Unlike prevalent health conditions with standard treatment plans, musculoskeletal health and related disorders are often left unaddressed until functional independence is challenged. The integrated function of skeletal muscle, bone, joints, tendons, and ligaments is critical for mobility, independence in activities of daily living, and overall quality of life. Declines in bone mineral density (BMD), along with age-related reductions in muscle mass and strength, clinically defined as sarcopenia, contribute to frailty and disability in older adults. These functional limitations, or declines in musculoskeletal health, create a substantial healthcare burden in older adults [1]. Nutritional strategies that support bone and muscle health may help palliate these changes. Nut consumption is among potential dietary approaches that have gained interest due to nuts’ nutrient density and bioactive compounds beneficial to musculoskeletal health.

Nuts such as pistachios, almonds, and pecans are highest in phytosterols, which may provide cholesterol-lowering and anti-inflammatory effects [2]. Brazil nuts are rich in selenium and phenols, and are a good source of healthy fats, calcium, and magnesium. These compounds work to reduce free radicals responsible for oxidative stress, inflammation, and low-density lipoprotein, and support bone health [3]. As the only tree nut considered an excellent source of the plant-based omega-3 essential fatty acid alpha-linolenic acid (ALA), walnuts are highly recognized for reducing inflammation, supporting cardiovascular and brain health, and for their versatility and nutrient-dense composition [4–6]. Griel et al. [7] found that a diet high in ALA, provided by walnuts and flaxseed oil, significantly reduced bone turnover in middle-aged adults. Another study found that higher total omega-3 levels and ALA levels in red blood cells may be useful predictors for lower hip fracture risk in postmenopausal women [8]. Walnuts, along with almonds, are also rich in potassium, magnesium, and polyphenols. These compounds may help to repair muscles and reduce inflammation after exercise [9, 10]. Potassium plays an important role in maintaining electrolyte balance, muscle membrane excitability, and normal muscle function during and after exercise. Changes in the distribution of potassium ions during intense exercise may contribute to muscular fatigue by altering muscle membrane excitability [9, 11]. Magnesium is needed for energy metabolism and plays a crucial role in muscle relaxation and contraction, while polyphenols help to alleviate post-exercise muscle damage by providing anti-inflammatory and antioxidant benefits [9, 10]. Peanuts have bioactive compounds that promote longevity. A good source of phenolic acids, flavonoids, phytosterols, and coenzyme Q10, peanuts also contain all 20 amino acids, with high amounts of arginine [12]. L-arginine is necessary to keep joints and muscles healthy. L-arginine serves as a precursor for nitric oxide synthesis, which contributes to vasodilation and the regulation of blood flow and may influence skeletal muscle function during exercise [12]. These bioactive compounds, along with the nutrient-dense profile found in nuts, provide a unique nutritional strategy for musculoskeletal health. This makes nuts an ideal component of the everyday diet, not only for the general population or older adults but for athletes seeking nutritional interventions for improved muscle recovery.

Epidemiologic study designs across diverse populations consistently associate higher nut intake with improved functional status, reduced disability risk, and lower prevalence of sarcopenia and frailty [13–16]. Evidence from randomized controlled trials (RCTs) has higher variability. While some studies have found a positive impact of nut consumption on BMD, muscle recovery, and endurance, other studies report mixed effects with varying individual responses [17–20]. The latter suggests that outcomes are heavily influenced by nut type, dosage, study duration, population characteristics, and concurrent interventions.

With increasing longevity of the global population comes a growing burden of sarcopenia, frailty, age-related functional decline, and dependency. With growing interest in food-based strategies to support musculoskeletal health in both athletes and the general population, a thorough review of the existing evidence is warranted. To elucidate the strength of existing evidence and identify priorities for future research, this systematic review critically examines observational and interventional studies on nut consumption and musculoskeletal outcomes, including muscle strength, sarcopenia, frailty, bone metabolism, physical function, and exercise recovery.

