Effect of Exercise and Dietary Supplementation on Body Composition and Physical Function in Older Adults with Sarcopenia: A Systematic Review

The paper addresses sarcopenia, a progressive age-related loss of muscle mass and function affecting about 10% of people over 65 and up to 30% of men over 80. Given the growing older population, sarcopenia’s impact on autonomy, physical disability, quality of life, and mortality is a major public health concern. While exercise and nutrition/supplementation are each known to mitigate sarcopenia, few studies have examined their synergistic, longer-term effects. This systematic review aims to evaluate the combined effects of exercise and dietary supplementation on body composition and physical function in older adults with sarcopenia.

Prior work indicates multiple exercise modalities (resistance, aerobic, and combined training) can improve muscle mass and reduce fat, with combined training often yielding the largest effects. Mechanistic studies highlight resistance training’s influence on anabolic signaling (e.g., follistatin, myostatin, growth differentiation factors, mTOR). Nutritional trials show protein supplementation across various doses and durations can reduce fat mass and increase lean mass, though effects on physical function are inconsistent; other supplements such as HMB and selenium have shown potential body composition benefits. The literature suggests outcomes may depend on the type, timing, and intensity of exercise, as well as adherence and overall energy/protein intake. Few studies have rigorously tested sustained, synergistic effects of combined exercise and supplementation protocols in older adults with sarcopenia.

The review followed PRISMA guidance and was registered in PROSPERO (CRD42022344284). Databases searched: EBSCO, Scopus, and PubMed. Search terms used: ("Older adults" OR "Elderly") AND "Supplementation" AND ("Physical Activity" OR "Exercise") AND "Body composition" AND "Physical function". The search covered January 2012 to December 2022. Inclusion criteria (PICO): Participants—healthy older adults ≥60 years; Intervention—protocols including a supplementation-plus-exercise group with at least two sessions per week; Comparison—studies including supplementation-only or exercise-only comparators; Outcomes—primary outcomes included changes in body composition or physical function; Design—randomized controlled trials (full text). Exclusion criteria: duplicates; interventions <8 weeks; inclusion of older adults with significant pathologies; non-specific supplements; inadequate control or inconsistent results. Risk of bias was assessed using the PEDro scale (10 items; poor <4, fair 4–5, good 6–8, excellent 9–10). Data were summarized in a matrix capturing trial characteristics and outcomes. Study selection: 73 records identified, 35 duplicates removed; 38 abstracts screened; 18 excluded (short duration, pathological populations, non-specific supplements); 20 full texts assessed; 4 excluded for PEDro <7; 16 RCTs included in the final review.

- Sixteen RCTs with 1585 participants ≥60 years were included. Interventions lasted 8–40 weeks and included strengthening, resistance-band, bodyweight, balance, aerobic, or daily functional exercises; supplements included whey and other proteins, essential amino acids (EAAs), vitamin D (often combined with protein/amino acids), catechins, and plant proteins. - Body composition: Protein plus vitamin D commonly maintained or increased lean mass in sarcopenic older adults. Examples: Yamada et al.—10 g whey + 800 IU vitamin D for 12 weeks maintained appendicular muscle mass vs. control losing 720 g. Rondanelli et al.—22 g whey + 100 IU vitamin D with moderate-intensity training yielded a net 1.4 kg fat-free mass gain in 12 weeks. Miller et al.—protein 40 g + vitamin D 2000 IU produced a 140 g appendicular lean mass gain; gains were 142% higher when combined with progressive resistance training. Zhu et al.—additive benefits on appendicular mass were 4× greater with supplementation + exercise vs. placebo + exercise. Some trials reported no added effect of supplementation beyond training alone (e.g., Griffen; Chalé). Adherence moderated outcomes: high adherence produced 63% higher fat-free mass gains than low adherence in a combined intervention. - Physical function: About one-third of studies showed significant strength benefits (leg extension, leg press, back strength, handgrip) with combined interventions; gains were enhanced with whey protein/EAAs compared with exercise alone in several trials. Gait speed and distance improved more with combined supplementation and exercise than with supplementation or placebo alone, including increases of approximately 15–17% in walking speed in some studies and superior coordination and gait stability; compared with exercise-only, combined protein + vitamin D and exercise yielded about 60% higher improvements in some measures. Improvements extended to longer-distance performance (e.g., 400 m walk) in at least one trial. - Biochemical markers: No consistent changes in general nutritional markers (creatinine, prealbumin, albumin). Inflammatory markers were mixed across studies (e.g., some increases in IL-10, decreases in IL-6 and TNF-α; other studies found opposite or unclear trends). - Quality of life: Few studies assessed QoL; two reported improvements in vitality and general health; one reported reduced caregiver time, but overall QoL outcomes remain underexplored. - PEDro methodological quality: All included trials scored ≥7; two trials scored 10 (excellent).

The synthesis indicates that combined resistance or multicomponent exercise with appropriate dietary supplementation can mitigate sarcopenia by maintaining or increasing lean mass and improving physical function. Complete proteins, especially dairy-derived (whey, caseinates), likely drive benefits by providing essential amino acids and leucine to stimulate mTOR-mediated anabolism. Vitamin D deficiency is common in older adults, and vitamin D may modulate gene expression linked to muscle atrophy; combined with protein and exercise, it supports favorable adaptations. Despite mechanistic plausibility, not all trials demonstrated additive effects of supplementation, particularly when supplements lacked complete amino acid profiles or when adherence and total protein/energy intake were not ensured. Adherence is a key moderator, with higher adherence yielding substantially greater gains. Biochemical outcomes are difficult to interpret due to exercise-induced transient inflammatory responses and concurrent changes in adiposity influencing cytokine profiles. Overall, the findings support a synergistic model in which resistance training restores anabolic sensitivity and protein/vitamin D supplementation provides substrates and signals to promote muscle accretion and functional gains.

Resistance exercise performed regularly (reported as at least five times per week in effective protocols) combined with daily essential amino acids (approximately 3 g) or whey protein (22–36 g) improves maintenance or increases in appendicular/skeletal muscle mass and total lean mass in older adults with sarcopenia. The combined approach also enhances strength, gait speed, stability, and aspects of quality of life, suggesting a synergistic effect that may reduce the burden of musculoskeletal disease. Future research should optimize protocols by rigorously monitoring and improving adherence to both exercise and dietary/supplementation prescriptions, include appropriate comparator arms to separate additive effects, and incorporate comprehensive quality-of-life assessments.

- Some included trials lacked comprehensive comparator arms (e.g., only control vs. exercise+supplement), limiting attribution of additive vs. single-factor effects. - Adherence to both exercise and supplementation was inconsistently monitored; when monitored, higher adherence was associated with substantially better outcomes, indicating potential bias where adherence is low or unmeasured. - Dietary intake (calories/protein) was often not tracked; supplements may have displaced usual intake, masking net protein/energy increases. - Heterogeneity in exercise modalities, intensities, frequencies, and supplementation types/doses complicates direct comparisons and generalization. - Biochemical marker findings were mixed and difficult to interpret due to exercise-induced inflammatory responses and concurrent changes in adiposity. - Quality-of-life outcomes were underreported, limiting conclusions about broader functional and psychosocial benefits.