Blood beta-hydroxybutyrate correlates better with seizure reduction due to ketogenic diet than do ketones in the urine

A New Nomenclature for the Very Low-Calorie Ketogenic Diet (VLCKD): Very Low-Energy Ketogenic Therapy (VLEKT). Ketodiets and Nutraceuticals Expert Panels: "KetoNut", Italian Society of Nutraceuticals (SINut) and the Italian Association of Dietetics and Clinical Nutrition (ADI)

PURPOSE OF REVIEW

In an attempt to clarify the most appropriate nomenclature for the very low-calorie ketogenic diets (VLCKD), we propose to change the nomenclature and acronym of this medical nutrition therapy. The new definition and acronym proposed by the "KetoNut" panel of experts of the Italian Society of Nutraceuticals (SINut) and the Italian Association of Dietetics and Clinical Nutrition (ADI) is Very Low-Energy Ketogenic Therapy (VLEKT).

RECENT FINDINGS

In the last few years, different authors have focused on the issue of confusion in the nomenclature of ketogenic diets. In detail, have been differentiated the VLCKD that provides < 800 kcal per day, which is intended for the weight loss in the medical treatment of obesity, and a eucaloric ketogenic diet, which contains more calories from fat (predominantly unsaturated) and with specific ketogenic ratios, for allow growth in children while helping, at the same time, to establish epileptic seizure control. In recent years, ketogenic diets have attracted great interest for their efficacy in the treatment of epilepsy and other neurological diseases but also in patients with overweight and obesity-related metabolic disorders. Nevertheless, although ketogenic diets are a dietary intervention designed to induce nutritional ketosis, different diets with different macronutrients' composition have been called with this name. The confusion in the nomenclature of ketogenic diets may result in significant bias and mistakes in the interpretation of the current scientific evidence.

Characterization of β-Hydroxybutyrate as a Cell Autonomous Fuel for Active Excitatory and Inhibitory Neurons: β-Hydroxybutyrate as a Fuel for Active Neurons

The ketogenic diet is an effective treatment for drug-resistant epilepsy, but the therapeutic mechanisms are poorly understood. Although ketones are able to fuel the brain, it is not known whether ketones are directly metabolized by neurons on a time scale sufficiently rapid to fuel the bioenergetic demands of sustained synaptic transmission. Here, we show that nerve terminals can use the ketone β-hydroxybutyrate in a cell- autonomous fashion to support neurotransmission in both excitatory and inhibitory nerve terminals and that this flexibility relies on Ca2+ dependent upregulation of mitochondrial metabolism. Using a genetically encoded ATP sensor, we show that inhibitory axons fueled by ketones sustain much higher ATP levels under steady state conditions than excitatory axons, but that the kinetics of ATP production following activity are slower when using ketones as fuel compared to lactate/pyruvate for both excitatory and inhibitory neurons.

The dentate gyrus differentially metabolizes glucose and alternative fuels during rest and stimulation

The metabolic demands of neuronal activity are both temporally and spatially dynamic, and neurons are particularly sensitive to disruptions in fuel and oxygen supply. Glucose is considered an obligate fuel for supporting brain metabolism. Although alternative fuels are often available, the extent of their contribution to central carbon metabolism remains debated. Differential fuel metabolism likely depends on cell type, location, and activity state, complicating its study. While biosensors provide excellent spatial and temporal information, they are limited to observations of only a few metabolites. On the other hand, mass spectrometry is rich in chemical information, but traditionally relies on cell culture or homogenized tissue samples. Here, we use mass spectrometry imaging (MALDI-MSI) to focus on the fuel metabolism of the dentate granule cell (DGC) layer in murine hippocampal slices. Using stable isotopes, we explore labeling dynamics at baseline, as well as in response to brief stimulation or fuel competition. We find that at rest, glucose is the predominant fuel metabolized through glycolysis, with little to no measurable contribution from glycerol or fructose. However, lactate/pyruvate, β-hydroxybutyrate (βHB), octanoate, and glutamine can contribute to TCA metabolism to varying degrees. In response to brief depolarization with 50 mM KCl, glucose metabolism was preferentially increased relative to the metabolism of alternative fuels. With an increased supply of alternative fuels, both lactate/pyruvate and βHB can outcompete glucose for TCA cycle entry. While lactate/pyruvate modestly reduced glucose contribution to glycolysis, βHB caused little change in glycolysis. This approach achieves broad metabolite coverage from a spatially defined region of physiological tissue, in which metabolic states are rapidly preserved following experimental manipulation. Using this powerful methodology, we investigated metabolism within the dentate gyrus not only at rest, but also in response to the energetic demand of activation, and in states of fuel competition.

Tolerance, adherence, and acceptability of a ketogenic 2.5:1 ratio, nutritionally complete, medium chain triglyceride-containing liquid feed in children and adults with drug-resistant epilepsy following a ketogenic diet

OBJECTIVE

To investigate incorporating a ready-to-use 2.5:1 ratio liquid feed into a ketogenic diet (KD) in children and adults with drug-resistant epilepsy.

METHODS

Following a three-day baseline, patients (n = 19; age: 19 years [SD 13], range: 8-46 years) followed a KD for 28 days (control period), then incorporated ≥200 mL/day of a ready-to-use liquid feed, made with a ratio of 2.5 g of fat to 1 g of protein plus carbohydrate and including medium chain triglycerides ([MCTs]; 25.6% of total fat/100 mL) for 28 days as part of their KD (intervention period). Outcome measures (control vs intervention period) included gastrointestinal (GI) tolerance, adherence to KD and intervention feed, dietary intake, blood ß-hydroxybutyrate (BHB) concentration, seizure outcomes, health-related quality of life (HRQoL), acceptability and safety.

RESULTS

Compared to the control period, during the intervention period, the percentage of patients reporting no GI symptoms increased (+5% [SD 5], p = 0.02); adherence to the KD prescription was similar (p = 0.92) but higher in patients (n = 5) with poor adherence (<50%) to KD during the control period (+33% [SD 26], p = 0.049); total MCT intake increased (+12.1 g/day [SD 14.0], p = 0.002), driven by increases in octanoic (C8; +8.3 g/day [SD 6.4], p < 0.001) and decanoic acid (C10; +5.4 g/day [SD 5.4], p < 0.001); KD ratio decreased (p = 0.047), driven by a nonsignificant increase in protein intake (+11 g/day [SD 44], p = 0.29); seizure outcomes were similar (p ≥ 0.63) but improved in patients (n = 6) with the worst seizure outcomes during the control period (p = 0.04); and HRQoL outcomes were similar. The intervention feed was well adhered to (96% [SD 8]) and accepted (≥88% of patients confirmed).

SIGNIFICANCE

These findings provide an evidence-base to support the effective management of children and adults with drug-resistant epilepsy following a KD with the use of a ready-to-use, nutritionally complete, 2.5:1 ratio feed including MCTs.

PLAIN LANGUAGE SUMMARY

This study examined the use of a ready-to-use, nutritionally complete, 2.5:1 ratio (2.5 g of fat to 1 g of protein plus carbohydrate) liquid feed, including medium chain triglycerides (MCTs), into a ketogenic diet (KD) in children and adults with drug-resistant epilepsy. The results show that the 2.5:1 ratio feed was well tolerated, adhered to, and accepted in these patients. Increases in MCT intake (particularly C8 and C10) and improvements in seizure outcomes (reduced seizure burden and intensity) and KD adherence also occurred with the 2.5:1 ratio feed in patients with the worst seizures and adherence, respectively.

Ketogenic diet for epilepsy and obesity: Is it the same?

The term "ketogenic diet" (KD) is used for a wide variety of diets with diverse indications ranging from obesity to neurological diseases, as if it was the same diet. This terminology is confusing for patients and the medical and scientific community. The term "ketogenic" diet implies a dietary regimen characterized by increased levels of circulating ketone bodies that should be measured in blood (beta-hydroxybutyrate), urine (acetoacetate) or breath (acetone) to verify the "ketogenic metabolic condition". Our viewpoint highlights that KDs used for epilepsy and obesity are not the same; the protocols aimed at weight loss characterized by low-fat, low-CHO and moderate/high protein content are not ketogenic by themselves but may become mildly ketogenic when high calorie restriction is applied. In contrast, there are standardized protocols for neurological diseases treatment for which ketosis has been established to be part of the mechanism of action. Therefore, in our opinion, the term ketogenic dietary therapy (KDT) should be reserved to the protocols considered for epilepsy and other neurological diseases, as suggested by the International Study Group in 2018. We propose to adjust the abbreviations in VLCHKD for Very Low CarboHydrate Ketogenic Diet and VLEKD for Very Low Energy Ketogenic Diet, to clarify the differences in dietary composition. We recommend that investigators describe the researchers describing efficacy or side effects of KDs, to clearly specify the dietary protocol used with its unique acronym and level of ketosis, when ketosis is considered as a component of the diet's mechanism of action.

