Inverse association between yerba mate consumption and idiopathic Parkinson's disease. A case-control study

Physiological effects of yerba maté (Ilex paraguariensis): a systematic review

CONTEXT

Clinical studies have found an association between yerba maté intake and beneficial physiological effects. Nevertheless, no systematic reviews have been conducted to shed light on the data supporting this association.

OBJECTIVE

The present systematic review aimed to investigate the physiological effects of yerba maté.

DATA SOURCES

Searches were performed in 6 databases (Embase, LILACS, Scopus, PubMed, SciELO, Web of Science) and 3 grey literature databases (OpenGrey, ProQuest, Google Scholar). Relevant publications were identified, and the reference lists of included studies were searched manually for randomized clinical trials, nonrandomized clinical trials, and observational studies investigating the physiological effects of yerba maté.

DATA EXTRACTION

Risk of bias was assessed using the Cochrane risk of bias tool for randomized trials and the Cochrane ROBINS-I (Risk Of Bias In Nonrandomized Studies of Interventions) tool. Joanna Briggs Institute critical appraisal tools were used for cross-sectional, case series, cohort, and case-control studies. The overall certainty of the evidence was estimated using the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) working group summary of findings table.

DATA ANALYSIS

Of 1096 studies identified, 32 were included. Studies showed consistent effects of yerba maté intake on metabolism improvement and antioxidant and anti-inflammatory activities in different populations. Benefits for body weight and composition, exercise performance, mood, and appetite, in addition cardio- and neuroprotective effects, were also observed. Risk of bias was categorized as high in 22 studies, moderate in 9 studies, and low in 1 study. The certainty of evidence ranged from moderate to very low.

CONCLUSION

The available literature indicates that yerba maté can be used within a balanced and healthy diet for prevention and adjuvant treatment of chronic diseases.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42020200196.

Alcohol and Parkinson's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

A substantial body of research has examined the relationship between alcohol consumption and risk of Parkinson's disease (PD).

OBJECTIVE

To provide an updated systematic review and meta-analysis of observational studies examining the relationship between alcohol consumption and risk of PD.

METHODS

Eligible studies comparing PD risk in ever vs. never alcohol drinkers were sourced from six databases. Outcomes were pooled using standard meta-analysis techniques. Separate female and male estimates were generated from studies reporting sex-specific data. Additionally, cohort studies stratifying participants by quantity of alcohol intake were integrated in a dose-response analysis.

RESULTS

52 studies were included, totaling 63,707 PD patients and 9,817,924 controls. Our meta-analysis supported a statistically significant overrepresentation of never drinkers among PD subjects; odds ratio (OR) for ever drinking alcohol 0.84 (95% confidence interval (CI) 0.76 - 0.92). A subgroup analysis revealed similar effect estimates in females and males. A further synthesis of seven cohort studies suggested a negative, dose-dependent association between alcohol and risk of PD.

CONCLUSION

In the absence of a known neuroprotective pathway, there may be reason to doubt a true biological effect. The role of survivor bias, selection and recall bias, misclassification, and residual confounding requires consideration. Alternatively, observations might be attributable to reverse causation if those predestined for PD alter their alcohol habits during the preclinical phase. Major limitations of our study include high between-study heterogeneity (I2 = 93.2%) and lack of adjustment for key confounders, namely smoking status.

The taste of neuroinflammation: Molecular mechanisms linking taste sensing to neuroinflammatory responses

Evidence indicates a critical role of neuroinflammatory response as an underlying pathophysiological process in several central nervous system disorders, including neurodegenerative diseases. However, the molecular mechanisms that trigger neuroinflammatory processes are not fully known. The discovery of bitter taste receptors in regions other than the oral cavity substantially increased research interests on their functional roles in extra-oral tissues. It is now widely accepted that bitter taste receptors, for instance, in the respiratory, intestinal, reproductive and urinary tracts, are crucial not only for sensing poisonous substances, but also, act as immune sentinels, mobilizing defense mechanisms against pathogenic aggression. The relatively recent discovery of bitter taste receptors in the brain has intensified research investigation on the functional implication of cerebral bitter taste receptor expression. Very recent data suggest that responses of bitter taste receptors to neurotoxins and microbial molecules, under normal condition, are necessary to prevent neuroinflammatory reactions. Furthermore, emerging data have revealed that downregulation of key components of the taste receptor signaling cascade leads to increased oxidative stress and inflammasome signaling in neurons that ultimately culminate in neuroinflammation. Nevertheless, the mechanisms that link taste receptor mediated surveillance of the extracellular milieu to neuroinflammatory responses are not completely understood. This review integrates new data on the molecular mechanisms that link bitter taste receptor sensing to neuroinflammatory responses. The role of bitter taste receptor-mediated sensing of toxigenic substances in brain disorders is also discussed. The therapeutic significance of targeting these receptors for potential treatment of neurodegenerative diseases is also highlighted.

