Research into the (Cost-) effectiveness of the ketogenic diet among children and adolescents with intractable epilepsy: design of a randomized controlled trial

Ketogenic diet in pharmacoresistant epilepsies: a clinical nutritional assessment

BACKGROUND

 Epilepsies are among the most prevalent chronic neurological diseases, usually beginning in childhood. About 30% of children with epilepsies develop seizures that are difficult to control with medication. Recurrent epileptic seizures hinder diet intake, impairing the nutritional status. Although non-pharmacological interventions (e.g., ketogenic diet therapy) can improve epileptic seizure frequency, few studies analyzed their impact on the nutritional status of children and adolescents with epilepsies.

OBJECTIVE

 The aim was to evaluate the effects of a ketogenic diet on the nutritional status and clinical course of patients with pharmacoresistant epilepsies.

METHODS

 This cross-sectional study included patients under 18 years of age followed up at the Ketogenic Diet Ambulatory Clinic of the Instituto de Medicina Integral Prof. Fernando Figueira between December 2015 and December 2021. Socioeconomic, clinical, nutritional, and laboratory data were collected from medical records at different time points during the ketogenic diet.

RESULTS

 The sample comprised 49 patients aged between 5 months and 17 years (median = 4.4 years), mostly male (62.1%), and from Recife and the metropolitan region (51%). Underweight patients (BMI-for-age) improved their nutritional status in six months. However, patients who were normal weight and overweight maintained their nutritional status. Dyslipidemia was a common and short-term adverse effect. Moreover, the treatment decreased epileptic seizure frequency and antiseizure medication intake.

CONCLUSION

 The ketogenic diet prevented malnutrition from worsening and reduced epileptic seizures and antiseizure medication intake.

Epilepsy in Africa: a multifaceted perspective on diagnosis, treatment, and community support

Epilepsy is the most widespread neurological disorder in Africa, affecting an estimated 25 million people. The disorder is characterized by recurrent seizures, which can be caused by a variety of factors, including past trauma, central nervous system infections, and genetic disorders. Diagnosis and treatment of epilepsy are challenging in African patients due to several factors, including the low socioeconomic status of the residents and limited access to appropriate medication. Phenobarbital remains the only drug widely available to patients, but it is not always effective and can have significant side effects. In addition to the medical challenges, individuals with epilepsy also face a lot of social stigmas in Africa. Widespread superstitions and false beliefs lead to prejudices against these people, making it difficult for them to live fulfilling social lives. With the development of new treatment modalities, such as gene therapy, stem cell therapy, and P-glycoprotein inhibitors, it is more important now than ever to increase the research output for the African region to create the best possible treatment and maximize patient outcomes.

Insights into the Cellular Interactions and Molecular Mechanisms of Ketogenic Diet for Comprehensive Management of Epilepsy

A high-fat diet with appropriate protein and low carbohydrate content, widely known as the ketogenic diet (KD), is considered as an effective non-pharmacotherapeutic treatment option for certain types of epilepsies. Several preclinical and clinical studies have been carried out to elucidate its mechanism of antiepileptic action. Ketone bodies produced after KD's breakdown interact with cellular excito-inhibitory processes and inhibit abnormal neuronal firing. The generated ketone bodies decrease glutamate release by inhibiting the vesicular glutamate transporter 1 and alter the transmembrane potential by hyperpolarization. Apart from their effect on the well-known pathogenic mechanisms of epilepsy, some recent studies have shown the interaction of KD metabolites with novel neuronal targets, particularly adenosine receptors, adenosine triphosphate-sensitive potassium channel, mammalian target of rapamycin, histone deacetylase, hydroxycarboxylic acid receptors, and the NLR family pyrin domain containing 3 inflammasomes to suppress seizures. The role of KD in augmenting gut microbiota as a potential mechanism for epileptic seizure suppression has been established. Furthermore, some recent findings also support the beneficial effect of KD against epilepsy- associated comorbidities. Despite several advantages of the KD in epilepsy management, its use is also associated with a wide range of side effects. Hypoglycemia, excessive ketosis, acidosis, renal stones, cardiomyopathies, and other metabolic disturbances are the primary adverse effects observed with the use of KD. However, in some recent studies, modified KD has been tested with lesser side effects and better tolerability. The present review discusses the molecular mechanism of KD and its role in managing epilepsy and its associated comorbidities.

