Dietary factors and nutritional guidelines for sarcopenia in older adults: a narrative review

Abstract

Objectives

Sarcopenia is a condition characterized by the loss of muscle mass and function and is often accompanied by aging and chronic diseases such as diabetes and obesity. It increases the risk of falls, frailty, disability, hospitalization, and mortality in older adults. Its global prevalence is estimated as approximately 10%–27% in adults aged > 60 years. This review analyzes evidence from research findings and recommendations to provide a comprehensive overview of dietary factors and nutritional strategies for preventing and managing sarcopenia in older adults.

Methods

Literatures were searched to integrate findings from observational studies, clinical trials, systematic reviews, and meta-analyses on dietary factors and nutritional guidelines for the prevention and management of sarcopenia. Particularly, points were emphasized on protein intake, micronutrient adequacy, dietary patterns, and combined lifestyle interventions relevant to older populations.

Results

Sarcopenia develops through multifactorial mechanisms such as dysfunction in muscle protein synthesis, chronic inflammation, mitochondrial dysfunction, and aging-related hormonal decline. Nutritional factors, particularly protein intake, play a central role in its development and management. Adequate protein intake is typically 1.0–1.2 g/kg/day for healthy older adults and more than 1.2 g/kg/day for individuals with sarcopenia or frailty. High-quality protein intake, sufficient leucine intake, and amino acids or β-hydroxy-β-methylbutyrate supplementation may help to counteract dysfunction in muscle protein synthesis. The adequacy of vitamin D supports musculoskeletal health. Dietary patterns, such as the Mediterranean and Dietary Approaches to Stop Hypertension diets have been consistently associated with better muscle mass, strength, and function. Strong evidence has demonstrated synergistic benefits when optimized nutrition is combined with resistance exercise.

Conclusion

The comprehensive management of sarcopenia in older adults requires an integrated strategy that prioritizes adequate protein and energy intake, vitamin D adequacy, healthy dietary patterns, and regular resistance exercise.

INTRODUCTION

Sarcopenia is a musculoskeletal disease characterized by a progressive decline in skeletal muscle mass, strength, and muscle-related physical functions with advancing age [1]. Sarcopenia increases the risk of falls, frailty, disability, hospitalization, and mortality and serves as a major factor in reducing independence and quality of life among community-dwelling older adults [2, 3]. As sarcopenia leads to increased socioeconomic costs through higher healthcare expenditure and expanded caregiving burdens, the need for the prevention and management of sarcopenia in community nutrition and public health has been growing [4, 5].

The pathogenic mechanisms of sarcopenia are complex and involve interactions between anabolic resistance accompanying aging, decreased muscle protein synthesis, chronic inflammation, and mitochondrial dysfunction [6-8]. Additionally, chronic diseases such as obesity, type 2 diabetes, and kidney disease accelerate these biological changes, increasing the risk of sarcopenia in older adults [9-11]. Nutritional imbalances, including insufficient protein and energy intakes in older adults, are core factors in the development and progression of sarcopenia; inappropriate dietary patterns, micronutrient intake status, and dietary habits also play important roles [12, 13]. Nutritional management is a modifiable and effective key intervention for the prevention and management of sarcopenia in older adults.

Recent studies have consistently reported that adequate protein intake, high-quality protein foods, leucine, vitamin D intake, healthy diets such as the Mediterranean diet, and Dietary Approaches to Stop Hypertension (DASH) diet help maintain muscle mass and function [12-17]. Additionally, reports showing that nutritional interventions and resistance exercise demonstrate complementary effects emphasize the importance of managing overall lifestyle [18, 19]. Accordingly, this study aimed to comprehensively analyze observational studies, clinical trials, systematic reviews, and meta-analyses on dietary factors and nutritional guidelines for the prevention and management of sarcopenia, and to present nutritional management strategies applicable to community-dwelling older adults.

METHODS

Ethics statement

As this study is a narrative review, it did not require institutional review board approval or individual consent.

Study design

This study is a narrative review utilizing PubMed, Web of Science, Korean Studies Information Service System, and DBpia. Search terms used included “sarcopenia,” “elderly,” “protein,” “vitamin D,” “diet,” “dietary pattern,” and “nutrition,” with no restrictions on publication year. In addition, papers published in Korean and English were included in the analysis.