This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) [21]. The review protocol was registered in the Open Science Framework (OSF) database. Studies were included on the basis of the following inclusion criteria: (1) human adult population (≥ 18 years of age or older), (2) RCTs and observational studies, (3) intervention with any type of nut consumption, with ≥ 2 weeks of intervention for clinical trials, and (4) musculoskeletal outcome. Studies were excluded if they were not written or available in English, full text, or published in a peer-reviewed journal. Studies with interventions that consisted of individual nutrients (e.g., magnesium, vitamin E, omega-3 fatty acids), nut oil, or food patterns only (without nut focus), or included participants with chronic disease were also excluded.

The results of this systematic review indicate that nut consumption may have beneficial effects on musculoskeletal health, particularly in relation to muscle recovery, strength, functional capacity, and reduced risk of frailty. Bioactive compounds in nuts, like polyphenols, antioxidants, and ALA, make them an ideal snack recommendation for nutrition-focused muscle recovery and overall musculoskeletal health. Walnut consumption in the concurrent training trial showed a greater rise in subjective sleep quality and selective gains in cognition and dual-task balance, implying a stronger benefit of walnuts for neuro health than muscle health [25]. The rich source of ALA in walnuts has been shown to be neuroprotective, as well as beneficial for cardiovascular health [6, 34]. While physical training improved muscle strength, the added benefit of walnut consumption can be seen in cognition-related measures (cognition, dual-task balance, sleep quality) rather than muscle growth compared to training alone.

The exercise-recovery studies were more favorable for almonds than for pistachios, but the effects were modest and came from small crossover trials. One pistachio trial reported a 4.8% slower performance time in a 75-km cycling trial compared with the control condition, and no meaningful improvement on inflammatory biomarkers [17]. Researchers postulate that this slower performance with pre-exercise pistachio consumption is attributed to the high short-chain carbohydrate content, particularly raffinose, which remains undigested in the upper gastrointestinal tract. Gut bacteria begin to ferment raffinose, producing gas and causing discomfort while cycling or performing other physical activity. Foods high in short-chain carbohydrates, known as high fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) foods, are linked to an increase in leaky gut, which triggers an immune system reaction to release toxins that can lead to impaired energy production in the muscles and reduce overall performance [35, 36]. In contrast, the other two pistachio studies used pistachio as a recovery rather than before exercise. These studies found reduced muscle soreness in the group with a high pistachio dose versus a low pistachio dose and improvements in recovery markers following eccentric exercise or downhill running protocols in physically active people [18, 26]. Key compounds in pistachios that contribute to recovery are leucine and other essential amino acids for muscle protein synthesis, along with antioxidants that reduce inflammation and attenuate perceived muscle soreness [26]. Taking into consideration that all three pistachio RCTs were 2 weeks in duration, had a small sample size, and the same pistachio dose for the experimental group, these findings suggest that pistachios may be more beneficial in decreasing exercise-induced muscle damage and enhancing recovery, rather than as a fuel source (pre-exercise) for improved performance. Almond trials reported improvements across both studies. One crossover trial found that 2.0 oz/day of almonds modestly reduced pain, better maintained muscle strength, and reduced CK levels after eccentric exercise [28], while another study reported a roughly 24% reduction in soreness over a 72-hour recovery window [27]. Almonds are a rich source of branched-chain amino acids, arginine, vitamin E, and magnesium. It is these essential nutrients, along with polyphenols in almonds, that contribute to a shift in oxylipin metabolism, promoting a reduction in muscle damage and perceived muscle soreness while improving muscle recovery [37].

