins; Muscle Strength; Muscle, Skeletal; Nutritional Status; Physical Functional Performance; Sarcopenia
PubMed: 30624580
DOI: 10.1093/advances/nmy065 -
Nutrients Jun 2019Published meta-analyses indicate significant but inconsistent incident type-2 diabetes(T2D)-dietary glycemic index (GI) and glycemic load (GL) risk ratios or risk... (Meta-Analysis)
Meta-Analysis
Published meta-analyses indicate significant but inconsistent incident type-2 diabetes(T2D)-dietary glycemic index (GI) and glycemic load (GL) risk ratios or risk relations (RR). It is nowover a decade ago that a published meta-analysis used a predefined standard to identify validstudies. Considering valid studies only, and using random effects dose-response meta-analysis(DRM) while withdrawing spurious results ( < 0.05), we ascertained whether these relationswould support nutrition guidance, specifically for an RR > 1.20 with a lower 95% confidence limit>1.10 across typical intakes (approximately 10th to 90th percentiles of population intakes). Thecombined T2D-GI RR was 1.27 (1.15-1.40) ( < 0.001, = 10 studies) per 10 units GI, while that forthe T2D-GL RR was 1.26 (1.15-1.37) ( < 0.001, = 15) per 80 g/d GL in a 2000 kcal (8400 kJ) diet.The corresponding global DRM using restricted cubic splines were 1.87 (1.56-2.25) ( < 0.001, =10) and 1.89 (1.66-2.16) ( < 0.001, = 15) from 47.6 to 76.1 units GI and 73 to 257 g/d GL in a 2000kcal diet, respectively. In conclusion, among adults initially in good health, diets higher in GI or GLwere robustly associated with incident T2D. Together with mechanistic and other data, thissupports that consideration should be given to these dietary risk factors in nutrition advice.Concerning the public health relevance at the global level, our evidence indicates that GI and GLare substantial food markers predicting the development of T2D worldwide, for persons ofEuropean ancestry and of East Asian ancestry.
Topics: Adult; Blood Glucose; Diabetes Mellitus, Type 2; Diet; Dietary Carbohydrates; Female; Glycemic Index; Glycemic Load; Humans; Male; Middle Aged; Odds Ratio; Prospective Studies; Risk Factors
PubMed: 31195724
DOI: 10.3390/nu11061280 -
BMJ (Clinical Research Ed.) Aug 2019To assess effects of increasing omega-3, omega-6, and total polyunsaturated fatty acids (PUFA) on diabetes diagnosis and glucose metabolism. (Meta-Analysis)
Meta-Analysis
Omega-3, omega-6, and total dietary polyunsaturated fat for prevention and treatment of type 2 diabetes mellitus: systematic review and meta-analysis of randomised controlled trials.
OBJECTIVE
To assess effects of increasing omega-3, omega-6, and total polyunsaturated fatty acids (PUFA) on diabetes diagnosis and glucose metabolism.
DESIGN
Systematic review and meta-analyses.
DATA SOURCES
Medline, Embase, Cochrane CENTRAL, WHO International Clinical Trials Registry Platform, Clinicaltrials.gov, and trials in relevant systematic reviews.
ELIGIBILITY CRITERIA
Randomised controlled trials of at least 24 weeks' duration assessing effects of increasing α-linolenic acid, long chain omega-3, omega-6, or total PUFA, which collected data on diabetes diagnoses, fasting glucose or insulin, glycated haemoglobin (HbA), and/or homoeostatic model assessment for insulin resistance (HOMA-IR).
DATA SYNTHESIS
Statistical analysis included random effects meta-analyses using relative risk and mean difference, and sensitivity analyses. Funnel plots were examined and subgrouping assessed effects of intervention type, replacement, baseline risk of diabetes and use of antidiabetes drugs, trial duration, and dose. Risk of bias was assessed with the Cochrane tool and quality of evidence with GRADE.