A Review of the Multi-Systemic Complications of a Ketogenic Diet in Children and Infants with Epilepsy

Ketogenic diets (KDs) are highly effective in the treatment of epilepsy. However, numerous complications have been reported. During the initiation phase of the diet, common side effects include vomiting, hypoglycemia, metabolic acidosis and refusal of the diet. While on the diet, the side effects involve the following systems: gastrointestinal, hepatic, cardiovascular, renal, dermatological, hematologic and bone. Many of the common side effects can be tackled easily with careful monitoring including blood counts, liver enzymes, renal function tests, urinalysis, vitamin levels, mineral levels, lipid profiles, and serum carnitine levels. Some rare and serious side effects reported in the literature include pancreatitis, protein-losing enteropathy, prolonged QT interval, cardiomyopathy and changes in the basal ganglia. These serious complications may need more advanced work-up and immediate cessation of the diet. With appropriate monitoring and close follow-up to minimize adverse effects, KDs can be effective for patients with intractable epilepsy.

Community health workers to improve adherence to anti-seizure medication in rural South Africa: Is it cost-effective?

OBJECTIVE

Epilepsy is a common, chronic neurological disorder that disproportionately affects individuals living in low- and middle-income countries (LMICs), where the treatment gap remains high and adherence to medication remains low. Community health workers (CHWs) have been shown to be effective at improving adherence to chronic medications, yet no study assessing the costs of CHWs in epilepsy management has been reported.

METHODS

Using a Markov model with age- and sex-varying transition probabilities, we determined whether deploying CHWs to improve epilepsy treatment adherence in rural South Africa would be cost-effective. Data were derived using published studies from rural South Africa. Official statistics and international disability weights provided cost and health state values, respectively, and health gains were measured using quality adjusted life years (QALYs).

RESULTS

The intervention was estimated at International Dollars ($) 123 250 per annum per sub-district community and cost $1494 and $1857 per QALY gained for males and females, respectively. Assuming a costlier intervention and lower effectiveness, cost per QALY was still less than South Africa's Gross Domestic Product per capita of $13 215, the cost-effectiveness threshold applied.

SIGNIFICANCE

CHWs would be cost-effective and the intervention dominated even when costs and effects of the intervention were unfavorably varied. Health system re-engineering currently underway in South Africa identifies CHWs as vital links in primary health care, thereby ensuring sustainability of the intervention. Further research on understanding local health state utility values and cost-effectiveness thresholds could further inform the current model, and undertaking the proposed intervention would provide better estimates of its efficacy on reducing the epilepsy treatment gap in rural South Africa.

Ketogenic diet in Zambia: Managing drug-resistant epilepsy in a low and middle income country

Globally, drug-resistant epilepsy affects one third of people living with epilepsy. With limitations in treatment options for refractory epilepsy in resource-limited regions, ketogenic diet therapy is an important option to consider. Utilizing the 2015 International League Against Epilepsy recommended minimum requirements for ketogenic diet therapy, three male children with refractory epilepsy, aged 2.5, 6.5 and 10 years, were initiated on the classical ketogenic diet using locally available food in August 2017 at University Teaching Hospitals-Children's Hospital in Lusaka, Zambia, through partnership with the Epilepsy Program at Boston Children's Hospital in the United States. Following successful initiation in all three children, the diet was discontinued in the 10-year-old due to difficulties complying with the diet. The youngest child demonstrated an over 50% seizure reduction and gained developmental milestones. The third child achieved seizure freedom and showed marked improvement in behaviour. This pilot demonstrates the feasibility of ketogenic diet as an important therapeutic option for refractory epilepsy in Zambia. Given the limitations in treatment choices and medication accessibility, dietary therapy offers an alternative management strategy in our setting. Collaboration with an established ketogenic diet centre contributes to a successful program.

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Ketogenic diet is a feasible and safe therapeutic option for managing paediatric refractory epilepsy.

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Despite widespread use in developed countries, it is not routinely offered in resource limited settings.

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We describe the successful use of ketogenic diet therapy in Zambia for the management of paediatric refractory epilepsy.

