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Trial of the MIND Diet for Prevention of Cognitive Decline in Older Persons.
Barnes, LL, Dhana, K, Liu, X, Carey, VJ, Ventrelle, J, Johnson, K, Hollings, CS, Bishop, L, Laranjo, N, Stubbs, BJ, et al
The New England journal of medicine. 2023;389(7):602-611
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Lifestyle interventions targeting diet are a possible approach that could affect public health. Most clinical trials have investigated comprehensive diets, in contrast to dietary manipulation of single foods or nutrients. The aim of this study was to evaluate the effects of a 3-year dietary intervention on cognitive decline and brain-imaging markers of dementia and Alzheimer’s disease in older, cognitively unimpaired adults at risk for dementia because of family history. This study was a 3-year, two-site, randomised, controlled trial. The participants were randomly assigned to follow the MIND diet with mild caloric restriction for weight loss or their usual diet with the same mild caloric restriction for weight loss (control diet). Participants were randomly assigned in a 1:1 ratio. Results showed that the participants who followed the MIND diet had small improvements in a global measure of cognition that were similar to those who followed a control diet with mild caloric restriction. Authors concluded that brain health, cognitive function and brain imaging outcomes (after 3 years) did not differ significantly between participants who followed the MIND diet and those who followed a control diet with a mild caloric restriction.
Abstract
BACKGROUND Findings from observational studies suggest that dietary patterns may offer protective benefits against cognitive decline, but data from clinical trials are limited. The Mediterranean-DASH Intervention for Neurodegenerative Delay, known as the MIND diet, is a hybrid of the Mediterranean diet and the DASH (Dietary Approaches to Stop Hypertension) diet, with modifications to include foods that have been putatively associated with a decreased risk of dementia. METHODS We performed a two-site, randomized, controlled trial involving older adults without cognitive impairment but with a family history of dementia, a body-mass index (the weight in kilograms divided by the square of the height in meters) greater than 25, and a suboptimal diet, as determined by means of a 14-item questionnaire, to test the cognitive effects of the MIND diet with mild caloric restriction as compared with a control diet with mild caloric restriction. We assigned the participants in a 1:1 ratio to follow the intervention or the control diet for 3 years. All the participants received counseling regarding adherence to their assigned diet plus support to promote weight loss. The primary end point was the change from baseline in a global cognition score and four cognitive domain scores, all of which were derived from a 12-test battery. The raw scores from each test were converted to z scores, which were averaged across all tests to create the global cognition score and across component tests to create the four domain scores; higher scores indicate better cognitive performance. The secondary outcome was the change from baseline in magnetic resonance imaging (MRI)-derived measures of brain characteristics in a nonrandom sample of participants. RESULTS A total of 1929 persons underwent screening, and 604 were enrolled; 301 were assigned to the MIND-diet group and 303 to the control-diet group. The trial was completed by 93.4% of the participants. From baseline to year 3, improvements in global cognition scores were observed in both groups, with increases of 0.205 standardized units in the MIND-diet group and 0.170 standardized units in the control-diet group (mean difference, 0.035 standardized units; 95% confidence interval, -0.022 to 0.092; P = 0.23). Changes in white-matter hyperintensities, hippocampal volumes, and total gray- and white-matter volumes on MRI were similar in the two groups. CONCLUSIONS Among cognitively unimpaired participants with a family history of dementia, changes in cognition and brain MRI outcomes from baseline to year 3 did not differ significantly between those who followed the MIND diet and those who followed the control diet with mild caloric restriction. (Funded by the National Institute on Aging; ClinicalTrials.gov number, NCT02817074.).
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Acute responses of hepatic fat content to consuming fat, glucose and fructose alone and in combination in non-obese non-diabetic individuals with non-alcoholic fatty liver disease.
