Intermittent fasting protects the nigral dopaminergic neurons from MPTP-mediated dopaminergic neuronal injury in mice

The effects of ketone bodies and ketogenesis on the PI3K/AKT/mTOR signaling pathway: A systematic review

Ketogenesis and the PI3K/AKT/mTOR pathway are linked to metabolic imbalance and disease progression. While ketone metabolism and mTOR inhibition are mechanistically connected, their functional relationship across disease models remains unclear. Although ketogenesis can be induced by ketone ingestion, ketogenic diet, or fasting, their individual effects on this pathway require further clarification. This study systematically reviews the relationship between ketogenesis and PI3K/AKT/mTOR signaling, following PRISMA guidelines across 3 databases. Eligible studies that met the selection criteria were evaluated using the risk of bias tools. In most studies involving the ketogenic diet or ketone bodies, suppression of the signaling pathway may lead to positive outcomes in terms of survival rate, lifespan, improved metabolic homeostasis, enhanced neurovascular function and suppressed progression of tumors. By contrast, β-hydroxybutyrate supplementation is associated with the up-regulation of AKT and downstream markers. It may exert an anabolic activity by activating the mTOR signaling pathway in muscle atrophy models and is associated with muscle recovery. Although fasting increases p-AKT expression, this may not necessarily indicate activation of the downstream mTOR signaling cascade, as it could result from an insulin response or regulatory feedback mechanisms. Regulation of the mTOR signaling by ketogenesis may be tissue-specific. Inhibition of PI3K/AKT/mTOR in ketogenesis-induced circumstances may justify the importance of a ketogenic-based diet regimen in combating metabolic diseases. However, future studies should consider standardizing factors such as the duration of fasting, timing, composition of the ketogenic diet and target tissues as these factors may affect study outcomes.

Energy Metabolism and Brain Aging: Strategies to Delay Neuronal Degeneration

Aging is characterized by a gradual decline in physiological functions, with brain aging being a major risk factor for numerous neurodegenerative diseases. Given the brain's high energy demands, maintaining an adequate ATP supply is crucial for its proper function. However, with advancing age, mitochondria dysfunction and a deteriorating energy metabolism lead to reduced overall energy production and impaired mitochondrial quality control (MQC). As a result, promoting healthy aging has become a key focus in contemporary research. This review examines the relationship between energy metabolism and brain aging, highlighting the connection between MQC and energy metabolism, and proposes strategies to delay brain aging by targeting energy metabolism.

Intermittent fasting and neurodegenerative diseases: Molecular mechanisms and therapeutic potential

Neurodegenerative disorders are straining public health worldwide. During neurodegenerative disease progression, aberrant neuronal network activity, bioenergetic impairment, adaptive neural plasticity impairment, dysregulation of neuronal Ca2+ homeostasis, oxidative stress, and immune inflammation manifest as characteristic pathological changes in the cellular milieu of the brain. There is no drug for the treatment of neurodegenerative disorders, and therefore, strategies/treatments for the prevention or treatment of neurodegenerative disorders are urgently needed. Intermittent fasting (IF) is characterized as an eating pattern that alternates between periods of fasting and eating, requiring fasting durations that vary depending on the specific protocol implemented. During IF, depletion of liver glycogen stores leads to the production of ketone bodies from fatty acids derived from adipocytes, thereby inducing an altered metabolic state accompanied by cellular and molecular adaptive responses within neural networks in the brain. At the cellular level, adaptive responses can promote the generation of synapses and neurons. At the molecular level, IF triggers the activation of associated transcription factors, thereby eliciting the expression of protective proteins. Consequently, this regulatory process governs central and peripheral metabolism, oxidative stress, inflammation, mitochondrial function, autophagy, and the gut microbiota, all of which contribute to the amelioration of neurodegenerative disorders. Emerging evidence suggests that weight regulation significantly contributes to the neuroprotective effects of IF. By alleviating obesity-related factors such as blood-brain barrier dysfunction, neuroinflammation, and β-amyloid accumulation, IF enhances metabolic flexibility and insulin sensitivity, further supporting its potential in mitigating neurodegenerative disorders. The present review summarizes animal and human studies investigating the role and underlying mechanisms of IF in physiology and pathology, with an emphasis on its therapeutic potential. Furthermore, we provide an overview of the cellular and molecular mechanisms involved in regulating brain energy metabolism through IF, highlighting its potential applications in neurodegenerative disorders. Ultimately, our findings offer novel insights into the preventive and therapeutic applications of IF for neurodegenerative disorders.

