Soy protein based supplementation supports metabolic effects of resistance training in previously untrained middle aged males

Comparative Efficacy of Different Protein Supplements on Muscle Mass, Strength, and Physical Indices of Sarcopenia among Community-Dwelling, Hospitalized or Institutionalized Older Adults Undergoing Resistance Training: A Network Meta-Analysis of Randomized Controlled Trials

Aging-related sarcopenia exerts harmful impacts on muscle mass, strength, and physical mobility. Protein supplementation has been demonstrated to augment efficacy of resistance training (RT) in elderly. This study compared the relative effects of different protein supplements on muscle mass, strength, and mobility outcomes in middle-aged and older individuals undergoing RT. A comprehensive search of online databases was performed to identify randomized controlled trials (RCTs) examining the efficacy of protein supplement plus RT in untrained community-dwelling adults, hospitalized, or institutionalized residents who suffered acute or chronic health conditions. Network meta-analysis (NMA) was performed using a frequentist method for all analyses. Treatment effects for main outcomes were expressed as standard mean difference (SMD) with 95% confidence interval (CI). We used the surface-under-the cumulative-ranking (SUCRA) scores to rank probabilities of effect estimation among all identified treatments. Meta-regression analyses were performed to identify any relevant moderator of the treatment efficacy and results were expressed as β with 95% credible interval (CrI). We finally included 78 RCTs (5272 participants) for analyses. Among the six protein sources identified in this NMA, namely whey, milk, casein, meat, soy, and peanut, whey supplement yielded the most effective treatments augmenting efficacy of RT on muscle mass (SMD = 1.29, 95% CI: 0.96, 1.62; SUCRA = 0.86), handgrip strength (SMD = 1.46, 95% CI: 0.92, 2.00; SUCRA = 0.85), and walking speed (SMD = 0.73, 95% CI: 0.39, 1.07; SUCRA = 0.84). Participant's health condition, sex, and supplementation dose were significant factors moderating the treatment efficacy on muscle mass (β = 0.74; 95% CrI: 0.22, 1.25), handgrip strength (β = -1.72; 95% CrI: -2.68, -0.77), and leg strength (β = 0.76; 95% CrI: 0.06, 1.47), respectively. Our findings suggest whey protein yields the optimal supplements to counter sarcopenia in older individuals undergoing RT.

Additive impact of soy protein dietary intake and exercise on visceral fat mass reduction and mitochondrial complex I activation in skeletal muscle

Soy protein has shown remarkable effectiveness in reducing fat mass compared with other protein sources, and exercise has the potential to further enhance this fat loss effect. Previous studies have demonstrated that soy protein intake leads to decreased fatty acid synthesis, which contributes to its fat-loss properties. However, the exact mechanism by which these lipids are consumed remains unclear. To investigate this, we conducted a comprehensive study using C57/BL6 male mice, comparing the effects of soy and casein proteins with and without exercise (Casein-Sed, Casein-Ex, Soy-Sed, and Soy-Ex groups) under high- and low-protein conditions (14% or 40% protein). Our findings revealed that combining soy protein intake with exercise significantly reduced epididymal white adipose tissue (eWAT) weight, particularly in the high-protein diet group. Further analysis revealed that exercise increased the expression of lipid oxidation-regulatory proteins, including mitochondrial oxidative phosphorylation protein (OXPHOS) complexes, in the plantaris muscle regardless of the protein source. Although soy protein intake did not directly affect muscle mitochondrial protein expression, the activity of OXPHOS complex I was additively enhanced by exercise and soy protein under the 40% protein condition. Notably, complex I activity inversely correlated with eWAT weight in the soy protein diet group. These results highlight the potential link between improved complex I activity induced by soy protein and fat mass reduction, which emphasizes the promising benefits of combining soy protein with exercise in promoting fat loss.NEW & NOTEWORTHY The findings revealed that soy protein intake combined with exercise resulted in reduced adipose tissue weight compared with that obtained with casein protein intake. Furthermore, the joint impact of exercise and soy protein consumption resulted in enhanced activity of oxidative phosphorylation protein (OXPHOS) complex I in fast-twitch muscles, which appears to be associated with fat mass reduction. These findings elucidate the potential additive effects of soy protein and exercise on body weight management.

Effects of Physical Activity Interventions on Strength, Balance and Falls in Middle-Aged Adults: A Systematic Review and Meta-Analysis

BACKGROUND

Weak lower body strength and balance impairments are fundamental risk factors for mobility impairments and falls that can be improved by physical activity (PA). Previous meta-analyses have focused on these risk factors in adults aged ≥ 65 years. Yet, the potential of PA for improving these risk factors in middle-aged populations has not been systematically investigated. This systematic review and meta-analysis aim to examine the effect of general and structured PA on lower limb strength, postural balance and falls in middle-aged adults.

METHODS

A computerized systematic literature search was conducted in the electronic databases MEDLINE, CINAHL, Web of Science and Cochrane Library. PA intervention types were classified according to the ProFaNE taxonomy. Randomized controlled trials exploring the effects of PA on strength (e.g., leg press one-repetition-maximum), balance (e.g., single limb stance) and falls (e.g., fall rates) in adults aged 40-60 years were systematically searched and included in a network analysis. Moderator analyses were performed for specific subgroups (age, sex, low PA). The methodological quality of the included studies was assessed using the Physiotherapy Evidence Database (PEDro) Scale.

RESULTS

Out of 7170 articles screened, 66 studies (median PEDro score 5) with 3387 participants were included. Strong, significant effects on muscle strength were found for strength (SMD = 1.02), strength-aerobic (SMD = 1.41), strength-endurance (SMD = 0.92) and water-based (SMD = 1.08) training (52 studies, I² = 79.3%). Strength training (SMD = 1.16), strength-aerobic (SMD = 0.98) and 3D training (SMD = 1.31) improved postural balance (30 studies, I² = 88.1%). Moderator analyses revealed significant effects of specific intervention types on certain subgroups and subdomains of strength and balance. No studies were found measuring falls.

CONCLUSIONS

Structured PA interventions in middle-aged adults improve strength and balance outcomes related to functional impairments and falls. Strength training increases both strength and balance and can be recommended to prevent age-related functional decline. However, the interpretability of the results is limited due to considerable heterogeneity and the overall low methodological quality of the included studies. Long-term trials are needed to determine the preventive potential of PA on strength, balance and falls. This meta-analysis may inform guidelines for tailored training during middle age to promote healthy aging. Prospero registration: CRD42020218643.