Ketogenic diets for drug-resistant epilepsy

BACKGROUND

Ketogenic diets (KDs) are high in fat and low in carbohydrates and have been suggested to reduce seizure frequency in people with epilepsy. Such diets may be beneficial for children with drug-resistant epilepsy. This is an update of a review first published in 2003, and last updated in 2018.

OBJECTIVES

To assess the effects of ketogenic diets for people with drug-resistant epilepsy.

SEARCH METHODS

For this update, we searched the Cochrane Register of Studies (CRS Web) and MEDLINE (Ovid, 1946 to 26 April 2019) on 29 April 2019. The Cochrane Register of Studies includes the Cochrane Epilepsy Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), and randomised controlled trials (RCTs) from Embase, ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We imposed no language restrictions. We checked the reference lists of retrieved studies for additional relevant studies.

SELECTION CRITERIA

RCTs or quasi-RCTs of KDs for people of any age with drug-resistant epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied predefined criteria to extract data and evaluated study quality. We assessed the outcomes: seizure freedom, seizure reduction (50% or greater reduction in seizure frequency), adverse effects, cognition and behaviour, quality of life, and attrition rate. We incorporated a meta-analysis. We utilised an intention-to-treat (ITT) population for all primary analyses. We presented the results as risk ratios (RRs) with 95% confidence intervals (CIs).

MAIN RESULTS

We identified 13 studies with 932 participants; 711 children (4 months to 18 years) and 221 adults (16 years and over). We assessed all 13 studies to be at high risk of performance and detection bias, due to lack of blinding. Assessments varied from low to high risk of bias for all other domains. We rated the evidence for all outcomes as low to very low certainty. Ketogenic diets versus usual care for children Seizure freedom (RR 3.16, 95% CI 1.20 to 8.35; P = 0.02; 4 studies, 385 participants; very low-certainty evidence) and seizure reduction (RR 5.80, 95% CI 3.48 to 9.65; P < 0.001; 4 studies, 385 participants; low-certainty evidence) favoured KDs (including: classic KD, medium-chain triglyceride (MCT) KD combined, MCT KD only, simplified modified Atkins diet (MAD) compared to usual care for children. We are not confident that these estimated effects are accurate. The most commonly reported adverse effects were vomiting, constipation and diarrhoea for both the intervention and usual care group, but the true effect could be substantially different (low-certainty evidence). Ketogenic diet versus usual care for adults In adults, no participants experienced seizure freedom. Seizure reduction favoured KDs (MAD only) over usual care but, again, we are not confident that the effect estimated is accurate (RR 5.03, 95% CI 0.26 to 97.68; P = 0.29; 2 studies, 141 participants; very low-certainty evidence). Adults receiving MAD most commonly reported vomiting, constipation and diarrhoea (very low-certainty evidence). One study reported a reduction in body mass index (BMI) plus increased cholesterol in the MAD group. The other reported weight loss. The true effect could be substantially different to that reported. Ketogenic diet versus ketogenic diet for children Up to 55% of children achieved seizure freedom with a classical 4:1 KD after three months whilst up to 85% of children achieved seizure reduction (very low-certainty evidence). One trial reported a greater incidence of seizure reduction with gradual-onset KD, as opposed to fasting-onset KD. Up to 25% of children were seizure free with MAD and up to 60% achieved seizure reduction. Up to 25% of children became seizure free with MAD and up to 60% experienced seizure reduction. One study used a simplified MAD (sMAD) and reported that 15% of children gained seizure freedom rates and 56% achieved seizure reduction. We judged all the evidence described as very low certainty, thus we are very unsure whether the results are accurate. The most commonly reported adverse effects were vomiting, constipation and diarrhoea (5 studies, very low-certainty evidence). Two studies reported weight loss. One stated that weight loss and gastrointestinal disturbances were more frequent, with 4:1 versus 3:1 KD, whilst one reported no difference in weight loss with 20 mg/d versus 10 mg/d carbohydrates. In one study, there was a higher incidence of hypercalcuria amongst children receiving classic KD compared to MAD. All effects described are unlikely to be accurate. Ketogenic diet versus ketogenic diet for adults One study randomised 80 adults (aged 18 years and over) to either MAD plus KetoCal during the first month with MAD alone for the second month, or MAD alone for the first month followed by MAD plus KetoCal for the second month. No adults achieved seizure freedom. More adults achieved seizure reduction at one month with MAD alone (42.5%) compared to MAD plus KetoCal (32.5%), however, by three months only 10% of adults in both groups maintained seizure reduction. The evidence for both outcomes was of very low certainty; we are very uncertain whether the effects are accurate. Constipation was more frequently reported in the MAD plus KetoCal group (17.5%) compared to the MAD only group (5%) (1 study, very low-certainty evidence). Diarrhoea and increase/change in seizure pattern/semiology were also commonly reported (17.5% to 20% of participants). The true effects of the diets could be substantially different to that reported.