CK is a key indirect biomarker for assessing muscle strain and recovery. High serum CK levels are indicative of muscle strain, muscle damage, or overtraining. During eccentric exercise, muscle cells experience mechanical stress and localized bursts of reactive oxygen species (ROS), leading to microscopic tears that allow CK to leak into the bloodstream. If serum CK levels peak and then return to normal, this pattern is consistent with the repair of muscle damage. Intracellular CK is important because it catalyzes the transfer of a high-energy phosphate group from phosphocreatine to ADP, rapidly regenerating adenosine triphosphate (ATP) and helping muscle cells restore energy during high-intensity contraction. Oxidative stress can not only damage muscle tissue and increase CK release into the bloodstream but also inactivate intracellular CK by oxidizing its sensitive thiol groups and reducing its ability to regenerate ATP [38, 39]. Glutathione peroxidase 1 (GPX1) is a major intracellular antioxidant enzyme that scavenges hydrogen peroxide and other peroxides. As a selenoenzyme, GPX1 requires selenium to synthesize its active selenocysteine site; therefore, selenium availability may influence its expression and protective capacity [40]. GPX1 activity and serum CK levels may be negatively correlated, particularly under conditions of oxidative stress or muscle damage. When GPX1 activity is low, cells may have insufficient antioxidant protection against ROS, resulting in greater oxidative damage to muscle cells and increased CK release into the blood. Moriguchi Watanabe et al. [29] investigated whether selenium supplementation through consumption of one Brazil nut daily could increase GPx1 activity and thereby reduce elevated serum CK levels in statin-treated individuals. Responses to supplementation and CK levels depended on genetic variation in selenoprotein-related genes (SELENOP variants), suggesting that gene-nutrient interactions influence muscle-related biochemical responses to selenium intake [29]. A limitation of this study is that muscle function and recovery were not directly assessed; therefore, the observed changes in CK cannot be definitively linked to improvements in muscle homeostasis.

The study by Garrido-Miguel et al. [30] associated high nut consumption (≥ 5 portions of 30 g/week) with healthier body composition and better physical fitness. However, the overall results imply that body composition benefits from nut consumption are independent of cardiorespiratory fitness level [30]. This implies that eating nuts improves body composition regardless of fitness levels, whereas overall physical activity remains the primary driver of strength. In the study by Jun and Shin [31], older male adult nut consumers had a 45% reduced risk of low muscle strength, and older female adult nut consumers had a 31% reduced risk [31]. Total protein intake was considered as a variable in one of their regression models to rule out that the beneficial effects on muscle strength were coming from protein intake and not nut consumption. This adjustment still resulted in significant outcomes between nuts and low muscle strength in older men and women. The benefit is attributed to, in part, the monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) sources in nuts. Researchers in this study suggest that the high ratio of MUFA or PUFA to saturated fatty acids in nuts may provide anti-inflammatory benefits, helping to promote and improve muscle function, thereby reducing the onset of sarcopenia. The large data set and validated methods used are strengths of this study. Limitations include no formal diagnosis of sarcopenia, possible reverse causation from the cross-sectional nature of the KNHANES used, and use of one 24-hour recall to measure nut intake [31]. Collectively, data from these studies suggest that nut consumption may primarily benefit muscle recovery through reduced oxidative stress.

The study by Oliver-Pons et al. [19] found that daily walnut consumption for two years had a neutral effect on BMD, with potential beneficial impacts observed only in specific subgroups. This study suggests that walnuts may provide a stronger benefit for cardiovascular risk factors, fitting within the broader context of the WAHA trial, but are a safe dietary strategy that does not compromise bone health. Postprandial serum analysis from an ex vivo study suggests that almond consumption may inhibit osteoclastogenesis, determined by reduced tartrate-resistant acid phosphatase, decreased calcium release, and lower expression of bone-resorption genes in vitro [32]. These findings are mechanistically interesting but serve as surrogate markers and cannot establish direct clinical benefit. While the Bangladesh study did not measure BMD or bone remodeling dynamics directly, it assessed self-reported osteo-related diseases [33]. This study linked weekly nut intake, within a broader functional-food pattern, to lower odds of osteo-related disease. It is important to note that this was a cross-sectional observational study, so causation cannot be ascertained from results. While results from this study are suggestive that functional foods, like nuts, may positively influence bone metabolism and musculoskeletal health, direct evidence for musculoskeletal benefits is limited [33]. In contrast, the Bulló et al. [20] study was a randomized intervention trial that directly assessed bone metabolism and remodeling. Frequent nut consumption is sometimes viewed negatively, as there is a potential impact on the acid-base balance and bone health due to the high dietary acid load produced by certain types of nuts. When blood acid levels rise, the body uses a buffer system to maintain pH. A consequence of this buffer system is increased breakdown of bone to release calcium (an alkaline compound) to neutralize the acid. A primary regulator of this bone breakdown, or resorption, is PTH. While this study did find higher PTH levels in the Mediterranean diet with nuts group, downstream skeletal harm was not observed. This is supported by existing research that refutes the idea that dietary acid load is a major causal driver of osteoporosis or bone loss, referred to as the acid-ash hypothesis [41]. Despite the insufficient evidence to support it, the consensus regarding the acid-ash hypothesis remains split. It should be noted that the overall diet quality of the Mediterranean diet could contribute to the neutral finding of a diet with high dietary acid load.