Hypocarnitinemia and its effect on seizure control in adult patients with intractable epilepsy on the modified Atkins diet

Introduction

Previous studies have demonstrated the safety and efficacy of the modified Atkins diet (MAD) in attenuating seizures in patients with intractable epilepsy. MAD works by achieving ketosis, which is heavily dependent on the metabolic compound, carnitine, to facilitate the transport of long-chain fatty acids across the mitochondria for beta-oxidation. The effect of carnitine on ketogenic diet therapy is not well-defined in the current literature. Thus, the purpose of our study is to investigate the effects of hypocarnitinemia on the efficacy of MAD.

Methods

A retrospective chart review was conducted, and 58 adults with epilepsy undergoing MAD were evaluated. Generalized linear mixed effects models were used to compare the low carnitine status with normal carnitine group in patient measures of body mass index, seizure frequency and severity, number of anti-seizure medications, beta-hydroxybutyrate, triglyceride, and carnitine levels across baseline, 3-9-month follow-up (timepoint 1), 1-2-year follow-up (timepoint 2), and 2+ year follow-up (timepoint 3).

Results

Our study revealed that 38.3% of adult patients with epilepsy following MAD experienced low free carnitine at some point through the course of diet therapy. Patients with hypocarnitinemia at timepoint 2 showed a significant percent seizure increase while seizures continued to decrease in the normal carnitine group. Fasting triglyceride levels at timepoint 1 were significantly increased in the low carnitine group compared to normal carnitine group. Change in BHB, BMI, seizure severity, and number of ASMs showcased no significant differences between the low and normal carnitine groups.

Discussion

It may be important for clinicians to monitor for hypocarnitinemia in adults on MAD and provide carnitine supplementation when low. Further investigations into carnitine and MAD may inform clinical decisions on carnitine supplementation to maximize the efficacy of MAD therapy.

Bipolar mania and epilepsy pathophysiology and treatment may converge in purine metabolism: A new perspective on available evidence

Decreased ATPergic signaling is an increasingly recognized pathophysiology in bipolar mania disease models. In parallel, adenosine deficit is increasingly recognized in epilepsy pathophysiology. Under-recognized ATP and/or adenosine-increasing mechanisms of several antimanic and antiseizure therapies including lithium, valproate, carbamazepine, and ECT suggest a fundamental pathogenic role of adenosine deficit in bipolar mania to match the established role of adenosine deficit in epilepsy. The depletion of adenosine-derivatives within the purine cycle is expected to result in a compensatory increase in oxopurines (uric acid precursors) and secondarily increased uric acid, observed in both bipolar mania and epilepsy. Cortisol-based inhibition of purine conversion to adenosine-derivatives may be reflected in observed uric acid increases and the well-established contribution of cortisol to both bipolar mania and epilepsy pathology. Cortisol-inhibited conversion from IMP to AMP as precursor of both ATP and adenosine may represent a mechanism for treatment resistance common in both bipolar mania and epilepsy. Anti-cortisol therapies may therefore augment other treatments both in bipolar mania and epilepsy. Evidence linking (i) adenosine deficit with a decreased need for sleep, (ii) IMP/cGMP excess with compulsive hypersexuality, and (iii) guanosine excess with grandiose delusions may converge to suggest a novel theory of bipolar mania as a condition characterized by disrupted purine metabolism. The potential for disease-modification and prevention related to adenosine-mediated epigenetic changes in epilepsy may be mirrored in mania. Evaluating the purinergic effects of existing agents and validating purine dysregulation may improve diagnosis and treatment in bipolar mania and epilepsy and provide specific targets for drug development.

Ketonemia variability through menstrual cycle in patients undergoing classic ketogenic diet

Introduction

Ketogenic dietary therapies (KDT) are well-established, safe, non-pharmacologic treatments used for children and adults with drug-resistant epilepsy and other neurological disorders. Ketone bodies (KBs) levels are recognized as helpful to check compliance to the KDT and to attempt titration of the diet according to the individualized needs. KBs might undergo inter-individual and intra-individual variability and can be affected by several factors. Possible variations in glycemia and ketone bodies blood levels according to the menstrual cycle have not been systematically assessed yet, but this time window deserves special attention because of hormonal and metabolic related changes.

Methods

This study aims at searching for subtle changes in KBs blood level during menstrual cycle in female patients undergoing a stable ketogenic diet, by analyzing 3-months daily measurement of ketone bodies blood levels and glucose blood levels throughout the menstrual cycle.

Results

We report the preliminary results on six female patients affected by GLUT1DS or drug resistant epilepsy, undergoing a stable classic ketogenic diet. A significant increase in glucose blood levels during menstruation was found in the entire cohort. As far as the ketone bodies blood levels, an inversely proportional trend compared to glycemia was noted.

Conclusion

Exploring whether ketonemia variations might occur according to the menstrual cycle is relevant to determine the feasibility of transient preventive diet adjustments to assure a continuative treatment efficacy and to enhance dietary behavior support.

Clinical trial registration

clinicaltrials.gov, identifier NCT05234411.

Does the ketogenic ratio matter when using ketogenic diet therapy in pediatric epilepsy?

The ketogenic diet (KD) is a widely used therapeutic option for individuals with medically refractory epilepsy. As the diet's name implies, ketosis is a historically important component of the diet, but it is not well understood how important ketosis is for seizure control. The ketogenic ratio is defined as the ratio of fat to carbohydrate plus protein by weight in the diet (grams). Traditionally, the classic KD contains a 4:1 ratio, and a very high proportion of fat in the diet. The classic KD, with its high proportion of fat and limited carbohydrate intake can be restrictive for patients with epilepsy. Recently, there is experience with use of lower ketogenic ratios and less-restrictive diets such as the modified Atkins diet and the low glycemic index treatment. In this narrative review, we examine the role of ketosis and ketogenic ratios in determining the efficacy of the KD in children with epilepsy.

Analysis of the efficacy and safety of inpatient and outpatient initiation of KD for the treatment of pediatric refractory epilepsy using generalized estimating equations

Objective

To compare the efficacy and safety of inpatient and outpatient initiation ketogenic diet (KD) protocol of pediatric refractory epilepsy.

Methods

Eligible children with refractory epilepsy were randomly assigned to receive KD with inpatient and outpatient initiation. The generalized estimation equation (GEE) model was used to analyze the longitudinal variables of seizure reduction, ketone body, weight, height, body mass index (BMI), and BMI Z-score at different follow-up times between the two groups.

Results

Between January 2013 and December 2021, 78 and 112 patients were assigned to outpatient and inpatient KD initiation groups, respectively. There were no statistical differences between the two groups based on baseline demographics and clinical characteristics (all Ps > 0.05). The GEE model indicated that the rate of reduction of seizures≥50% in the outpatient initiation group was higher than that of the inpatient initiation group (p = 0.049). A negative correlation was observed between the seizure reduction and blood ketone body at 1, 6, and 12 months (all Ps < 0.05). There were no significant differences in height, weight, BMI, and BMI Z-score between the two groups over the 12-month period by the GEE models (all Ps > 0.05). Adverse events were reported by 31 patients (43.05%) in the outpatient KD initiation group and 46 patients (42.20%) in the inpatient KD initiation group, but these differences were not statistically significant (p = 0.909).

Conclusion

Our study shows that outpatient KD initiation is a safe and effective treatment for children with refractory epilepsy.