AUTHORS' CONCLUSIONS

The evidence suggests that KDs could demonstrate effectiveness in children with drug-resistant epilepsy, however, the evidence for the use of KDs in adults remains uncertain. We identified a limited number of studies which all had small sample sizes. Due to the associated risk of bias and imprecision caused by small study populations, the evidence for the use of KDs was of low to very low certainty. More palatable but related diets, such as the MAD, may have a similar effect on seizure control as the classical KD, but could be associated with fewer adverse effects. This assumption requires more investigation. For people who have drug-resistant epilepsy or who are unsuitable for surgical intervention, KDs remain a valid option. Further research is required, particularly for adults with drug-resistant epilepsy.

Ketogenic diet for the treatment of pediatric epilepsy: review and meta-analysis

The ketogenic diet (KD), containing high levels of fat and low levels of carbohydrates, has been used to treat refractory epilepsy since the 1920s. In the past few decades, there has been more interest in less restrictive KDs such as the modified Atkins diet (MAD).

PURPOSE

Our aim was to review all evidence regarding the efficacy and tolerability of the KD and MAD from randomized controlled trials (RCTs) in children and adolescents with refractory epilepsy.

METHODS

We reviewed the current literature using Cochrane, EMBASE, and MEDLINE (using PubMed). We implemented predefined criteria regarding dataextraction and study quality.

RESULTS

We identified five RCTs that generated seven publications and recruited 472 children and adolescents with refractory epilepsy (≤ 18 years). The primary outcome (seizure frequency reduction (SFR) ≥ 50%) was attained in 35-56.1% of the participants in the intervention group, compared with 6-18.2% in the control group. Our meta-analysis underlined the significant efficacy of the KD compared with the control group: RR = 5.1 (95% CI 3.18-8.21, p < 0.001). Additionally, only two studies mentioned possible biomarkers to objectively evaluate the efficacy. Secondary outcomes, such as seizure severity and quality of life, were studied in three trials, leading to indecisive generalization of these findings. Gastro-intestinal adverse effects were the most prevalent, and no severe adverse effects were reported.

CONCLUSION

Despite the heterogeneity between all studies, the beneficial results underline that dietary interventions should be considered for children and adolescents with refractory epilepsy who are not eligible for epilepsy surgery. Future studies should be multi-center and long-term, and evaluate potential biomarkers and adverse effects.

Ketogenic food pyramid for patients with refractory epilepsy: From theory to clinical practice

ABSTRACT Objective: To develop a graphical representation in the form of a food pyramid for a ketogenic diet for dietary treatment in children and adolescents with refractory epilepsy. Methods: The pyramid was constructed based on: the estimation of energy requirements for different age groups, macronutrient distribution, food groups, and the number of servings and respective amounts of food according to the ketogenic diet. Serving sizes were based on the calculation of energy and macronutrient requirements according to age and nutritional status. Results: The pyramid was divided into three tiers and 5 food groups (fats, proteins, type 1 vegetables, type 2 vegetables, and fruits). Four portion size lists were defined for the following age groups: 1-3 years, 4-6 years, 7-10 years, and 11-19 years. Conclusion: The ketogenic diet food pyramid can be used as nutritional guidance for patients undergoing this dietary therapy by illustrating the variety of foods that can be eaten during the treatment, optimizing adherence to the treatment, and guaranteeing beneficial effects on seizure control.

A randomized controlled trial of the ketogenic diet in refractory childhood epilepsy

OBJECTIVE

To evaluate the efficacy and tolerability of the ketogenic diet (KD) during the first 4 months of a randomized controlled trial (RCT) in refractory epilepsy patients aged 1-18 years.