Nutrition and exercise interventions to improve body composition for persons with overweight or obesity near retirement age: A systematic review and network meta-analysis of randomised controlled trials

The retirement phase is an opportunity to integrate healthy (nutrition/exercise) habits into daily life. We conducted this systematic review to assess which nutrition and exercise interventions most effectively improve body composition (fat/muscle mass), body mass index (BMI) and waist circumference (WC) in persons with obesity/overweight near retirement age (ages 55-70). We conducted a systematic review and network-meta-analysis (NMA) of randomised controlled trials, searching four databases from their inception up to 12 July 2022. The NMA was based on a random effects model, pooled mean differences, standardised mean differences, their 95% confidence intervals, and correlations with multi-arm studies. Subgroup and sensitivity analyses were also conducted. 92 studies were included, 66 of which with 4957 participants could be used for the NMA. Identified interventions were clustered into 12 groups: no intervention, energy restriction (i.e. 500-1000 kcal), energy restriction plus high protein (HP) intake (1.1-1.7 g/kg/body weight), intermittent fasting, mixed exercise (aerobic and resistance), resistance training (RT), aerobic training (AT), HP plus RT, energy restriction plus HP plus exercise, energy restriction plus RT, energy restriction plus AT, and energy restriction plus mixed exercise (ME). Intervention durations ranged from 8 weeks to 6 months. Body fat was reduced with energy restriction plus any exercise or plus HP intake. Energy restriction alone was less effective and tended to decrease muscle mass. Muscle mass was only significantly increased with ME. All other interventions including exercise effectively preserved muscle mass. A BMI and/or WC decrease was achieved with all interventions except AT/RT alone or RT plus HP. Overall, the most effective strategy for nearly all outcomes was combining energy restriction with RT or ME and HP. Healthcare professionals involved in the management of persons with obesity need to be aware that an energy-restricted diet alone may contribute to sarcopenic obesity in persons near retirement age. This network meta-analysis is registered at https://www.crd.york.ac.uk/prospero/as CRD42021276465.

Food proteins in the regulation of blood glucose control

Food proteins, depending on their origin, possess unique characteristics that regulate blood glucose via multiple physiological mechanisms, including the insulinotropic effects of amino acids, the activation of incretins, and slowing gastric emptying rate. The strategies aimed at curbing high blood glucose are important in preventing impaired blood glucose control, including insulin resistance, prediabetes and diabetes. The effect of proteins on blood glucose control can be achieved with high-protein foods short-term, and high-protein diets long-term using foods that are naturally high in protein, such as dairy, meat, soy and pulses, or by formulating high-protein functional food products using protein concentrates and isolates, or blended mixtures of proteins from different sources. Commercial sources of protein powders are represented by proteins and hydrolysates of caseins, whey proteins and their fractions, egg whites, soy, yellow pea and hemp which will be reviewed in this chapter. The effective doses of food protein that are capable of reducing postprandial glycemia start from 7 to 10g and higher per serving; however, the origin of protein, and macronutrient composition of a meal will determine the magnitude and duration of their effect on glycemia. The theoretical and methodological framework to evaluate the effect of foods, including food proteins, on postprandial glycemia for substantiation of health claims on food has been proposed in Canada and is discussed in the context of global efforts to harmonize the international food regulation and labeling.

Effects of beta-alanine supplementation on body composition: a GRADE-assessed systematic review and meta-analysis

Purpose

Previous studies have suggested that beta-alanine supplementation may benefit exercise performance, but current evidence regarding its effects on body composition remains unclear. This systematic review and meta-analysis aimed to investigate the effects of beta-alanine supplementation on body composition indices.

Methods

Online databases, including PubMed/Medline, Scopus, Web of Science, and Embase, were searched up to April 2021 to retrieve randomized controlled trials (RCTs), which examined the effect of beta-alanine supplementation on body composition indices. Meta-analyses were carried out using a random-effects model. The I² index was used to assess the heterogeneity of RCTs.

Results

Among the initial 1413 studies that were identified from electronic databases search, 20 studies involving 492 participants were eligible. Pooled effect size from 20 studies indicated that beta-alanine supplementation has no effect on body mass (WMD: −0.15 kg; 95% CI: −0.78 to 0.47; p = 0.631, I² = 0.0%, p = 0.998), fat mass (FM) (WMD: −0.24 kg; 95% CI: −1.16 to 0.68; p = 0.612, I² = 0.0%, p = 0.969), body fat percentage (BFP) (WMD: −0.06%; 95% CI: −0.53 to 0.40; p = 0.782, I² = 0.0%, p = 0.936), and fat-free mass (FFM) (WMD: 0.05 kg; 95% CI: −0.71 to 0.82; p = 0.889, I² = 0.0%, p = 0.912). Subgroup analyses based on exercise type (resistance training [RT], endurance training [ET], and combined training [CT]), study duration (<8 and ≥8 weeks), and beta-alanine dosage (<6 and ≥6 g/d) demonstrated similar results. Certainty of evidence across outcomes ranged from low to moderate.

Conclusions

This meta-analysis study suggests that beta-alanine supplementation is unlikely to improve body composition indices regardless of supplementation dosage and its combination with exercise training. No studies have examined the effect of beta-alanine combined with both diet and exercise on body composition changes as the primary variable. Therefore, future studies examining the effect of the combination of beta-alanine supplementation with a hypocaloric diet and exercise programs are warranted.