Exploring the role of ketone bodies in the diagnosis and treatment of psychiatric disorders

In recent times, advances in the field of metabolomics have shed greater light on the role of metabolic disturbances in neuropsychiatric conditions. The following review explores the role of ketone bodies and ketosis in both the diagnosis and treatment of three major psychiatric disorders: major depressive disorder, anxiety disorders, and schizophrenia. Distinction is made between the potential therapeutic effects of the ketogenic diet and exogenous ketone preparations, as exogenous ketones in particular offer a standardized, reproducible manner for inducing ketosis. Compelling associations between symptoms of mental distress and dysregulation in central nervous system ketone metabolism have been demonstrated in preclinical studies with putative neuroprotective effects of ketone bodies being elucidated, including effects on inflammasomes and the promotion of neurogenesis in the central nervous system. Despite emerging pre-clinical data, clinical research on ketone body effectiveness as a treatment option for psychiatric disorders remains lacking. This gap in understanding warrants further investigating, especially considering that safe and acceptable ways of inducing ketosis are readily available.

Modified low ratio ketogenic therapy in the treatment of adults with super-refractory status epilepticus

BACKGROUND

Induction of ketosis by manipulation of nutrition intake has been proposed as an adjunctive treatment for super-refractory status epilepticus (SRSE). However, the classical 4:1 ketogenic ratio may not meet the nutrition needs, specifically protein for critically ill adults. The aim of this study was to analyze the outcomes of adults with SRSE who received a lower ketogenic ratio of 2:1 grams of fat to non-fat grams, including 20%-30% of energy from medium chain triglycerides.

METHODS

We reviewed patients aged ≥18 years with SRSE treated with ketogenic therapy between July 2015 and December 2020 at two quaternary teaching hospitals in Melbourne, Australia. Data collected from medical records included patient demographics, nutrition prescription, clinical outcomes, and ketogenic therapy-related complications. The primary outcome of the study was to assess tolerability of ketogenic therapy.

RESULTS

Twelve patients (female = 7) were treated with ketogenic therapy for SRSE. Patients received between 4 and 8 antiseizure medications and 1-5 anesthetic agents prior to commencement of ketogenic therapy. Blood beta-hydroxybutyrate concentrations were variable (median = 0.5 mmol/L, range: 0.0-6.1 mmol/L). SRSE resolved in 10 cases (83%) after a median of 9 days (range: 2-21 days) following commencement of ketogenic therapy. Ketogenic therapy-associated complications were reported in five patients, leading to cessation in two patients.

CONCLUSION

Despite the challenge in maintaining ketosis during critical illness, low ratio 2:1 ketogenic therapy incorporating medium chain triglycerides is tolerable for adults with SRSE. Further studies are required to determine the optimal timing, nutrition prescription and duration of ketogenic therapy for SRSE treatment.

Core outcome set development for childhood epilepsy treated with ketogenic diet therapy: Results of a scoping review and parent interviews

PURPOSE

Clinical trials on childhood epilepsy treated with ketogenic diet (KD) use a wide range of outcomes, however, patients and decision-makers often do not perceive the outcomes used as the most important. We sought parental opinion on outcomes of importance and compared these to outcomes reported in published research.

METHODS

Ethical approval (London-Surrey-REC19/LO/1680). A scoping review identified outcomes reported in previous studies of childhood epilepsy and KD. Parents were recruited from nine KD centres (UK), charities and social media (international), then interviewed (Jan-April 2020) to explore priority outcomes. Content analysis identified all outcomes in transcripts. Parent identified outcomes were compared with those in the scoping review. Outcomes were collated and grouped into domains according to the COMET Taxonomy.

RESULTS

Of 2663 articles;147 met inclusion criteria. 921 verbatim outcomes were sorted into 90 discrete outcomes, reduced to 70 in consultation with the study advisory group, then classified into 21 domains. Parents (n = 21) identified 39 outcomes as important from the scoping review and seven new outcomes. They prioritised both physiological and functional outcomes in contrast to past studies, which prioritised physiological outcomes.

CONCLUSION

Little consistency exists in the outcomes used in childhood epilepsy and KD research. Those traditionally used do not adequately reflect parents' important outcomes for their child. Clinical trials should consider the broader priorities of parents when choosing outcomes, in particular, functional outcomes. Identified outcomes will inform an international two-round Delphi-study with parent, professional and researcher participants to develop a core outcome set for this clinical area (COMET registration #1116).

Exogenous Ketones and Lactate as a Potential Therapeutic Intervention for Brain Injury and Neurodegenerative Conditions

Metabolic dysfunction is a ubiquitous underlying feature of many neurological conditions including acute traumatic brain injuries and chronic neurodegenerative conditions. A central problem in neurological patients, in particular those with traumatic brain injuries, is an impairment in the utilization of glucose, which is the predominant metabolic substrate in a normally functioning brain. In such patients, alternative substrates including ketone bodies and lactate become important metabolic candidates for maintaining brain function. While the potential neuroprotective benefits of ketosis have been recognized for up to almost a century, the majority of work has focused on the use of ketogenic diets to induce such a state, which is inappropriate in cases of acute disease due to the prolonged periods of time (i.e., weeks to months) required for the effects of a ketogenic diet to be seen. The following review seeks to explore the neuroprotective effects of exogenous ketone and lactate preparations, which have more recently become commercially available and are able to induce a deep ketogenic response in a fraction of the time. The rapid response of exogenous preparations makes their use as a therapeutic adjunct more feasible from a clinical perspective in both acute and chronic neurological conditions. Potentially, their ability to globally moderate long-term, occult brain dysfunction may also be relevant in reducing lifetime risks of certain neurodegenerative conditions. In particular, this review explores the association between traumatic brain injury and contusion-related dementia, assessing metabolic parallels and highlighting the potential role of exogenous ketone and lactate therapies.

Ketone Supplementation: Meeting the Needs of the Brain in an Energy Crisis

Diverse neurological disorders are associated with a deficit in brain energy metabolism, often characterized by acute or chronic glucose hypometabolism. Ketones serve as the brain's only significant alternative fuel and can even become the primary fuel in conditions of limited glucose availability. Thus, dietary supplementation with exogenous ketones represents a promising novel therapeutic strategy to help meet the energetic needs of the brain in an energy crisis. Preliminary evidence suggests ketosis induced by exogenous ketones may attenuate damage or improve cognitive and motor performance in neurological conditions such as seizure disorders, mild cognitive impairment, Alzheimer's disease, and neurotrauma.

Evaluation of the seizure control and the tolerability of ketogenic diet in Chinese children with structural drug-resistant epilepsy

OBJECTIVES

In this study, we aimed to evaluate the efficacy and tolerability of ketogenic diet (KD) in Chinese children with drug-resistant epilepsy (DRE) due to structural etiology.

METHODS

We retrospectively analyzed data from 23 pediatric patients with DRE due to structural etiology who were treated with KD at Department of Neurology, between May 2014 and December 2020. Based on etiological classifications, the patients were divided into a neonatal brain injury (Group 1), an intracranial infection group (Group2) and a group that showed malformations of cortical development (MCDs) (Group 3).

RESULTS

The 23 patients remained on the KD for a mean duration of 15.3 ± 9.7 months. The response rates for the control of seizures were 60.9% (14/23), 52.2 % (12/23), 47.8% (11/23) at 3, 6 and 12 months, respectively. Subjective improvements in cognition were observed in 87.0% (20/23) of the children during follow-up. Reductions in the frequency of seizures of > 50% were more commonly achieved by patients in group 1 (75.0%, 9/12) compared to the patients in groups 2 (60.0%, 3/5) and 3 (33.4%, 2/6). Further analysis of the patients in Group 1 showed that children with a history of hypoxic ischemic encephalopathy (HIE) (100.0%, 6/6) had the highest rate of > 50% seizure reduction. The main reasons for the discontinuation of the KD were due to lack of efficacy and poor compliance. Most of the side effects associated with the KD diet were minor and easily corrected by appropriately adjusting the diet. Only 1 patient discontinued the diet due to severe refusal to eat.

CONCLUSIONS

KD is an effective and safe treatment for Chinese children with DRE due to structural etiology. Better efficacy of seizure control was observed in patients with a history of neonatal brain injury. Patients with DRE secondary to HIE may be particularly responsive to the KD therapy, and so KD should be considered earlier in those patients.

