Aging is the result of a complex interplay of physical, environmental, and social factors, leading to an increased prevalence of chronic age-related diseases that burden health and social care systems. As the global population ages, it is crucial to understand the aged immune system, which undergoes declines in both innate and adaptive immunity. This immune decline exacerbates the aging process, creating a feedback loop that accelerates the onset of diseases, including infectious diseases, autoimmune disorders, and cancer. Intervention strategies, including dietary adjustments, pharmacological treatments, and immunomodulatory therapies, represent promising approaches to counteract immunosenescence. These interventions aim to enhance immune function by improving the activity and interactions of aging-affected immune cells, or by modulating inflammatory responses through the suppression of excessive cytokine secretion and inflammatory pathway activation. Such strategies have the potential to restore immune homeostasis and mitigate age-related inflammation, thus reducing the risk of chronic diseases linked to aging. In summary, this review provides insights into the effects and underlying mechanisms of immunosenescence, as well as its potential interventions, with particular emphasis on the relationship between aging, immunity, and nutritional factors.

Polycystic ovary syndrome (PCOS) is a prevalent endocrine and metabolic disorder that affects premenopausal women. The etiology of PCOS is multifaceted, involving various genetic and epigenetic factors, hypothalamic–pituitary–ovarian dysfunction, androgen excess, insulin resistance, and adipose-related mechanisms. High-fat diets (HFDs) has been linked to the development of metabolic disorders and weight gain, exacerbating obesity and impairing the function of the hypothalamic–pituitary–ovarian axis. This results in increased insulin resistance, hyperinsulinemia, and the release of inflammatory adipokines, leading to heightened fat synthesis and reduced fat breakdown, thereby worsening the metabolic and reproductive consequences of PCOS. Effective management of PCOS requires lifestyle interventions such as dietary modifications, weight loss, physical activity, and psychological well-being, as well as medical or surgical interventions in some cases. This article systematically examines the pathological basis of PCOS and the influence of HFDs on its development, with the aim of raising awareness of the connection between diet and reproductive health, providing a robust approach to lifestyle interventions, and serving as a reference for the development of targeted drug treatments.

Aging negatively affects B cell production, resulting in a decrease in B-1 and B-2 cells and impaired antibody responses. Age-related B cell subsets contribute to inflammation. Investigating age-related alterations in the B-cell pool and developing targeted therapies are crucial for combating autoimmune diseases in the elderly. Additionally, optimal nutrition, including carbohydrates, amino acids, vitamins, and especially lipids, play a vital role in supporting immune function and mitigating the age-related decline in B cell activity. Research on the influence of lipids on B cells shows promise for improving autoimmune diseases. Understanding the aging B-cell pool and considering nutritional interventions can inform strategies for promoting healthy aging and reducing the age-related disease burden.

The interaction between the gut microbiota and the host immune system is pivotal in maintaining health or driving disease pathogenesis. The gut microbiota directly or indirectly modulates immune cells activation and inflammatory cytokines secretion through microbial metabolites, including short-chain fatty acids (SCFAs), tryptophan metabolites, bile acids, and polyamines. Conversely, the immune system regulates microbial community composition by maintaining the integrity of the epithelial barrier. In addition, antibiotics and probiotics can further regulate the inflammatory response by altering gut microbiota structure and microbial metabolites levels. This review systematically examines the bidirectional regulatory mechanisms among the gut microbiota, microbial metabolites, and inflammatory cytokines, and explores the impact of antibiotics and probiotics on this interaction network. These insights provide new targets for immune-related diseases.

Hematopoietic stem cells (HSCs) are crucial for the life maintenance of bio-organisms. However, the mechanism of HSC regulation is intricate. Studies have shown that there are various factors, either intrinsically or extrinsically, that shape the profile of HSCs. This review systematically summarizes the intrinsic factors (i.e., RNA-binding protein, modulators in epigenetics and enhancer–promotor-mediated transcription) that are reported to play a pivotal role in the function of HSCs, therapies for bone marrow transplantation, and the relationship between HSCs and autoimmune diseases. It also demonstrates the current studies on the effects of high-fat diets and nutrients (i.e., vitamins, amino acids, probiotics and prebiotics) on regulating HSCs, providing a deep insight into the future HSC research.

RNA-binding proteins (RBPs) are critical regulators of post-transcriptional processes, playing essential roles in nutrient metabolism and metabolic homeostasis. This literature review explores how RBPs influence the metabolism of glucose, lipid, and amino acid metabolism by controlling processes like mRNA stability and translation regulation. The dysregulation of RBPs, including HuR, PTB, and YTHDF1, is linked to metabolic diseases such as obesity, diabetes, and non-alcoholic fatty liver disease. Advances in techniques like TREX technology and transcriptome analysis have deepened our understanding of RBP functions. Additionally, RBPs show promise as potential biomarkers and targets for new therapies. Future research directions in RBPs could focus on tissue-specific regulation and nutrient–RBP interactions. This could pave the way for more personalized treatments and improved metabolic health.