Nutritional habits, risk, and progression of Parkinson disease

The complex relationship between obesity and neurodegenerative diseases: an updated review

Obesity is a global epidemic, affecting roughly 30% of the world's population and predicted to rise. This disease results from genetic, behavioral, societal, and environmental factors, leading to excessive fat accumulation, due to insufficient energy expenditure. The adipose tissue, once seen as a simple storage depot, is now recognized as a complex organ with various functions, including hormone regulation and modulation of metabolism, inflammation, and homeostasis. Obesity is associated with a low-grade inflammatory state and has been linked to neurodegenerative diseases like multiple sclerosis (MS), Alzheimer's (AD), and Parkinson's (PD). Mechanistically, reduced adipose expandability leads to hypertrophic adipocytes, triggering inflammation, insulin and leptin resistance, blood-brain barrier disruption, altered brain metabolism, neuronal inflammation, brain atrophy, and cognitive decline. Obesity impacts neurodegenerative disorders through shared underlying mechanisms, underscoring its potential as a modifiable risk factor for these diseases. Nevertheless, further research is needed to fully grasp the intricate connections between obesity and neurodegeneration. Collaborative efforts in this field hold promise for innovative strategies to address this complex relationship and develop effective prevention and treatment methods, which also includes specific diets and physical activities, ultimately improving quality of life and health.

Common and Trace Metals in Alzheimer's and Parkinson's Diseases

Trace elements and metals play critical roles in the normal functioning of the central nervous system (CNS), and their dysregulation has been implicated in neurodegenerative disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD). In a healthy CNS, zinc, copper, iron, and manganese play vital roles as enzyme cofactors, supporting neurotransmission, cellular metabolism, and antioxidant defense. Imbalances in these trace elements can lead to oxidative stress, protein aggregation, and mitochondrial dysfunction, thereby contributing to neurodegeneration. In AD, copper and zinc imbalances are associated with amyloid-beta and tau pathology, impacting cognitive function. PD involves the disruption of iron and manganese levels, leading to oxidative damage and neuronal loss. Toxic metals, like lead and cadmium, impair synaptic transmission and exacerbate neuroinflammation, impacting CNS health. The role of aluminum in AD neurofibrillary tangle formation has also been noted. Understanding the roles of these elements in CNS health and disease might offer potential therapeutic targets for neurodegenerative disorders. The Codex Alimentarius standards concerning the mentioned metals in foods may be one of the key legal contributions to safeguarding public health. Further research is needed to fully comprehend these complex mechanisms and develop effective interventions.

Mediterranean diet is associated with a lower probability of prodromal Parkinson's disease and risk for Parkinson's disease/dementia with Lewy bodies: A longitudinal study

BACKGROUND AND PURPOSE

Lifestyle factors have been implicated in the long-lasting neurodegenerative process in prodromal Parkinson's disease (pPD). The aim was to investigate the associations between adherence to a Mediterranean diet (MeDi) and longitudinal changes of pPD probability and the development of Parkinson's disease (PD) or pPD in a Mediterranean older population.

METHODS

Data from the Hellenic Longitudinal Investigation of Aging and Diet cohort (community-dwelling individuals, aged ≥ 65 years) were used. A detailed food frequency questionnaire was used to evaluate dietary intake and calculate MeDi adherence score, ranging from 0 to 55, with higher scores indicating higher adherence. The probability of pPD was calculated according to the updated Movement Disorder Society research criteria.

RESULTS

In all, 1047 non-PD/dementia with Lewy bodies (DLB) participants were followed for 3 ± 1 years. MeDi adherence was associated with lower increase in pPD probability over time (b = -0.003, 95% confidence interval -0.006 to -0.001, p = 0.010). Forty-nine participants had incident possible/probable pPD (i.e., pPD probability ≥ 30%). Compared to the participants in the lowest quartile of MeDi adherence, those in the higher quartiles had an approximately 60%-70% lower risk for possible/probable pPD (p for trend 0.003). MeDi-pPD associations were driven by both motor and non-motor pPD markers and not from risk markers. Also, 21 participants were diagnosed with PD/DLB at follow-up. For each unit increase in the MeDi score, there was a 9%-10% lower risk for PD/DLB (hazard ratio 0.906 [95% confidence interval 0.823-0.997], p = 0.044).

CONCLUSIONS

Mediterranean diet adherence is associated with lower increase in pPD probability over time and lower possible/probable pPD and PD/DLB incidence in older Mediterranean people. More studies are needed to confirm our results in other populations.

Epidemiology of neurodegenerative diseases in the East African region: A meta-analysis

INTRODUCTION

There is a scarcity of epidemiological data on neurodegenerative diseases (NDs) in East Africa. This meta-analysis provides the regional prevalence of NDs, their contributing factors, and evidence of change over time concerning gender per age or year.

METHODS

Articles were retrieved from electronic databases following the PRISMA standard.