Resistance training effectiveness on body composition and body weight outcomes in individuals with overweight and obesity across the lifespan: A systematic review and meta-analysis

To systematically review and analyze the effects of resistance-based exercise programs on body composition, regional adiposity, and body weight in individuals with overweight/obesity across the lifespan. Using PRISMA guidelines, randomized controlled trials were searched in nine electronic databases up to December 2020. Meta-analyses were performed using random-effects model. One-hundred sixteen articles describing 114 trials (n = 4184 participants) were included. Interventions involving resistance training and caloric restriction were the most effective for reducing body fat percentage (ES = -3.8%, 95% CI: -4.7 to -2.9%, p < 0.001) and whole-body fat mass (ES = -5.3 kg, 95% CI: -7.2 to -3.5 kg, p < 0.001) compared with groups without intervention. Significant results were also observed following combined resistance and aerobic exercise (ES = -2.3% and -1.4 kg, p < 0.001) and resistance training alone (ES = -1.6% and -1.0 kg, p < 0.001) compared with no training controls. Resistance training alone was the most effective for increasing lean mass compared with no training controls (ES = 0.8 kg, 95% CI: 0.6 to 1.0 kg, p < 0.001), whereas lean mass was maintained following interventions involving resistance training and caloric restriction (ES = ~ - 0.3 kg, p = 0.550-0.727). Results were consistently observed across age and sex groups (p = 0.001-0.011). Reductions in regional adiposity and body weight measures were also observed following combined resistance and aerobic exercise and programs including caloric restriction (p < 0.001). In conclusion, this study provides evidence that resistance-based exercise programs are effective and should be considered within any multicomponent therapy program when caloric restriction is utilized in individuals with overweight or obesity.

Systematic review and meta-analysis of protein intake to support muscle mass and function in healthy adults

We performed a systematic review, meta-analysis, and meta-regression to determine if increasing daily protein ingestion contributes to gaining lean body mass (LBM), muscle strength, and physical/functional test performance in healthy subjects. A protocol for the present study was registered (PROSPERO, CRD42020159001), and a systematic search of Medline, Embase, CINAHL, and Web of Sciences databases was undertaken. Only randomized controlled trials (RCT) where participants increased their daily protein intake and were healthy and non-obese adults were included. Research questions focused on the main effects on the outcomes of interest and subgroup analysis, splitting the studies by participation in a resistance exercise (RE), age (<65 or ≥65 years old), and levels of daily protein ingestion. Three-level random-effects meta-analyses and meta-regressions were conducted on data from 74 RCT. Most of the selected studies tested the effects of additional protein ingestion during RE training. The evidence suggests that increasing daily protein ingestion may enhance gains in LBM in studies enrolling subjects in RE (SMD [standardized mean difference] = 0.22, 95% CI [95% confidence interval] 0.14:0.30, P < 0.01, 62 studies, moderate level of evidence). The effect on LBM was significant in subjects ≥65 years old ingesting 1.2-1.59 g of protein/kg/day and for younger subjects (<65 years old) ingesting ≥1.6 g of protein/kg/day submitted to RE. Lower-body strength gain was slightly higher by additional protein ingestion at ≥1.6 g of protein/kg/day during RE training (SMD = 0.40, 95% CI 0.09:0.35, P < 0.01, 19 studies, low level of evidence). Bench press strength is slightly increased by ingesting more protein in <65 years old subjects during RE training (SMD = 0.18, 95% CI 0.03:0.33, P = 0.01, 32 studies, low level of evidence). The effects of ingesting more protein are unclear when assessing handgrip strength and only marginal for performance in physical function tests. In conclusion, increasing daily protein ingestion results in small additional gains in LBM and lower body muscle strength gains in healthy adults enrolled in resistance exercise training. There is a slight effect on bench press strength and minimal effect performance in physical function tests. The effect on handgrip strength is unclear.

Does Androgen Deprivation for Prostate Cancer Affect Normal Adaptation to Resistance Exercise?

BACKGROUND

Loss of muscle mass and muscle function is a common side effect from androgen deprivation therapy (ADT) for prostate cancer (PCa). Here, we explored effects of heavy-load resistance training (RT) on lean body mass and muscle strength changes reported in randomized controlled trials (RCTs) among PCa patients on ADT and in healthy elderly men (HEM), by comparison of results in separate meta-analysis.

METHODS

RCTs were identified through databases and reference lists.

RESULTS

Seven RCTs in PCa patients (n = 449), and nine in HEM (n = 305) were included. The effects of RT in lean body mass change were similar among PCa patients (Standardized mean difference (SMD): 0.4, 95% CI: 0.2, 0.7) and HEM (SMD: 0.5, 95% CI: 0.2, 0.7). It is noteworthy that the within group changes showed different patterns in PCa patients (intervention: 0.2 kg; control: -0.6 kg) and HEM (intervention: 1.2 kg; control: 0.2 kg). The effects of RT on change in muscle strength (measured as 1 RM) were similar between PCa patients and HEM, both for lower body- (PCa: SMD: 1.9, 95% CI: 1.2, 2.5; HEM: SMD: 2.2, 95% CI: 1.0, 3.4), and for upper body exercises (PCa: SMD: 2.0, 95% CI: 1.3, 2.7; HEM: SMD: 1.9, 95% CI: 1.3, 2.6).

CONCLUSIONS

The effects of RT on lean body mass and 1 RM were similar in PCa patients on ADT and HEM, but the mechanism for the intervention effect might differ between groups. It seems that RT counteracts loss of lean body mass during ADT in PCa patients, as opposed to increasing lean body mass in HEM.

Protein, Calcium, Vitamin D Intake and 25(OH)D Status in Normal Weight, Overweight, and Obese Older Adults: A Systematic Review and Meta-Analysis

The aging process is often accompanied by increase in body weight. Older adults with overweight or obesity might have an overconsumption in energy that is accompanied by inadequate intake of protein, vitamin D, and calcium. It is unclear if intake of protein and vitamin D and calcium is sufficient in older adults with overweight/obesity, and whether it differs from older adults with normal weight, since a recent overview of the literature review is lacking. Therefore, we systematically analyzed the current evidence on differences in nutrient intake/status of protein, vitamin D and calcium between older adults with different body mass index (BMI) categories. Randomized controlled trials and prospective cohort studies were identified from PubMed and EMBASE. Studies reporting nutrient intake/status in older adults aged ≥50 years with overweight/obesity and studies comparing between overweight/obesity and normal weight were included. Nutrient intake/status baseline values were reviewed and when possible calculated for one BMI category (single-group meta-analysis), or compared between BMI categories (meta-analysis). Nutrient intake/status was compared with international recommendations. Mean protein (N = 8) and calcium intake (N = 5) was 0.98 gram/kilogram body weight/day (g/kg/d) [95% Confidence Interval (CI) 0.89-1.08] and 965 mg [95% CI: 704-1225] in overweight/obese. Vitamin D intake was insufficient in all BMI categories (N = 5). The pooled mean for vitamin D intake was 6 ug [95% CI 4-9]. For 25(OH)D, the pooled mean was 54 nmol/L [95% CI 45-62], 52 nmol/L [95% CI 46-58], and 48 nmol/l [95% CI 33-62] in normal (N = 7), combined overweight and obese (N = 12), and obese older adults (N = 4), respectively. In conclusion, older adults with overweight and obesity have a borderline sufficient protein and sufficient calcium intake, but insufficient vitamin D intake. The 25(OH)D concentration is deficient for the obese older adults.

