Effects of whey and soy protein supplementation on inflammatory cytokines in older adults: a systematic review and meta-analysis

The British Journal of Nutrition
Q1
Jun 2022
Citations:45
Influential Citations:1
Systematic Reviews / Meta-Analyses
90
S2 IconPDF Icon

Enhanced Details

Methods
31 randomized controlled trials in older adults (mean age 50–80 years; both sexes). Designs included randomized, double-blind, single-blind, and unblinded parallel and crossover trials. Populations encompassed healthy older adults, and individuals with sarcopenia, pre-frailty, abdominal obesity, COPD, type 2 diabetes, cancer, hypercholesterolemia, chronic liver disease, and other conditions.
Intervention
Whey protein: oral whey protein supplementation; regimens varied across trials (doses up to 44 g/day; in one study, 1.5 g/kg body weight/day); durations ranged from about 2 weeks to 18 months; some regimens included additional nutrients (e.g., vitamin D, vitamin E, calcium, magnesium, zinc, selenium, medium-chain fatty acids). Soy protein: oral soy protein supplementation often with isoflavones or phytoestrogens; isoflavone doses ranged roughly from 66 mg/day to 160 mg/day; durations ranged from 8 weeks to 3 months; some regimens included phytoestrogens and/or other nutrients.
Results
Whey protein supplementation significantly reduced IL-6 levels; soy protein supplementation significantly reduced TNF-α levels. Addition of soy isoflavones further reduced TNF-α and may influence CRP in some analyses. In subgroup analyses, whey reduced IL-6 more in those with sarcopenia/pre-frailty and with shorter treatment, while soy reduced TNF-α more in older adults ≥60 years and with BMI ≥25 kg/m2; isoflavone co-supplementation enhanced anti-inflammatory effects. No consistent changes in hs-CRP or CRP were observed with whey; soy effects on CRP were variable and sometimes increased with isoflavones. Overall, whey and soy proteins appear to have anti-inflammatory effects in older adults, particularly in sarcopenic/pre-frail individuals and when isoflavones are included, but heterogeneity and study quality call for cautious interpretation.
Limitations
High heterogeneity across studies; diverse participant health statuses and durations; some trials without placebo; risk of bias in several studies; moderate overall quality of evidence; limited data for some subgroups; potential confounding from co-interventions and unreported dietary factors.

Abstract

Abstract 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 ...