Whey protein improves muscle in sarcopenic older adults

Sarcopenia — the age-related loss of muscle mass, strength and physical function — undermines independence and quality of life in older adults. Protein supplementation is one of the most accessible countermeasures, and whey is a popular choice, but evidence in people formally diagnosed with sarcopenia, rather than merely older or frail, has been scattered across individual trials. This review set out to pool the randomised evidence on whey protein-enriched supplements, taken with or without resistance training, in older adults meeting recognised diagnostic criteria for sarcopenia, to establish whether it genuinely moves muscle mass, strength and physical performance.

The researchers searched PubMed, Embase, Web of Science and the Cochrane Library for randomised controlled trials up to 1 June 2023, including studies of older patients from community or hospital settings diagnosed with sarcopenia under the EWGSOP or AWGS criteria. Ten RCTs with 1,154 participants were pooled. Comparisons were whey protein versus isocaloric placebo or routine consultation, and whey protein plus resistance training versus the same controls. Primary outcomes were changes in muscle mass, strength and physical performance, with inflammatory and nutritional biomarkers as secondary outcomes, analysed as standardised mean differences.

Whey protein alone significantly increased appendicular skeletal muscle mass index (SMD 0.47), appendicular skeletal muscle mass (SMD 0.28) and gait speed (SMD 1.13) compared with placebo or routine consultation. When whey was combined with resistance training, handgrip strength rose significantly (SMD 0.67). On secondary outcomes, whey reduced interleukin-6, increased insulin-like growth factor-1 and albumin, boosted total energy and protein intake, and improved activities-of-daily-living scores. Notably, it had no significant effect on BMI, body weight or fat mass, suggesting the gains were in lean tissue and function rather than overall size.

This strengthens the case that protein supplementation is not just for gym-goers: it produced measurable improvements in people who already met formal diagnostic criteria for sarcopenia. The finding that strength gains emerged specifically when whey was paired with resistance training fits the broader principle that protein supplies the raw material while training provides the stimulus. The authors are candid that more studies are needed to validate the results and to disentangle the separate and combined effects of whey and training. How long benefits persist, and optimal dosing, remain open questions.

For older adults — or anyone thinking about ageing parents — this is a reason to take dietary protein seriously as muscle declines, since supplementation improved muscle mass, walking speed and daily function in diagnosed sarcopenia. The pattern here is also informative: whey alone helped mass and gait speed, but the strength benefit showed up when it was combined with resistance training, suggesting the two work best together. The absence of any effect on weight or fat mass indicates this is about rebuilding lean tissue, not gaining bulk. This summarises trial evidence and is not medical advice.