RESULTS

Forty-two studies were reviewed, and 25 were meta-analyzed with a random-effects model. The pool estimate proportion of 15.27%, 95% CI (0.09-0.23) (I² = 98.25%), (Q = 1,369.15, p < 0.0001) among a population of 15,813 male/female and 1,257 with NDs. Epidemiological characteristics associated with NDs include Dyskinesias prevalence 55.4%, 95% CI (13.5; 90.9), I² (96%) and subsistence farming prevalence 11.3%, 95% CI (5.8; 20.9), I² (99%). Publication bias by Egger test was (z = 4.1913, p < 0.0001), while rank correlation test using Kendall's model was (tau = 0.1237, p = 0.3873). Heterogeneity (R² design = 5.23%, p design < 0.0001; R² size = 52.163%, p size < 0.001; and R² period = 48.13, p period < 0.0001. Covariates (R² design + size + period = 48.41%, p < 0.001).

CONCLUSION

There is a high prevalence of NDs in the East African region, which could impact life expectancy, morbidity, and quality of life. Thus, early screening and regular surveillance could assist in management strategies.

Antibiotic Consumption Patterns in European Countries Are Associated with the Prevalence of Parkinson’s Disease; the Possible Augmenting Role of the Narrow-Spectrum Penicillin

Parkinson’s disease: Parkinson’s disease (PD) is the second-most common neurodegenerative disease, affecting at least 0.3% of the worldwide population and over 3% of those over 80 years old. According to recent research (2018), in 2016, 6.1 million (95% uncertainty interval (UI) 5.0–7.3) individuals had Parkinson’s disease globally, compared with 2.5 million (2.0–3.0) in 1990. The pandemic-like spreading of PD is considered a slow-moving disaster. Most recent studies indicated the possible role of an altered microbiome, dysbiosis, in the development of PD, which occurs long before the clinical diagnosis of PD. Antibiotics are considered as major disruptors of the intestinal flora and we have hypothesized that, as different classes of antibiotics might induce different dysbiosis, certain classes of antibiotics could trigger the PD-related dysbiosis as well. Comparative analyses were performed between the average yearly antibiotic consumption of 30 European countries (1997–2016) and the PD prevalence database (estimated for 2016). We divided the time frame of antibiotic consumption of 1997–2016 into four subsections to estimate the possible time lapse between antibiotic exposure and the prevalence, prevalence change, and PD-related death rates estimated for 2016. Our results indicated that countries with high consumption of narrow-spectrum penicillin experienced a higher increase in PD prevalence than the others. Countries reporting a decline in PD from 1990 to 2016 demonstrated a reduction in the consumption of narrow-spectrum penicillin in this period.

Dietary Insights in Neurological Diseases

PURPOSE OF REVIEW

Dietary interventions may play a role in the pathophysiology of common neurological disorders such as Alzheimer's disease, Parkinson's disease, stroke, migraines, multiple sclerosis, and epilepsy. This article describes the most common and impactful dietary regimens for commonly encountered neurological disorders.

RECENT FINDINGS

Plant-based, low-fat, high-fiber diets, rich in antioxidants and other lifestyle interventions may reduce the burden and disability of common neurological disorders. The ketogenic diet, the diet of choice for the treatment of refractory epilepsy, is such an example. Diverse neurological disorders demonstrate several common pathophysiological mechanisms including increased oxidative stress, neuroinflammation, and disrupted metabolism. Dietary interventions can potentially influence these pathophysiological processes and thus favorably alter clinical outcomes. Adequate dietary choices should be considered as part of a continuum of healthy lifestyle choices.

Prediction of Parkinson's Disease Risk Based on Genetic Profile and Established Risk Factors

Background: Parkinson’s disease (PD) is a neurodegenerative disorder, and literature suggests that genetics and lifestyle/environmental factors may play a key role in the triggering of the disease. This study aimed to evaluate the predictive performance of a 12-Single Nucleotide Polymorphisms (SNPs) polygenic risk score (PRS) in combination with already established PD-environmental/lifestyle factors. Methods: Genotypic and lifestyle/environmental data on 235 PD-patients and 464 controls were obtained from a previous study carried out in the Cypriot population. A PRS was calculated for each individual. Univariate logistic-regression analysis was used to assess the association of PRS and each risk factor with PD-status. Stepwise-regression analysis was used to select the best predictive model for PD combining genetic and lifestyle/environmental factors. Results: The 12-SNPs PRS was significantly increased in PD-cases compared to controls. Furthermore, univariate analyses showed that age, head injury, family history, depression, and Body Mass Index (BMI) were significantly associated with PD-status. Stepwise-regression suggested that a model which includes PRS and seven other independent lifestyle/environmental factors is the most predictive of PD in our population. Conclusions: These results suggest an association between both genetic and environmental factors and PD, and highlight the potential for the use of PRS in combination with the classical risk factors for risk prediction of PD.