K.Vita: a feasibility study of a blend of medium chain triglycerides to manage drug-resistant epilepsy

This prospective open-label feasibility study aimed to evaluate acceptability, tolerability and compliance with dietary intervention with K.Vita, a medical food containing a unique ratio of decanoic acid to octanoic acid, in individuals with drug-resistant epilepsy. Adults and children aged 3-18 years with drug-resistant epilepsy took K.Vita daily whilst limiting high-refined sugar food and beverages. K.Vita was introduced incrementally with the aim of achieving ≤35% energy requirements for children or 240 ml for adults. Primary outcome measures were assessed by study completion, participant diary, acceptability questionnaire and K.Vita intake. Reduction in seizures or paroxysmal events was a secondary outcome. 23/35 (66%) children and 18/26 (69%) adults completed the study; completion rates were higher when K.Vita was introduced more gradually. Gastrointestinal disturbances were the primary reason for discontinuation, but symptoms were similar to those reported from ketogenic diets and incidence decreased over time. At least three-quarters of participants/caregivers reported favourably on sensory attributes of K.Vita, such as taste, texture and appearance, and ease of use. Adults achieved a median intake of 240 ml K.Vita, and children 120 ml (19% daily energy). Three children and one adult had ß-hydroxybutyrate >1 mmol/l. There was 50% (95% CI 39-61%) reduction in mean frequency of seizures/events. Reduction in seizures or paroxysmal events correlated significantly with blood concentrations of medium chain fatty acids (C10 and C8) but not ß-hydroxybutyrate. K.Vita was well accepted and tolerated. Side effects were mild and resolved with dietetic support. Individuals who completed the study complied with K.Vita and additional dietary modifications. Dietary intervention had a beneficial effect on frequency of seizures or paroxysmal events, despite absent or very low levels of ketosis. We suggest that K.Vita may be valuable to those with drug-resistant epilepsy, particularly those who cannot tolerate or do not have access to ketogenic diets, and may allow for more liberal dietary intake compared to ketogenic diets, with mechanisms of action perhaps unrelated to ketosis. Further studies of effectiveness of K.Vita are warranted.

Measuring ketone bodies for the monitoring of pathologic and therapeutic ketosis

BACKGROUND

The ketone bodies β-hydroxybutyrate (BOHB) and acetone are generated as a byproduct of the fat metabolism process. In healthy individuals, ketone body levels are ∼0.1 mM for BOHB and ∼1 part per million for breath acetone (BrAce). These levels can increase dramatically as a consequence of a disease process or when used therapeutically for disease treatment. For example, increased ketone body concentration during weight loss is an indication of elevated fat metabolism. Ketone body measurement is relatively inexpensive and can provide metabolic insights to help guide disease management and optimize weight loss.

METHODS

This review of the literature provides metabolic mechanisms and typical concentration ranges of ketone bodies, which can give new insights into these conditions and rationale for measuring ketone bodies.

RESULTS

Diseases such as heart failure and ketoacidosis can affect caloric intake and macronutrient management, which can elevate BOHB 30-fold and BrAce 1000-fold. Other diseases associated with obesity, such as brain dysfunction, cancer, and diabetes, may cause dysfunction because of an inability to use glucose, excessive reliance on glucose, or poor insulin signaling. Elevating ketone body concentrations (e.g., nutritional ketosis) may improve these conditions by forcing utilization of ketone bodies, in place of glucose, for fuel. During weight loss, monitoring ketone body concentration can demonstrate program compliance and can be used to optimize the weight-loss plan.

CONCLUSIONS

The role of ketone bodies in states of pathologic and therapeutic ketosis indicates that accurate measurement and monitoring of BOHB or BrAce will likely improve disease management. Bariatric surgery is examined as a case study for monitoring both types of ketosis.

International Recommendations for the Management of Adults Treated With Ketogenic Diet Therapies

OBJECTIVE

To evaluate current clinical practices and evidence-based literature to establish preliminary recommendations for the management of adults using ketogenic diet therapies (KDTs).

METHODS

A 12-topic survey was distributed to international experts on KDTs in adults consisting of neurologists and dietitians at medical institutions providing KDTs to adults with epilepsy and other neurologic disorders. Panel survey responses were tabulated by the authors to determine the common and disparate practices between institutions and to compare these practices in adults with KDT recommendations in children and the medical literature. Recommendations are based on a combination of clinical evidence and expert opinion regarding management of KDTs.

RESULTS

Surveys were obtained from 20 medical institutions with >2,000 adult patients treated with KDTs for epilepsy or other neurologic disorders. Common side effects reported are similar to those observed in children, and recommendations for management are comparable with important distinctions, which are emphasized. Institutions differ with regard to recommended biochemical assessment, screening, monitoring, and concern for long-term side effects, and further investigation is warranted to determine the optimal clinical management. Differences also exist between screening and monitoring practices among adult and pediatric providers.

CONCLUSIONS

KDTs may be safe and effective in treating adults with drug-resistant epilepsy, and there is emerging evidence supporting the use in other adult neurologic disorders and general medical conditions as well. Therefore, expert recommendations to guide optimal care are critical as well as further evidence-based investigation.

Dietary-Induced Ketogenesis: Adults Are Not Children

There is increasing interest in the use of a ketogenic diet for various adult disorders; however, the ability of adults to generate ketones is unknown. Our goal was to challenge the hypothesis that there would be no difference between adults and children regarding their ability to enter ketosis. Methods: Two populations were studied, both treated with identical very low-carbohydrate high-fat diets: a retrospective series of children with epilepsy or/and metabolic disorders (2009–2016) and a prospective clinical trial of adults with glioblastoma. Dietary intake was assessed based upon written food diaries and 24-h dietary recall. Ketogenic ratio was calculated according to [grams of fat consumed]/[grams of carbohydrate and protein consumed]. Ketone levels (β-hydroxybutyrate) were measured in blood and/or urine. Results: A total of 168 encounters amongst 28 individuals were analyzed. Amongst both children and adults, ketone levels correlated with nutritional ketogenic ratio; however, the absolute ketone levels in adults were approximately one quarter of those seen in children. This difference was highly significant in a multivariate linear regression model, p < 0.0001. Conclusions: For diets with comparable ketogenic ratios, adults have lower blood ketone levels than children; consequently, high levels of nutritional ketosis are unobtainable in adults.

3-Hydroxybutyrate as a Metabolite and a Signal Molecule Regulating Processes of Living Organisms

3-hydroxybutyrate (3-HB) as a very important metabolite occurs in animals, bacteria and plants. It is well known that in animals, 3-HB is formed as a product of the normal metabolism of fatty acid oxidation and can therefore be used as an energy source in the absence of sufficient blood glucose. In microorganisms, 3-HB mainly serves as a substrate for the synthesis of polyhydroxybutyrate, which is a reserve material. Recent studies show that in plants, 3-HB acts as a regulatory molecule that most likely influences the expression of genes involved in DNA methylation, thereby altering DNA methylation levels. Additionally, in animals, 3-HB is not only an intermediate metabolite, but also an important regulatory molecule that can influence gene expression, lipid metabolism, neuronal function, and overall metabolic rate. Some of these effects are the direct effects of 3-HB itself, while others are indirect effects, regulated by the metabolites into which 3-HB is converted. One of the most important regulatory functions of 3-HB is the inhibition of the activity of histone deacetylases and thus the epigenetic regulation of many genes. Due to the number of functions of this compound, it also shows promising therapeutic properties.

Differential ketogenic diet-induced shift in CSF lipid/carbohydrate metabolome of pediatric epilepsy patients with optimal vs. no anticonvulsant response: a pilot study

Background

The low carbohydrate, high fat ketogenic diet can be an effective anticonvulsant treatment in some pediatric patients with pharmacoresistant epilepsy. Its mechanism(s) of action, however, remain uncertain. Direct sampling of cerebrospinal fluid before and during metabolic therapy may reveal key changes associated with differential clinical outcomes. We characterized the relationship between seizure responsiveness and changes in lipid and carbohydrate metabolites.

Methods

We performed metabolomic analysis of cerebrospinal fluid samples taken before and during ketogenic diet treatment in patients with optimal response (100% seizure remission) and patients with no response (no seizure improvement) to search for differential diet effects in hallmark metabolic compounds in these two groups. Optimal responders and non-responders were similar in age range and included males and females. Seizure types and the etiologies or syndromes of epilepsy varied but did not appear to differ systematically between responders and non-responders.