Dietary and nutritional interventions for human diseases: their modulatory effects on ferroptosis

A balanced diet is essential for maintaining human health. Increasing evidence suggests that dietary and nutritional interventions contribute to disease management and are associated with reduced healthcare costs and economic burden. Ferroptosis, a novel type of regulated cell death (RCD) driven by lipid peroxidation, has been shown to be involved in various pathological conditions, including diabetes, ischemia/reperfusion (I/R) injury, inflammation-related diseases, and cancer. Therefore, specifically targeting the uncontrolled ferroptosis process may offer new therapeutic opportunities. Of note, certain interventions, such as small-molecule compounds, natural products, herbal medicines, and non-pharmacological approaches, have been reported to prevent and treat multiple human diseases by reversing the dysregulation of ferroptosis. In this review, we present the key molecular mechanisms that regulate ferroptosis. Importantly, interventions targeting ferroptosis are summarized from the perspective of dietary patterns, food and nutrients. By understanding these advances, innovative ideas can be provided for individualized dietary interventions and treatment strategies.

The impact of continuous calorie restriction and fasting on cognition in adults without eating disorders

Research into the effects of calorie restriction continues to intrigue those interested in whether it may allow humans to live longer and healthier lives. Animal studies of continuous calorie restriction (CCR) and fasting have demonstrated substantial advantages to health and longevity. However, concerns remain about the impact of restricting calorie intake on human health and cognition. Given the emerging evidence of cognitive impairments in eating disorders, studies investigating restricted calorie intake in healthy humans (in an ethical way) may also have implications for understanding restrictive eating disorders. In this review, the published literature on the impact of CCR and fasting on cognitive function in healthy human participants is synthesized. Of the 33 studies of CCR and fasting in humans identified, 23 demonstrated significant changes in cognition. Despite variation across the cognitive domains, results suggest CCR benefits inhibition, processing speed, and working memory, but may lead to impairments in cognitive flexibility. The results of fasting studies suggest fasting is associated with impairments in cognitive flexibility and psychomotor abilities. Overall, the results of these studies suggest the degree (ie, the severity) of calorie restriction is what most likely predicts cognitive improvements as opposed to impairments. For individuals engaging in sustained restriction, this may have serious, irreversible consequences. However, there are mixed findings regarding the impact of CCR and fasting on this aspect of human functioning, suggesting further research is required to understand the costs and benefits of different types of calorie restriction.

Effects of Caloric Restriction and Intermittent Fasting and Their Combined Exercise on Cognitive Functioning: A Review

PURPOSE OF REVIEW

The impact of dietary habits on cognitive function is increasingly gaining attention. The review is to discuss how caloric restriction (CR) and intermittent fasting (IF) can enhance cognitive function in healthy states through multiple pathways that interact with one another. Secondly, to explore the effects of CR and IF on cognitive function in conditions of neurodegenerative diseases, obesity diabetes and aging, as well as potential synergistic effects in combination with exercise to prevent cognitively related neurodegenerative diseases.

RECENT FINDINGS

With age, the human brain ages and develops corresponding neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and epilepsy, which in turn trigger cognitive impairment. Recent research indicates that the impact of diet and exercise on cognitive function is increasingly gaining attention. The benefits of exercise for cognitive function and brain plasticity are numerous, and future research can examine the efficacy of particular dietary regimens during physical activity when combined with diet which can prevent cognitive decline.

Intermittent fasting, fatty acid metabolism reprogramming, and neuroimmuno microenvironment: mechanisms and application prospects

Intermittent fasting (IF) has demonstrated extensive health benefits through the regulation of fatty acid metabolism and modulation of the neuroimmune microenvironment, primarily via the activation of key signaling pathways such as AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1). IF not only facilitates fatty acid oxidation and improves metabolic health, but also enhances mitochondrial function, mitigates oxidative stress, promotes autophagy, and inhibits apoptosis and ferroptosis. These mechanisms contribute to its substantial preventive and therapeutic potential in various conditions, including neurodegenerative disorders such as Alzheimer's and Parkinson's diseases, autoimmune diseases, and neurotraumatic conditions. While supportive evidence has been obtained from animal models and preliminary clinical studies, further large-scale, long-term randomized controlled trials are imperative to establish its safety and evaluate its clinical efficacy comprehensively.