Effects of Dietary Food Components on Cognitive Functions in Older Adults

Population aging has recently been an important issue as the number of elderly people is growing worldwide every year, and the extension of social security costs is financially costly. The increase in the number of elderly people with cognitive decline is a serious problem related to the aging of populations. Therefore, it is necessary to consider not only physical care but also cognitive patterns in the future care of older adults. Since food contains a variety of bioactive substances, dietary patterns may help improve age-related cognitive decline. However, the relationship between cognitive function and individual food components remains ambiguous as no clear efficacy or mechanism has been confirmed. Against this background, this review summarizes previous reports on the biological process of cognitive decline in the elderly and the relationship between individual compounds in foods and cognitive function, as well as the role of individual components of food in cognitive function, in the following order: lipids, carotenoids, vitamins, phenolic compounds, amino acids, peptides, and proteins. Based on the research presented in this review, a proper diet that preserves cognitive function has the potential to improve age-related cognitive decline, Alzheimer's disease, and Parkinson's disease. Hopefully, this review will help to trigger the development of new foods and technologies that improve aging and cognitive functions and extend the healthy life span.

Mechanisms Underlying the Biological Effects of Molecular Hydrogen

Aberrant redox-sensitive reactions and accumulation of oxidative damage can impair body functions and contribute to the development of various pathologies and aging. Although antioxidant substances have long been recognized as a measure of alleviating oxidative stress and restoring redox balance, the arsenal of effective means of preventing the development of various disorders, is still limited. There is an emerging field that utilizes molecular hydrogen (H₂) as a scavenger of free radicals and reactive oxygen species (ROS). Among the remarkable characteristics of H₂ is its ability to counteract the harmful effects of hydroxyl radical and peroxynitrite without affecting the activity of functionally important ROS, such as hydrogen peroxide and nitric oxide. The beneficial effects of H₂ have been documented in numerous clinical studies and studies on animal models and cell cultures. However, the established scavenging activity of H₂ can only partially explain its beneficial effects because the effects are achieved at very low concentrations of H₂. Given the rate of H₂ diffusion, such low concentrations may not be sufficient to scavenge continuously generated ROS. H₂ can also act as a signaling molecule and induce defense responses. However, the exact targets and mechanism(s) by which H₂ exerts these effects are unknown. Here, we analyzed both positive and negative effects of the endogenous H₂, identified the redox-sensitive components of the pathways affected by molecular hydrogen, and also discussed the potential role of molecular hydrogen in regulating cellular redox.

Nutritional aspects in Parkinson's disease

The links between diet and Parkinson's disease (PD) are unclear and incomprehensible. However, numerous studies have demonstrated the correlation between diet, nutrients and health condition in PD patients. They indicate the possibility of management of the disease, which might be possible through nutrition. Pharmaceutical treatment as well as a complementary holistic approach to the patients should be considered. It is of critical importance to understand how the diet and nutrients might influence PD. A better understanding of the relationship between diet and PD could help to better manage the disease explain promising therapeutic approaches, minimize motor and nonmotor symptoms and disease progression based on a personalized diet. In this review, the recent literature on the observed nutrition disorders and the possible role of diet and nutrients in the prevention and potential regression of PD, as well as dietary interventions and supplementation used to manage the disease is revised.

Plant-Based Nutritional Supplementation Attenuates LPS-Induced Low-Grade Systemic Activation

Plant-based nutritional supplementation has been shown to attenuate and reduce mortality in the processes of both acute and chronic disorders, including diabetes, obesity, cardiovascular disease, cancer, inflammatory diseases, and neurological and neurodegenerative disorders. Low-level systemic inflammation is an important contributor to these afflictions and diets enriched in phytochemicals can slow the progression. The goal of this study was to determine the impact of lipopolysaccharide (LPS)-induced inflammation on changes in glucose and insulin tolerance, performance enhancement, levels of urinary neopterin and concentrations of neurotransmitters in the striatum in mouse models. Both acute and chronic injections of LPS (2 mg/kg or 0.33 mg/kg/day, respectively) reduced glucose and insulin tolerance and elevated neopterin levels, which are indicative of systemic inflammatory responses. In addition, there were significant decreases in striatal neurotransmitter levels (dopamine and DOPAC), while serotonin (5-HT) levels were essentially unchanged. LPS resulted in impaired execution in the incremental loading test, which was reversed in mice on a supplemental plant-based diet, improving their immune function and maintaining skeletal muscle mitochondrial activity. In conclusion, plant-based nutritional supplementation attenuated the metabolic changes elicited by LPS injections, causing systemic inflammatory activity that contributed to both systemic and neurological alterations.

Is Gut Dysbiosis an Epicenter of Parkinson's Disease?