RESULTS
83 randomised controlled trials (mainly assessing effects of supplementary long chain omega-3) were included; 10 were at low summary risk of bias. Long chain omega-3 had little or no effect on likelihood of diagnosis of diabetes (relative risk 1.00, 95% confidence interval 0.85 to 1.17; 58 643 participants, 3.7% developed diabetes) or measures of glucose metabolism (HbA mean difference -0.02%, 95% confidence interval -0.07% to 0.04%; plasma glucose 0.04, 0.02 to 0.07, mmol/L; fasting insulin 1.02, -4.34 to 6.37, pmol/L; HOMA-IR 0.06, -0.21 to 0.33). A suggestion of negative outcomes was observed when dose of supplemental long chain omega-3 was above 4.4 g/d. Effects of α-linolenic acid, omega-6, and total PUFA on diagnosis of diabetes were unclear (as the evidence was of very low quality), but little or no effect on measures of glucose metabolism was seen, except that increasing α-linolenic acid may increase fasting insulin (by about 7%). No evidence was found that the omega-3/omega-6 ratio is important for diabetes or glucose metabolism.
CONCLUSIONS
This is the most extensive systematic review of trials to date to assess effects of polyunsaturated fats on newly diagnosed diabetes and glucose metabolism, including previously unpublished data following contact with authors. Evidence suggests that increasing omega-3, omega-6, or total PUFA has little or no effect on prevention and treatment of type 2 diabetes mellitus.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO CRD42017064110.
Topics: Adult; Blood Glucose; Diabetes Mellitus, Type 2; Dietary Fats, Unsaturated; Dietary Supplements; Fasting; Fatty Acids, Omega-3; Fatty Acids, Omega-6; Fatty Acids, Unsaturated; Female; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Male; Primary Prevention; Randomized Controlled Trials as Topic; Secondary Prevention
PubMed: 31434641
DOI: 10.1136/bmj.l4697 -
Advances in Nutrition (Bethesda, Md.) Dec 2021Although levodopa remains the most effective drug for symptomatic management of Parkinson's Disease (PD), treatment during advanced disease stages may raise...
Although levodopa remains the most effective drug for symptomatic management of Parkinson's Disease (PD), treatment during advanced disease stages may raise unpredictable motor fluctuations and other complications. Counteracting these complications with other pharmacological therapies may prompt a vicious circle of side effects, and here, nutritional therapy may have great potential. Knowledge about the role of diet in PD is emerging and multiple studies have investigated nutritional support specifically with respect to levodopa therapy. With this systematic review, we aim to give a comprehensive overview of dietary approaches to optimize levodopa treatment in PD. A systematic search was performed using the databases of PubMed and Scopus between January 1985 and September 2020. Nutritional interventions with the rationale to optimize levodopa therapy in human PD patients were eligible for this study and their quality was assessed with the Cochrane risk-of-bias tool. In total, we included 22 papers that addressed the effects of dietary proteins (n = 10), vitamins (n = 7), fiber (n = 2), soybeans (n = 1), caffeine (n = 1), and ketogenic diets (n = 1) on levodopa therapy. Interventions with protein redistribution diets (PRDs), dietary fiber, vitamin C, and caffeine improved levodopa absorption, thereby enhancing clinical response and reducing motor fluctuations. Furthermore, supplementation of vitamin B-12, vitamin B-6, and folic acid successfully reduced high homocysteine concentrations that emerged from levodopa metabolism and promoted many metabolic and clinical complications, such as neuropathology and osteoporosis. In conclusion, dietary interventions have the potential to optimize levodopa efficacy and control side effects. Nutrition that improves levodopa absorption, including PRDs, fiber, vitamin C, and caffeine, is specifically recommended when fluctuating clinical responses appear. Supplements of vitamin B-12, vitamin B-6, and folic acid are advised along with levodopa initiation to attenuate hyperhomocysteinemia, and importantly, their potential to treat consequent metabolic and clinical complications warrants future research.
Topics: Antiparkinson Agents; Diet; Humans; Levodopa; Parkinson Disease; Vitamin B 12
PubMed: 34113965
DOI: 10.1093/advances/nmab060 -
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 -
The Journal of Nutrition Nov 2018Higher-protein (HP) diets are advocated for several reasons, including mitigation of sarcopenia, but their effects on kidney function are unclear. (Meta-Analysis)
Meta-Analysis
BACKGROUND
Higher-protein (HP) diets are advocated for several reasons, including mitigation of sarcopenia, but their effects on kidney function are unclear.