Effects of soy intake on circulating levels of TNF-α and interleukin-6: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

Pro-inflammatory mediators, including serum tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6), can be used as biomarkers to indicate or monitor disease. This study was designed to ascertain the effects of soy products on TNF-α and IL-6 levels.

METHODS

PubMed, EMBASE, Science Direct, Web of Science, Google Scholar and the Cochrane Central Register of Controlled Trials were searched to November 2019 for RCTs around the effects of soy-based products on TNF-α and IL-6. A random effects model was used to calculate overall effect size.

RESULTS

In total, 29 eligible publications were considered in the present systematic review, of which 25 were included in this meta-analysis. The overall effect of soy products on TNF-α and IL-6 levels failed to reach statistical significance (MD = - 0.07; 95% CI - 0.22-0.09; I² 50.9; MD = 0.03; 95% CI - 0.07-0.14; I² 42.1, respectively). According to a subgroup analysis, natural soy products led to a reduction in TNF-α concentration compared with processed soy products (MD = - 0.32; 95% CI - 0.45 to - 0.19; I² 0.0). Moreover, IL-6 reduction was stronger in participants who were affected by different diseases (MD = - 0.04; 95% CI - 0.07 to - 0.02; I² 0.0).

CONCLUSIONS

A review of RCTs published to November 2019 found that natural soy products are effective in lowering TNF-α levels. While the beneficial effects on reduction of IL-6 appeared stronger in individuals affected by different diseases, this finding cannot be generalized to all individuals affected by different diseases.

Neither soy nor isoflavone intake affects male reproductive hormones: An expanded and updated meta-analysis of clinical studies

Concerns that the phytoestrogens (isoflavones) in soy may feminize men continue to be raised. Several studies and case-reports describing feminizing effects including lowering testosterone levels and raising estrogen levels in men have been published. For this reason, the clinical data were meta-analyzed to determine whether soy or isoflavone intake affects total testosterone (TT), free testosterone (FT), estradiol (E₂), estrone (E₁), and sex hormone binding globulin (SHBG). PubMed and CAB Abstracts databases were searched between 2010 and April 2020, with use of controlled vocabulary specific to the databases. Peer-reviewed studies published in English were selected if (1) adult men consumed soyfoods, soy protein, or isoflavone extracts (from soy or red clover) and [2] circulating TT, FT, SHBG, E2 or E1 was assessed. Data were extracted by two independent reviewers. With one exception, studies included in a 2010 meta-analysis were included in the current analysis. A total of 41 studies were included in the analyses. TT and FT levels were measured in 1753 and 752 men, respectively; E₂ and E₁ levels were measured in 1000 and 239 men, respectively and SHBG was measured in 967 men. Regardless of the statistical model, no significant effects of soy protein or isoflavone intake on any of the outcomes measured were found. Sub-analysis of the data according to isoflavone dose and study duration also showed no effect. This updated and expanded meta-analysis indicates that regardless of dose and study duration, neither soy protein nor isoflavone exposure affects TT, FT, E₂ or E₁ levels in men.

The effects of soy supplementation on inflammatory biomarkers: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Soy products contain several compounds with anti-inflammatory properties like genistein and daidzein which reported to act through different pathways. Present study conducted considering the inconsistent results and lack of any comprehensive review regarding randomized controlled trials which assess the effect of soy products on inflammatory markers.

METHODS

Following electronic databases were searched up to March 2020: PubMed, Scopus, ISI web of science, and Cochrane Library All randomized trials which assessed the effect of soy product supplementation on c-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) were included for last analysis. Treatment effects were expressed as mean difference (MD) and the standard deviation (SD) of outcomes. To estimate the overall effect the random-effects model was employed.

RESULTS

Finally, 51 randomized trial were included for present study. Last analysis showed that soy product supplementation lead to significant reduction in CRP (MD -0.27 mg/L; 95% CI: -0.51, -0.02, p = 0.028) but it did not affect IL-6 (MD 0.0 pg/ml; 95% CI: -0.06, 0.06, p = 0.970) and TNF-α (MD = -0.04 pg/ml; 95% CI: -0.11, 0.03, p = 0.252). Subgroup analysis showed that soy supplementation had a significant impact on decreasing IL-6 and TNF-α levels when studies had a long-term intervention (≥12 weeks) and used low dose isoflavone (<100 mg/day).

CONCLUSION

In conclusion, present systematic review and meta-analysis found a significant reduction in CRP levels after soy supplementation whiles IL-6 and TNF-α did not affect.

Resistance training effect on serum insulin-like growth factor 1 in the serum: a meta-analysis

BACKGROUND

The resistance exercise has drawn considerable attention to the level of insulin-like growth factor 1 in the serum. However, the relationship between resistance exercise and the level of insulin-like growth factor 1 in the serum is conflicting. This meta-analysis was performed to evaluate this relationship.

METHODS

A systematic literature search up to May 2020 was performed and 22 studies were detected with 680 subjects. They reported relationships between resistance exercise and the level of insulin-like growth factor 1 in the serum. Odds ratio (OR) with 95% confidence intervals (CIs) was calculated comparing the resistance exercise and the level of insulin-like growth factor 1 in the serum using the continuous method with a random or fixed-effect model.

RESULTS

Significantly higher insulin-like growth factor 1 was observed in subjects performing resistance training for less than 16 weeks (OR, 4.03; 95% CI, 2.49-5.57, p<.001); subjects performing resistance training for more than 16 weeks (OR, 11.55; 95% CI, 6.58-16.52, p<.001); subjects older than 60 years (OR, 11.88; 95% CI, 9.84-13.93, p<.001); females (OR, 3.87; 95% CI, 2.26-5.49, p<.001) and males (OR, 16.82; 95% CI, 7.29-26.35, p<.001). However, significantly lower insulin-like growth factor 1 was observed in subjects younger than 60 years (OR, -4.80; 95% CI, -7.74 to -1.86, p=.001).