Targeting sleep and the circadian system as a novel treatment strategy for Parkinson's disease

There is a growing appreciation of the wide range of sleep-wake disturbances that occur frequently in Parkinson's disease. These are known to be associated with a range of motor and non-motor symptoms and significantly impact not only on the quality of life of the patient, but also on their bed partner. The underlying causes for fragmented sleep and daytime somnolence are no doubt multifactorial but there is clear evidence for circadian disruption in Parkinson's disease. This appears to be occurring not only as a result of the neuropathological changes that occur across a distributed neural network, but even down to the cellular level. Such observations indicate that circadian changes may in fact be a driver of neurodegeneration, as well as a cause for some of the sleep-wake symptoms observed in Parkinson's disease. Thus, efforts are now required to evaluate approaches including the prescription of precision medicine to modulate photoreceptor activation ratios that reflect daylight inputs to the circadian pacemaker, the use of small molecules to target clock genes, the manipulation of orexin pathways that could help restore the circadian system, to offer novel symptomatic and novel disease modifying strategies.

Intermittent Fasting on Neurologic Diseases: Potential Role of Gut Microbiota

As the global population ages, the prevalence of neurodegenerative diseases is surging. These disorders have a multifaceted pathogenesis, entwined with genetic and environmental factors. Emerging research underscores the profound influence of diet on the development and progression of health conditions. Intermittent fasting (IF), a dietary pattern that is increasingly embraced and recommended, has demonstrated potential in improving neurophysiological functions and mitigating pathological injuries with few adverse effects. Although the precise mechanisms of IF's beneficial impact are not yet completely understood, gut microbiota and their metabolites are believed to be pivotal in mediating these effects. This review endeavors to thoroughly examine current studies on the shifts in gut microbiota and metabolite profiles prompted by IF, and their possible consequences for neural health. It also highlights the significance of dietary strategies as a clinical consideration for those with neurological conditions.

Ketone bodies mediate alterations in brain energy metabolism and biomarkers of Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia. AD is a progressive neurodegenerative disorder characterized by cognitive dysfunction, including learning and memory deficits, and behavioral changes. Neuropathology hallmarks of AD such as amyloid beta (Aβ) plaques and neurofibrillary tangles containing the neuron-specific protein tau is associated with changes in fluid biomarkers including Aβ, phosphorylated tau (p-tau)-181, p-tau 231, p-tau 217, glial fibrillary acidic protein (GFAP), and neurofilament light (NFL). Another pathological feature of AD is neural damage and hyperactivation of astrocytes, that can cause increased pro-inflammatory mediators and oxidative stress. In addition, reduced brain glucose metabolism and mitochondrial dysfunction appears up to 15 years before the onset of clinical AD symptoms. As glucose utilization is compromised in the brain of patients with AD, ketone bodies (KBs) may serve as an alternative source of energy. KBs are generated from the β-oxidation of fatty acids, which are enhanced following consumption of ketogenic diets with high fat, moderate protein, and low carbohydrate. KBs have been shown to cross the blood brain barrier to improve brain energy metabolism. This review comprehensively summarizes the current literature on how increasing KBs support brain energy metabolism. In addition, for the first time, this review discusses the effects of ketogenic diet on the putative AD biomarkers such as Aβ, tau (mainly p-tau 181), GFAP, and NFL, and discusses the role of KBs on neuroinflammation, oxidative stress, and mitochondrial metabolism.

Healthy lifestyles and wellbeing reduce neuroinflammation and prevent neurodegenerative and psychiatric disorders

Since the mid-20th century, Western societies have considered productivity and economic outcomes are more important than focusing on people's health and wellbeing. This focus has created lifestyles with high stress levels, associated with overconsumption of unhealthy foods and little exercise, which negatively affect people's lives, and subsequently lead to the development of pathologies, including neurodegenerative and psychiatric disorders. Prioritizing a healthy lifestyle to maintain wellbeing may slow the onset or reduce the severity of pathologies. It is a win-win for everyone; for societies and for individuals. A balanced lifestyle is increasingly being adopted globally, with many doctors encouraging meditation and prescribing non-pharmaceutical interventions to treat depression. In psychiatric and neurodegenerative disorders, the inflammatory response system of the brain (neuroinflammation) is activated. Many risks factors are now known to be linked to neuroinflammation such as stress, pollution, and a high saturated and trans fat diet. On the other hand, many studies have linked healthy habits and anti-inflammatory products with lower levels of neuroinflammation and a reduced risk of neurodegenerative and psychiatric disorders. Sharing risk and protective factors is critical so that individuals can make informed choices that promote positive aging throughout their lifespan. Most strategies to manage neurodegenerative diseases are palliative because neurodegeneration has been progressing silently for decades before symptoms appear. Here, we focus on preventing neurodegenerative diseases by adopting an integrated "healthy" lifestyle approach. This review summarizes the role of neuroinflammation on risk and protective factors of neurodegenerative and psychiatric disorders.