Insulin resistance (IR) is a metabolic disorder characterized by an impaired response to insulin. This condition is associated with excess adiposity and metabolic inflammation, contributing to an increased risk for related chronic diseases. Single-nucleotide polymorphisms (SNPs) can affect genes related to metabolic pathways which are related to IR and the individual response to nutrients and dietary patterns, affecting metabolic inflammation and insulin sensitivity. This narrative review explores the current evidence on interactions between genetic variants and dietary factors, specifically their effects in modulating IR and metabolic inflammation. A comprehensive search of the literature was conducted in PubMed, Google Scholar, and Web of Science, and a total of 95 articles were reviewed. The key findings reveal that SNPs in the TCF7L2, ADIPOQ, and TNF genes significantly influence metabolic responses and modulate the effects of the Mediterranean diet on biomarkers of inflammation and IR. Genotype-dependent variations in IR and inflammation biomarkers were observed in the response to different diets for SNPs in the TCF7L2, ADIPOQ, and TNF genes. Additionally, polygenic risk scores (PRSs) can also predict the response to the intake of nutrients and specific diets, and offer a promising tool for assessing genetic predisposition to IR. This review underscores the pivotal role of an individual’s genetic background in the effects of their nutrient intake and in the responses to dietetic interventions, thereby laying the foundation for personalized and effective nutritional strategies tailored to each individual’s necessity in mitigating IR and its associated risk factors for chronic diseases.

Oxidative stress (OS) is an important process related to the pathophysiology of rheumatoid arthritis and can be increased by the low intake of antioxidants. Zinc (Zn) is an important antioxidant trace-element for human health and the assessment of the nutritional status of this micronutrient in these patients is of relevance. This study aimed to evaluate Zn nutritional status in rheumatoid arthritis patients and its relation to OS. A case–control study was carried out with 51 patients diagnosed with rheumatoid arthritis (RA group) recruited in Hospital São Paulo (São Paulo, Brazil) and 55 healthy women (CO group) from the campus of the University of São Paulo. Blood and 24-hour urine collection were used for biochemical parameters related to Zn status and OS. The assessment of dietary Zn was performed by three 24-hour dietary recalls. The RA group presented significative low Zn intake (p < 0.001) and plasma concentration (p = 0.040) of this mineral compared to the CO group. However, both groups were Zn deficient and the disease activity (DAS28 score) for RA patients did not influence Zn biomarkers. In addition, the antioxidant enzymes (superoxide dismutase and glutathione peroxidase) activity and the urinary 8-isoprostanes were reduced in RA patients. The evaluation of dietary intake and biochemical biomarkers indicates that rheumatoid arthritis patients are zinc deficient and have increased OS.