Low-carbohydrate ketogenic diets, glucose homeostasis, and nonalcoholic fatty liver disease

Gut Microbiota Disorders and Metabolic Syndrome: Tales of a Crosstalk Process

The microbiota in humans consists of trillions of microorganisms that are involved in the regulation of the gastrointestinal tract and immune and metabolic homeostasis. The gut microbiota (GM) has a prominent impact on the pathogenesis of metabolic syndrome (MetS). This process is reciprocal, constituting a crosstalk process between the GM and MetS. In this review, GM directly or indirectly inducing MetS via the host-microbial metabolic axis has been systematically reviewed. Additionally, the specifically altered GM in MetS are detailed in this review. Moreover, short-chain fatty acids (SCFAs), as unique gut microbial metabolites, have a remarkable effect on MetS, and the role of SCFAs in MetS-related diseases is highlighted to supplement the gaps in this area. Finally, the existing therapeutics are outlined, and the superiority and shortcomings of different therapeutic approaches are discussed, in hopes that this review can contribute to the development of potential treatment strategies.

The Impact of Ketogenic Nutrition on Obesity and Metabolic Health: Mechanisms and Clinical Implications

The ketogenic diet (KD) has recently gained increasing popularity. This high-fat, adequate-protein, and carbohydrate-poor eating pattern leads to nutritional ketosis. The KD has long been known for its antidiabetic and antiepileptic effects and has been used therapeutically in these contexts. Recently, the KD, due to its effectiveness in inducing weight loss, has also been proposed as a possible approach to treat obesity. Likewise, a KD is currently explored as a supporting element in the treatment of obesity-associated metabolic disorders and certain forms of cancer. Here, we discuss the metabolic and biochemical mechanisms at play during the shift of metabolism to fatty acids and fatty acid-derived ketone bodies as main fuel molecules, in the substitution of carbohydrates, in ketogenic nutrition. Different sources of ketone bodies and KDs as alternatives to glucose and carbohydrates as main energy substrates are discussed, together with an attempt to weigh the benefits and risks posed by the chronic use of a KD in the context of weight loss, and also considering the molecular effects that ketone bodies exert on metabolism and on the endocrine system.

Ketogenic diet in clinical populations-a narrative review

Ketogenic diet (KD) is a high-fat, low-carbohydrate (CHO) diet, designed to induce a metabolic state of ketosis in which the body metabolizes primarily lipids for energy production. Various forms of KD are being promoted as promising treatments for numerous health conditions from chronic headaches to weight-loss and even different forms of cancer and are becoming increasingly more popular. KD appears to be an efficacious approach for weight-loss, and maintenance, improved glycemia, cognitive function and cancer prognosis. However, there is a controversy regarding the safety of KD, and the potential health risks that might be associated with long-term exposure to KD. There is a gap between the acceptance and utilization of KD in individuals with health conditions and the criticism and negative attitudes toward KD by some clinicians. Many individuals choose to follow KD and are encouraged by the positive results they experience. Although the medical establishment does not endorse KD as a first line of treatment, clinicians need to be informed about KD, and offer support and medical supervision for patients who self-select to follow KD. This can ensure that within the boundaries of KD, patients will make good and healthy dietary choices and prevent clinical disengagement in extreme cases. To that end, there is an urgent need for good quality research to address the issues of long-term safety of KD in different clinical populations and for standardization of KD both in research and in the clinic.

Mapping the evolution and impact of ketogenic diet research on diabetes management: a comprehensive bibliometric analysis from 2005 to 2024

Objective

The ketogenic diet (KD) has been explored for diabetes management; however, a quantitative synthesis of its specific effects on diabetes has not yet been conducted. This study aims to examine the current status and research hotspots of KD in diabetes management from 2005 to 2024, providing a reference for future research.

Methods

We retrieved articles published between 2005 and 2024 from the Web of Science database and analyzed them using R software, VOSviewer, and CiteSpace.

Results

This study includes 432 relevant publications. From 2005 to 2024, the volume of literature in this field has shown a steady upward trend, with a notable increase from 2017 to 2021, and a slight decline observed from 2021 to 2023. The United States is the leading country in terms of the number of publications, followed by China, Australia, and Canada. The United States not only leads in publication volume but also maintains a broader international collaboration network. Nutrients and the American Journal of Clinical Nutrition are the most frequently published and cited journals. Current research hotspots primarily focus on the impact of KD on blood glucose control, insulin resistance, and lipid metabolism in diabetic patients. Mechanistic studies on KD in diabetes management concentrate on aspects such as the "regulation of genes by β-hydroxybutyrate," "anti-inflammatory effects," and "oxidative stress." The role of the gut microbiome is also emerging as an important research area. Currently, exploring the application of KD in managing different age groups and types of diabetes has become a significant research trend.

Conclusion

As an emerging dietary intervention, KD is gradually attracting widespread attention from researchers around the world and is expected to become a major research focus in the future for diabetes management and control. This paper provides a systematic review and analysis of the current research status and hotspots of KD in diabetes management, offering important references and insights for future research in related fields.

Lifestyle intervention for metabolic dysfunction-associated fatty liver disease: a 24-h integrated behavior perspective

INTRODUCTION

The prevalence, health and socioeconomic burden of metabolic dysfunction-associated fatty liver disease (MAFLD) is growing, increasing the need for novel evidence-based lifestyle approaches. Lifestyle is the cornerstone for MAFLD management and co-existing cardiometabolic dysfunction. The aim of this review was to evaluate the evidence for lifestyle management of MAFLD, with a specific lens on 24-hour integrated behaviour and provide practical recommendations for implementation of the evidence.

RESULTS

Weight loss ≥ 7-10% is central to lifestyle management; however, liver and cardiometabolic benefits are attainable with improved diet quality and exercise even without weight loss. Lifestyle intervention for MAFLD should consider an integrated '24-h' approach that is cognisant of diet, physical activity/exercise, sedentary behavior, smoking, alcohol intake and sleep. Dietary management emphasises energy deficit and improved diet quality, especially the Mediterranean diet, although sociocultural adaptations to meet preferences should be considered. Increasing physical activity and reducing sedentary behavior can prevent MAFLD, with strongest evidence in MAFLD supporting regular structured moderate-vigorous aerobic exercise for 150-240 min/week. Resistance training in addition to aerobic exercise should be considered and prioritised for those who are losing body mass via diet and/or pharmacological approaches and those with sarcopenia, to minimise bone and lean mass loss. Limited evidence suggests that sleep is important for MAFLD prevention. Emerging novel approaches to diet and exercise may address some of the key barriers to behaviour change (e.g. lack of time, access to resources and social support).

FUTURE DIRECTIONS

Large-scale multidisciplinary trials in people with MAFLD with long-term follow-up, that can be scaled up into mainstream healthcare, are required. Future management guidelines should consider the heterogeneity of MAFLD and specialised models of care that coordinate the health workforce to manage the increased and growing MAFLD population.

Ketogenic diet improves fertility in patients with polycystic ovary syndrome: a brief report

Introduction

Polycystic ovary syndrome (PCOS) affects up to 20 % of reproductive-age individuals and is strongly linked to obesity. The impacts of ketogenic diet on fertility in people with PCOS are unknown. This study aims to determine the effect of a ketogenic diet on restoration of regular menstrual cycles and fertility.

Methods

After approval from the Institutional Review Boards of Cleveland Clinic, a retrospective analysis was conducted using the electronic health record system. We analyzed data from thirty patients (n = 30) with polycystic ovary syndrome who followed a ketogenic diet for at least 3 months at the Cleveland Clinic, Cleveland, Ohio, USA. Main outcomes were percentage of women with restoration of regular menstrual cycles and pregnancy rate.