OVERVIEW OF SARCOPENIA

Sarcopenia is a disease associated with aging and various conditions characterized by the progressive loss of muscle mass, featuring a pathophysiological state in which muscle protein breakdown predominates over muscle protein synthesis owing to an imbalance in muscle protein homeostasis [20]. These changes result in decreased muscle strength and function.

Several diagnostic criteria for sarcopenia have been published, with the most widely used being the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) and the Asian Working Group for Sarcopenia (AWGS) guidelines (Table 1) [21, 22]. The EWGSOP2 guideline uses the strength, assistance in walking, rise from a chair, climb stairs, and falls (SARC-F) questionnaire, a self-assessment questionnaire for sarcopenia as a screening tool for individuals at risk [21]. Five items (strength, assistance in walking, rise from a chair, climb stairs, and falls) were each scored 0–2 points, and individuals scoring 4 or more out of 10 points were screened as being at risk for sarcopenia. Subsequently, muscle strength was evaluated first and if reduced muscle strength was confirmed, muscle mass was additionally measured; if muscle mass was also decreased, sarcopenia was diagnosed [21]. The AWGS guideline screens individuals at risk for sarcopenia when calf circumference is below the standard (men 34 cm, women 33 cm) or the SARC-F score is 4 points or higher and diagnoses sarcopenia when muscle mass is decreased along with a reduction in either muscle strength or physical function [22].

Table 1.

Comparison of diagnostic algorithm between European Working Group on Sarcopenia in Older People 2 (EWGSOP2) and Asian Working Group for Sarcopenia (AWGS) [21, 22]

	EWGSOP2	AWGS
Case finding	Recommends SARC-F questionnaire and clinical suspicion to identify individuals at risk (Find–Assess–Confirm–Severity, F-A-C-S)	Suggests use of SARC-F, calf circumference, or other simple measures for community screening in Asian settings
First diagnostic step	Low muscle strength defines “probable sarcopenia”	Either low muscle strength or low physical performance warrants further evaluation; the AWGS also defines “possible sarcopenia” for use in primary care settings
Confirmation of sarcopenia	Add evidence of low muscle quantity/quality (DXA, BIA, CT, MRI)	Low muscle mass plus low muscle strength and/or low physical performance, but with Asian-specific cut-offs and methods
Severe sarcopenia	Low muscle strength + low muscle mass + low physical performance	Low muscle strength + low muscle mass + low physical performance

Data from Cruz-Jentoft et al. (Age Ageing 2019; 48(1): 16-31) [21].

Data from Chen et al. (J Am Med Dir Assoc 2020; 21(3): 300-307.e2) [22].

SARC-F, strength, assistance in walking, rise from a chair, climb stairs, and falls; DXA, dual-energy X-ray absorptiometry; BIA, bioelectrical impedance analysis; CT, computed tomography; MRI, magnetic resonance imaging.

With global population aging, the prevalence of sarcopenia is increasing. A systematic literature review and meta-analysis of cross-sectional studies or cohort studies targeting adults aged 18 years and older reported that 8%–36% of the population < 60 years and 10%–27% of the population aged 60 years and older have sarcopenia [23]. Among community-dwelling older adults aged 70 years and older enrolled in the Korean Frailty and Aging Cohort Study, 21.3% of men and 13.8% of women had sarcopenia [24].

Sarcopenia can be caused by aging, chronic diseases, physical inactivity, medications, and malnutrition, resulting in falls, fractures, frailty, activity limitations, respiratory impairment, cognitive decline, decreased independence, and reduced quality of life [8]. As the causes of sarcopenia are complex and various drugs for sarcopenia treatment remain in the development and research stages, the need for management centered on nutrition and exercise is high.