METHODS

Children and adolescents with refractory epilepsy, not eligible for epilepsy surgery, were included. Following 1 month at baseline, patients were randomized to either the KD or to care as usual (CAU).Primary outcome is the proportion of patients with at least 50% reduction in seizure frequency at 4 months. Secondary outcomes are mean percentage of baseline seizures, seizure severity, and side effects.

RESULTS

Fifty-seven patients were randomized; nine dropped out, leaving 48 for analysis (i.e., 26 KD, 22 CAU). In an intention-to-treat analysis, 13 patients (50%) treated with the KD and four patients (18.2%) of the CAU group were responders.Mean seizure frequency at 4 months compared to baseline, after removal of two outliers in the KD group, was significantly lower (P = 0.024) in the KD group (56%) (95% CI: 36-76) than in the CAU group (99%) (95% CI: 65-133%).Twice as many patients in the KD group had a relevant decrease in seizure severity score (P = 0.070).Patients treated with the KD had a significantly higher score for gastrointestinal symptoms (P = 0.021) without an increase in the total score of side effects.

CONCLUSIONS

This trial provides class I evidence that the KD is an effective therapy in children and adolescents with refractory epilepsy compared with CAU. Most often reported side effects are gastrointestinal symptoms.The study has been registered with the Netherlands Trial Registry (NTR2498).

A systematic review of economic evaluations of treatments for patients with epilepsy

The increasing number of treatment options and the high costs associated with epilepsy have fostered the development of economic evaluations in epilepsy. It is important to examine the availability and quality of these economic evaluations and to identify potential research gaps. As well as looking at both pharmacologic (antiepileptic drugs [AEDs]) and nonpharmacologic (e.g., epilepsy surgery, ketogenic diet, vagus nerve stimulation) therapies, this review examines the methodologic quality of the full economic evaluations included. Literature search was performed in MEDLINE, EMBASE, NHS Economic Evaluation Database (NHS EED), Econlit, Web of Science, and CEA Registry. In addition, Cochrane Reviews, Cochrane DARE and Cochrane Health Technology Assessment Databases were used. To identify relevant studies, predefined clinical search strategies were combined with a search filter designed to identify health economic studies. Specific search strategies were devised for the following topics: (1) AEDs, (2) patients with cognitive deficits, (3) elderly patients, (4) epilepsy surgery, (5) ketogenic diet, (6) vagus nerve stimulation, and (7) treatment of (non)convulsive status epilepticus. A total of 40 publications were included in this review, 29 (73%) of which were articles about pharmacologic interventions. Mean quality score of all articles on the Consensus Health Economic Criteria (CHEC)-extended was 81.8%, the lowest quality score being 21.05%, whereas five studies had a score of 100%. Looking at the Consolidated Health Economic Evaluation Reporting Standards (CHEERS), the average quality score was 77.0%, the lowest being 22.7%, and four studies rated as 100%. There was a substantial difference in methodology in all included articles, which hampered the attempt to combine information meaningfully. Overall, the methodologic quality was acceptable; however, some studies performed significantly worse than others. The heterogeneity between the studies stresses the need to define a reference case (e.g., how should an economic evaluation within epilepsy be performed) and to derive consensus on what constitutes "standard optimal care."

Ketogenic Diet Decreases Emergency Room Visits and Hospitalizations Related to Epilepsy

Background. Approximately, one-third of patients with epilepsy are refractory to pharmacological treatment which mandates extensive medical care and imposes significant economic burden on patients and their societies. This study intends to assess the impact of the treatment with ketogenic diet (KD) on reducing seizure-related emergency room visits and hospitalizations in children with refractory epilepsy. Methods. This is a retrospective review of children treated with the KD in one tertiary center. We compared a 12 months' period prior to KD with 12 months after the diet was started in regard to the number of emergency department (ED) visits, hospitalizations, and hospital days as well as their associated charges. Results. 37 patients (57% males) were included. Their ages at time of KD initiation were (4.0 ± 2.78) years. Twelve months after the KD initiation, the total number of ED visits was reduced by 36% with a significant decrease of associated charges (p = 0.038). The number of hospital admissions was reduced by 40% and the number of hospital days was reduced by 39%. The cumulative charges showed net cost savings after 9 months when compared to the prediet baseline. Conclusion. In children with refractory epilepsy, treatment with the ketogenic diet reduces the number of ED visits and hospitalizations and their corresponding costs.