CONCLUSIONS

However, the resistance exercise significantly increases insulin-like growth factor 1 in subjects older than 60 years, both males and females, and subjects performing resistance exercise for all any period. Surprisingly, resistance exercise significantly decreases insulin-like growth factor 1 in subjects younger than 60 years. This relationship forces us to recommend the resistance exercise to improve insulin-like growth factor 1 in serum.

Animal, Plant, Collagen and Blended Dietary Proteins: Effects on Musculoskeletal Outcomes

Dietary protein is critical for the maintenance of musculoskeletal health, where appropriate intake (i.e., source, dose, timing) can mitigate declines in muscle and bone mass and/or function. Animal-derived protein is a potent anabolic source due to rapid digestion and absorption kinetics stimulating robust increases in muscle protein synthesis and promoting bone accretion and maintenance. However, global concerns surrounding environmental sustainability has led to an increasing interest in plant- and collagen-derived protein as alternative or adjunct dietary sources. This is despite the lower anabolic profile of plant and collagen protein due to the inferior essential amino acid profile (e.g., lower leucine content) and subordinate digestibility (versus animal). This review evaluates the efficacy of animal-, plant- and collagen-derived proteins in isolation, and as protein blends, for augmenting muscle and bone metabolism and health in the context of ageing, exercise and energy restriction.

The effect of soy intervention on insulin-like growth factor 1 levels: A meta-analysis of clinical trials

A low insulin-like growth factor 1 (IGF-1) level is known to be associated with many disorders. Several studies have shown that soy consumption may influence IGF-1, but the findings remain inconclusive. In this work, we conducted a systematic review and meta-analysis to provide a more accurate estimation of the effect of soy consumption on plasma IGF-1. A comprehensive systematic search was performed in Scopus, Embase, Web of Science, and PubMed/MEDLINE databases from inception until October 2019. Eight studies fulfilled the eligibility criteria. The pooled weighted mean difference (WMD) of the eligible studies was calculated with random-effects approach. Overall, a significant increment in plasma IGF-1 was observed following soy intervention (WMD: 13.5 ng/ml, 95% CI: 5.2, 21.8, I2 = 97%). Subgroup analyses demonstrated a significantly greater increase in IGF-1, when soy was administered at a dosage of ≤40 g/day (WMD: 11.7 ng/ml, 95% CI: 10.9 to 12.6, I2 = 98%), and when the intervention duration was <12 weeks (WMD: 26.6 ng/ml, 95% CI: 9.1 to 44.1, I2 = 0.0%). In addition, soy intervention resulted in a greater increase in IGF-1 among non-healthy subjects (WMD: 36 ng/ml, 95% CI: 32.7 to 39.4, I2 = 84%) than healthy subjects (WMD: 9.8 ng/ml, 95% CI: 8.9 to 10.7, I2 = 90%). In conclusion, this study provided the first meta-analytical evidence that soy intake may increase IGF-1 levels, but the magnitude of the increase is dependent on the intervention dosage, duration, and health status of the participants.

Potential Markers of Dietary Glycemic Exposures for Sustained Dietary Interventions in Populations without Diabetes

There is considerable interest in dietary and other approaches to maintaining blood glucose concentrations within the normal range and minimizing exposure to postprandial hyperglycemic excursions. The accepted marker to evaluate the sustained maintenance of normal blood glucose concentrations is glycated hemoglobin A1c (HbA1c). However, although this is used in clinical practice to monitor glycemic control in patients with diabetes, it has a number of drawbacks as a marker of efficacy of dietary interventions that might beneficially affect glycemic control in people without diabetes. Other markers that reflect shorter-term glycemic exposures have been studied and proposed, but consensus on the use and relevance of these markers is lacking. We have carried out a systematic search for studies that have tested the responsiveness of 6 possible alternatives to HbA1c as markers of sustained variation in glycemic exposures and thus their potential applicability for use in dietary intervention trials in subjects without diabetes: 1,5-anhydroglucitol (1,5-AG), dicarbonyl stress, fructosamine, glycated albumin (GA), advanced glycated end products (AGEs), and metabolomic profiles. The results suggest that GA may be the most promising for this purpose, but values may be confounded by effects of fat mass. 1,5-AG and fructosamine are probably not sensitive enough to the range of variation in glycemic exposures observed in healthy individuals. Use of measures based on dicarbonyls, AGEs, or metabolomic profiles would require further research into possible specific molecular species of interest. At present, none of the markers considered here is sufficiently validated and sensitive for routine use in substantiating the effects of sustained variation in dietary glycemic exposures in people without diabetes.

Consequences on aging process and human wellness of generation of nitrogen and oxygen species during strenuous exercise

Impairment of antioxidant defense system and increase in metabolic rate and production of reactive oxygen species have been demonstrated in strenuous exercise. Both at rest and during contractile activity, skeletal muscle generates a very complex set of reactive nitrogen and oxygen species; the main generated are superoxide and nitric oxide. The nature of the contractile activity influences the pattern and the magnitude of this reactive oxygen and nitrogen species (ROS) generation. The intracellular pro-oxidant/antioxidant homeostasis undergoes alteration owing to strenuous exercise and the major identified sources of intracellular free radical generation during physical activity are the mitochondrial electron transport chain, polymorphoneutrophil, and xanthine oxidase. Reactive oxygen species increased tissue susceptibility to oxidative damage and pose a serious threat to the cellular antioxidant defense system. The possible dangerous consequences of the aging process and human wellness are emphasized in this review.