Results

Analysis showed a strong effect of ketogenic diet treatment on the cerebrospinal fluid metabolome. Longitudinal and between-subjects analyses revealed that many lipids and carbohydrates were changed significantly by ketogenic diet, with changes typically being of larger magnitude in responders. Notably, responders had more robust changes in glucose and the ketone bodies β-hydroxybutyrate and acetoacetate than non-responders; conversely, non-responders had significant increases in fructose and sorbose, which did not occur in responders.

Conclusions

The data suggest that a differential and stronger metabolic response to the ketogenic diet may predict a better anticonvulsant response, and such variability is likely due to inherent biological factors of individual patients. Strategies to boost the metabolic response may be beneficial.

Pearls and Pitfalls of Introducing Ketogenic Diet in Adult Status Epilepticus: A Practical Guide for the Intensivist

Background: Status epilepticus (SE) carries an exceedingly high mortality and morbidity, often warranting an aggressive therapeutic approach. Recently, the implementation of a ketogenic diet (KD) in adults with refractory and super-refractory SE has been shown to be feasible and effective. Methods: We describe our experience, including the challenges of achieving and maintaining ketosis, in an adult with new onset refractory status epilepticus (NORSE). Case Vignette: A previously healthy 29-year-old woman was admitted with cryptogenic NORSE following a febrile illness; course was complicated by prolonged super-refractory SE. A comprehensive work-up was notable only for mild cerebral spinal fluid (CSF) pleocytosis, elevated nonspecific serum inflammatory markers, and edematous hippocampi with associated diffusion restriction on magnetic resonance imaging (MRI). Repeat CSF testing was normal and serial MRIs demonstrated resolution of edema and diffusion restriction with progressive hippocampal and diffuse atrophy. She required prolonged therapeutic coma with high anesthetic infusion rates, 16 antiseizure drug (ASD) trials, empiric immunosuppression and partial bilateral oophorectomy. Enteral ketogenic formula was started on hospital day 28. However, sustained beta-hydroxybutyrate levels >2 mmol/L were only achieved 37 days later following a comprehensive adjustment of the care plan. KD was challenging to maintain in the intensive care unit (ICU) and was discontinued due to poor nutritional state and pressure ulcers. KD was restarted again in a non-ICU unit facilitating ASD tapering without re-emergence of SE. Discussion: There are inconspicuous carbohydrates in commonly administered medications for SE including antibiotics, electrolyte repletion formulations, different preparations of the same drug (i.e., parenteral, tablet, or suspension) and even solutions used for oral care-all challenging the use of KD in the hospitalized patient. Tailoring comprehensive care and awareness of possible complications of KD are important for the successful implementation and maintenance of ketosis.

The Early Response to Dietary Therapy can Predict the Late Outcome in Children with Intractable Epilepsy

BACKGROUND AND PURPOSE

Dietary therapy (DT), including the ketogenic diet (KD), is one of the nonpharmacological treatment options for patient with drug-resistant epilepsy. However, maintaining DT in patients without seizure reduction is very difficult, so it is critical for clinicians to decide when to stop this intervention.

METHODS

We retrospectively analyzed early clinical and laboratory findings and the clinical characteristics of children who received DT. The maintenance of DT and the clinical seizure frequency were assessed at 1, 3, 6, 12, and 24 months after KD initiation. Responders were defined as patients showing an overall reduction in seizure frequency of >50% relative to the baseline.

RESULTS

We included 67 patients who received DT, but only 23 (34.3%) of these patients remained on DT at 6 months. Only 1 (5%) of the 20 responders at 1 month became a nonresponder at 6 months. The response rate at 6 months was significantly higher among patients under 2 years of age (15/17, 88.2%) than older patients (2/6, 33.3%; p=0.021). Moreover, the 6-month responders were significantly younger (29.4±38.6 months, mean±SD) than the nonresponders (98.9±84.6 months, p=0.012) at the initiation of the diet. A high blood β-hydroxybutyrate (BHB) level at 1 month predicted a good DT response at 6 months.

CONCLUSIONS

Most 1-month responders maintained their response on DT for up to 6 months. The blood BHB level at 1 month was significantly correlated with the 6-month seizure outcome. Confirming clinical and laboratory biomarkers for the efficacy of DT requires further studies with larger cohorts.

Social and Economic Challenges to Implementing the Ketogenic Diet: A Case Series

The ketogenic diet (KD) is a powerful therapeutic tool that can reduce seizure activity in patients with refractory epilepsy. However, dietary implementation can be difficult for patients and families due to the time and resource intensive nature of the diet. These challenges are particularly pronounced in economically disadvantaged or socially unstable patient populations. The first case of this series describes the successful implementation of KD in a low-income, homeless patient through the use of innovative KD recipes and access to social programs offered through Boston Medical Center. The second case illustrates the importance of consistent parental support to the success of KD and describes mechanisms used to improve familial support within a nonunified household. Collectively, these cases demonstrate ways by which health care providers can make this powerful dietary treatment accessible to low-resource patients.

Ketogenic diet treatment of children in the intensive care unit: Safety, tolerability, and effectiveness

PURPOSE

The ketogenic diet (KD) is initiated emergently in the intensive care unit (ICU) for patients with super refractory status epilepticus (SRSE) and epileptic encephalopathies (EE). However, few data are available regarding safety, effectiveness, and long-term outcomes.

METHODS

We performed a retrospective cohort study of consecutive patients with KD initiated in the ICU from 2010 to 2018 for SRSE and EE. We characterized time to ketosis, adverse effects, and seizure outcomes. Responders were defined as having ≥50 % reduction in seizure frequency compared to prior to KD initiation.

RESULTS

We identified 29 patients. KD was initiated for SRSE in 12 patients, EE in 8 patients, and EE with SRSE in 9 patients. KD was initiated after a median of 9 days. Ketosis was achieved 2 days faster in fasted patients (p < 0.0001). All patients had at least 1 KD-related adverse effect, most often hypoglycemia, constipation, or acidosis. There was ≥50 % reduction in seizure frequency compared to prior to KD initiation by 1 week in 17/28 patients, seizure-freedom by 2 weeks in 7/28 patients, and weaned off anesthetics in 11/17 patients. All KD-responders at 1 month had continued response at 6 months. Mortality at 1 year was 24 %. There was no difference in KD response or mortality between KD indication groups.

CONCLUSION

Emergent KD initiation in the ICU is feasible, safe, and often effective for SRSE and EE. Expected adverse effects were common but treatable. Morbidity and mortality in this group was high. A ≥ 50 % reduction in seizure is achieved in most responders by 1-2 weeks.

Low-Carbohydrate and Very-Low-Carbohydrate Diets in Patients With Diabetes

Low-carbohydrate diets have been advocated as an effective method for promoting weight loss in overweight and obese individuals and preventing and treating type 2 diabetes. This article reviews the differences between various low-carbohydrate eating plans and discusses the benefits and drawbacks of such a diet based on available evidence. It also offers practical pointers for clinicians.

The ketogenic diet for paediatric patients with super-refractory status epilepticus in febrile infection-related epilepsy syndrome

Objective

To investigate the effect and safety of ketogenic diet (KD) for the treatment of paediatric patients with super-refractory status epilepticus (SRSE) in febrile infection-related epilepsy syndrome (FIRES).

Method

From January 1, 2015 to October 31, 2017, ten critically ill paediatric patients with SRSE in FIRES were included in this study and treated with KD. The treatment effects of KD were evaluated by using continuous encephalography (CEEG) and amplitude-integrated electro-encephalography (aEEG).

Results

All 10 patients fulfilled the diagnostic criteria of SRSE in FIRES and achieved ketosis within 24–72 h following the administration of KD. CEEG and aEEG were monitored for several weeks to assess the efficacy of KD on status epilepticus (SE). SE was contained in 8 patients within 2 to 19 days after initiation of KD, and KD was discontinued in the other 2 patients. One of the 10 patients demonstrated severe adverse effects.

Conclusion

KD may be an alternative and safe treatment option in critical paediatric patients with SRSE in FIRES.

Clinical Implications of Ketosis in Children with Benign Convulsions with Mild Gastroenteritis

Background and Purpose

The pathophysiologic mechanisms underlying benign convulsions with mild gastroenteritis (CwG) in children remain unclear. We investigated the incidence of ketosis in CwG and whether this is related to seizures.