Cognitive and behavioral impact of the ketogenic diet in children and adolescents with refractory epilepsy: A randomized controlled trial

PURPOSE

The ketogenic diet (KD) is increasingly used for the treatment of refractory epilepsy in childhood because of the beneficial effect on seizure reduction. The aim of the current study was to objectively assess cognition and aspects of behavior during the first 4months of a randomized controlled study in children and adolescents.

METHODS

Participants from a tertiary epilepsy center were randomized to a KD group (intervention) or a care-as-usual (CAU) group (control). Follow-up assessments on cognition and behavior were performed approximately 4months after initiation of the KD with a combination of parent report questionnaires and individually administered psychological tests for the children.

RESULTS

A total of 50 patients were enrolled in this study, 28 patients from the KD group and 22 patients from the CAU group. The KD group showed lower levels of anxious and mood-disturbed behavior and was rated as more productive. Cognitive test results showed an improvement of activation in the KD group.

CONCLUSIONS

This study showed a positive impact of the KD on behavioral and cognitive functioning in children and adolescents with refractory epilepsy. More specifically, an activated mood and cognitive activation were observed in patients treated with the KD.

Ketogenic diet in epileptic children: impact on lipoproteins and oxidative stress

OBJECTIVES

Ketogenic diet (KD) is an important therapy used in the control of drug-refractory seizures. The major goal of this review is to update the knowledge about the adverse effects of KD on lipoproteins, lipid profile, and cardiometabolic risk.

METHODS

Articles on the effect of the KD on plasma lipoproteins of children and adolescents with refractory epilepsy, which were published in the past 15 years and indexed in the PubMed and MedLine databases, were included.

RESULTS

Dyslipidemia was recurrent in children, and adolescents treated with KD. Evidence suggests that hypercholesterolemia promotes structural modifications in low-density lipoprotein particles. Such modifications possibly favor oxidative processes and contribute to changes in the size of lipoproteins, particularly related to small and denser LDL. However, oxidative modifications in LDL of children on KD are not described in the literature.

DISCUSSION

The positive effects of KD on the health of children and adolescents with refractory epilepsy are unquestionable. Conversely, this positive role is associated with significant and negative changes in lipid metabolism. Moreover, the positive effects are possibly related to oxidative reactions and unbalance of antioxidants that can contribute to an increased cardiometabolic risk. Therefore, this review invites clinicians and researchers to investigate the lipid and oxidative metabolism in their clinical practice and trials, respectively.

First Application of Ketogenic Diet on a Child With Intractable Epilepsy in Ghana

The prevalence of epilepsy in sub-Saharan Africa is higher than in other parts of the world, but it is short of the effective measure on treating intractable epilepsy. Epilepsy surgery is not easy to be performed due to the high cost and demand of operational skills. The authors planned to perform ketogenic diet therapy for the children with intractable epilepsy in Ghana with regard to its low cost and simple procedure. The candidate is a 10-month-old girl with epilepsy with unknown etiology. Her seizures couldn't be controlled by more than 3 antiepileptic drugs. Her development delayed severely due to frequent seizures. The authors successfully applied ketogenic diet for her. Her seizures were completely controlled after 2 weeks' therapy. Her mental condition was improved after that. The authors get much experience from this case for further developing ketogenic diet in Africa. This is the first report that ketogenic diet was applied to control intractable epilepsy in West Africa.

Neurobiochemical mechanisms of a ketogenic diet in refractory epilepsy

A ketogenic diet is an important therapy used in the control of drug-refractory seizures. Many studies have shown that children and adolescents following ketogenic diets exhibit an over 50% reduction in seizure frequency, which is considered to be clinically relevant. These benefits are based on a diet containing high fat (approximately 90% fat) for 24 months. This dietary model was proposed in the 1920s and has produced variable clinical responses. Previous studies have shown that the mechanisms underlying seizure control involve ketone bodies, which are produced by fatty acid oxidation. Although the pathways involved in the ketogenic diet are not entirely clear, the main effects of the production of ketone bodies appear to be neurotransmitter modulation and antioxidant effects on the brain. This review highlights the impacts of the ketogenic diet on the modulation of neurotransmitters, levels of biogenic monoamines and protective antioxidant mechanisms of neurons. In addition, future perspectives are proposed.