Neither Chia Flour nor Whey Protein Supplementation Further Improves Body Composition or Strength Gains after a Resistance Training Program in Young Subjects with a Habitual High Daily Protein Intake

Effect of Plant Versus Animal Protein on Muscle Mass, Strength, Physical Performance, and Sarcopenia: A Systematic Review and Meta-analysis of Randomized Controlled Trials

CONTEXT

Dietary protein is recommended for sarcopenia-a debilitating condition of age-related loss of muscle mass and strength that affects 27% of older adults. The effects of protein on muscle health may depend on protein quality.

OBJECTIVE

The aim was to synthesize randomized controlled trial (RCT) data comparing plant with animal protein for muscle health.

DATA SOURCES

Forty-three eligible RCTs were sourced from Medline, Embase, Scopus, Web of Science, and CENTRAL databases.

DATA EXTRACTION

Four reviewers (R.J.R.-M., S.F.B., N.A.W., D.L.) extracted data from RCTs (study setting, population, intervention characteristics, outcomes, summary statistics) and conducted quality assessment using the Cochrane Risk of Bias 2.0.

DATA ANALYSIS

Standardized mean differences (SMDs) (95% CIs) were combined using a random-effects meta-analysis and forest plots were generated. I2 statistics were calculated to test for statistical heterogeneity.

CONCLUSION

Thirty RCTs (70%) were eligible for meta-analysis and all examined muscle mass outcomes. Compared with animal protein, plant protein resulted in lower muscle mass following the intervention (SMD = -0.20; 95% CI: -0.37, -0.03; P = .02), with stronger effects in younger (<60 years; SMD = -0.20; 95% CI: -0.37, -0.03; P = .02) than in older (≥60 years; SMD = -0.05; 95% CI: -0.32, 0.23; P = .74) adults. There was no pooled effect difference between soy and milk protein for muscle mass (SMD = -0.02; 95% CI: -0.20, 0.16; P = .80) (n = 17 RCTs), yet animal protein improved muscle mass compared with non-soy plant proteins (rice, chia, oat, and potato; SMD = -0.58; 95% CI: -1.06, -0.09; P = .02) (n = 5 RCTs) and plant-based diets (SMD = -0.51; 95% CI: -0.91, -0.11; P = .01) (n = 7 RCTs). No significant difference was found between plant or animal protein for muscle strength (n = 14 RCTs) or physical performance (n = 5 RCTs). No trials examined sarcopenia as an outcome. Animal protein may have a small beneficial effect over non-soy plant protein for muscle mass; however, research into a wider range of plant proteins and diets is needed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42020188658.

Effects of chia (Salvia hispanica. L) on anthropometric measures and other cardiometabolic risk factors: A systematic review and dose-response meta-analysis

BACKGROUND

Findings of available randomized controlled trials (RCTs) on the effects of chia are inconsistent. Although previous meta-analyses summarized available findings in this regard, some limitations may distort their findings. Moreover, none of these meta-analyses examined the dose-response association of chia on cardiometabolic risk factors (CMRFs). Therefore, the present study aimed to evaluate the effect of chia consumption on CMRFs.

METHODS

Relevant RCTs were included by searching the ISI Web of Science, PubMed, and Scopus databases up to June 2, 2023. Mean differences (MD) and 95 % confidence intervals (CI) were pooled using random-effects model.

RESULTS

Ten publications were included in this systematic review and the meta-analysis. The results showed a significant reduction in systolic blood pressure (SBP) (MD = -7.87 mmHg; 95 % CI: - 12.92 to - 2.82; I2 = 71.3 %, P heterogeneity = 0.004), diastolic blood pressure (MD = -6.33 mmHg; 95 %CI: - 7.33 to - 5.34, I2 = 0 %, P heterogeneity = 0.42) and high-density lipoprotein cholesterol (HDL-c) (MD = -4.09 mg/dl; 95 %CI: - 6.76 to - 1.43, I2 = 12.4 %, P heterogeneity = 0.33). However, the effects of chia on the other risk factors were not significant. Based on the dose-response analysis, a 10-g/d increase in chia consumption significantly reduced SBP (MD = -2.20 mmHg; 95 %CI: - 3.75 to - 0.66, I2 = 78.9 %, P heterogeneity < 0.001) and HDL-c (MD = -1.10 mg/dl; 95 %CI: - 1.72 to - 0.49, I2 = 0 %, P heterogeneity = 0.52).

CONCLUSION

Chia consumption might have a beneficial effect on lowering blood pressure. Chia consumption can also lead to a slight reduction in HDL-c levels. As the quality of the included studies was mostly low, the findings should be interpreted with caution. Well-designed trials with larger sample sizes and longer duration of follow-up are needed to provide additional insight into the dose-dependent effects of chia consumption.