Results

All women (n = 30) had restoration of regular menstrual cycles. The overall pregnancy rate of women desiring pregnancy (n = 18) was 55.6% (n = 10). Pregnancy rate was 38.5% for women on metformin and 100% for those who were not (P = 0.036). Pregnancy rate was 62.5% for women using ovulation induction agents and 50.0% for those who did not (P = 0.66). Percent weight change between the pregnant and non-pregnant groups did not significantly differ [-8.1 ± 6.2, vs -6.4 ± 8.4, P = 0.64, respectively].

Conclusion

This study reports a higher rate of pregnancy with the ketogenic diet in women with PCOS compared to existing literature.

Effective reduction in seizure severity and prevention of a fatty liver by a novel low ratio ketogenic diet composition in the rapid kindling rat model of epileptogenesis

Drug-resistant epilepsy patients may benefit from non-pharmacological therapies, such as the ketogenic diet (KD). However, its high fat content poses compliance challenges and metabolic risks. To mitigate this, we developed a novel KD composition with less fat and additional nutrients (citrate, nicotinamide riboside, and omega-3 fatty acids) for ketone-independent neuroprotection. The efficacy, metabolic and neuropathological effects of the novel KD and a classic KD were compared to a control diet in the rapid kindling model of temporal lobe epilepsy. Both KD groups entered ketosis before kindling onset, with higher ketone levels in the classic KD group. Remarkably, rats on the novel KD had slower progression of behavioral seizures as compared to rats on a control diet, while this was not the case for rats on a classic KD. Both KDs reduced electrographic after-discharge duration, preserved neurons in the dorsal hippocampus, and normalized activity in open field tests. The novel KD, despite lower fat and ketone levels, demonstrated effective reduction of behavioral seizure severity while the classic KD did not, suggesting alternative mode(s) of action are involved. Additionally, the novel KD significantly mitigated liver triglyceride and plasma fatty acid levels compared to the classic KD, indicating a reduced risk of long-term liver steatosis. Our findings highlight the potential of the novel KD to enhance therapeutic efficacy and compliance in epilepsy patients.

The Relationship between Pathogenesis and Possible Treatments for the MASLD-Cirrhosis Spectrum

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a term that entails a broad spectrum of conditions that vary in severity. Its development is influenced by multiple factors such as environment, microbiome, comorbidities, and genetic factors. MASLD is closely related to metabolic syndrome as it is caused by an alteration in the metabolism of fatty acids due to the accumulation of lipids because of an imbalance between its absorption and elimination in the liver. Its progression to fibrosis is due to a constant flow of fatty acids through the mitochondria and the inability of the liver to slow down this metabolic load, which generates oxidative stress and lipid peroxidation, triggering cell death. The development and progression of MASLD are closely related to unhealthy lifestyle habits, and nutritional epigenetic and genetic mechanisms have also been implicated. Currently, lifestyle modification is the first-line treatment for MASLD and nonalcoholic steatohepatitis; weight loss of ≥10% produces resolution of steatohepatitis and fibrosis regression. In many patients, body weight reduction cannot be achieved; therefore, pharmacological treatment should be offered in particular populations.

Pathophysiology and Nutritional Approaches in Polycystic Ovary Syndrome (PCOS): A Comprehensive Review

PURPOSE OF REVIEW

Polycystic ovary syndrome (PCOS) is the most common endocrine and metabolic disorder in women of reproductive age worldwide. This disease causes menstrual, metabolic, and biochemical abnormalities such as hyperandrogenism, oligo-anovulatory menstrual cycles, polycystic ovary, hyperleptinemia, insulin resistance (IR), and cardiometabolic disorders, often associated with overweight or obesity and visceral adiposity.

RECENT FINDINGS

The etiology and pathophysiology of PCOS are not yet fully understood, but insulin seems to play a key role in this disease. PCOS shares an inflammatory state with other chronic diseases such as obesity, type II diabetes, and cardiovascular diseases; however, recent studies have shown that a healthy nutritional approach can improve IR and metabolic and reproductive functions, representing a valid therapeutic strategy to ameliorate PCOS symptomatology. This review aimed to summarize and collect evidence about different nutritional approaches such as the Mediterranean diet (MedDiet) and the ketogenic diet (KD), as well as bariatric surgery and nutraceutical supplementation as probiotics, prebiotics, and synbiotics, among the others, used in patients with PCOS.

Non-pharmacological management options for MAFLD: a practical guide

Lifestyle changes should be the main basis for any treatment for metabolic dysfunction-associated fatty liver disease (MAFLD), aiming to increase energy expenditure, reduce energy intake and improve the quality of nutrients consumed. As it is a multifactorial disease, approaches such as physical exercise, a better dietary pattern, and possible pharmacological intervention are shown to be more efficient when used simultaneously to the detriment of their applications. The main treatment for MAFLD is a lifestyle change consisting of diet, activity, exercise, and weight loss. The variables for training prescription such as type of physical exercise (aerobic or strength training), the weekly frequency, and the intensity most indicated for the treatment of MAFLD remain uncertain, that is, the recommendations must be adapted to the clinical conditions comorbidities, and preferences of each subject in a way individual. This review addresses recent management options for MAFLD including diet, nutrients, gut microbiota, and physical exercise.

Ketogenic diet restrains herpes simplex encephalitis via gut microbes

Herpes simplex virus type 1 (HSV-1) infection-associated herpes simplex encephalitis (HSE) is an occasionally but severe neuronal disease that causes behavioral disorder and impairs cognition. Herein, we demonstrate that the consumption of ketogenic diet (KD), a low-carbohydrate high-fat diet, restricts the neurotropic infection of HSV-1 and HSE progression in mice. KD reduced weight loss, neurodegenerative symptoms, virus production and neuroinflammation, resulting in the enhanced survival rate of HSE mice. Notably, depletion of gut microbes by antibiotics attenuated the protective function of KD on HSV-1-related neuroinflammation and HSE development. Therefore, KD represents as an alternative therapeutic strategy to alleviate or prevent HSE via gut microbiota.

Clinical Evidence of Low-Carbohydrate Diets against Obesity and Diabetes Mellitus

The popularity of low-carbohydrate diets (LCDs) in the last few decades has motivated several research studies on their role in a variety of metabolic and non-morbid conditions. The available data of the results of these studies are put under the research perspective of the present literature review of clinical studies in search of the effects of LCDs on Obesity and Diabetes Mellitus. The electronic literature search was performed in the databases PubMed, Cochrane, and Embase. The literature search found seven studies that met the review's inclusion and exclusion criteria out of a total of 2637 studies. The included studies involved randomized controlled trials of at least 12 weeks' duration, in subjects with BMI ≥ 25 kg/m², with dietary interventions. The results of the study on the effects of LCDs on obesity showed their effectiveness in reducing Body Mass Index and total body fat mass. In addition, LCDs appear to cause drops in blood pressure, low-density lipoprotein (LDL), and triglycerides, and seem to improve high-density lipoprotein (HDL) values. Regarding the effectiveness of LCDs in Diabetes Mellitus, their effect on reducing insulin resistance and fasting blood glucose and HbA1c values are supported. In conclusion, the results suggest the critical role of LCDs to improve the health of people affected by obesity or diabetes.

The spleen-strengthening and liver-draining herbal formula treatment of non-alcoholic fatty liver disease by regulation of intestinal flora in clinical trial

OBJECTIVE

As a metabolic disease, one important feature of non-alcoholic fatty liver disease (NAFLD) is the disturbance of the intestinal flora. Spleen-strengthening and liver-draining formula (SLF) is a formula formed according to the theory of "One Qi Circulation" (Qing Dynasty, 1749) of Traditional Chinese Medicine (TCM), which has shown significant therapeutic effect in patients with NAFLD in a preliminary clinical observation. In this study, we aim to explore the mechanism of SLF against NAFLD, especially its effect on glucolipid metabolism, from the perspective of intestinal flora.

