n-3 Polyunsaturated Fatty Acids and Sarcopenia: Recent Advances and Mechanistic Research

Sarcopenia is an age-related syndrome characterized by the progressive loss of skeletal muscle mass, strength, and function, significantly impairing older adults' independence and quality of life. Given their anti-inflammatory, antioxidant, and metabolic regulatory properties, n-3 polyunsaturated fatty acids (n-3 PUFAs) have emerged as a promising nutritional strategy to mitigate this muscle degeneration. This review systematically synthesizes existing evidence regarding the association between n-3 PUFAs and sarcopenia. To capture the relevant literature, we searched PubMed, Web of Science, CNKI, and Wanfang Data using a combination of subject headings and free-text terms. We supplemented primary search terms-such as "n-3 polyunsaturated fatty acids," "omega-3 fatty acids," "sarcopenia," and "muscle mass"-with mechanism-related keywords like "inflammation," "muscle satellite cells," and "oxidative stress." We also manually screened the reference lists of the included literature. Our inclusion criteria encompassed interventional studies, observational studies, and high-quality reviews, while excluding conference abstracts, duplicate publications, and studies with incomplete data. This review first outlines the established biological mechanisms linking n-3 PUFAs to the pathological progression of sarcopenia, specifically detailing how these fatty acids improve muscle satellite cell function, suppress inflammation and oxidative stress, and ameliorate metabolic disorders. Next, we critically evaluate recent clinical studies and reviews, analyzing sources of study heterogeneity such as variations in sample size, intervention dose and duration, outcome measures, and baseline participant characteristics. We also highlight current research hotspots-including specialized pro-resolving mediators (SPMs), the gut-organ axis, combined interventions, and precision nutrition strategies-while emphasizing the functional differences between EPA and DHA to guide future intervention designs. Current evidence indicates that while n-3 PUFA supplementation can improve muscle strength and physical performance in older adults, its effects on muscle mass remain inconsistent. Addressing key research gaps, particularly the lack of standardized core outcome measures and unclear dose-response relationships, is critical. Ultimately, future research must prioritize developing high-bioavailability formulations, conducting personalized trials based on baseline n-3 PUFA status, and deepening investigations into inter-organ networks to translate these nutritional insights into effective sarcopenia prevention and management strategies.