NUTRITIONAL MANAGEMENT OF SARCOPENIA

Protein

Adequate protein intake is the primary consideration in the nutritional management of sarcopenia. Since the major mechanism underlying sarcopenia is dysregulation of muscle protein homeostasis, where muscle protein breakdown exceeds muscle protein synthesis, it is essential to consume sufficient high-quality protein that can promote muscle protein synthesis to offset this imbalance. Analysis results of the Korea National Health and Nutrition Examination Survey showed that the average protein intake of the population aged 60 years and older was 1.03 g/kg/day for men and 0.90 g/kg/day for women, with 47.9% of men and 60.1% of women having insufficient protein intake compared to the recommended amount [25]. Particularly in the older population, the protein intake of older adults with sarcopenia is significantly lower than those without sarcopenia [26], and research results showed that protein intake at a level of 1.5 g/kg/day is most effective in preventing sarcopenia and frailty in the older population, supporting the importance of protein intake in the nutritional management of sarcopenia [27]. Based on these and other previous studies, the Korean Nutrition Society and Korean Geriatrics Society recommend consuming > 1.2 g/kg/day of protein to prevent sarcopenia in older populations [28]. The nutritional recommendations for community-dwelling older adults recently published by the AWGS suggest that healthy older adults consume 1.0–1.2 g/kg/day or more of protein, and older adults with sarcopenia or frailty consume 1.2 g/kg/day or more of protein [15, 29]. Additionally, they recommended prioritizing protein intake through meals and using protein supplements only in limited cases when sufficient intake from meals is not possible for specific reasons [29].

Amino acids

In the prevention and management of sarcopenia, along with sufficient protein intake, the intake of essential amino acids and β-hydroxy-β-methylbutyrate (β-HMB) can be considered. In particular, the branched-chain amino acids leucine, isoleucine, and valine, and β-HMB, a metabolite of leucine, promote protein synthesis by activating the mammalian target of rapamycin signaling pathway [30, 31]. Previous studies have reported administration of specific amino acids or β-HMB alone or in various forms such as amino acid beverages, enteral nutrition solutions, or components of whey protein products [15]. For example, leucine was consumed alone or in combination with other products at doses ranging from 2 to 17.6 g per day, and its effects on the preservation or improvement of muscle mass and function were verified [15]. Synthesizing current research findings, there is insufficient evidence to clearly identify an optimal intake of specific amino acids or β-HMB. However, the Korean Nutrition Society and Korean Geriatrics Society suggest that an intake > 20 g of essential amino acids per day may be helpful in preventing sarcopenia in the elderly population [28].

Vitamin D

Vitamin D is well known to be essential for skeletal metabolism and plays an important role in muscle production and maintenance by regulating muscle protein production and mitochondrial function [32]. Several studies concerning community-dwelling older adults have reported that low blood vitamin D levels are significantly associated with decreased muscle strength and function [33-35]. Additionally, there are reports that vitamin D supplementation alone or in combination improves muscle strength and function in the older population [36, 37]. The nutritional recommendations for community-dwelling older adults recently published by the AWGS suggest that a vitamin D intake of 800–1,000 IU per day is necessary to prevent sarcopenia in the older population [29, 38].

Dietary patterns

Healthy dietary patterns can reduce the risk of sarcopenia, and Mediterranean and DASH diets can be considered for the prevention and improvement of sarcopenia [39]. The Mediterranean diet consists mainly of plant-based foods such as fruits, vegetables, whole grains, legumes, nuts, seeds, and olive oil, with moderate consumption of dairy products, eggs, fish, poultry, and wine, while restricting the intake of red meat, sweets, and processed foods [40]. This diet reduces the risk of cardiovascular disease and promotes healthy aging [41, 42]. A cross-sectional study analysis of individuals aged 50 years and older reported that high adherence to the Mediterranean diet reduces the risk of sarcopenia [17]. Additionally, a systematic literature review and meta-analysis of adults over 50 years of age reported that among various dietary patterns, the Mediterranean diet has the greatest effect in reducing the risk of sarcopenia, although specific contributing factors could not be identified [39]. This suggests that the Mediterranean diet, as an integrated dietary pattern rather than a single factor, prevents and improves sarcopenia.