Soy Products Ameliorate Obesity-Related Anthropometric Indicators in Overweight or Obese Asian and Non-Menopausal Women: A Meta-Analysis of Randomized Controlled Trials

Background: The effect of soy products on the weight of overweight or obese people is controversial, so we aimed to conduct a systematic review and a meta-analysis of published randomized controlled trials to analyze whether supplementation with soy products can help them to lose weight. Methods: The relevant data before January 2019 in PubMed, Embase and Cochrane Library were searched. A random-effect model was adopted to calculate the weighted average difference of net changes of body weight, body mass index (BMI), body fat percentage, fat mass, waist circumference, etc. Results: A total of 22 trials (870 overweight or obese participants) were reflected in the present meta-analysis. Analysis showed that soy products significantly reduced body weight, BMI, body fat percent and waist circumference in overweight or obese Asian populations (−0.37 kg, P = 0.010; −0.27 kg/m², P = 0.042; −0.36%, P = 0.032; −0.35 cm, P = 0.049) and more significant effects were observed in non-menopausal women reduced body weight (−0.59 kg, P = 0.041), BMI (−0.59, P = 0.041) and waist circumference (−0.59 cm, P = 0.041) in overweight or obese populations. Conclusion: This meta-analysis showed that soy products have weight loss effects, mainly due to soy protein, isoflavone and soy fiber.

A systematic review and meta-analysis of the effects of soy on serum hs-CRP

BACKGROUND & AIM

The results of studies about the effect of soy products on serum highly sensitive C-reactive protein (hs-CRP) are inconsistent. The aim of this systematic review and meta-analysis of randomized clinical trials (RCTs) was to investigate the effect of soy products intake on serum hs-CRP concentration.

METHODS

We searched PubMed, EMBASE, Science Direct, ISI Web of Science, Google Scholar and Cochrane Central Register of Controlled Trials up to December 2016 without language restrictions. Random-effect model was used for quantitative data synthesis.

RESULTS

Thirty-six studies were included in our analyses. A meta-analysis revealed a non-significant reduction in serum hs-CRP concentrations following soy products consumption, -0.19 (mg/L) (95% CI: -0.49 to 0.09; I2 = 95.6%). Subgroup analyses suggested that natural soya products may reduce plasma levels of CRP by -0.18 mg/L (95% CI: -0.28 to -0.08; I2: 11.6) in comparison to other source of isoflavones (soya extracts, supplements). Moreover, the effect was stronger among subjects with baseline hs-CRP concentrations of less than 2.52 mg/L, -0.15 (95% CI: -0.27 to -0.02; I2: 34.6). A meta-regression analysis revealed that dosage of isoflavones seems to be a strong predictor of the effect of soya on serum hs-CRP levels.

CONCLUSION

Present review of RCTs published up to December 2016 did not provide strong evidence regarding the beneficial effect of soya products consumption on blood hs-CRP concentrations. However, it appears that natural soya products may reduce plasma levels of hs-CRP in comparison to other source of isoflavones. Large and well-designed studies are recommended to confirm this conclusion.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018069371.

Effect of Strength Training on Lipid and Inflammatory Outcomes: Systematic Review With Meta-Analysis and Meta-Regression

Background: The aim of this study was to perform a systematic review with meta-analysis and meta-regressions evaluating the effects of isolated strength training (ST), compared with a control group, on total cholesterol (TC), triglycerides (TG), low-density (LDL), high-density lipoprotein (HDL), C-reactive protein (CRP), and adiponectin of adults. Methods: Embase, PubMed, Cochrane, and Scopus data sources were searched up to May 2017. Clinical trials that compared ST with a control group of adults older than 18 years, which evaluated blood TC, TG, LDL, HDL, CRP, or adiponectin as an outcome were included. Random effect was used and the effect size (ES) was calculated by using the standardized mean difference with a 95% confidence interval. Results: ST promotes a reduction in TC (ES: -0.399; P < .001), TG (ES: -0.204; P = .002), LDL (ES: -0.451; P < .001), and CRP (ES: -0.542; P = .01) levels. In addition, ST is associated to an increase in HDL (ES: 0.363; P < .001) and adiponectin concentrations (ES: 1.105; P = .01). Conclusion: ST promotes decreases in TC, TG, LDL, and CRP levels and increases HDL and adiponectin concentrations. Thus, progressive ST could be a potential therapeutic option for improving abnormalities in lipid and inflammatory outcomes in adults.

The Effect of Chronic Exercise Training on Leptin: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Leptin is a hormone associated with satiety, lipid oxidation, energy expenditure, and energy homeostasis. To date, the current body of research examining the effect of chronic exercise training on leptin has yielded inconsistent results.

OBJECTIVE

The purpose of this meta-analysis was to provide a quantitative estimate of the magnitude of change in leptin levels following participation in exercise interventions lasting ≥ 2 weeks.

METHODS

All studies included were peer-reviewed and published in English. To be included, studies randomized human participants to an exercise training group or non-exercise comparison group for an exercise training intervention. Leptin levels were measured at baseline, during, and/or after completion of the exercise training program. Random-effects models were used to aggregate a mean effect size (ES) and 95% confidence intervals (CIs), and identify potential moderators.

RESULTS

Seventy-two randomized controlled trials met the inclusion criteria and resulted in 107 effects (n = 3826). The mean ES of 0.24 (95% CI 0.16-0.32, p < 0.0001) indicated a decrease in leptin following an exercise training program. A decrease in %Fat (β = - 0.07, p < 0.01) was associated with a decrease in leptin after accounting for the type of control group (β = - 0.38, p < 0.0001) used in each study.

CONCLUSION

These results suggest that engaging in chronic exercise training (≥ 2 weeks) is associated with a decrease in leptin levels for individuals regardless of age and sex. However, a greater decrease in leptin occurred with a decreased percentage of body fat.

Concurrent training protocol for men with androgen deficiency in the aging male: a randomized clinical trial

BACKGROUND

The androgen deficiency in the aging male (ADAM) affects physical, sexual, and psychological aspects with characteristics symptoms of middle-aged men. The practice of regular physical activity and physical exercise can attenuate these symptoms. The aim of this randomized clinical trial is to propose a physical exercise protocol based on concurrent training for middle-aged men with ADAM.

METHOD

Randomized clinical trial with a 6-month intervention will randomly divided into two groups: experimental group (EG) and control group (CG). Four evaluations will be carried out, (1) pre-intervention; (2) in the first month of intervention; (3) in the third month of intervention; (4) post-intervention, evaluating: physical, psychological, sexual, and hormonal aspects. The intervention protocol with concurrent training will have duration of 6 months; frequency of 3 times weekly, with 60 min per session. The two-way ANOVA test will be used for the inter-group and intra-group comparisons with repeated measurements, and also Sydak's comparison test.