A Case-Control Study of the Effects of Chimarrão (Ilex paraguariensis) and Coffee on Parkinson's Disease

Introduction: Coffee has been inversely associated with Parkinson's disease (PD) in many studies, and caffeine is the leading candidate to mediate this effect. Mate (Ilex paraguariensis, IP), a caffeinated beverage rich in antioxidants consumed in South America, was also inversely associated with PD in one study from Argentina. Other varieties of IP infusion, such as chimarrão, were never studied in PD. Chimarrão is a common caffeinated beverage consumed in Brazil made with the leaves and stems of IP.

Methods: A case–control study was conducted to evaluate the relationship between chimarrão ingestion and PD in southern Brazil. All subjects answered a questionnaire about the frequency of chimarrão and coffee intake. A multiple regression analysis adjusted for age and sex was performed to assess the association between PD and chimarrão consumption.

Results: We included 200 PD patients and 200 healthy controls. High consumption of chimarrão was inversely associated with PD (OR = 0.44, 95% CI = 0.24–0.81, P = 0.008). High consumption of coffee was also inversely associated with PD, as expected. Chimarrão remained associated when adjusted for coffee consumption, smoking history, and age (OR 0.46, 95% CI = 0.25–0.86, P = 0.014). These two exposures showed an additive effect.

Conclusion:Chimarrão consumption was inversely associated with PD, even after adjusting for coffee intake, suggesting a possible protective role. IP's effect can be mediated by caffeine and through its antioxidant components. Chimarrão has a lower concentration of caffeine compared with coffee and has numerous substances with antioxidative effects that may be important to PD protection. Further studies are needed to test this hypothesis.

Clinical trials in REM sleep behavioural disorder: challenges and opportunities

The rapid eye movement sleep behavioural disorder (RBD) population is an ideal study population for testing disease-modifying treatments for synucleinopathies, since RBD represents an early prodromal stage of synucleinopathy when neuropathology may be more responsive to treatment. While clonazepam and melatonin are most commonly used as symptomatic treatments for RBD, clinical trials of symptomatic treatments are also needed to identify evidence-based treatments. A comprehensive framework for both disease-modifying and symptomatic treatment trials in RBD is described, including potential treatments in the pipeline, cost-effective participant recruitment and selection, study design, outcomes and dissemination of results. For disease-modifying treatment clinical trials, the recommended primary outcome is phenoconversion to an overt synucleinopathy, and stratification features should be used to select a study population at high risk of phenoconversion, to enable more rapid clinical trials. For symptomatic treatment clinical trials, objective polysomnogram-based measurement of RBD-related movements and vocalisations should be the primary outcome measure, rather than subjective scales or diaries. Mobile technology to enable objective measurement of RBD episodes in the ambulatory setting, and advances in imaging, biofluid, tissue, and neurophysiological biomarkers of synucleinopathies, will enable more efficient clinical trials but are still in development. Increasing awareness of RBD among the general public and medical community coupled with timely diagnosis of these diseases will facilitate progress in the development of therapeutics for RBD and associated neurodegenerative disorders.

Health Benefits of Bioactive Compounds from the Genus Ilex, a Source of Traditional Caffeinated Beverages

Tea and coffee are caffeinated beverages commonly consumed around the world in daily life. Tea from Camellia sinensis is widely available and is a good source of caffeine and other bioactive compounds (e.g., polyphenols and carotenoids). Other tea-like beverages, such as those from the genus Ilex, the large-leaved Kudingcha (Ilex latifolia Thunb and Ilex kudingcha C.J. Tseng), Yerba Mate (Ilex paraguariensis A. St.-Hil), Yaupon Holly (Ilex vomitoria), and Guayusa (Ilex guayusa Loes) are also traditional drinks, with lesser overall usage, but have attracted much recent attention and have been subjected to further study. This review summarizes the distribution, composition, and health benefits of caffeinated beverages from the genus Ilex. Plants of this genus mainly contain polyphenols and alkaloids, and show diverse health benefits, which, as well as supporting their further popularization as beverages, may also lead to potential applications in the pharmaceutical or nutraceutical industries.

Epidemiology of Parkinson's Disease-East Versus West

Background

The cause of PD at present remains unknown. A number of epidemiological studies have been conducted across the globe to ascertain the disease burden and the possible risk factors. In this review, we analyze the various studies from East and West with an aim to observe the important similarities and differences in the disease occurrence and risk factor profile.

Methods

A comprehensive search of descriptive and analytical epidemiological studies was undertaken. The descriptive studies and meta-analysis providing the standardised population rates were selected. The demographics, ethnicity and geographical differences between East and West were analysed. In analytical epidemiology, more established and well-studied non-genetic risk factors for PD were reviewed utilising the prospective cohort studies, case control studies and meta-analysis where available.

Results and Conclusion

PD is more common with increasing age and shows male predominance, which is more obvious in Western studies. The PD prevalence and incidence rates are slightly lower in the East compared to the West. Incidence studies on different ethnic populations in the same country have also found a lower occurrence of PD amongst Easterners compared to Westerners. Setting methodological differences aside, studies from East and West suggest a role for both environmental and genetic risk factors in PD causation. Smoking, caffeine intake and pesticide exposure are well-established risk factors across regions. There is a robust data for dairy product consumption, urate levels and physical activity in the West while studies on certain risk factors like head injury and alcohol show conflicting and mixed results.