Once recognized as one of the most esoteric diseases of the central nervous system, Parkinson's disease (PD) is now deemed to be a chronic illness contributed by the central, autonomic and enteric nervous systems. Most likely, an accumulation of α-synuclein in the central and enteric nervous systems is the key that supports this viewpoint. Constipation, one of the non-motor hallmarks in roughly two-third of PD patients, is regulated by the composition of gut bacteria, which is assumed to set off the enteric α-synuclein accrual. Vagus nerve is suggested to direct the signal for α-synuclein over-expression and accumulation to the brain. While trillions of microorganisms reside in the intestinal tract, only one third of the proportion inhabits evenly in all individuals. Existence of an impaired gut-microbe-brain axis consonant with dysbiosis could be an epicenter of this inexplicable disorder. Any alteration in the structure and function of the gastrointestinal tract owing to exposure of endogenous or exogenous chemicals or toxicants could lead to dysbiosis. However, inconsistency in the symptoms even after exposure to same chemical or toxicant in PD patients emphatically creates a conundrum. While the level of a few specific neurotransmitters and metabolites is influenced by microbes, implication of dysbiosis is still debatable. Nevertheless, the scientific literature is overflowing with the remarkable observations supporting the role of dysbiosis in PD. Lack of specificity to differentially diagnose PD with non-PD or PD-plus syndrome, to identify highly precise drug targets and to develop therapeutic stratagems to encounter the disease on the basis of this approach, causes us to be open-minded about the dysbiosis theory. The article reviews the facts supporting gut dysbiosis as the foremost trigger for PD onset along with disagreements.

Role and Mechanism of Vitamin A Metabolism in the Pathophysiology of Parkinson's Disease

Evidence shows that altered retinoic acid signaling may contribute to the pathogenesis and pathophysiology of Parkinson's disease (PD). Retinoic acid is the bioactive derivative of the lipophilic vitamin A. Vitamin A is involved in several important homeostatic processes, such as cell differentiation, antioxidant activity, inflammation and neuronal plasticity. The role of vitamin A and its derivatives in the pathogenesis and pathophysiology of neurodegenerative diseases, and their potential as therapeutics, has drawn attention for more than 10 years. However, the literature sits in disparate fields. Vitamin A could act at the crossroad of multiple environmental and genetic factors of PD. The purpose of this review is to outline what is known about the role of vitamin A metabolism in the pathogenesis and pathophysiology of PD. We examine key biological systems and mechanisms that are under the control of vitamin A and its derivatives, which are (or could be) exploited for therapeutic potential in PD: the survival of dopaminergic neurons, oxidative stress, neuroinflammation, circadian rhythms, homeostasis of the enteric nervous system, and hormonal systems. We focus on the pivotal role of ALDH1A1, an enzyme expressed by dopaminergic neurons for the detoxification of these neurons, which is under the control of retinoic acid. By providing an integrated summary, this review will guide future studies on the potential role of vitamin A in the management of symptoms, health and wellbeing for PD patients.

Effect of family history, occupation and diet on the risk of Parkinson disease: A case-control study

BACKGROUND

The aetiology of Parkinson's disease (PD) is still very controversial, with a peculiar lack of established risk factors or protective behavior.

METHODS

We carried out a case-control study of 634 idiopathic PD patients admitted from 2011 to 2015 to two hospitals located in central Italy and 532 controls matched by hospital, gender and age (± 5 years). The study questionnaire included questions on host factors, family history, residence, occupation and lifestyle. Odds ratios (ORs) for PD and 95% confidence intervals (CIs) were estimated with logistic regression, adjusting for actual and potential confounders.

RESULTS

A lower OR was observed in females (0.74; 95%CI:0.58-0.96), while older age classes showed a constantly increased risk for PD (p<0.005) starting from the class 65-69 years. Subjects who reported a first degree relative affected by PD showed a borderline increase which was more evident in those enrolled in the urban center of Rome (OR = 1.65; 95%CI: 1.09-2.50). Significant reduction of the risk was associated to current smoking (OR = 0.48; 95%CI: 0.24-0.54), and to vegetables consumption (p<0.03), while borderline increases were associated to meat and cold cut consumption. Occupational activities classified according to ISCO-08 categories did not show increased risk, while higher ORs' were found for pilots and physicians.

CONCLUSIONS

The results from this study confirmed the higher risk of PD in males and in elderly, and the inverse association with smoking habit. The possible etiological role of familial clustering, dietary habit, and some job tasks is suggested.

Diet Quality and Risk of Parkinson's Disease: A Prospective Study and Meta-Analysis

BACKGROUND

Several dietary components have been shown to be neuroprotective against risk of neurodegeneration. However, limited observational studies have examined the role of overall diet quality on risk of Parkinson's disease.

OBJECTIVES

We examined the associations between diet quality and risk of Parkinson's disease in a prospective cohort study and meta-analysis.