CONCLUSION

This protocol was developed with the intent of easing the symptoms of ADAM. In addition, it is believed that the concurrent training protocol could be capable to recover hormonal, physical, psychological, and sexual aspect of middle-aged men with ADAM.

Effect of resistance training on inflammatory markers of older adults: A meta-analysis

INTRODUCTION

Low-grade inflammation is associated with several deleterious health outcomes and may aggravate sarcopenia and dynapenia during aging. A strategy to alleviate these conditions is resistance training (RT). Thus, the aim was to critically examine the effects of regular RT on inflammatory markers of older adults from previous studies.

METHODS

The search was conducted on MEDLINE, July 2017. Only randomized controlled trials (RCTs) testing RT effects on C-reactive protein (CRP), tumor necrosis factor-α (TNF-α) and/or interleukin-6 (IL-6) of adults over 50 years-of-age were selected by two independent reviewers.

RESULTS

The main meta-analyses showed RT reduced CRP in older adults (standard mean difference [SMD] = -0.61, 95%CI = -0.83; -0.31, p < 0.001), tended to reduce IL-6 (SMD = -0.19, 95%CI = -0.42; 0.02, p = 0.07) and did not change TNF-α. Further exploratory sub-group analyses showed a potential association of muscle mass for both CRP and TNF-α changes. Reductions in CRP and TNF-α only occurred in RCTs performing a higher number of exercises (>8), higher weekly frequency (3 times/week) and longer durations than 12 weeks.

CONCLUSIONS

Anti-inflammatory effects of RT were significant only for CRP with a tendency for a decrease in IL-6 as well. The exploratory analyses suggested the reduction in inflammatory markers could be dependent on increases in muscle mass and higher volume of RT protocols. These potential mediators of RT anti-inflammatory effects should be addressed in future meta-analyses to clarify the effects of RT on inflammatory markers of older adults with very specific conditions and larger numbers of studies.

A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults

OBJECTIVE

We performed a systematic review, meta-analysis and meta-regression to determine if dietary protein supplementation augments resistance exercise training (RET)-induced gains in muscle mass and strength.

DATA SOURCES

A systematic search of Medline, Embase, CINAHL and SportDiscus.

ELIGIBILITY CRITERIA

Only randomised controlled trials with RET ≥6 weeks in duration and dietary protein supplementation.

DESIGN

Random-effects meta-analyses and meta-regressions with four a priori determined covariates. Two-phase break point analysis was used to determine the relationship between total protein intake and changes in fat-free mass (FFM).

RESULTS

Data from 49 studies with 1863 participants showed that dietary protein supplementation significantly (all p<0.05) increased changes (means (95% CI)) in: strength-one-repetition-maximum (2.49 kg (0.64, 4.33)), FFM (0.30 kg (0.09, 0.52)) and muscle size-muscle fibre cross-sectional area (CSA; 310 µm² (51, 570)) and mid-femur CSA (7.2 mm² (0.20, 14.30)) during periods of prolonged RET. The impact of protein supplementation on gains in FFM was reduced with increasing age (-0.01 kg (-0.02,-0.00), p=0.002) and was more effective in resistance-trained individuals (0.75 kg (0.09, 1.40), p=0.03). Protein supplementation beyond total protein intakes of 1.62 g/kg/day resulted in no further RET-induced gains in FFM.

SUMMARY/CONCLUSION

Dietary protein supplementation significantly enhanced changes in muscle strength and size during prolonged RET in healthy adults. Increasing age reduces and training experience increases the efficacy of protein supplementation during RET. With protein supplementation, protein intakes at amounts greater than ~1.6 g/kg/day do not further contribute RET-induced gains in FFM.

Does soy protein affect circulating levels of unbound IGF-1?

INTRODUCTION

Despite the enormous amount of research that has been conducted on the role of soyfoods in the prevention and treatment of chronic disease, the mechanisms by which soy exerts its physiological effects are not fully understood. The clinical data show that neither soyfoods nor soy protein nor isoflavones affect circulating levels of reproductive hormones in men or women. However, some research suggests that soy protein, but not isoflavones, affects insulin-like growth factor I (IGF-1).

METHODS

Since IGF-1 may have wide-ranging physiological effects, we sought to determine the effect of soy protein on IGF-1 and its major binding protein insulin-like growth factor-binding protein (IGFBP-3). Six clinical studies were identified that compared soy protein with a control protein, albeit only two studies measured IGFBP-3 in addition to IGF-1.

RESULTS

Although the data are difficult to interpret because of the different experimental designs employed, there is some evidence that large amounts of soy protein (>25 g/day) modestly increase IGF-1 levels above levels observed with the control protein.

CONCLUSION

The clinical data suggest that a decision to incorporate soy into the diet should not be based on its possible effects on IGF-1.

Soy and Health Update: Evaluation of the Clinical and Epidemiologic Literature

Soyfoods have long been recognized as sources of high-quality protein and healthful fat, but over the past 25 years these foods have been rigorously investigated for their role in chronic disease prevention and treatment. There is evidence, for example, that they reduce risk of coronary heart disease and breast and prostate cancer. In addition, soy alleviates hot flashes and may favorably affect renal function, alleviate depressive symptoms and improve skin health. Much of the focus on soyfoods is because they are uniquely-rich sources of isoflavones. Isoflavones are classified as both phytoestrogens and selective estrogen receptor modulators. Despite the many proposed benefits, the presence of isoflavones has led to concerns that soy may exert untoward effects in some individuals. However, these concerns are based primarily on animal studies, whereas the human research supports the safety and benefits of soyfoods. In support of safety is the recent conclusion of the European Food Safety Authority that isoflavones do not adversely affect the breast, thyroid or uterus of postmenopausal women. This review covers each of the major research areas involving soy focusing primarily on the clinical and epidemiologic research. Background information on Asian soy intake, isoflavones, and nutrient content is also provided.

Effect of exercise training on C reactive protein: a systematic review and meta-analysis of randomised and non-randomised controlled trials

PURPOSE

C-reactive protein (CRP) is a marker of chronic systemic inflammation frequently used in cardiovascular disease risk assessment. The purpose of this meta-analysis was to provide a quantitative estimate of the magnitude of change in CRP following participation in physical exercise interventions.