Methods

This retrospective study included children aged from 6 months to 6 years who visited our emergency department and were diagnosed as CwG between June 2015 and December 2018. The clinical and laboratory data were analyzed for these cases. Ketosis and severe ketosis were defined as blood β-hydroxybutyrate levels of ≥0.6 and ≥4.5 mmol/L, respectively.

Results

We enrolled 42 pediatric CwG patients aged 21.0±11.5 months (mean±SD) whose blood β-hydroxybutyrate level was 3.65±1.51 mmol/L. Ketosis was observed in 95.2% of these children, while 35.7% had severe ketosis. Compared to the non-severe-ketosis group (n=27), the severe-ketosis group (n=15) demonstrated significantly lower blood glucose levels (68.8 vs. 82.6 mg/dL, p=0.020) and sodium levels (134.2 vs. 135.6 mEq/L, p=0.018), and included a larger proportion of low-body-weight children (defined as adjusted weight <50th percentile for age and sex) (53.3% vs. 18.5%, p=0.019). However, the incidence of repetitive seizures (two or more during an illness period) did not differ between these groups. Moreover, severe ketosis was not associated with the risk of seizure recurrence in the emergency department.

Conclusions

Children with CwG are in a state of considerable ketosis. Severe ketosis in CwG may be associated with low blood glucose and sodium levels but does not reduce seizure recurrence.

Histone Butyrylation/ Acetylation Remains Unchanged in Triple Negative Breast Cancer Cells after a Long Term Metabolic Reprogramming

Background:

Altered metabolism is one of the hallmarks of the cancer cells which reciprocally interrelate with epigenetic processes, such as post-translational histone modifications to maintain their desired gene expression profiles. The role of beta-hydroxybutyrate as a ketone body in cancer cell biology and histone modifications are reported. The present study aimed to evaluate the impacts of long-term metabolic reprogramming via glucose restriction and beta-hydroxybutyrate treatment on histone acetylation and butyrylation in MDA-MB231 cells as a model of triple negative stem-like breast cancer.

Methods:

For long-term treatment, cells were set up in three groups receiving DMEM with restricted glucose (250 mg/L), DMEM with restricted glucose but enriched with five millimolar beta-hydroxybutyrate and DMEM with standard glucose (1g\L) and investigated for a month. Histone modifications, including H3 acetylation and butyrylation, were investigated by immunoblotting after an acid extraction of the histone proteins.

Results and Conclusion:

Neither beta-hydroxybutyrate enrichment nor glucose restriction elicited a significant effect on the butyrylation or acetylation level of histone H3 upon a long-term treatment. Metabolic plasticity of cancer cells, mainly stem-like triple negative breast cancer cells alleviate or neutralize the impact of long-term metabolic reprogramming via restriction of glucose and histone modifications enrichment. These results shed new light upon the mechanism of controversial efficacy of ketogenic diets in clinical trials.

Therapeutic strategies for ketosis induction and their potential efficacy for the treatment of acute brain injury and neurodegenerative diseases

The therapeutic use of ketone bodies (KB) against acute brain injury and neurodegenerative disorders has lately been suggested by many studies. Several mechanisms responsible for the protective action of KB have been described, including metabolic, anti-inflammatory and epigenetic. However, it is still not clear whether a specific mechanism of action can be associated with a particular neurological disorder. Different strategies to induce ketosis including the ketogenic diet (KD), caloric restriction (CR), intermittent fasting (IF), as well as the administration of medium chain triglycerides (MCTs), exogenous ketones or KB derivatives, have been used in animal models of brain injury and in humans. They have shown different degrees of success to prevent neuronal damage, motor alterations and cognitive decline. However, more investigation is needed in order to establish safe protocols for clinical application. Throughout the present review, we describe the different approaches that have been used to elevate blood KB and discuss their effectiveness considering their advantages and limitations, as tested in models of brain injury, neurodegeneration and clinical research. We also describe the mechanisms of action of KB in non-pathologic conditions and in association with their protective effect against neuronal damage in acute neurological disorders and neurodegenerative diseases.

Cerebral Ketones Detected by 3T MR Spectroscopy in Patients with High-Grade Glioma on an Atkins-Based Diet

BACKGROUND AND PURPOSE

Ketogenic diets are being explored as a possible treatment for several neurological diseases, but the physiologic impact on the brain is unknown. The objective of this study was to evaluate the feasibility of 3T MR spectroscopy to monitor brain ketone levels in patients with high-grade gliomas who were on a ketogenic diet (a modified Atkins diet) for 8 weeks.

MATERIALS AND METHODS

Paired pre- and post-ketogenic diet MR spectroscopy data from both the lesion and contralateral hemisphere were analyzed using LCModel software in 10 patients.

RESULTS

At baseline, the ketone bodies acetone and β-hydroxybutyrate were nearly undetectable, but by week 8, they increased in the lesion for both acetone (0.06 ± 0.03 ≥ 0.27 ± 0.06 IU, P = .005) and β-hydroxybutyrate (0.07 ± 0.07 ≥ 0.79 ± 0.32 IU, P = .046). In the contralateral brain, acetone was also significantly increased (0.041 ± 0.01 ≥ 0.16 ± 0.04 IU, P = .004), but not β-hydroxybutyrate. Acetone was detected in 9/10 patients at week 8, and β-hydroxybutyrate, in 5/10. Acetone concentrations in the contralateral brain correlated strongly with higher urine ketones (r = 0.87, P = .001) and lower fasting glucose (r = -0.67, P = .03). Acetoacetate was largely undetectable. Small-but-statistically significant decreases in NAA were also observed in the contralateral hemisphere at 8 weeks.

CONCLUSIONS

This study suggests that 3T MR spectroscopy is feasible for detecting small cerebral metabolic changes associated with a ketogenic diet, provided that appropriate methodology is used.

Fasting as a Therapy in Neurological Disease

Fasting is deeply entrenched in evolution, yet its potential applications to today’s most common, disabling neurological diseases remain relatively unexplored. Fasting induces an altered metabolic state that optimizes neuron bioenergetics, plasticity, and resilience in a way that may counteract a broad array of neurological disorders. In both animals and humans, fasting prevents and treats the metabolic syndrome, a major risk factor for many neurological diseases. In animals, fasting probably prevents the formation of tumors, possibly treats established tumors, and improves tumor responses to chemotherapy. In human cancers, including cancers that involve the brain, fasting ameliorates chemotherapy-related adverse effects and may protect normal cells from chemotherapy. Fasting improves cognition, stalls age-related cognitive decline, usually slows neurodegeneration, reduces brain damage and enhances functional recovery after stroke, and mitigates the pathological and clinical features of epilepsy and multiple sclerosis in animal models. Primarily due to a lack of research, the evidence supporting fasting as a treatment in human neurological disorders, including neurodegeneration, stroke, epilepsy, and multiple sclerosis, is indirect or non-existent. Given the strength of the animal evidence, many exciting discoveries may lie ahead, awaiting future investigations into the viability of fasting as a therapy in neurological disease.

Ketone Administration for Seizure Disorders: History and Rationale for Ketone Esters and Metabolic Alternatives

The ketogenic diet (KD) is a high-fat, low-carbohydrate treatment for medically intractable epilepsy. One of the hallmark features of the KD is the production of ketone bodies which have long been believed, but not yet proven, to exert direct anti-seizure effects. The prevailing view has been that ketosis is an epiphenomenon during KD treatment, mostly due to clinical observations that blood ketone levels do not correlate well with seizure control. Nevertheless, there is increasing experimental evidence that ketone bodies alone can exert anti-seizure properties through a multiplicity of mechanisms, including but not limited to: (1) activation of inhibitory adenosine and ATP-sensitive potassium channels; (2) enhancement of mitochondrial function and reduction in oxidative stress; (3) attenuation of excitatory neurotransmission; and (4) enhancement of central γ-aminobutyric acid (GABA) synthesis. Other novel actions more recently reported include inhibition of inflammasome assembly and activation of peripheral immune cells, and epigenetic effects by decreasing the activity of histone deacetylases (HDACs). Collectively, the preclinical evidence to date suggests that ketone administration alone might afford anti-seizure benefits for patients with epilepsy. There are, however, pragmatic challenges in administering ketone bodies in humans, but prior concerns may largely be mitigated through the use of ketone esters or balanced ketone electrolyte formulations that can be given orally and induce elevated and sustained hyperketonemia to achieve therapeutic effects.