METHODS

Included in the cohort study were 3,653 participants (1,519 men and 2,134 women; mean age: 81.5 years) in the Geisinger Rural Aging Study longitudinal cohort in Pennsylvania. Diet quality was assessed using a validated dietary screening tool containing 25 food- and behavior-specific questions in 2009. Potential Parkinson's cases were identified using electronic health records based on ICD9 (332.*), ICD10 (G20), and Parkinson-related treatments. Hazard ratios (HRs) and 95% confidence intervals (CIs) across diet quality tertiles were calculated using Cox proportional hazards models after adjusting for potential confounders. We further performed a meta-analysis by pooling our study with four published papers on this topic. Random-effects model was utilized to calculate the pooled risk ratios and 95% CIs.

RESULTS

During a mean of 6.94 years of follow-up, 47 incident Parkinson's cases were documented. Having high diet quality at baseline was associated with lower Parkinson's disease risk (adjusted HR for the highest vs the lowest diet quality tertile = 0.39; 95% CI: 0.17, 0.89; p-trend = 0.02). The meta-analysis including 140,617 individuals also showed that adherence to high diet quality or a healthy dietary pattern was associated with lower risk of Parkinson's disease (pooled risk ratio = 0.64; 95% CI: 0.49, 0.83).

CONCLUSION

Having high diet quality or a healthy dietary pattern was associated with lower future risk of Parkinson's disease.

Diet, Microbiota and Brain Health: Unraveling the Network Intersecting Metabolism and Neurodegeneration

Increasing evidence gives support for the idea that extra-neuronal factors may affect brain physiology and its predisposition to neurodegenerative diseases. Epidemiological and experimental studies show that nutrition and metabolic disorders such as obesity and type 2 diabetes increase the risk of Alzheimer's and Parkinson's diseases after midlife, while the relationship with amyotrophic lateral sclerosis is uncertain, but suggests a protective effect of features of metabolic syndrome. The microbiota has recently emerged as a novel factor engaging strong interactions with neurons and glia, deeply affecting their function and behavior in these diseases. In particular, recent evidence suggested that gut microbes are involved in the seeding of prion-like proteins and their spreading to the central nervous system. Here, we present a comprehensive review of the impact of metabolism, diet and microbiota in neurodegeneration, by affecting simultaneously several aspects of health regarding energy metabolism, immune system and neuronal function. Advancing technologies may allow researchers in the future to improve investigations in these fields, allowing the buildup of population-based preventive interventions and development of targeted therapeutics to halt progressive neurologic disability.

The effect of the Mediterranean diet on cognitive function in patients with Parkinson's disease: A randomized clinical controlled trial

OBJECTIVES

Parkinson's disease (PD) is the second most common neurodegenerative disorder. It is proposed that adherence to the Mediterranean diet might have a beneficial effect on the prevention and treatment of PD and its complications. Thus, the aim of this study was to investigate the effects of the Mediterranean diet on cognitive function in patients with PD.

DESIGN

The study was a single-center, randomized clinical trial. Eighty patients with idiopathic PD were randomly allocated to the Mediterranean diet (n = 40) or control (n = 40) group. Patients in the intervention group received an individualized dietary plan based on Mediterranean diet for 10 weeks. The Persian version of Montreal Cognitive Assessment (MoCA) test was used to assess the cognitive function at baseline and the end of the study.

RESULTS

Thirty-five PD patients with a mean age of 59.3 ± 8.3 and 35 patients with a mean age of 58.6 ± 9.3 finished the study in intervention and control groups, respectively. After the intervention, the mean score of the dimensions of executive function, language, attention, concentration, and active memory and the total score of cognitive assessment significantly increased in the intervention compared with the control group (p < 0.05, for all). Nevertheless, the mean of the other scores including spatial-visual ability, memory learning task, and navigation versus time and place did not significantly change in both intervention and control groups.

CONCLUSIONS

The findings of this study showed that adherence to the Mediterranean diet remarkably increased the dimensions of executive function, language, attention, concentration, and active memory and finally the total score of cognitive assessment in PD patients.

Diet in Parkinson's Disease: Critical Role for the Microbiome

Background: Parkinson's disease (PD) is the most common movement disorder affecting up to 1% of the population above the age of 60 and 4–5% of those above the age of 85. Little progress has been made on efforts to prevent disease development or halt disease progression. Diet has emerged as a potential factor that may prevent the development or slow the progression of PD. In this review, we discuss evidence for a role for the intestinal microbiome in PD and how diet-associated changes in the microbiome may be a viable approach to prevent or modify disease progression.

Methods: We reviewed studies demonstrating that dietary components/foods were related to risk for PD. We reviewed evidence for the dysregulated intestinal microbiome in PD patients including abnormal shifts in the intestinal microbiota composition (i.e., dysbiosis) characterized by a loss of short chain fatty acid (SCFA) bacteria and increased lipopolysaccharide (LPS) bacteria. We also examined several candidate mechanisms by which the microbiota can influence PD including the NLRP3 inflammasome, insulin resistance, mitochondrial function, vagal nerve signaling.