Of the four studies in this systematic review that focused on frailty and functional limitations, higher nut consumption was consistently associated with more favorable age-related outcomes in older adults. These favorable outcomes include lower risk of frailty and sarcopenia, improved quality of life, fewer functional limitations, and greater likelihood of disability-free survival. Wang et al. [13] found that long-term nut intake was associated with a statistically significant lower risk of frailty in older women. Similar to what other studies in this systematic review have suggested, the proposed mechanisms for this lower risk of frailty include reduced inflammation from phytochemicals, vitamins, minerals, and PUFAS, improving muscle recovery; protein synthesis promotion and protein degradation prevention, mitigating sarcopenia; and nutrient density of nuts providing body composition and cardiovascular benefits, which promotes overall health [13]. The prospective cohort study by Wild et al. [14] further supports these findings and proposed mechanisms, demonstrating that nut consumption was associated with improvement in disability-free survival among community-dwelling older adults [14]. The NHANES cross-sectional study and the Xu et al. [16] study also found notable benefits in higher nut consumption in older populations. The NHANES study found that higher nut consumption resulted in improved quality of life, lower odds of functional limitations, and lower severity of limitations. This study noted an inverse association between nut consumption and prevalence of sarcopenia, even after adjustment for covariates [16]. The overall findings of these studies are consistent with prior and current literature demonstrating benefits of foods high in unsaturated fats and antioxidants, like nuts, on healthy aging, frailty prevention, and functional independence. Despite consistent findings, limitations should be considered. All four studies were observational, with different populations (sex/race), which limits causal inference. It is also impossible to rule out benefits of other lifestyle habits, like higher physical activity levels, greater healthcare access, or a healthier overall diet. Although statistical adjustments were performed in some of the studies, unmeasured confounders cannot be excluded. Self-reported dietary intake introduces potential recall bias and measurement errors, and optimal dosage, frequency, or type of nuts cannot be determined from observational studies. Strengths of the studies include large cohort populations, long follow-up durations, and consistent findings across geographically and culturally diverse populations.

In conclusion, the findings of this systematic review suggest that regular nut consumption may have beneficial effects on musculoskeletal health, through mechanisms related to reduced oxidative stress and inflammation, muscle recovery, and preservation of functional capacity. Of the studies reviewed, pistachios and almonds demonstrated modest benefits for improving muscle soreness and exercise recovery, while walnuts showed greater impact and potential benefit for neuro and cardiovascular health. Findings on bone health were limited and mixed, with walnuts providing a neutral benefit and almond results providing mechanistic insight rather than clinically significant outcomes. However, these findings support that regular nut intake does not adversely affect bone remodeling or skeletal health. Observational studies consistently attributed higher nut intake to a lower risk of frailty, sarcopenia, functional limitation, and improved disability-free survival in older adults. These findings strongly support the potential role of nuts within healthy aging dietary patterns. Polyphenols, anti-inflammatory and antioxidant properties, amino acids, MUFAs and PUFAs, vitamins, and minerals present in nuts collectively contribute to the beneficial outcomes on musculoskeletal health. Reliance on observational data or short-term trials, high heterogeneity, and limited evidence for some outcomes make it difficult to establish optimal intake recommendations, and small study sizes and self-reported data reduce confidence in the causal relationship between nut intake and musculoskeletal health. Larger long-term RCTs are needed to clarify and strengthen dose-response relationships and confirm clinically meaningful musculoskeletal and bone health outcomes. However, currently available evidence suggests that regular nut consumption appears to be safe and a potentially beneficial strategy for supporting muscle recovery, functional independence and healthy aging.