METHODS

A prospective, randomized, controlled clinical study was designed to observe the efficacy and safety of SLF in the treatment of NAFLD. The study participants were randomly and evenly divided into control group and treatment group (SLF group). The control group made lifestyle adjustments, while the SLF group was treated with SLF on top of the control group. Both groups were participated in the study for 12 consecutive weeks. Furthermore, the feces of the two groups were collected before and after treatment. The intestinal flora of each group and healthy control (HC) were detected utilizing 16S rRNA gene sequencing.

RESULTS

Compared with the control group, the SLF group showed significant improvements in liver function, controlled attenuation parameter (CAP), and liver stiffness measurement (LSM), meanwhile, patients had significantly lower lipid and homeostasis model assessment of insulin resistance (HOMA-IR) with better security. Intestinal flora 16S rRNA gene sequencing results indicated reduced flora diversity and altered species abundance in patients with NAFLD. At the phylum level, Desulfobacterota levels were reduced. Although Firmicutes and Bacteroidetes did not differ significantly between HC and NAFLD, when grouped by alanine transaminase (ALT) and aspartate transaminase (AST) levels in NAFLD, Firmicutes levels were significantly higher in patients with ALT or AST abnormalities, while Bacteroidetes was significantly lower. Clinical correlation analysis showed that Firmicutes positively correlated with gender, age, ALT, AST, LSM, and Fibroscan-AST (FAST) score, while the opposite was true for Bacteroidetes. At the genus level, the levels of Alistipes, Bilophila, Butyricimonas, Coprococcus, Lachnospiraceae_NK4A136 group Phascolarctobacterium, Ruminococcus, UCG-002, and UCG-003 were reduced, whereas abundance of Tyzzerella increased. There was no statistically significant difference in Firmicutes and Bacteroidota levels in the SLF group before and after treatment, but both bacteria tended to retrace. At the genus level, Coprococcus (Lachnospiraceae family), Lachnospiraceae_NK4A136 group (Lachnospiraceae family), and Ruminococcus (Ruminococcaceae family) were significantly higher in the SLF group after treatment, and there was also a tendency for Bilophila (Desulfovibrionaceae family) to be back-regulated toward HC.

CONCLUSIONS

SLF can improve liver function and glucolipid metabolism in patients with NAFLD and lower down liver fat content to some extent. SLF could be carried out by regulating the disturbance of intestinal flora, especially Coprococcus, Lachnospiraceae_NK4A136 group, and Ruminococcus genus.

Adherence to low carbohydrate diets and non-alcoholic fatty liver disease: a case control study

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is defined as the excessive accumulation of fat in the liver cells of people who do not drink alcohol. The aim of study is investigated the association between low carbohydrate diets (LCDs) and NAFLD.

METHODS

This age and gender-matched case-control study was conducted on 120 patients newly diagnosed with NAFLD and 120 adults without NAFLD. Diagnosis of NAFLD based on laboratory tests and abdominal ultrasound. Low carbohydrate diets score calculated on the percentage of energy as carbohydrate, fat, and protein. Participants in the highest rank intake of fat and protein and lowest intake of carbohydrate received 10 points. Multivariable logistic odds ratio was used for examine the relation between LCDs and NAFLD.

RESULTS

This study showed subjects in the highest tertile of LCD has more intake of zinc and vitamin B12 compare to lowest. Also, intake of protein (p = 0.02) carbohydrate (p < 0.02) and cholesterol (p = 0.02) were significantly higher in patient with NAFLD compare to control subjects. There was no significant association between LCD and risk of NAFLD (OR: 1.36; 95% CI: 0.97-1.92; P-trend = 0.13) in crude and adjusted (OR: 1.31; 95% CI: 0.84-2.04; P-trend = 0.23) model.

CONCLUSION

However, we showed that intake of protein, carbohydrate and cholesterol are higher in NAFLD, but our results of study showed that LCDs with higher proportion intakes of protein and fat was not associated with NAFLD. Further prospective studies are required for confirm these associations.

Nutritional co-therapy with 1,3-butanediol and multi-ingredient antioxidants enhances autophagic clearance in Pompe disease

Alglucosidase alpha is an orphan drug approved for enzyme replacement therapy (ERT) in Pompe disease (PD); however, its efficacy is limited in skeletal muscle because of a partial blockage of autophagic flux that hinders intracellular trafficking and enzyme delivery. Adjunctive therapies that enhance autophagic flux and protect mitochondrial integrity may alleviate autophagic blockage and oxidative stress and thereby improve ERT efficacy in PD. In this study, we compared the benefits of ERT combined with a ketogenic diet (ERT-KETO), daily administration of an oral ketone precursor (1,3-butanediol; ERT-BD), a multi-ingredient antioxidant diet (ERT-MITO; CoQ10, α-lipoic acid, vitamin E, beetroot extract, HMB, creatine, and citrulline), or co-therapy with the ketone precursor and multi-ingredient antioxidants (ERT-BD-MITO) on skeletal muscle pathology in GAA-KO mice. We found that two months of 1,3-BD administration raised circulatory ketone levels to ≥1.2 mM, attenuated autophagic buildup in type 2 muscle fibers, and preserved muscle strength and function in ERT-treated GAA-KO mice. Collectively, ERT-BD was more effective vs. standard ERT and ERT-KETO in terms of autophagic clearance, dampening of oxidative stress, and muscle maintenance. However, the addition of multi-ingredient antioxidants (ERT-BD-MITO) provided the most consistent benefits across all outcome measures and normalized mitochondrial protein expression in GAA-KO mice. We therefore conclude that nutritional co-therapy with 1,3-butanediol and multi-ingredient antioxidants may provide an alternative to ketogenic diets for inducing ketosis and enhancing autophagic flux in PD patients.

Adaptation to short-term extreme fat consumption alters intestinal lipid handling in male and female mice

The small intestine is a highly adaptable organ serving as both a barrier to the external environment and a conduit for nutrient absorption. Enterocytes package dietary triglycerides (TG) into chylomicrons for transport into circulation; the remaining TGs are stored in cytosolic lipid droplets (CLDs). The current study aimed to characterize the impact of diet composition on intestinal lipid handling in male and female wild-type mice. Mice were continued on their grain-based diet (GBD) and switched to a high-fat, high cholesterol Western-style diet (WD) or a ketogenic diet (KD) for 3 or 5 weeks. KD-fed mice displayed significantly higher plasma TG levels in response to an olive oil gavage than WD- and GBD-fed mice; TG levels were ~2-fold higher in male KD-fed mice than female KD-fed mice. Poloxamer-407 experiments revealed enhanced intestinal-TG secretion rates in male mice fed a KD upon olive oil gavage, whereas secretion rates were unchanged in female mice. Surprisingly, jejunal CLD size and TG mass after oil gavage were similar among the groups. At fasting, TG mass was significantly higher in the jejunum of male KD-fed mice and the duodenum of female KD-fed mice, providing increased substrate for chylomicron formation. In addition to greater fasting intestinal TG stores, KD-fed male mice displayed longer small intestinal lengths, while female mice displayed markedly longer jejunal villi lengths. After 5 week of diet, 12 h fasting-2 h refeeding experiments revealed jejunal TG levels were similar between diet groups in male mice; however, in female mice, jejunal TG mass was significantly higher in KD-fed mice compared to GBD- and WD-fed mice. These experiments reveal that KD feeding promotes distinct morphological and functional changes to the small intestine compared to the WD diet. Moreover, changes to intestinal lipid handling in response to carbohydrate and protein restriction manifest differently in male and female mice.

Dietary patterns in non-alcoholic fatty liver disease (NAFLD): Stay on the straight and narrow path!