2-Deoxyglucose and Beta-Hydroxybutyrate: Metabolic Agents for Seizure Control

Current anti-seizure drugs (ASDs) are believed to reduce neuronal excitability through modulation of ion channels and transporters that regulate excitability at the synaptic level. While most patients with epilepsy respond to ASDs, many remain refractory to medical treatment but respond favorably to a high-fat, low-carbohydrate metabolism-based therapy known as the ketogenic diet (KD). The clinical effectiveness of the KD has increasingly underscored the thesis that metabolic factors also play a crucial role in the dampening neuronal hyperexcitability that is a hallmark feature of epilepsy. This notion is further amplified by the clinical utility of other related metabolism-based diets such as the modified Atkins diet and the low-glycemic index treatment (LGIT). Traditional high-fat diets are characterized by enhanced fatty acid oxidation (which produces ketone bodies such as beta-hydroxybutyrate) and a reduction in glycolytic flux, whereas the LGIT is predicated mainly on the latter observation of reduced blood glucose levels. As dietary implementation is not without challenges regarding clinical administration and patient compliance, there is an inherent desire and need to determine whether specific metabolic substrates and/or enzymes might afford similar clinical benefits, hence validating the concept of a “diet in a pill.” Here, we discuss the evidence for one glycolytic inhibitor, 2-deoxyglucose (2DG) and one metabolic substrate, β-hydroxybutyrate (BHB) exerting direct effects on neuronal excitability, highlight their mechanistic differences, and provide the strengthening scientific rationale for their individual or possibly combined use in the clinical arena of seizure management.

Efficacy and tolerability of olive oil-based ketogenic diet in children with drug-resistant epilepsy: A single center experience from Turkey

PURPOSE

Ketogenic diet (KD) is an effective non-pharmacological treatment for drug-resistant epilepsy. The aim of this study was to investigate the efficacy, tolerability and complications of olive oil-based KD in epileptic children.

METHOD

In this single-center, prospective study, patients were followed up at 1, 3, 6 and 12 months after KD initiation. Initially, blood ketone levels were measured daily, and as needed thereafter to maintain the levels between 4 and 5 mmol/L. Patient demographics, seizure frequency, serum biochemistry, abdominal ultrasonography and adverse effects were recorded. Efficacy of KD was defined as ≥50% seizure reduction.

RESULTS

A total of 389 patients with drug-resistant epilepsy receiving KD from 2012 to 2016 were included. One hundred patients (25.7%) stopped the diet for different reasons in the first year, and 369, 314, 225 and 160 patients have been receiving KD treatment for 1, 3, 6 and 12 months, respectively. At 1, 3, 6 and 12th months, 65.8% (243/369), 74.7% (235/314), 70.6% (159/225) and 83.1% (133/160) of the patients were responders, respectively. None of the children had an increased seizure-frequency. Hyperlipidemia (50.8%), selenium deficiency (26.9%), constipation (26.2%), sleep disturbances (20.0%), nephrolithiasis (3.0%), hyperuricemia (3.0) and hepatic side effects (2.6%) were the most common complications of KD. Previous adrenocorticotropic hormone (ACTH) use due to epileptic encephalopathy and presence of constipation at baseline or during KD treatment were found the predictors of treatment efficacy.

CONCLUSION

KD is an effective and well-tolerated treatment option for patients with drug-resistant epilepsy. Previous history of ACTH use and constipation during KD treatment are important factors that affect the efficacy of KD treatment.

Ketogenic Diets for Adult Neurological Disorders

The current review highlights the evidence supporting the use of ketogenic diet therapies in the management of a growing number of neurological disorders in adults. An overview of the scientific literature supporting posited mechanisms of therapeutic efficacy is presented including effects on neurotransmission, oxidative stress, and neuro-inflammation. The clinical evidence supporting ketogenic diet use in the management of adult epilepsy, malignant glioma, Alzheimer's disease, migraine headache, motor neuron disease, and other neurologic disorders is highlighted and reviewed. Lastly, common adverse effects of ketogenic therapy in adults, including gastrointestinal symptoms, weight loss, and transient dyslipidemia are discussed.

The Expanding Role of Ketogenic Diets in Adult Neurological Disorders

The current review highlights the evidence supporting the use of ketogenic diet therapies in the management of adult epilepsy, adult malignant glioma and Alzheimer's disease. An overview of the scientific literature, both preclinical and clinical, in each area is presented and management strategies for addressing adverse effects and compliance are discussed.

β-Hydroxybutyrate Detection with Proton MR Spectroscopy in Children with Drug-Resistant Epilepsy on the Ketogenic Diet

BACKGROUND AND PURPOSE

The ketogenic diet, including both classic and modified forms, is an alternative to antiepileptic medications used in the treatment of drug-resistant epilepsy. We sought to evaluate the utility of proton MR spectroscopy for the detection of β-hydroxybutyrate in a cohort of children with epilepsy treated with the ketogenic diet and to correlate brain parenchymal metabolite ratios obtained from spectroscopy with β-hydroxybutyrate serum concentrations.

MATERIALS AND METHODS

Twenty-three spectroscopic datasets acquired at a TE of 288 ms in children on the ketogenic diet were analyzed with LCModel using a modified basis set that included a simulated β-hydroxybutyrate resonance. Brain parenchymal metabolite ratios were calculated. Metabolite ratios were compared with serum β-hydroxybutyrate concentrations, and partial correlation coefficients were calculated using patient age as a covariate.

RESULTS

β-hydroxybutyrate blood levels were highly correlated to brain β-hydroxybutyrate levels, referenced as either choline, creatine, or N-acetylaspartate. They were inversely but more weakly associated with N-acetylaspartate, regardless of the ratio denominator. No strong concordance with lactate was demonstrated.

CONCLUSIONS

Clinical MR spectroscopy in pediatric patients on the ketogenic diet demonstrated measurable β-hydroxybutyrate, with a strong correlation to β-hydroxybutyrate blood levels. These findings may serve as an effective tool for noninvasive monitoring of ketosis in this population. An inverse correlation between serum β-hydroxybutyrate levels and brain tissue N-acetylaspartate suggests that altered amino acid handling contributes to the antiepileptogenic effect of the ketogenic diet.

Metabolism and epilepsy: Ketogenic diets as a homeostatic link

Metabolic dysfunction can underlie seizure disorders, and metabolism-based treatments can afford seizure control and promote homeostasis. This relationship between metabolism and the risk of sporadic seizures was observed historically with the clinical success of a low-carbohydrate, high-fat, ketosis-inducing ketogenic diet - a treatment that remains relevant today, and one that has been shown to be effective against medically refractory epilepsy. Mechanisms underlying the success of the ketogenic diet are a topic of intense research efforts - not only because of proven success in arresting treatment-resistant seizures, but also because recent evidence suggests that altering metabolism with a ketogenic diet enables a homeostatic state in the brain that is less excitable, and hence raises the threshold for seizure genesis. Metabolic therapy with a ketogenic diet has been shown to normalize a range of abnormal physiological and behavioral parameters and may also make the central nervous system more resilient to other insults or physiological stresses. Because the therapeutic ability of such a diet may be more limited than a drug because of a dose "ceiling", investigations are underway to develop and test analogous or supplemental approaches. In addition, significant efforts have been made to demonstrate broader applications of metabolic therapy in promoting health and preventing disease, including conditions where epileptic seizures manifest in a comorbid fashion.

Optimal clinical management of children receiving dietary therapies for epilepsy: Updated recommendations of the International Ketogenic Diet Study Group

Ketogenic dietary therapies (KDTs) are established, effective nonpharmacologic treatments for intractable childhood epilepsy. For many years KDTs were implemented differently throughout the world due to lack of consistent protocols. In 2009, an expert consensus guideline for the management of children on KDT was published, focusing on topics of patient selection, pre‐KDT counseling and evaluation, diet choice and attributes, implementation, supplementation, follow‐up, side events, and KDT discontinuation. It has been helpful in outlining a state‐of‐the‐art protocol, standardizing KDT for multicenter clinical trials, and identifying areas of controversy and uncertainty for future research. Now one decade later, the organizers and authors of this guideline present a revised version with additional authors, in order to include recent research, especially regarding other dietary treatments, clarifying indications for use, side effects during initiation and ongoing use, value of supplements, and methods of KDT discontinuation. In addition, authors completed a survey of their institution's practices, which was compared to responses from the original consensus survey, to show trends in management over the last 10 years.