OBJECTIVE
This meta-analysis was conducted to determine the effect of HP intakes on kidney function in healthy adults.
METHODS
We conducted a systematic review and meta-analysis of trials comparing HP (≥1.5 g/kg body weight or ≥20% energy intake or ≥100 g protein/d) with normal- or lower-protein (NLP; ≥5% less energy intake from protein/d compared with HP group) intakes on kidney function. Medline and EMBASE databases were searched. Randomized controlled trials comparing the effects of HP with NLP (>4 d duration) intakes on glomerular filtration rate (GFR) in adults without kidney disease were included.
RESULTS
A total of 2144 abstracts were reviewed, with 40 articles selected for full-text review; 28 of these were analyzed and included data from 1358 participants. Data were analyzed using random-effects meta-analysis (RevMan 5; The Cochrane Collaboration), meta-regression (STATA; StataCorp), and dose-response analysis (Prism; GraphPad). Analyses were conducted using postintervention (post) GFR and the change in GFR from preintervention to post. The post-only comparison showed a trivial effect for GFR to be higher after HP intakes [standardized mean difference (SMD): 0.19; 95% CI: 0.07, 0.31; P = 0.002]. The change in GFR did not differ between interventions (SMD: 0.11; 95% CI: -0.05, 0.27; P = 0.16). There was a linear relation between protein intake and GFR in the post-only comparison (r = 0.332, P = 0.03), but not between protein intake and the change in GFR (r = 0.184, P = 0.33). The main limitation of the current analysis is the unclear risk of selection bias of the included trials.
CONCLUSIONS
Postintervention GFR comparisons indicate that HP diets result in higher GFRs; however, when changes in GFR were compared, dietary protein had no effect. Our analysis indicates that HP intakes do not adversely influence kidney function on GFR in healthy adults.
Topics: Adult; Diet, Protein-Restricted; Dietary Proteins; Glomerular Filtration Rate; Humans
PubMed: 30383278
DOI: 10.1093/jn/nxy197 -
Annals of Oncology : Official Journal... May 2018Driven by reduced nutritional intakes and metabolic alterations, malnutrition in cancer patients adversely affects quality of life, treatment tolerance and survival. We... (Meta-Analysis)
Meta-Analysis
Systematic review and meta-analysis of the evidence for oral nutritional intervention on nutritional and clinical outcomes during chemo(radio)therapy: current evidence and guidance for design of future trials.
BACKGROUND
Driven by reduced nutritional intakes and metabolic alterations, malnutrition in cancer patients adversely affects quality of life, treatment tolerance and survival. We examined evidence for oral nutritional interventions during chemo(radio)therapy.
DESIGN
We carried out a systematic review of randomized controlled trials (RCT) with either dietary counseling (DC), high-energy oral nutritional supplements (ONS) aiming at improving intakes or ONS enriched with protein and n-3 polyunsaturated fatty acids (PUFA) additionally aiming for modulation of cancer-related metabolic alterations. Meta-analyses were carried out on body weight (BW) response to nutritional interventions, with subgroup analyses for DC and/or high-energy ONS or high-protein n-3 PUFA-enriched ONS.
RESULTS
Eleven studies were identified. Meta-analysis showed overall benefit of interventions on BW during chemo(radio)therapy (+1.31 kg, 95% CI 0.24-2.38, P = 0.02, heterogeneity Q = 21.1, P = 0.007). Subgroup analysis showed no effect of DC and/or high-energy ONS (+0.80 kg, 95% CI -1.14 to 2.74, P = 0.32; Q = 10.5, P = 0.03), possibly due to limited compliance and intakes falling short of intake goals. A significant effect was observed for high-protein n-3 PUFA-enriched intervention compared with isocaloric controls (+1.89 kg, 95% CI 0.51-3.27, P = 0.02; Q = 3.1 P = 0.37). High-protein, n-3 PUFA-enriched ONS studies showed attenuation of lean body mass loss (N = 2 studies) and improvement of some quality of life domains (N = 3 studies). Overall, studies were limited in number, heterogeneous, and inadequately powered to show effects on treatment toxicity or survival.