Results: The PD-associated microbiome is associated with decreased production of SCFA and increased LPS and it is believed that these changes may contribute to the development or exacerbation of PD. Diet robustly impacts the intestinal microbiome and the Western diet is associated with increased risk for PD whereas the Mediterranean diet (including high intake of dietary fiber) decreases PD risk. Mechanistically this may be the consequence of changes in the relative abundance of SCFA-producing or LPS-containing bacteria in the intestinal microbiome with effects on intestinal barrier function, endotoxemia (i.e., systemic LPS), NLRP3 inflammasome activation, insulin resistance, and mitochondrial dysfunction, and the production of factors such as glucagon like peptide 1 (GLP-1) and brain derived neurotrophic factor (BDNF) as well as intestinal gluconeogenesis.

Conclusions: This review summarizes a model of microbiota-gut-brain-axis regulation of neuroinflammation in PD including several new mechanisms. We conclude with the need for clinical trials in PD patients to test this model for beneficial effects of Mediterranean based high fiber diets.

Exercise, diet and stress as modulators of gut microbiota: Implications for neurodegenerative diseases

The last decade has witnessed an exponentially growing interest in gut microbiota and the gut-brain axis in health and disease. Accumulating evidence from preclinical and clinical research indicate that gut microbiota, and their associated microbiomes, may influence pathogenic processes and thus the onset and progression of various diseases, including neurological and psychiatric disorders. In fact, gut dysbiosis (microbiota dysregulation) has been associated with a range of neurodegenerative diseases, including Alzheimer's, Parkinson's, Huntington's and motor neuron disease, as well as multiple sclerosis. The gut microbiota constitutes a dynamic microbial system constantly challenged by many biological variables, including environmental factors. Since the gut microbiota constitute a changeable and experience-dependent ecosystem, they provide potential therapeutic targets that can be modulated as new interventions for dysbiosis-related disorders, including neurodegenerative diseases. This article reviews the evidence for environmental modulation of gut microbiota and its relevance to brain disorders, exploring in particular the implications for neurodegenerative diseases. We will focus on three major environmental factors that are known to influence the onset and progression of those diseases, namely exercise, diet and stress. Further exploration of environmental modulation, acting via both peripheral (e.g. gut microbiota and associated metabolic dysfunction or 'metabolopathy') and central (e.g. direct effects on CNS neurons and glia) mechanisms, may lead to the development of novel therapeutic approaches, such as enviromimetics, for a wide range of neurological and psychiatric disorders.

Enriched Environmental Conditions Modify the Gut Microbiome Composition and Fecal Markers of Inflammation in Parkinson's Disease

Recent findings suggest an implication of the gut microbiome in Parkinson's disease (PD) patients. PD onset and progression has also been linked with various environmental factors such as physical activity, exposure to pesticides, head injury, nicotine, and dietary factors. In this study, we used a mouse model, overexpressing the complete human SNCA gene (SNCA-TG mice) modeling familial and sporadic forms of PD to study whether environmental conditions such as standard vs. enriched environment changes the gut microbiome and influences disease progression. We performed 16S rRNA DNA sequencing on fecal samples for microbiome analysis and studied fecal inflammatory calprotectin from the colon of control and SNCA-TG mice kept under standard environment (SE) and enriched environment (EE) conditions. The overall composition of the gut microbiota was not changed in SNCA-TG mice compared with WT in EE with respect to SE. However, individual gut bacteria at genus level such as Lactobacillus sp. was a significant changed in the SNCA-TG mice. EE significantly reduced colon fecal inflammatory calprotectin protein in WT and SNCA-TG EE compared to SE. Moreover, EE reduces the pro-inflammatory cytokines in the feces and inflammation inducing genes in the colon. Our data suggest that an enriched social environment has a positive effect on the induction of SNCA mediated inflammation in the intestine and by modulating anti-inflammatory gut bacteria.

Nonpharmacological Modulation of Chronic Inflammation in Parkinson's Disease: Role of Diet Interventions

Neuroinflammation is increasingly recognized as an important pathophysiological feature of neurodegenerative diseases such as Parkinson's disease (PD). Recent evidence suggests that neuroinflammation in PD might originate in the intestine and the bidirectional communication between the central and enteric nervous system, the so-called "gut-brain axis," has received growing attention due to its contribution to the pathogenesis of neurological disorders. Diet targets mediators of inflammation with various mechanisms and combined with dopaminergic treatment can exert various beneficial effects in PD. Food-based therapies may favorably modulate gut microbiota composition and enhance the intestinal epithelial integrity or decrease the proinflammatory response by direct effects on immune cells. Diets rich in pre- and probiotics, polyunsaturated fatty acids, phenols including flavonoids, and vitamins, such as the Mediterranean diet or a plant-based diet, may attenuate chronic inflammation and positively influence PD symptoms and even progression of the disease. Dietary strategies should be encouraged in the context of a healthy lifestyle with physical activity, which also has neuroimmune-modifying properties. Thus, diet adaptation appears to be an effective additive, nonpharmacological therapeutic strategy that can attenuate the chronic inflammation implicated in PD, potentially slow down degeneration, and thereby modify the course of the disease. PD patients should be highly encouraged to adopt corresponding lifestyle modifications, in order to improve not only PD symptoms, but also general quality of life. Future research should focus on planning larger clinical trials with dietary interventions in PD in order to obtain hard evidence for the hypothesized beneficial effects.