Non-alcoholic fatty liver disease (NAFLD) is the most frequent hepatic disease globally. NAFLD patients are at an increased risk of both liver and cardiovascular morbidity and mortality, as well as all-cause death. NAFLD prevalence is rapidly increasing worldwide and, thus, there is an urgent need for health policies to tackle its development and complications. Currently, since there is no drug therapy officially indicated for this disease, lifestyle interventions remain the first-line therapeutic option. In the present narrative review, we discuss the effects of certain dietary patterns on NAFLD incidence and progression. The Mediterranean diet is regarded as the diet of choice for the prevention/treatment of NAFLD and its complications, based on the available evidence. Other plant-based dietary patterns (poor in saturated fat, refined carbohydrates, red and processed meats) are also beneficial [i.e., Dietary Approaches to Stop Hypertension (DASH) and vegetarian/vegan diets], whereas more data are needed to establish the role of ketogenic, intermittent fasting and paleo diets in NAFLD. Nevertheless, there is no "one-size-fits-all" dietary intervention for NAFLD management. Clinicians should discuss with their patients and define the diet that each individual prefers and is able to implement in his/her daily life.

Ketogenic Diets and Hepatocellular Carcinoma

The ketogenic diet (KD) is a low-carbohydrate, high-fat diet regarded as a potential intervention for cancers owing to its effects on tumor metabolism and behavior. Hepatocellular carcinoma (HCC) is the most prevalent type of liver cancer, and its management is worth investigating because of the high fatality rate. Additionally, as the liver is the glucose and lipid metabolism center where ketone bodies are produced, the application of KD to combat HCC is promising. Prior studies have reported that KD could reduce the energy supply and affect the proliferation and differentiation of cancer cells by lowering the blood glucose and insulin levels. Furthermore, KD can increase the expression of hydroxymethylglutaryl-CoA synthase 2 (HMGCS2) in hepatocytes and regulate lipid metabolism to inhibit the progression of HCC. In addition, β-hydroxybutyrate can induce histone hyperacetylation and reduce the expression of inflammatory factors to alleviate damage to hepatocytes. However, there are few relevant studies at present, and the specific effects and safety of KD on HCC warrant further research. Optimizing the composition of KD and combining it with other therapies to enhance its anti-cancer effects warrant further exploration.

Dietary Approaches for Management of Non-Alcoholic Fatty Liver Disease: A Clinician's Guide

Non-alcoholic fatty liver disease (NAFLD) is closely associated with obesity, insulin resistance, and hyperlipidemia. There is strong clinical evidence that reduction in at least 5-7% total body weight is associated with improvement in hepatic steatosis and regression of fibrosis, with weight loss representing the primary approach to treatment. This guide reviews recent data on dietary approaches studied in NAFLD management. The strongest evidence currently supports a hypocaloric diet to induce weight loss and subsequent improvement in liver enzymes and histology, as well as a Mediterranean diet, which can lead to improvement in steatosis even in the absence of weight reduction. The purpose of this paper is to provide clinicians with tools to engage patients in conversations about nutrition in the setting of NAFLD, ultimately guiding suitable personalized dietary recommendations.

Dietary Interventions: A Promising Treatment for Polycystic Ovary Syndrome

BACKGROUND

Dietary interventions as a first-line treatment for patients with polycystic ovary syndrome (PCOS) have been evaluated, but the optimal diet has not been determined. Proper diet and the maintenance of adequate nutritional status are of great importance in the prevention of this disorder, and therapeutics and dietary habits play an important role in the recovery of patients with PCOS.

SUMMARY

A range of dietary patterns have been shown to impact weight loss and insulin resistance (IR) and improve reproductive function, including the Mediterranean diet, the ketogenic diet, Dietary Approaches to Stop Hypertension, and other dietary patterns. Key Messages: Diets that can reduce rates of obesity and IR are beneficial to women with PCOS, the status of obesity and IR should be determined at the early stage of the disease, so as to develop individualized and sustainable dietary intervention. The long-term efficacy, safety, and health benefits of diet management in patients with PCOS need to be tested by further researches.

Ketogenic diet: A promising neuroprotective composition for managing Alzheimer's diseases and its pathological mechanisms

Ketogenic diet and ketone bodies gained significant attention in recent years due to their ability to influence the specific energy metabolism and restoration of mitochondrial homeostasis that can help in hindering the progression of many metabolic diseases including diabetes and neurodegenerative diseases. Ketogenic diet consists of high fat and low carbohydrate contents which makes the body glucose deprived and rely on alternative sources (ketone bodies) for energy. It has been initially designed and supplemented for the treatment of epilepsy and later its influence on many energy-deriving biochemical pathways made it a highly sorted food supplement for many metabolic diseases and even by healthy individuals for body building and calorie restriction. Among the reported therapeutic action over a range of diseases, neurodegenerative disorders especially Alzheimer's disease gained the attention of many researchers and clinicians because of its potency and its easier supplementation as a food additive. Complex pathology and multiple influencing factors of Alzheimer's disease make exploration of its therapeutic strategies a demanding task. It was a common phenomenon that energy deprivation in neurological disorders including Alzheimer's disease, to progress rapidly. The ability of ketone bodies to stabilize the mitochondrial energy metabolism makes it a suitable intervening agent. In this review, we will discuss various research progress made with regards to ketone bodies/ketogenic diet for management of Alzheimer's disease and elaborate in detail about the mechanisms that are influenced during their therapeutic action.

Ketogenic Diets and Chronic Disease: Weighing the Benefits Against the Risks

Very-low-carbohydrate ketogenic diets have been long been used to reduce seizure frequency and more recently have been promoted for a variety of health conditions, including obesity, diabetes, and liver disease. Ketogenic diets may provide short-term improvement and aid in symptom management for some chronic diseases. Such diets affect diet quality, typically increasing intake of foods linked to chronic disease risk and decreasing intake of foods found to be protective in epidemiological studies. This review examines the effects of ketogenic diets on common chronic diseases, as well as their impact on diet quality and possible risks associated with their use. Given often-temporary improvements, unfavorable effects on dietary intake, and inadequate data demonstrating long-term safety, for most individuals, the risks of ketogenic diets may outweigh the benefits.

Targeting hepatocyte carbohydrate transport to mimic fasting and calorie restriction

The pervasion of three daily meals and snacks is a relatively new introduction to our shared experience and is coincident with an epidemic rise in obesity and cardiometabolic disorders of overnutrition. The past two decades have yielded convincing evidence regarding the adaptive, protective effects of calorie restriction (CR) and intermittent fasting (IF) against cardiometabolic, neurodegenerative, proteostatic, and inflammatory diseases. Yet, durable adherence to intensive lifestyle changes is rarely attainable. New evidence now demonstrates that restricting carbohydrate entry into the hepatocyte by itself mimics several key signaling responses and physiological outcomes of IF and CR. This discovery raises the intriguing proposition that targeting hepatocyte carbohydrate transport to mimic fasting and caloric restriction can abate cardiometabolic and perhaps other fasting-treatable diseases. Here, we review the metabolic and signaling fates of a hepatocyte carbohydrate, identify evidence to target the key mediators within these pathways, and provide rationale and data to highlight carbohydrate transport as a broad, proximal intervention to block the deleterious sequelae of hepatic glucose and fructose metabolism.

The Low-Carbohydrate Diet: Short-Term Metabolic Efficacy Versus Longer-Term Limitations

Background: Diets have been a central component of lifestyle modification for decades. The Low-Carbohydrate Diet (LCD), originally conceived as a treatment strategy for intractable epilepsy (due to its association with ketogenesis), became popular in the 1970s and since then has risen to prominence as a weight loss strategy. Objective: To explore the efficacy, limitations and potential safety concerns of the LCD. Data Sources: We performed a narrative review, based on relevant articles written in English from a Pubmed search, using the terms ‘low carbohydrate diet and metabolic health’. Results: Evidence supports the efficacy of the LCD in the short-term (up to 6-months) for reduction in fat mass and remission of Type 2 Diabetes Mellitus (T2D). However, the longer-term efficacy of the LCD is disappointing, with diminishment of weight loss potential and metabolic benefits of the LCD beyond 6-months of its adoption. Furthermore, practical limitations of the LCD include the associated restriction of food choices that restrict the acceptability of the LCD for the individual, particularly over the longer term. There are also safety concerns of the LCD that stem from nutritional imbalances (with a relative excess of dietary fat and protein intake with associated dyslipidaemia and increased risk of insulin resistance and T2D development) and ketotic effects. Finally, the LCD often results in a reduction in dietary fibre intake, with potentially serious adverse consequences for overall health and the gut microbiota. Conclusions: Although widely adopted, the LCD usually has short-lived metabolic benefits, with limited efficacy and practicality over the longer term. Dietary modification needs tailoring to the individual, with careful a priori assessments of food preferences to ensure acceptability and adherence over the longer term, with avoidance of dietary imbalances and optimization of dietary fibre intake (primarily from plant-based fruit and vegetables), and with a posteriori assessments of the highly individual responses to the LCD. Finally, we need to change our view of diets from simply an excipient for weight loss to an essential component of a healthy lifestyle.

