Type 3 diabetes (T3D) is characterized by chronic insulin resistance and insulin deficiency in the brain, leading to neuronal death, inflammation, oxidative stress, apoptosis, and synaptic dysfunction. These pathological processes contribute to cognitive decline and neurodegenerative disorders such as Alzheimer’s disease. However, despite increasing evidence that links insulin resistance to cognitive impairment, the precise mechanisms that underly T3D remain largely unknown. This highlights a critical gap in research and potential therapeutic strategies. Given the significant impact of diet on metabolic health, investigating the correlation between the gut–brain axis may offer novel insights into the prevention and management of T3D. This review aims to elucidate the potential connections between insulin resistance and cognitive decline while also proposing interventions to slow aging and reduce the risk of early cognitive decline. At the same time, we acknowledge that the classification of type 3 diabetes is debatable and there is uncertainty as to whether insulin resistance is a primary driver or secondary manifestation of neurodegeneration.

One in 36 children were identified with autism in 2020, a 22% increase from 2018 and a 98% increase from 2010. Simultaneously, attention-deficit/hyperactivity disorder (ADHD) diagnoses increased 36% from 2003 to 2016–2019. Despite this surge, their etiologies remain largely unknown. However, numerous studies document higher incidences of mitochondrial abnormalities in affected individuals. Additionally, acetaminophen has been implicated in these disorders in longitudinal studies and murine models. This paper is a compilation of literature aiming to explore a theoretical framework for acetaminophen-induced mitochondrial damage in utero. It focuses on a toxic metabolite of acetaminophen, N-acetyl-p-benzoquinone imine (NAPQ1), and its role in neuroinflammation. Based on our findings, we recommend further research studying fetal mitochondria after maternal acetaminophen usage.

Type 2 diabetes (T2D) is a growing global health concern characterized by peripheral insulin resistance and impaired insulin secretion from pancreatic β-cells. Emerging evidence suggests that the gut microbiome, specifically gut dysbiosis, defined as an imbalance in the gut microbial composition and function, is a critical modulator of the pathophysiology of T2D. Dietary polyphenols, a diverse group of bioactive compounds that are abundant in plant-based foods, have gained increasing attention for their potential to attenuate metabolic disorders through their antioxidant and anti-inflammatory properties. These compounds work through the modulation of gut microbial composition and activity. This process effectively ameliorates dysbiosis. However, the diabetic state itself may influence polyphenol metabolism, absorption, and bioavailability, potentially limiting their therapeutic efficacy. This review examines the complex interrelationships between T2D, dietary polyphenols, and the gut microbiota and proposes a dynamic triangular interaction between these factors that might inform novel strategies for the prevention and management of metabolic disease.