METHODS

All studies included in the meta-analysis were peer reviewed and published in English. Human participants were assigned to a non-exercise comparison group or exercise training group, with the intervention lasting ≥2 weeks. CRP levels were measured at baseline, during and/or after completion of the exercise training programme. Random-effects models were used to aggregate a mean effect size (ES), 95% CIs and potential moderators.

RESULTS

83 randomised and non-randomised controlled trials met the inclusion criteria and resulted in 143 effects (n=3769). The mean ES of 0.26 (95% CI 0.18 to 0.34, p<0.001) indicated a decrease in CRP following exercise training. A decrease in body mass index (BMI; β=1.20, SE=0.25, p<0.0001) and %Fat (β=0.76, SE=0.21, p=0.0002) were associated with a decrease in CRP, independently accounting for 11.1% and 6.6% of the variation in response, respectively. Exercise training led to a greater reduction in CRP when accompanied by a decrease in BMI (ES=0.38, 95% CI 0.26 to 0.50); however, a significant improvement in CRP occurred in the absence of weight loss (ES=0.19, 95% CI 0.10 to 0.28; both p<0.001).

CONCLUSIONS

These results suggest that engaging in exercise training is associated with a decrease in CRP levels regardless of the age or sex of the individual; however, greater improvements in CRP level occur with a decrease in BMI or %Fat.

Collagen peptide supplementation in combination with resistance training improves body composition and increases muscle strength in elderly sarcopenic men: a randomised controlled trial

Protein supplementation in combination with resistance training may increase muscle mass and muscle strength in elderly subjects. The objective of this study was to assess the influence of post-exercise protein supplementation with collagen peptides v. placebo on muscle mass and muscle function following resistance training in elderly subjects with sarcopenia. A total of fifty-three male subjects (72·2 (sd 4·68) years) with sarcopenia (class I or II) completed this randomised double-blind placebo-controlled study. All the participants underwent a 12-week guided resistance training programme (three sessions per week) and were supplemented with either collagen peptides (treatment group (TG)) (15 g/d) or silica as placebo (placebo group (PG)). Fat-free mass (FFM), fat mass (FM) and bone mass (BM) were measured before and after the intervention using dual-energy X-ray absorptiometry. Isokinetic quadriceps strength (IQS) of the right leg was determined and sensory motor control (SMC) was investigated by a standardised one-leg stabilisation test. Following the training programme, all the subjects showed significantly higher (P<0·01) levels for FFM, BM, IQS and SMC with significantly lower (P<0·01) levels for FM. The effect was significantly more pronounced in subjects receiving collagen peptides: FFM (TG +4·2 (sd 2·31) kg/PG +2·9 (sd 1·84) kg; P<0·05); IQS (TG +16·5 (sd 12·9) Nm/PG +7·3 (sd 13·2) Nm; P<0·05); and FM (TG -5·4 (sd 3·17) kg/PG -3·5 (sd 2·16) kg; P<0·05). Our data demonstrate that compared with placebo, collagen peptide supplementation in combination with resistance training further improved body composition by increasing FFM, muscle strength and the loss in FM.

Interactive effects of an isocaloric high-protein diet and resistance exercise on body composition, ghrelin, and metabolic and hormonal parameters in untrained young men: A randomized clinical trial

AIMS/INTRODUCTION

The interactive effects of resistance training and dietary protein on hormonal responses in adults are not clear and remain controversial. We tested the effect of an isocaloric high-protein diet on body composition, ghrelin, and metabolic and hormonal parameters during a 12-week resistance training program in untrained healthy young men.

MATERIAL AND METHODS

We randomized 18 healthy young men to a standard diet (ST group) or an isocaloric high protein diet (HP group). Both groups participated in a 12-week resistance exercise program. We measured body composition, lipid profile, homeostatic model assessment of insulin resistance (HOMA-IR) indices, total ghrelin, and exercise-related hormones at baseline and 12 weeks.

RESULTS

In the HP group, lean body mass (LBM), total ghrelin, growth hormone, testosterone and cortisol levels showed an increase, whereas body fat percentage and HOMA-IR showed a decrease at 12 weeks, compared with baseline (P ≤ 0.05). In the ST group, no changes in these parameters were observed during the 12-week period. During the 12-week period, significant differences in the pattern of change of LBM (P = 0.032), total ghrelin (P = 0.037), HOMA-IR (P = 0.040) and high-density lipoprotein cholesterol (P = 0.011) over time were observed between the groups.

CONCLUSIONS

The findings of the present study suggest that an isocaloric high-protein diet can ameliorate body composition, metabolic profiles and energy metabolism during a 12-week scheduled resistance training program in untrained healthy young men. This trial was registered with ClinicalTrials.gov (no. NCT01714700).

Effect of flavonoids on circulating levels of TNF-α and IL-6 in humans: a systematic review and meta-analysis

Epidemiological or in vitro evidence suggests a potential role for flavonoids as anti-inflammatory agents; we investigated the effect of flavonoids-rich foods or supplements on tumor necrosis factor- alpha (TNF-α) and interleukin-6 (IL-6) in long-term placebo-controlled human intervention trials. From 110 human intervention studies selected (MEDLINE, EMBASE, CHORANE, and FSTA databases), 32 long-term placebo-controlled trials were suitable for meta-analysis. After sensitivity analysis, seven studies imputed of bias were excluded and 25 studies were analyzed (TNF-α, n = 2404; IL-6, n = 2174). Levels of TNF-α decreased after flavonoid consumption in the fixed model only (mean difference (MD) (95% CI): -0.098 (-0.188, -0.009), p = 0.032), but metaregression results showed that neither higher dose, nor a longer duration of intervention were associated with a greater effect size. Subgroup analysis did not reveal any significant effect for quercetin and soy, but other sources (red wine, pomegranate, and tea extracts) showed a significant effect size both in fixed (MD (95% CI): TNF-α -0.449 (-0.619, -0.280), p < 0.001; IL-6 -0.346 (-0.612, -0.079), p = 0.011) and random (MD (95% CI): TNF-α -0.783 (-1.476, -0.090), p = 0.027; IL-6, -0.556 (-1.062, -0.050), p = 0.031) effect models. High-quality placebo-controlled trials are needed in order to identify flavonoids as the active ingredients.