A dietary ketone ester mitigates histological outcomes of NAFLD and markers of fibrosis in high-fat diet fed mice

Nutritional ketosis as a therapeutic tool has been extended to the treatment of metabolic diseases, including obesity, type 2 diabetes, and nonalcoholic fatty liver disease (NAFLD). The purpose of this study was to determine whether dietary administration of the ketone ester (KE) R,S-1,3-butanediol diacetoacetate (BD-AcAc2) attenuates markers of hepatic stellate cell (HSC) activation and hepatic fibrosis in the context of high-fat diet (HFD)-induced obesity. Six-week-old male C57BL/6J mice were placed on a 10-wk ad libitum HFD (45% fat, 32% carbohydrates, 23% proteins). Mice were then randomized to one of three groups (n = 10 per group) for an additional 12 wk: 1) control (CON), continuous HFD; 2) pair-fed (PF) to KE, and 3) KE (HFD + 30% energy from BD-AcAc2, KE). KE feeding significantly reduced histological steatosis, inflammation, and total NAFLD activity score versus CON, beyond improvements observed for calorie restriction alone (PF). Dietary KE supplementation also reduced the protein content and gene expression of profibrotic markers (α-SMA, COL1A1, PDGF-β, MMP9) versus CON (P < 0.05), beyond reductions observed for PF versus CON. Furthermore, KE feeding increased hepatic markers of anti-inflammatory M2 macrophages (CD163) and also reduced proinflammatory markers [tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and cellular communication network factor 1 (CCN1)] versus CON and PF (P ≤ 0.05), in the absence of changes in markers of total hepatic macrophage content (F4/80 and CD68; P > 0.05). These data highlight that the dietary ketone ester BD-AcAc2 ameliorates histological NAFLD and inflammation and reduces profibrotic and proinflammatory markers. Future studies to further explore potential mechanisms are warranted.NEW & NOTEWORTHY To our knowledge, this is the first study focusing on hepatic outcomes in response to dietary ketone ester feeding in male mice with HFD-induced NAFLD. Novel findings include that dietary ketone ester feeding ameliorates NAFLD outcomes via reductions in histological steatosis and inflammation. These improvements were beyond those observed for caloric restriction alone. Furthermore, dietary ketone ester feeding was associated with greater reductions in markers of hepatic fibrogenesis and inflammation compared with control and calorie-restricted mice.

Ketogenic Diet Enhances the Cholesterol Accumulation in Liver and Augments the Severity of CCl4 and TAA-Induced Liver Fibrosis in Mice

Persistent chronic liver diseases increase the scar formation and extracellular matrix accumulation that further progress to liver fibrosis and cirrhosis. Nevertheless, there is no antifibrotic therapy to date. The ketogenic diet is composed of high fat, moderate to low-protein, and very low carbohydrate content. It is mainly used in epilepsy and Alzheimer’s disease. However, the effects of the ketogenic diet on liver fibrosis remains unknown. Through ketogenic diet consumption, β-hydroxybutyrate (bHB) and acetoacetate (AcAc) are two ketone bodies that are mainly produced in the liver. It is reported that bHB and AcAc treatment decreases cancer cell proliferation and promotes apoptosis. However, the influence of bHB and AcAc in hepatic stellate cell (HSC) activation and liver fibrosis are still unclear. Therefore, this study aimed to investigate the effect of the ketogenic diet and ketone bodies in affecting liver fibrosis progression. Our study revealed that feeding a high-fat ketogenic diet increased cholesterol accumulation in the liver, which further enhanced the carbon tetrachloride (CCl₄)- and thioacetamide (TAA)-induced liver fibrosis. In addition, more severe liver inflammation and the loss of hepatic antioxidant and detoxification ability were also found in ketogenic diet-fed fibrotic mouse groups. However, the treatment with ketone bodies (bHB and AcAc) did not suppress transforming growth factor-β (TGF-β)-induced HSC activation, platelet-derived growth factor (PDGF)-BB-triggered proliferation, and the severity of CCl₄-induced liver fibrosis in mice. In conclusion, our study demonstrated that feeding a high-fat ketogenic diet may trigger severe steatohepatitis and thereby promote liver fibrosis progression. Since a different ketogenic diet composition may exert different metabolic effects, more evidence is necessary to clarify the effects of a ketogenic diet on disease treatment.

The Impact of Dietary Patterns and Nutrition in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) has become one of the most common causes of chronic liver disease worldwide. The prevalence of NAFLD has grown proportionally with the rise in obesity, sedentary lifestyle, unhealthy dietary patterns, and metabolic syndrome. Currently, in the absence of approved pharmacologic treatment, the keystone of treatment is lifestyle modification focused on achieving a weight loss of 7%-10%, cardiovascular exercise, and improving insulin sensitivity. The primary aim of this review is to outline the effect of different dietetic approaches against NAFLD and highlight the important micronutrient components in the management of NAFLD.

A Low-Carbohydrate Ketogenic Diet and Treadmill Training Enhanced Fatty Acid Oxidation Capacity but Did Not Enhance Maximal Exercise Capacity in Mice

The low-carbohydrate ketogenic diet (LCKD) is a dietary approach characterized by the intake of high amounts of fat, a balanced amount of protein, and low carbohydrates, which is insufficient for metabolic demands. Previous studies have shown that an LCKD alone may contribute to fatty acid oxidation capacity, along with endurance. In the present study, we combined a 10-week LCKD with an 8-week forced treadmill running program to determine whether training in conjunction with LCKD enhanced fatty acid oxidation capacity, as well as whether the maximal exercise capacity would be affected by an LCKD or training in a mice model. We found that the lipid pool and fatty acid oxidation capacity were both enhanced following the 10-week LCKD. Further, key fatty acid oxidation related genes were upregulated. In contrast, the 8-week training regimen had no effect on fatty acid and ketone body oxidation. Key genes involved in carbohydrate utilization were downregulated in the LCKD groups. However, the improved fatty acid oxidation capacity did not translate into an enhanced maximal exercise capacity. In summary, while favoring the fatty acid oxidation system, an LCKD, alone or combined with training, had no beneficial effects in our intensive exercise-evaluation model. Therefore, an LCKD may be promising to improve endurance in low- to moderate-intensity exercise, and may not be an optimal choice for those partaking in high-intensity exercise.

Ketogenic Diets and Cardio-Metabolic Diseases

While the prevalence of cardio-metabolic diseases (CMDs) has become a worldwide epidemic, much attention is paid to managing CMDs effectively. A ketogenic diet (KD) constitutes a high-fat and low-carbohydrate diet with appropriate protein content and calories. KD has drawn the interests of clinicians and scientists regarding its application in the management of metabolic diseases and related disorders; thus, the current review aimed to examine the evidences surrounding KD and the CMDs to draw the clinical implications. Overall, KD appears to play a significant role in the therapy of various CMDs, which is manifested by the effects of KDs on cardio-metabolic outcomes. KD therapy is generally promising in obesity, heart failure, and hypertension, though different voices still exist. In diabetes and dyslipidemia, the performance of KD remains controversial. As for cardiovascular complications of metabolic diseases, current evidence suggests that KD is generally protective to obese related cardiovascular disease (CVD), while remaining contradictory to diabetes and other metabolic disorder related CVDs. Various factors might account for the controversies, including genetic background, duration of therapy, food composition, quality, and sources of KDs. Therefore, it's crucial to perform more rigorous researches to focus on clinical safety and appropriate treatment duration and plan of KDs.