Nutritional Risk Factors, Microbiota and Parkinson's Disease: What Is the Current Evidence?

Parkinson’s disease (PD) is a frequent neurodegenerative disease among elderly people. Genetic and underlying environmental factors seem to be involved in the pathogenesis of PD related to degeneration of dopaminergic neurons in the striatum. In previous experimental researches oxidative stress, mitochondrial dysfunction, homocysteine, and neuroinflammation have been reported as potential mechanisms. Among environmental factors, nutrition is one of the most investigated areas as it is a potentially modifiable factor. The purpose of this review is to provide current knowledge regarding the relation between diet and PD risk. We performed a comprehensive review including the most relevant studies from the year 2000 onwards including prospective studies, nested case-control studies, and meta-analysis. Among dietary factors we focused on specific nutrients and food groups, alcoholic beverages, uric acid, and dietary patterns. Furthermore, we included studies on microbiota as recent findings have shown a possible impact on neurodegeneration. As a conclusion, there are still many controversies regarding the relationship between PD and diet which, beside methodological differences among studies, may be due to underlying genetic and gender-specific factors. However, some evidence exists regarding a potential protective effect of uric acid, poly-unsaturated fatty acids, coffee, and tea but mainly in men, whereas dairy products, particularly milk, might increase PD risk through contaminant mediated effect.

A Cross-Sectional Feasibility Study of Nutrient Intake Patterns in People With Parkinson's Compared to Government Nutrition Guidelines

Background: Diet could have implications for disease progression and management in people with Parkinson's disease (PwP). However, the knowledge of diet intake patterns in PwP is limited.Objectives: We set out to assess the feasibility of collecting diet data in PwP to determine food and nutrient intake, in order to compare to national nutrition guidelines and thus understand the habits in this population.Methods: In this cross-sectional feasibility study, PwP were approached through local support groups throughout the Thames Valley and were asked to complete a Food Frequency Questionnaire. Eligibility criteria included a self-reported neurologist confirmed diagnosis of Parkinson's disease. Completeness of questionnaires was reported and 80% was considered appropriate for each measure including demographic information.Results: Response rate was 61% and missing data rate for the 121 returned questionnaires was 74%; however, of the 90 used for analysis there was 100% completion of the questionnaires. Compared to the UK government guidelines, protein was significantly higher for both males and females and fluid intake was lower for both genders (p < 0.001). There were several other differences in nutrient intake compared to guidelines.Conclusion: We observed high levels of engagement from PwP and found that assessing food and nutrient patterns in PwP was feasible. Importantly, the diet was generally healthy overall, yet there were specific nutrients that may affect medication metabolism in PwP that were found to be high. Therefore further research into this emerging and important area is warranted.

An Interdisciplinary Weight Loss Program Improves Body Composition and Metabolic Profile in Adolescents With Obesity: Associations With the Dietary Inflammatory Index

Background and Aims: The prevalence of overweight and obesity consitutes a global epidemic and it is growing around the world. Food and nutrition are essential requirements for promoting health and protecting against non-communicable chronic diseases, such as obesity and cardiovascular disease. Specific dietary components may modulate inflammation and oxidative stress in obese individuals. The Dietary Inflammatory Index (DII®) was developed to characterize the anti- and pro-inflammatory effects of individuals' diet. Few studies have investigated the role of diet-associated inflammation in adolescents with obesity. The present study aims to investigate the effects of an interdisciplinary weight loss therapy on DII scores and cardiometabolic risk in obese adolescents and possibles correlations.

Methods: A total of 45 volunteers (14–19 years old) were recruited and enrolled for long-term interdisciplinary therapy including clinical, nutritional, psychological counseling, and exercise training. Adolescents had access to videos about health education weekly. Body composition and inflammatory and serum profiles were evaluated at baseline and after intervention. The food intake was obtained by 24-h food recall. Data was used to calculate energy-adjusted DII (E-DII) scores. Negative scores indicate an anti-inflammatory diet and positive scores indicates a pro-inflammatory diet. The sample was divided according to whether individuals increased or decreased E-DII scores after therapy.

Results: After therapy the body mass index (BMI), body weight, body fat, abdominal, waist, neck, and hip circumferences decreased significantly. The mean of high-density lipoprotein cholesterol (HDL-c) increased after the therapy. There was found an improvement of inflammatory and cardiometabolic parameters. In exploratory analyses, this occurred mainly when the EDII improved.

