Effects of High-Quality Protein Supplementation on Lipid and Lipoprotein Profiles in Overweight and Obese Adults: A GRADE-Assessed Systematic Review and Meta-Analysis of 32 Randomized Controlled Trials.

CONTEXT: Overweight (OW) and obesity (OB) are prevalent chronic conditions commonly associated with abnormalities in lipid metabolism. Recent research suggests that high-quality proteins (HQPs), such as milk protein (MP), casein protein (CP), whey protein (WP), and soy protein (SP), may ameliorate lipid profiles.

OBJECTIVE

This meta-analysis of randomized controlled trials (RCTs) assessed the impact of HQP supplementation on the lipid profiles in overweight and obese adults.

DATA SOURCES: RCTs that fulfilled the inclusion criteria were identified by a comprehensive literature search in PubMed, Scopus, and the ISI Web of Science databases.

DATA EXTRACTION: Data extracted included study characteristics, participant demographics, health status, sample size, intervention details (protein type, dose, and duration), cointerventions, and lipid outcomes.

DATA ANALYSIS: Fixed- or random-effects models were used to calculate weighted mean differences (WMDs) and 95% CIs. Thirty-two RCTs (39 intervention arms) with 1357 participants (710 intervention, 647 control) were included. Meta-analysis showed that HQP supplementation significantly reduced low-density lipoprotein cholesterol (LDL-C) (WMD, -3.45 mg/dL; 95% CI, -5.77 to -1.13, P = .004) and total cholesterol (TC) (WMD, -5.70 mg/dL; 95% CI, -10.20 to -1.20; P = .013). No significant effects were observed for triglycerides (TG) (WMD, -4.25 mg/dL; 95% CI, -10.49 to 1.99; P = .182) or high-density lipoprotein cholesterol (HDL-C) (WMD, 0.33 mg/dL; 95% CI, -0.82 to 1.48; P = .574).

CONCLUSIONS

The findings of this study indicate that supplementation with HQPs was associated with reductions in LDL-C and TC; however, these effects were attenuated when high-risk-of-bias studies were excluded. Supplementation with HPQs did not affect TG and HDL-C. Additional trials with longer follow-up periods are necessary to confirm our results.