Hepatic Mediators of Lipid Metabolism and Ketogenesis: Focus on Fatty Liver and Diabetes

BACKGROUND

Diabetes mellitus (DM) is a chronic disorder that it is caused by the absence of insulin secretion due to the inability of the pancreas to produce it (type 1 diabetes; T1DM), or due to defects of insulin signaling in the peripheral tissues, resulting in insulin resistance (type 2 diabetes; T2DM). Commonly, the occurrence of insulin resistance in T2DM patients reflects the high prevalence of obesity and non-alcoholic fatty liver disease (NAFLD) in these individuals. In fact, approximately 60% of T2DM patients are also diagnosed to have NAFLD, and this condition is strongly linked with insulin resistance and obesity. NAFLD is the hepatic manifestation of obesity and metabolic syndrome and includes a spectrum of pathological conditions, which range from simple steatosis (NAFL), non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma. NAFLD manifestation is followed by a series of hepatic lipid deregulations and the main abnormalities are increased triglyceride levels, increased hepatic production of VLDL and a reduction in VLDL catabolism. During the progression of NAFLD, the production of ketone bodies progressively reduces while hepatic glucose synthesis and output increases. In fact, most of the fat that enters the liver can be disposed of through ketogenesis, preventing the development of NAFLD and hyperglycemia.

OBJECTIVE

This review will focus on the pathophysiological aspect of hepatic lipid metabolism deregulation, ketogenesis, and its relevance in the progression of NAFLD and T2DM.

CONCLUSION

A better understanding of the molecular mediators involved in lipid synthesis and ketogenesis can lead to new treatments for metabolic disorders in the liver, such as NAFLD.

Dietary Energy Partition: The Central Role of Glucose

Humans have developed effective survival mechanisms under conditions of nutrient (and energy) scarcity. Nevertheless, today, most humans face a quite different situation: excess of nutrients, especially those high in amino-nitrogen and energy (largely fat). The lack of mechanisms to prevent energy overload and the effective persistence of the mechanisms hoarding key nutrients such as amino acids has resulted in deep disorders of substrate handling. There is too often a massive untreatable accumulation of body fat in the presence of severe metabolic disorders of energy utilization and disposal, which become chronic and go much beyond the most obvious problems: diabetes, circulatory, renal and nervous disorders included loosely within the metabolic syndrome. We lack basic knowledge on diet nutrient dynamics at the tissue-cell metabolism level, and this adds to widely used medical procedures lacking sufficient scientific support, with limited or nil success. In the present longitudinal analysis of the fate of dietary nutrients, we have focused on glucose as an example of a largely unknown entity. Even most studies on hyper-energetic diets or their later consequences tend to ignore the critical role of carbohydrate (and nitrogen disposal) as (probably) the two main factors affecting the substrate partition and metabolism.

A Fad too Far? Dietary Strategies for the Prevention and Treatment of NAFLD

Nonalcoholic fatty liver disease (NAFLD) is a major health problem, and its prevalence has increased in recent years, concurrent with rising rates of obesity and other metabolic diseases. Currently, there are no FDA-approved pharmacological therapies for NAFLD, and lifestyle interventions, including weight loss and exercise, remain the cornerstones for treatment. Manipulating diet composition and eating patterns may be a sustainable approach to NAFLD treatment. Dietary strategies including Paleolithic, ketogenic, Mediterranean, high-protein, plant-based, low-carbohydrate, and intermittent fasting diets have become increasingly popular because of their purported benefits on metabolic disease. This review highlights what is currently known about these popular dietary approaches in the management of NAFLD in clinical populations with mechanistic insight from animal studies. It also identifies key knowledge gaps to better inform future preclinical and clinical studies aimed at the treatment of NAFLD.

Branched chain amino acids and carbohydrate restriction exacerbate ketogenesis and hepatic mitochondrial oxidative dysfunction during NAFLD

Mitochondrial adaptation during non-alcoholic fatty liver disease (NAFLD) include remodeling of ketogenic flux and sustained tricarboxylic acid (TCA) cycle activity, which are concurrent to onset of oxidative stress. Over 70% of obese humans have NAFLD and ketogenic diets are common weight loss strategies. However, the effectiveness of ketogenic diets toward alleviating NAFLD remains unclear. We hypothesized that chronic ketogenesis will worsen metabolic dysfunction and oxidative stress during NAFLD. Mice (C57BL/6) were kept (for 16-wks) on either a low-fat, high-fat, or high-fat diet supplemented with 1.5X branched chain amino acids (BCAAs) by replacing carbohydrate calories (ketogenic). The ketogenic diet induced hepatic lipid oxidation and ketogenesis, and produced multifaceted changes in flux through the individual steps of the TCA cycle. Higher rates of hepatic oxidative fluxes fueled by the ketogenic diet paralleled lower rates of de novo lipogenesis. Interestingly, this metabolic remodeling did not improve insulin resistance, but induced fibrogenic genes and inflammation in the liver. Under a chronic "ketogenic environment," the hepatocyte diverted more acetyl-CoA away from lipogenesis toward ketogenesis and TCA cycle, a milieu which can hasten oxidative stress and inflammation. In summary, chronic exposure to ketogenic environment during obesity and NAFLD has the potential to aggravate hepatic mitochondrial dysfunction.

High carbohydrate and noodle/meat-rich dietary patterns interact with the minor haplotype in the 22q13 loci to increase its association with non-alcoholic fatty liver disease risk in Koreans

Non-alcoholic fatty liver(NAFLD) is prevalent in Asians despite the low obesity rate. We hypothesized that the haplotype of genetic variants in the 22q13 loci has a strong association with non-alcoholic fatty liver disease (NAFLD) that can be identified by genome-wide association study and that lifestyles may interact with the haplotype. We tested the hypothesis in middle-aged and elderly adults in a large city hospital-based cohort from the KoGES study. Men and women diagnosed with fatty liver, but who respectively consumed over 40 and 30 g ethanol per day were excluded. The haplotype of the selected SNPs from the 22q13 loci that influences NAFLD risk was generated. Among the 27374 participants, 1486 (5.4%) were diagnosed with NAFLD. LARGE_rs240072, RBFOX2_rs11089778, TRIOBP_rs12628603, PNPLA3_rs738409, and PARVB_rs2073080 in the 22q13 loci were included in the haplotype. Participants with the minor haplotype had 1.8, 2.3, and 1.8 times higher in the risk for NAFLD and serum AST and ALT activities, respectively, than those with the major haplotype. BMI, waist circumferences, serum glucose concentrations, and blood pressure interacted with the haplotype for NAFLD risk. We also found that a high carbohydrate intake and a dietary pattern characterized by high noodle and meat consumption significantly interacted with the minor haplotype to increase the risk of NAFLD. We hypothesized that the high incidence of NAFLD among Koreans, despite a relatively low incidence of obesity, might be due to genetic factors and perhaps their interactions with dietary patterns. The hypothesis was accepted since this study confirmed that participants with the minor allele of the haplotype in the 22q13 loci had a higher NAFLD risk that was exacerbated by high intakes of carbohydrates and a dietary pattern characterized by high noodle and meat consumption.