Furthermore, the DASH diet consists mainly of plant-based foods such as fruits, vegetables, nuts, legumes, and whole grains, along with low-fat dairy products, while restricting the intake of salt, red meat, processed meat, and sugar-sweetened beverages [43]. The DASH diet was designed to prevent and improve hypertension [44], and has demonstrated beneficial effects on metabolic syndrome, obesity, dyslipidemia, and kidney disease [45-47]. Analysis of the relationship between various dietary patterns and sarcopenia using National Health and Nutrition Examination Survey data showed that, among various dietary patterns, particularly high adherence to the DASH diet reduces sarcopenia risk, which was proposed to be due to the anti-inflammatory properties of the DASH diet and to synergistic effects among nutritional components [48, 49].

These two dietary patterns share the commonality of consisting primarily of plant-based foods. Although each dietary pattern includes factors other than plant-based foods that prevent and improve sarcopenia, this suggests that plant-based proteins, dietary fiber, and phytochemicals contained in plant-based foods may reduce the risk of sarcopenia. Evidence that plant-based diets or specific plant-based nutritional components reduce sarcopenia risk is insufficient, and large-scale, well-designed studies are needed to elucidate this.

Nutritional guidelines for the prevention and management of sarcopenia in older adults are summarized in Table 2 [15, 17, 28, 29, 38, 39, 48, 49].

Table 2.

Nutritional recommendations for sarcopenia in older adults

Factors	Recommendations	References
Protein	• 1.0–1.2 g/kg/day for healthy older adults	[15, 28, 29]
	• > 1.2 g/kg/day for individuals with sarcopenia or frailty
Amino acids	• > 20 g/day of essential amino acids	[15, 28]
	• Leucine and β-HMB help preserve muscle mass and function
Vitamin D	• An intake of 800–1,000 IU of vitamin D helps maintain muscle mass and function	[29, 38]
Mediterranean diet	• Greater adherence to the Mediterranean diet has been linked to a reduced prevalence of sarcopenia	[17, 39]
DASH diet	• High adherence to the DASH diet was inversely associated with the risk of sarcopenia	[48, 49]

β-HMB, β-hydroxy-β-methylbutyrate; DASH, Dietary Approaches to Stop Hypertension.

CONCLUSIONS

Sarcopenia is a disease with an increasing prevalence and associated burden in community-dwelling older populations with aging and increased chronic diseases. Therefore, nutritional management is becoming increasingly important as an effective intervention strategy for preventing and managing sarcopenia.

Nutritional strategies for the prevention and management of sarcopenia in older adults emphasize sufficient energy and protein intake. Energy that can maintain appropriate body weight and high-quality protein intake at levels of 1.0–1.2 g/kg/day for healthy older adults and 1.2 g/kg/day or more for older adults with sarcopenia or frailty are recommended. Additionally, specific amino acids including leucine and β-HMB have potential benefits in promoting muscle protein synthesis, but evidence for optimal intake is lacking. Essential amino acids, including branched-chain amino acids, should be consumed at more than 20 g per day. Furthermore, vitamin D should be consumed at levels of 800–1,000 IU to maintain adequate blood vitamin D concentrations.

The Mediterranean and DASH diets, known as healthy dietary patterns, are considered to reduce the risk of sarcopenia as integrated diets. This may be due to the increased plant-based food intake, anti-inflammatory effects, and interactive effects among plant-based nutritional components. Therefore, further research is needed to determine the sarcopenia-preventive effects of plant-based diets. Additionally, because nutritional interventions for sarcopenia prevention and improvement are more effective when combined with resistance exercises, the integrated management of nutrition and exercise is necessary when applied at the community level.

In conclusion, effective prevention and management of sarcopenia requires comprehensive consideration of adequate energy and protein intake, sufficient vitamin D intake, and healthy dietary patterns, and an integrated approach that includes regular resistance exercise is essential.

However, there are practical limitations and considerations when applying sarcopenia prevention and management strategies in communities. In particular, owing to differences in the economic levels and food accessibility of older adults, it may be difficult for them to continuously consume sufficient protein and high-quality foods. For example, older adults living alone or with a low income often have limited access to high-quality protein source foods and fresh vegetables and fruits. To address these limitations, policy support is needed to provide integrated intervention programs that combine nutrition and exercise by utilizing existing infrastructure such as community health centers and senior welfare facilities to screen for sarcopenia early.