Conclusion: Long-term interdisciplinary therapy combined with a health education website improved inflammatory serum markers in obese adolescents. Reduction in DII scores was associated with reduction of cardiometabolic parameters, suggesting that an anti-inflammatory diet may be an effective strategy to prevent and treat obesity and related comorbidities.

Trial:http://www.ensaiosclinicos.gov.br/rg/RBR-6txv3v/, Register Number: RBR-6txv3v

Dietary Variations in a Multiethnic Parkinson's Disease Cohort and Possible Influences on Nonmotor Aspects: A Cross-Sectional Multicentre Study

Dietary habits may differ between Parkinson's disease (PD) patients of different ethnicities. The primary aim of this cross-sectional analysis was to compare dietary habits in a multiethnic PD population and investigate potential nonmotor differences. All patients completed a dietary habits questionnaire. Besides basic demographics, patients' motor involvement (Hoehn and Yahr (HY)) and nonmotor symptoms (Nonmotor Symptoms Scale; Hospital Anxiety and Depression Scale) were assessed. 139 PD patients were included (mean age 66.8 ± 11.6 years; 61.2% male; mean disease duration 6.2 ± 5.2 years; median HY 3): 47.5% were White, 24.5% Asian, and 28.0% Black African and Caribbean (BAC). We found dietary differences between the groups, including a greater frequency of vegetarians and greater consumption of cumin, turmeric, and cinnamon as well as lower consumption of beef in Asian patients than in White and BAC and greater consumption of chili than in White patients and higher consumption of pork in White than Asian and BAC patients. There were no significant differences in dietary supplement consumption after correction for multiple comparisons. None of the dietary factors examined were associated with differences in nonmotor symptoms. Diet and supplement use vary in PD patients across ethnicities, this is both a problem and opportunity for nutritional medicine research. These data support the importance of considering ethnic diversity as part of recruitment strategy in nutrition and clinical studies.

Mediterranean diet adherence is related to reduced probability of prodromal Parkinson's disease

BACKGROUND

The International Parkinson and Movement Disorder Society recently introduced a methodology for probability score calculation for prodromal PD.

OBJECTIVES

To assess the probability of prodromal PD in an older population and investigate its possible association with Mediterranean diet adherence.

METHODS

Data from a population-based cohort study of older adults (HEllenic Longitudinal Investigation of Aging and Diet) in Greece were used. Probability of prodromal PD was calculated according to International Parkinson and Movement Disorder Society research criteria. A detailed food frequency questionnaire was used to evaluate dietary intake and calculate Mediterranean diet adherence score, ranging from 0 to 55, with higher scores indicating higher adherence.

RESULTS

Median probability of prodromal PD was 1.9%, ranging from 0.2 to 96.7% in 1,731 PD-free individuals aged ≥ 65 (41% male). Lower probability for prodromal PD (P < 0.001) in the higher Mediterranean diet adherence groups was noted, driven mostly by nonmotor markers of prodromal PD, depression, constipation, urinary dysfunction, and daytime somnolence. Each unit increase in Mediterranean diet score was associated with a 2% decreased probability for prodromal PD (P < 0.001). Compared to participants in the lowest quartile of Mediterranean diet adherence, those in the highest quartile were associated with a ∼21% lower probability for prodromal PD.

CONCLUSIONS

Adherence to the Mediterranean diet is associated with lower probability of prodromal PD in older people. Further studies are needed to elucidate the potential causality of this association, potential relation of the Mediterranean diet to delayed onset or lower incidence of PD, as well as the underlying neurobiological mechanisms. © 2018 International Parkinson and Movement Disorder Society.

Application of Precision Medicine in Neurodegenerative Diseases

One of the main challenges for healthcare systems is the increasing prevalence of neurodegenerative pathologies together with the rapidly aging populations. The enormous progresses made in the field of biomedical research and informatics have been crucial for improving the knowledge of how genes, epigenetic modifications, aging, nutrition, drugs and microbiome impact health and disease. In fact, the availability of high technology and computational facilities for large-scale analysis enabled a deeper investigation of neurodegenerative disorders, providing a more comprehensive overview of disease and encouraging the development of a precision medicine approach for these pathologies. On this subject, the creation of collaborative networks among medical centers, research institutes and highly qualified specialists can be decisive for moving the precision medicine from the bench to the bedside. To this purpose, the present review has been thought to discuss the main components which may be part of precise and personalized treatment programs applied to neurodegenerative disorders. Parkinson Disease will be taken as an example to understand how precision medicine approach can be clinically useful and provide substantial benefit to patients. In this perspective, the realization of web-based networks can be decisive for the implementation of precision medicine strategies across different specialized centers as well as for supporting clinical/therapeutical decisions and promoting a more preventive and participative medicine for neurodegenerative disorders. These collaborative networks are essentially addressed to find innovative, sustainable and effective strategies able to provide optimal and safer therapies, discriminate at risk individuals, identify patients at preclinical or early stage of disease, set-up individualized and preventative strategies for improving prognosis and patient's quality of life.