Beneficial effects of the ketogenic diet on nonalcoholic fatty liver disease: A comprehensive review of the literature

Nonalcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease, characterized by hepatic fat accumulation and possible development of inflammation, fibrosis, and cancer. The ketogenic diet (KD), with its drastic carbohydrate reduction, is a now popular weight loss intervention, despite safety concerns on a possible association with fatty liver. However, KDs were also reported to be beneficial on hepatic pathology, with ketone bodies recently proposed as effective modulators of inflammation and fibrosis. If the beneficial impact of weight loss on NAFLD is established, less is known on the effect of macronutrient distribution on such outcome. In a hypocaloric regimen, the latter seems not to be crucial, whereas at higher calorie intake, macronutrient ratio and, theoretically, ketosis, may become important. KDs could positively impact NAFLD for their very low carbohydrate content, and whether ketosis plays an additional role is unknown. Indeed, several mechanisms may directly link ketosis and NAFLD improvement, and elucidating these aspects would pave the way for new therapeutic strategies. We herein aimed at providing an accurate revision of current literature on KDs and NAFLD, focusing on clinical evidence, metabolic pathways involved, and strict categorization of dietary interventions.

An Overview of Lipid Metabolism and Nonalcoholic Fatty Liver Disease

The occurrence of nonalcoholic fatty liver disease (NAFLD) is associated with major abnormalities of hepatic lipid metabolism. We propose that lipid abnormalities directly or indirectly contribute to NAFLD, especially fatty acid accumulation, arachidonic acid metabolic disturbance, and ceramide overload. The effects of lipid intake and accumulation on NAFLD and NAFLD treatment are explained with theoretical and experimental details. Overall, these findings provide further understanding of lipid metabolism in NAFLD and may lead to novel therapies.

Loss of HMGCS2 Enhances Lipogenesis and Attenuates the Protective Effect of the Ketogenic Diet in Liver Cancer

Hepatocellular carcinoma (HCC) is the most common primary malignant liver tumor with limited treatment. The ketogenic diet (KD) emerged as a metabolic therapy for cancer; however, the antitumor effect on HCC remains controversial. We previously reported that the ketogenesis rate-limiting enzyme, 3-hydroxymethylglutaryl-CoA synthase 2 (HMGCS2), was downregulated in most patients with HCC. The knockdown of HMGCS2 enhanced the proliferation and metastasis ability of HCC cells. However, the role of HMGCS2 in affecting KD-mediated metabolic effects remains unclear. Here, we report that KD feeding upregulates HMGCS2 expression and inhibits HCC tumor growth, while a reverse correlation between tumor size and HMGCS2 expression was observed. We found that HCC cells with HMGCS2 downregulation possess altered lipid metabolism that increases fatty acid, triglyceride, and cholesterol synthesis. Under KD feeding, a higher tumor growth rate was observed in HMGCS2 knockdown tumors, which had increased lipid synthesis-related marker expression and a positive correlation between lipid quantity and tumor weight. In conclusion, these results demonstrate that the downregulation of HMGCS2 attenuates the protective effect of the KD by shifting ketone production to enhance de novo lipogenesis in HCC. Our study elucidates a new molecular mechanism underlying the crosstalk between HMGCS2 expression and the KD in cancer treatment, which provides more information for precision medicine in developing personalized treatment strategies.

Evaluation of Dietary Approaches for the Treatment of Non-Alcoholic Fatty Liver Disease: A Systematic Review

Lifestyle interventions, namely optimizing nutrition and increasing physical activity, remain the cornerstone of therapy for non-alcoholic fatty liver disease (NAFLD), as this can lead to the significant improvement or resolution of disease. The optimal nutritional approach to treat NAFLD remains unclear. The aim of this systematic review is to evaluate the effectiveness of different nutritional patterns on hepatic, metabolic, and weight-loss endpoints. MEDLINE via PubMed, Embase, Scopus, and Google Scholar were searched. Randomized trials of dietary interventions alone for adults with NAFLD were selected. Two authors independently reviewed articles, to select eligible studies, and performed data abstraction. Six studies, representing 317 patients, were included. The participants had a median age of 46, mean body mass index (BMI) 31.5 and were 64.3% male. The mean study duration was 16.33 ± 8.62 weeks. Reduction in hepatic steatosis (HS) was statistically significant in 3/5 Mediterranean Diet (MD), one low-carbohydrate, one intermittent fasting (IF) and 1/2 low fat (LF) diet interventions. A total of 3/5 studies using MD, 1/2 LF interventions, and the one IF intervention demonstrated significant reductions in weight. In conclusion, there appears to be most data in support of MD-based interventions, though further randomized trials are needed to assess comparative effectiveness for NAFLD.

A low-carbohydrate ketogenic diet induces the expression of very-low-density lipoprotein receptor in liver and affects its associated metabolic abnormalities

A low-carbohydrate ketogenic diet (LCKD) promotes the progression of hepatic steatosis in C57BL/6 wild-type mice, but improves the condition in leptin-deficient obese (ob/ob) mice. Here, we show a novel effect of LCKD associated with the conflicting effects on these mice. Gene expression microarray analyses showed that expression of the Vldlr gene, which encodes the very-low-density lipoprotein receptor (VLDLR), was induced in LCKD-fed ob/ob mice. Although the VLDLR is not normally expressed in the liver, the LCKD led to VLDLR expression in both ob/ob and wild-type mice. To clarify this effect on VLDL dynamics, we analyzed the lipid content of serum lipoproteins and found a marked decrease in VLDL-triglycerides only in LCKD-fed wild-type mice. Further analyses suggested that transport of triglycerides via VLDL from the liver to extrahepatic tissues was inhibited by LCKD-induced hepatic VLDLR expression, but rescued under conditions of leptin deficiency.

The effects of popular diets on type 2 diabetes management

Type 2 diabetes can be managed with the use of diabetes self-management skills. Diet and exercise are essential segments of the lifestyle changes necessary for diabetes management. However, diet recommendations can be complicated in a world full of different diets. This review aims to evaluate the evidence on the effects of three popular diets geared towards diabetes management: low-carbohydrate and ketogenic diet, vegan diet, and the Mediterranean diet. While all three diets have been shown to assist in improving glycaemic control and weight loss, patient adherence, acceptability, and long-term manageability play essential roles in the efficacy of each diet.

IMPACT OF CURRENT DIET AT THE RISK OF NON-ALCOHOLIC FATTY LIVER DISEASE (NAFLD)

The nonalcoholic fatty liver disease (NAFLD) affects approximately 20%-30% of general population and is even more prevalent among obese individuals. The risk factors mainly associated with NAFLD are diseases related to the metabolic syndrome, genetics and environment. In this review, we provide a literature compilation evaluating the evidence behind dietary components, including calories intake, fat, protein, fibers and carbohydrate, especially fructose which could be a trigger to development and progression of the NAFLD. In fact, it has been demonstrated that diet is an important factor for the development of NAFLD and its association is complex and extends beyond total energy intake.

Ketogenic diet in endocrine disorders: Current perspectives

Ketogenic diet (KD) is a high-fat, adequate-protein, and low-carbohydrate diet that leads to nutritional ketosis, long known for antiepileptic effects and has been used therapeutically to treat refractory epilepsy. This review attempts to summarize the evidence and clinical application of KD in diabetes, obesity, and other endocrine disorders. KD is usually animal protein based. An empiric vegetarian Indian variant of KD has been provided keeping in mind the Indian food habits. KD has beneficial effects on cardiac ischemic preconditioning, improves oxygenation in patients with respiratory failure, improves glycemic control in diabetics, is associated with significant weight loss, and has a beneficial impact on polycystic ovarian syndrome. Multivitamin supplementations are recommended with KD. Recently, ketones are being proposed as super-metabolic fuel; and KD is currently regarded as apt dietary therapy for "diabesity."

Fasting and rapamycin: diabetes versus benevolent glucose intolerance

Rapamycin (Sirolimus) slows aging, extends life span, and prevents age-related diseases, including diabetic complications such as retinopathy. Puzzlingly, rapamycin can induce insulin sensitivity, but may also induce insulin resistance or glucose intolerance without insulin resistance. This mirrors the effect of fasting and very low calorie diets, which improve insulin sensitivity and reverse type 2 diabetes, but also can cause a form of glucose intolerance known as benevolent pseudo-diabetes. There is no indication that starvation (benevolent) pseudo-diabetes is detrimental. By contrast, it is associated with better health and life extension. In transplant patients, a weak association between rapamycin/everolimus use and hyperglycemia is mostly due to a drug interaction with calcineurin inhibitors. When it occurs in cancer patients, the hyperglycemia is mild and reversible. No hyperglycemic effects of rapamycin/everolimus have been detected in healthy people. For antiaging purposes, rapamycin/everolimus can be administrated intermittently (e.g., once a week) in combination with intermittent carbohydrate restriction, physical exercise, and metformin.