CONCLUSION
This systematic review suggests an overall positive effect of nutritional interventions during chemo(radio)therapy on BW. Subgroup analyses showed effects were driven by high-protein n-3 PUFA-enriched ONS, suggesting the benefit of targeting metabolic alterations. DC and/or high-energy ONS were less effective, likely due to cumulative caloric deficits despite interventions. We highlight the need and provide recommendations for well-designed RCT to determine the effect of nutritional interventions on clinical outcomes, with specific focus on reaching nutritional goals and providing the right nutrients, as part of an integral supportive care approach.
Topics: Administration, Oral; Body Weight; Chemoradiotherapy; Counseling; Dietary Proteins; Dietary Supplements; Energy Intake; Enteral Nutrition; Fatty Acids, Omega-3; Humans; Neoplasms; Nutritional Status; Patient Compliance; Practice Guidelines as Topic; Progression-Free Survival; Quality of Life; Randomized Controlled Trials as Topic; Research Design
PubMed: 29788170
DOI: 10.1093/annonc/mdy114 -
Sports Medicine (Auckland, N.Z.) Dec 2023Protein supplements are important to maintain optimum health and physical performance, particularly in athletes and active individuals to repair and rebuild their...
Effect of Soy Protein Supplementation on Muscle Adaptations, Metabolic and Antioxidant Status, Hormonal Response, and Exercise Performance of Active Individuals and Athletes: A Systematic Review of Randomised Controlled Trials.
BACKGROUND
Protein supplements are important to maintain optimum health and physical performance, particularly in athletes and active individuals to repair and rebuild their skeletal muscles and connective tissues. Soy protein (SP) has gained popularity in recent years as an alternative to animal proteins.
OBJECTIVES
This systematic review evaluates the evidence from randomised controlled clinical trials of the effects of SP supplementation in active individuals and athletes in terms of muscle adaptations, metabolic and antioxidant status, hormonal response and exercise performance. It also explores the differences in SP supplementation effects in comparison to whey protein.
METHODS
A systematic search was conducted in PubMed, Embase and Web of Science, as well as a manual search in Google Scholar and EBSCO, on 27 June 2023. Randomised controlled trials that evaluated the applications of SPs supplementation on sports and athletic-related outcomes that are linked with exercise performance, adaptations and biomarkers in athletes and physically active adolescents and young adults (14 to 39 years old) were included, otherwise, studies were excluded. The risk of bias was assessed according to Cochrane's revised risk of bias tool.
RESULTS
A total of 19 eligible original research articles were included that investigated the effect of SP supplementation on muscle adaptations (n = 9), metabolic and antioxidant status (n = 6), hormonal response (n = 6) and exercise performance (n = 6). Some studies investigated more than one effect. SP was found to provide identical increases in lean mass compared to whey in some studies. SP consumption promoted the reduction of exercise-induced metabolic/blood circulating biomarkers such as triglycerides, uric acid and lactate. Better antioxidant capacity against oxidative stress has been seen with respect to whey protein in long-term studies. Some studies reported testosterone and cortisol fluctuations related to SP; however, more research is required. All studies on SP and endurance performance suggested the potential beneficial effects of SP supplementation (10-53.3 g) on exercise performance by improving high-intensity and high-speed running performance, enhancing maximal cardiac output, delaying fatigue and improving isometric muscle strength, improving endurance in recreational cyclists, increasing running velocity and decreasing accumulated lactate levels; however, studies determining the efficacy of soy protein on VOmax provided conflicted results.
CONCLUSION
It is possible to recommend SP to athletes and active individuals in place of conventional protein supplements by assessing their dosage and effectiveness in relation to different types of training. SP may enhance lean mass compared with other protein sources, enhance the antioxidant status, and reduce oxidative stress. SP supplementation had an inconsistent effect on testosterone and cortisol levels. SP supplementation may be beneficial, especially after muscle damage, high-intensity/high-speed or repeated bouts of strenuous exercise.
Topics: Adolescent; Adult; Humans; Young Adult; Antioxidants; Athletes; Biomarkers; Dietary Supplements; Hydrocortisone; Lactates; Muscle, Skeletal; Soybean Proteins; Testosterone; Whey Proteins; Randomized Controlled Trials as Topic
PubMed: 37603200
DOI: 10.1007/s40279-023-01899-w