Do ketone bodies mediate the anti-seizure effects of the ketogenic diet?

Although the mechanisms underlying the anti-seizure effects of the high-fat ketogenic diet (KD) remain unclear, a long-standing question has been whether ketone bodies (i.e., β-hydroxybutyrate, acetoacetate and acetone), either alone or in combination, contribute mechanistically. The traditional belief has been that while ketone bodies reflect enhanced fatty acid oxidation and a general shift toward intermediary metabolism, they are not likely to be the key mediators of the KD's clinical effects, as blood levels of β-hydroxybutyrate do not correlate consistently with improved seizure control. Against this unresolved backdrop, new data support ketone bodies as having anti-seizure actions. Specifically, β-hydroxybutyrate has been shown to interact with multiple novel molecular targets such as histone deacetylases, hydroxycarboxylic acid receptors on immune cells, and the NLRP3 inflammasome. Clearly, as a diet-based therapy is expected to render a broad array of biochemical, molecular, and cellular changes, no single mechanism can explain how the KD works. Specific metabolic substrates or enzymes are only a few of many important factors influenced by the KD that can collectively influence brain hyperexcitability and hypersynchrony. This review summarizes recent novel experimental findings supporting the anti-seizure and neuroprotective properties of ketone bodies.

Different ketogenesis strategies lead to disparate seizure outcomes

BACKGROUND

Despite the introduction of new medicines to treat epilepsy over the last 50 years, the number of patients with poorly-controlled seizures remains unchanged. Metabolism-based therapies are an underutilized treatment option for this population. We hypothesized that two different means of systemic ketosis, the ketogenic diet and intermittent fasting, would differ in their acute seizure test profiles and mitochondrial respiration.

METHODS

Male NIH Swiss mice (aged 3-4 weeks) were fed for 12-13 days using one of four diet regimens: ketogenic diet (KD), control diet matched to KD for protein content and micronutrients (CD), or CD with intermittent fasting (24 h feed/24 h fast) (CD-IF), tested post-feed or post-fast. Mice were subject to the 6 Hz threshold test or, in separate cohorts, after injection of kainic acid in doses based on their weight (Cohort I) or a uniform dose regardless of weight (Cohort II). Mitochondrial respiration was tested in brain tissue isolated from similarly-fed seizure-naïve mice.

RESULTS

KD mice were protected against 6 Hz-induced seizures but had more severe seizure scores in the kainic acid test (Cohorts I & II), the opposite of CD-IF mice. No differences were noted in mitochondrial respiration between diet regimens.

INTERPRETATION

KD and CD-IF do not share identical antiseizure mechanisms. These differences were not explained by differences in mitochondrial respiration. Nevertheless, both KD and CD-IF regimens protected against different types of seizures, suggesting that mechanisms underlying CD-IF seizure protection should be explored further.

Adenosine A1 Receptor Antagonism Abolished the Anti-seizure Effects of Exogenous Ketone Supplementation in Wistar Albino Glaxo Rijswijk Rats

The state of therapeutic ketosis can be achieved by using the ketogenic diet (KD) or exogenous ketone supplementation. It was suggested previously that the adenosinergic system may be involved in the mediating effect of KD on suppressing seizure activity in different types of epilepsies, likely by means of adenosine A1 receptors (A1Rs). Thus, we tested in the present study whether exogenous ketone supplements (ketone ester: KE, 2.5 g/kg/day; ketone salt/KS + medium chain triglyceride/MCT: KSMCT, 2.5 g/kg/day) applied sub-chronically (for 7 days) by intragastric gavage can modulate absence epileptic activity in genetically absence epileptic Wistar Albino Glaxo/Rijswijk (WAG/Rij) rats. The number of spike-wave discharges (SWDs) significantly and similarly decreased after both KE and KSMCT treatment between 3rd and 7th days of gavage. Moreover, blood beta-hydroxybutyrate (βHB) levels were significantly increased alike after KE and KSMCT gavage, compared to control levels. The SWD number and βHB levels returned to the baseline levels on the first day without ketone supplementation. To determine whether A1Rs can modify ketone supplement-evoked changes in absence epileptic activity, we applied a non-pro-epileptic dose of a specific A1R antagonist DPCPX (1,3-dipropyl-8-cyclopentylxanthine) (intraperitoneal/i.p. 0.2 mg/kg) in combination with KSMCT (2.5 g/kg/day, gavage). As expected, DPCPX abolished the KSMCT-evoked decrease in SWD number. Thus, we concluded that application of exogenous ketone supplements may decrease absence epileptic activity in WAG/Rij rats. Moreover, our results suggest that among others the adenosinergic system, likely via A1Rs, may modulate the exogenous ketone supplements-evoked anti-seizure effects.

Anticonvulsant effect of exogenous β-hydroxybutyrate on kainic acid-induced epilepsy

The present study aimed to investigate the anticonvulsant effects of β-hydroxybutyrate (BHB) in a kainic acid (KA)-induced rat seizure model. The concentrations of BHB and glucose were detected in the blood prior to exogenous BHB administration. Three different doses of BHB (2, 4 and 8 mmol/kg) were then injected into male Wistar rats intraperitoneally, and the concentrations of BHB and glucose in the blood were detected. Rats received 0.9% normal saline intraperitoneally at a dose of 4 ml/kg as a control. Subsequently, a KA-induced rat seizure model was established and the anticonvulsant effects of BHB were investigated. The onset time of seizure and the degree of seizure behavior were recorded. Nissl and Timm staining were used to evaluate neuronal loss and mossy fiber sprouting, respectively. The present study demonstrated that exogenous BHB administration could significantly increase BHB concentration in the blood and this concentration was maintained for 90 min without affecting blood glucose levels. Furthermore, it was determined that a dose of 4 mmol/kg BHB is optimal for exogenous administration. The onset time of seizure was significantly prolonged in BHB-pretreated rats (63.31±4.050 min) compared with the control group (37.08±1.958 min; P=0.039). In addition, neuronal loss and mossy fiber sprouting were both alleviated in the BHB-pretreated model group. Exogenous BHB administration at a dose of 4 mmol/kg may be an alternative to a ketogenic diet to exert a protective effect in the epileptic model induced by KA. The results of the present study may allow novel therapeutic strategies to be developed to treat epilepsy.

The relationship between d-beta-hydroxybutyrate blood concentrations and seizure control in children treated with the ketogenic diet for medically intractable epilepsy

Objective

The ketogenic diet (KD) is a proven treatment for drug‐resistant (DR) seizures in children and adolescents. However, the relationship between seizure control and the most commonly measured metabolite of the diet, the ketone body d‐beta‐hydroxybutyrate (D‐BHB), is controversial. This study was performed to clarify the relationship because specific ketone bodies may be useful as biomarkers of diet efficacy.

Methods

Families of children with DR seizures were approached for participation in this open‐label, prospective study when they were referred for the KD at two western Canadian children's hospitals. Inclusion criteria included documentation of DR seizures without exclusion based on age, sex, seizure, or syndrome type. Patients were excluded if they were referred for treatment of a metabolic disorder independent of seizures. Seizures were quantified via parental report and standardized as seizure frequency per 28 days. Epilepsy syndromes were identified on the basis of the medical record. Blood D‐BHB was determined by tandem mass spectrometry.

Results

A total of 23 patients were recruited from both sites. Data from five individuals were excluded because these seizures occurred in clusters, leaving 18 patients for the primary analysis. In the latter group, a clear positive correlation was present between measures of seizure frequency and D‐BHB concentrations. However, this failed to reach statistical significance, likely because of the relatively small numbers.

Significance

A trend clearly exists between seizure frequency and D‐BHB levels, so we should not be dissuaded by the lack of statistical significance because it possibly results from methodological techniques, especially sample size. These results call for a larger prospective study in which seizure frequency is assessed at the point of care in a standardized fashion so as to determine whether D‐BHB can be used as a reliable biomarker of KD efficacy.