The mystery of the ketogenic diet: benevolent pseudo-diabetes

Designed a century ago to treat epilepsy, the ketogenic diet (KD) is also effective against obesity and diabetes. Paradoxically, some studies in rodents have found that the KD seemingly causes diabetes, contradicting solid clinical data in humans. This paradox can be resolved by applying the concept of starvation pseudo-diabetes, which was discovered in starved animals almost two centuries ago, and has also been observed in some rapamycin-treated rodents. Intriguingly, use of the KD and rapamycin is indicated for a similar spectrum of diseases, including Alzheimer's disease and cancer. Even more intriguingly, benevolent (starvation) pseudo-diabetes may counteract type 2 diabetes or its complications.

Ketogenic diet in combination with voluntary exercise impacts markers of hepatic metabolism and oxidative stress in male and female Wistar rats

Ketogenic diets (KDs) are shown to benefit hepatic metabolism; however, their effect on the liver when combined with exercise is unknown. We investigated the effects of a KD versus a "western" diet (WD) on markers of hepatic lipid metabolism and oxidative stress in exercising rats. Male and female Wistar rats with access to voluntary running wheels were randomized to 3 groups (n = 8-14 per group): standard chow (SC; 17% fat), WD (42% fat), or KD (90.5% fat) for 7 weeks. Body fat percentage (BF%) was increased in WD and KD versus SC, although KD females displayed lower BF% versus WD (p ≤ 0.05). Liver triglycerides were higher in KD and WD versus SC but were attenuated in KD females versus WD (p ≤ 0.05). KD suppressed hepatic markers of de novo lipogenesis (fatty acid synthase, acetyl coenzyme A carboxylase) and increased markers of mitochondrial biogenesis/content (peroxisome proliferator activated receptor-1α, mitochondrial transcription factor A (TFAM), and citrate synthase activity). KD also increased hepatic glutathione peroxidase 1 and lowered oxidized glutathione. Female rats exhibited elevated hepatic markers of mitochondrial biogenesis (TFAM), mitophagy (light chain 3 II/I ratio, autophagy-related protein 12:5), and cellular energy homeostasis (phosphorylated 5'AMP-activated protein kinase/5'AMP-activated protein kinase) versus males. These data highlight that KD and exercise beneficially impacts hepatic metabolism and oxidative stress and merits further investigation. Novelty KD feeding combined with exercise improved hepatic oxidative stress, suppressed markers of de novo lipogenesis, and increased markers of mitochondrial content versus WD feeding. Males and females responded similarly to combined KD feeding and exercise. Female rats exhibited elevated hepatic markers of autophagy/mitophagy and energy homeostasis compared with male rats.

Lysosomal Acid Lipase as a Molecular Target of the Very Low Carbohydrate Ketogenic Diet in Morbidly Obese Patients: The Potential Effects on Liver Steatosis and Cardiovascular Risk Factors

A very low carbohydrate ketogenic diet (VLCKD) is an emerging technique to induce a significant, well-tolerated, and rapid loss of body weight in morbidly obese patients. The low activity of lysosomal acid lipase (LAL) could be involved in the pathogenesis of non-alcoholic fatty liver disease (NAFLD), which is a common feature in morbidly obese patients. Fifty-two obese patients suitable for a bariatric surgery intervention underwent a 25-day-long VLCKD. The biochemical markers of glucose and lipid metabolism, and flow-mediated dilation (FMD) of the brachial artery were measured before and after VLCKD. LAL activity was measured using the dried blood spot technique in 20 obese patients and in a control group of 20 healthy, normal-weight subjects. After VLCKD, we observed a significant reduction in body mass index, fasting glucose, insulinemia, and lipid profile parameters. No significant variation in FMD was observed. The number of patients with severe liver steatosis significantly decreased. LAL activity significantly increased, although the levels were not significantly different as compared to the control group. In conclusion, VLCKD induces the activity of LAL in morbidly obese subjects and reduces the secretion of all circulating lipoproteins. These effects could be attributed to the peculiar composition of the diet, which is particularly poor in carbohydrates and relatively rich in proteins.

The effect of ketogenic diet on behaviors and synaptic functions of naive mice

INTRODUCTION

Beyond its application as an epilepsy therapy, the ketogenic diet (KD) has been considered a potential treatment for a variety of other neurological and metabolic disorders. However, whether KD promotes functional restoration by reducing the pathological processes underlying individual diseases or through some independent mechanisms is not clear.

METHODS

In this study, we evaluated the effect of KD on a series of behaviors and synaptic functions of young adult naive mice. Wild-type C57BL/6J mice at age of 2-3 months were fed with control diet or KD for three months. Body weight and caloric intake were monitored throughout the experiments. We assessed behavioral performance with seizure induction, motor coordination and activity, anxiety level, spatial learning and memory, sociability, and depression. Synaptic transmission and long-term potentiation were also recorded.

RESULTS

KD-fed mice performed equivalent to control-diet-fed mice in the behavioral tests and electrophysiological assays except exhibiting slower weight gain and increased seizure threshold.

CONCLUSIONS

Our results contribute to the better understanding of effects of the KD on physiological behaviors and synaptic functions.

Role of Nutrition in the Pathogenesis and Prevention of Non-alcoholic Fatty Liver Disease: Recent Updates

Non-alcoholic fatty liver disease (NAFLD) is an acquired metabolic disease characterized by triglycerides (TGs) deposition in liver induced by other factors rather than alcohol consumption. NAFLD significantly contributes to liver diseases in children and adults. NAFLD pathogenesis is associated with age, gender, race and ethnicity. Insulin resistance, hyperinsulinemia, elevated plasma free fatty acids (FFAs), fatty liver, hepatocyte injury, liver inflammation, oxidative stress, mitochondrial dysfunction, imbalanced pro-inflammatory cytokines, and fibrosis are the characteristics of NAFLD. Factors including genetic and epigenetic pathways, sedentary lifestyle, sleep, and diet composition affect NAFLD pathogenesis. In this review, we discuss the aetiology, risk factors and pathogenesis of NAFLD. Special focus is given to macro and micro nutrition as causing factors and their role in the prevention of NAFLD pathogenesis.

Interorgan Metabolic Crosstalk in Human Insulin Resistance

Excessive energy intake and reduced energy expenditure drive the development of insulin resistance and metabolic diseases such as obesity and type 2 diabetes mellitus. Metabolic signals derived from dietary intake or secreted from adipose tissue, gut, and liver contribute to energy homeostasis. Recent metabolomic studies identified novel metabolites and enlarged our knowledge on classic metabolites. This review summarizes the evidence of their roles as mediators of interorgan crosstalk and regulators of insulin sensitivity and energy metabolism. Circulating lipids such as free fatty acids, acetate, and palmitoleate from adipose tissue and short-chain fatty acids from the gut effectively act on liver and skeletal muscle. Intracellular lipids such as diacylglycerols and sphingolipids can serve as lipotoxins by directly inhibiting insulin action in muscle and liver. In contrast, fatty acid esters of hydroxy fatty acids have been recently shown to exert a series of beneficial effects. Also, ketoacids are gaining interest as potent modulators of insulin action and mitochondrial function. Finally, branched-chain amino acids not only predict metabolic diseases, but also inhibit insulin signaling. Here, we focus on the metabolic crosstalk in humans, which regulates insulin sensitivity and energy homeostasis in the main insulin-sensitive tissues, skeletal muscle, liver, and adipose tissue.