By definition, aging is a natural, gradual and continuous process. On the other hand, frailty reflects the increase in vulnerability to stressors and shortens the time without disease (health span) while longevity refers to the length of life (lifespan). The average life expectancy has significantly increased during the last few decades. A longer lifespan has been accompanied by an increase in frailty and decreased independence in older adults, with major differences existing between men and women. For example, women tend to live longer than men but also experience higher rates of frailty and disability. Sex differences prevent optimization of lifestyle interventions and therapies to effectively prevent frailty. Sex differences in frailty and aging are rooted in a complex interplay between uncontrollable (genetic, epigenetic, physiological), and controllable factors (psychosocial and lifestyle factors). Thus, understanding the underlying causes of sex differences in frailty and aging is essential for developing personalized interventions to promote healthy aging and improve quality of life in older men and women. In this review, we have discussed the key contributors and knowledge gaps related to sex differences in aging and frailty.

Iron plays a crucial role in many physiological processes, including oxygen transport, bioenergetics, and immune function. Iron is assimilated from food and also recycled from senescent red blood cells. Iron exists in two dietary forms: heme (animal based) and non-heme (mostly plant based). The body uses iron for metabolic purposes, and stores the excess mainly in splenic and hepatic macrophages. Physiologically, iron excretion in humans is inefficient and not highly regulated, so regulation of intestinal absorption maintains iron homeostasis. Iron losses occur at a steady rate via turnover of the intestinal epithelium, blood loss, and exfoliation of dead skin cells, but overall iron homeostasis is tightly controlled at cellular and systemic levels. Aging can have a profound impact on iron homeostasis and induce a dyshomeostasis where iron deficiency or overload (sometimes both simultaneously) can occur, potentially leading to several disorders and pathologies. To maintain physiologically balanced iron levels, reduce risk of disease, and promote healthy aging, it is advisable for older adults to follow recommended daily intake guidelines and periodically assess iron levels. Clinicians can evaluate body iron status using different techniques but selecting an assessment method primarily depends on the condition being examined. This review provides a comprehensive overview of the forms, sources, and metabolism of dietary iron, associated disorders of iron dyshomeostasis, assessment of iron levels in older adults, and nutritional guidelines and strategies to maintain iron balance in older adults.

Arsenic exposure is a worldwide health concern associated with an increased risk of skin, lung, and bladder cancer but arsenic trioxide (AsIII) is also an effective chemotherapeutic agent. The current use of AsIII in chemotherapy is limited to acute promyelocytic leukemia (APL). However, AsIII was suggested as a potential therapy for other cancer types including chronic myeloid leukemia (CML), especially when combined with other drugs. Here, we carried out a genome-wide CRISPR-based approach to identify modulators of AsIII toxicity in K562, a human CML cell line. We found that disruption of KEAP1, the inhibitory partner of the key antioxidant transcription factor Nrf2, or TXNDC17, a thioredoxin-like protein, markedly increased AsIII tolerance. Loss of the water channel AQP3, the zinc transporter ZNT1 and its regulator MTF1 also enhanced tolerance to AsIII whereas loss of the multidrug resistance protein ABCC1 increased sensitivity to AsIII. Remarkably, disruption of any of multiple genes, EEFSEC, SECISBP2, SEPHS2, SEPSECS, and PSTK, encoding proteins involved in selenocysteine metabolism increased resistance to AsIII. Our data suggest a model in which an intracellular interaction between selenium and AsIII may impact intracellular AsIII levels and toxicity. Together this work revealed a suite of cellular components/processes which modulate the toxicity of AsIII in CML cells. Targeting such processes simultaneously with AsIII treatment could potentiate AsIII in CML therapy.

Age‐related decline in physical function is a hallmark of aging and a major driver of morbidity, disability, and loss of independence in older adults, yet the molecular processes linking muscle aging to functional deterioration remain incompletely defined. Emerging evidence implicates ferroptosis, defined as iron‐dependent, lipid peroxidation‐driven cell death, as a compelling but underexplored contributor to age‐related muscle wasting and weakness. Although ferroptosis signatures appear in aged muscle across cellular, animal, and human studies, their causal role in functional decline has not been clearly established. Here, we synthesize current evidence to propose a framework in which iron dyshomeostasis, impaired antioxidant defenses, and dysregulated ferritinophagy converge to create a pro‐ferroptotic milieu that compromises muscle energetics, structural integrity, and regenerative capacity. We delineate key knowledge gaps, including the absence of ferroptosis‐specific biomarkers in human muscle and limited longitudinal data linking ferroptotic stress to mobility outcomes. Finally, we highlight potential therapeutic opportunities targeting iron handling and lipid peroxidation pathways. A better understanding of the contribution of ferroptosis to muscle aging may enable development of mechanistically informed biomarkers and interventions to preserve strength and mobility in older adults.

Earlier analyses evaluating patterns of gut microbiota in individuals from different geographies and age groups are heterogeneous in methodology, precluding broader conclusions about the relationship between the gut microbiome and geographic region, age, and clinical health. Here, we systematically conducted a meta-analysis of 16s rRNA gut microbiome sequencing data representing 10,878 samples across North America, Europe, Africa, Asia and Oceania. Our analysis included 27 countries and three age groups (neonate to age 17, or AG01; ages 18 to 64, or AG02; 65 and above, or AG03). We identified that Firmicutes, Bacteriodetes, and Proteobacteria constitute core phyla across geographic regions. A differing predominance of top families alongside core family Lachnospiracaeae across regions comprised unique microbiome signatures. Countries also differed in their relative abundances of Bifidobacterium, Faecalibacterium, Lactobacillus and Bacteroides. We found in our age analyses that Proteobacteria and Actinobacteria were the most abundant phyla in AG01, and Actinobacteria abundance declined across all continents with increasing age. The relative abundance of Bacteriodetes increased between AG01 and AG02. Enrichment of asthma-associated Enterobacterieaceae in AG01 was highest for North America, followed by Europe and then in Asia. We discuss the correlation of these gut microbial patterns in the context of dietary patterns, populations health, clinical health trends, and healthy aging.

Sarcopenia is an age-related skeletal muscle disorder characterized by reduced muscle mass, strength, and physical performance, as well as increased risk of disability, hospitalization, and mortality. Emerging evidence suggests that gut microbiota alterations may contribute to muscle decline via a microbiota–gut–muscle axis, acting as a context-dependent modulator rather than a primary causal driver. This narrative review synthesizes mechanistic, clinical, and translational evidence linking gut dysbiosis to sarcopenia. Preclinical studies show that microbiota modulation (e.g., antibiotics, probiotics, prebiotics, postbiotics, fecal microbiota transplantation) affects muscle mass, strength, and metabolism through pathways including inflammation, mitochondrial dysfunction, altered short-chain fatty acid production, and impaired anabolic signaling. In humans, observational studies associate lower microbial diversity and reduced short-chain fatty acid-producing taxa with poorer muscle outcomes, but findings are heterogeneous and non-causal. Interventional trials remain limited and characterized by small sample sizes, with effects more consistent for functional outcomes than muscle mass. Overall, the gut microbiota represents a modifiable contributor within the complex biology of sarcopenia. Future studies should integrate microbiome profiling and multi-omics approaches within well-designed clinical trials to identify responder phenotypes and define the role of microbiota-targeted strategies within multimodal interventions.