Kovar, J, Dusilova, T, Sedivy, P, Bruha, R, Gottfriedova, H, Pavlikova, P, Pitha, J, Smid, V, Drobny, M, Dezortova, M, et al
Journal of physiology and pharmacology : an official journal of the Polish Physiological Society. 2021;72(1)
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Non-alcoholic fatty liver disease (NAFLD) is often associated with obesity or conditions related to obesity, such as type 2 diabetes. Steatosis is one of the four stages of NAFLD, where there is a small layer of fat build-up on the liver. Currently, one in three people in the UK has simple fatty liver or steatosis. A fascinating aspect of this study is exploring the long-term cumulative effects of daily fat intake when consumed with glucose or fructose and in the pathogenesis of steatosis. In this randomised controlled study, the researchers examined the immediate impact of high-fat loads on hepatic fat content (HFC) when administered with glucose or fructose in eight healthy overweight males with NFALD. The experiments lasted only eight hours. HFC was only transiently elevated by co-administration of glucose and high-fat loading. However, fructose co-administration with multiple high-fat loads promoted HFC. Small sample size and short duration are the limitations of this study. Long-term robust studies are needed to confirm the findings. Yet, healthcare professionals can use this study to distinguish between the immediate effects of fructose or glucose when combined with multiple doses of high fat on HFC in healthy and NAFLD subjects.
Abstract
We have recently demonstrated that a high-fat load can induce immediate increase in hepatic fat content (HFC) and that such an effect can be modified differently by co-administration of fructose or glucose in healthy subjects. Therefore, we addressed the question how consumption of these nutrients affects changes in HFC in subjects with non-alcoholic fatty liver disease (NAFLD). Eight male non-obese non-diabetic patients with NAFLD underwent 6 experiments each lasting 8 hours: 1. fasting, 2. high-fat load (150 g of fat (dairy cream) at time 0), 3. glucose (three doses of 50 g at 0, 2, and 4 hours), 4. high-fat load with three doses of 50 g of glucose, 5. fructose (three doses of 50 g at 0, 2, and 4 hours), 6. high-fat load with three doses of 50 g of fructose. HFC was measured using magnetic resonance spectroscopy prior to meal administration and 3 and 6 hours later. Plasma triglycerides, non-esterified fatty acids, glucose and insulin were monitored throughout each experiment. HFC increased by 10.4 ± 6.9% six hours after a high-fat load and by 15.2 ± 12.5% after high-fat load with fructose. When co-administering glucose with fat, HFC rose only transiently to return to baseline at 6 hours. Importantly, NAFLD subjects accumulated almost five times more fat in their livers than healthy subjects with normal HFC. Consumption of a high-fat load results in fat accumulation in the liver of NAFLD patients. Fat accumulation after a fat load is diminished by glucose but not fructose co-administration.
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Greater risk of severe COVID-19 in Black, Asian and Minority Ethnic populations is not explained by cardiometabolic, socioeconomic or behavioural factors, or by 25(OH)-vitamin D status: study of 1326 cases from the UK Biobank.
Raisi-Estabragh, Z, McCracken, C, Bethell, MS, Cooper, J, Cooper, C, Caulfield, MJ, Munroe, PB, Harvey, NC, Petersen, SE
Journal of public health (Oxford, England). 2020;42(3):451-460
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The coronavirus disease 2019 (COVID-19) pandemic has to date resulted in over 6 million cases. Growing reports highlight men and Black, Asian and Minority Ethnic (BAME) cohorts as at higher risk of adverse COVID-19 outcomes. The aim of this study was to investigate whether differential patterns of COVID-19 incidence and severity, by sex and ethnicity, might be explained by cardiometabolic, socio-economic, lifestyle and behavioural exposures. This study is a prospective cohort study of over half a million men and women from across the UK. Results showed that male sex, BAME ethnicity, higher body mass index and greater household size were associated with significantly greater odds of a positive result. However, the sex and ethnicity differential pattern of COVID-19 is not adequately explained by variations in cardiometabolic factors, 25(OH)-vitamin D levels, socio-economic or behavioural factors. Authors conclude that investigation of alternative biological and genetic susceptibilities as well as more comprehensive assessment of the complex economic, social and behavioural differences should be prioritised.
Abstract
BACKGROUND We examined whether the greater severity of coronavirus disease 2019 (COVID-19) amongst men and Black, Asian and Minority Ethnic (BAME) individuals is explained by cardiometabolic, socio-economic or behavioural factors. METHODS We studied 4510 UK Biobank participants tested for COVID-19 (positive, n = 1326). Multivariate logistic regression models including age, sex and ethnicity were used to test whether addition of (1) cardiometabolic factors [diabetes, hypertension, high cholesterol, prior myocardial infarction, smoking and body mass index (BMI)]; (2) 25(OH)-vitamin D; (3) poor diet; (4) Townsend deprivation score; (5) housing (home type, overcrowding) or (6) behavioural factors (sociability, risk taking) attenuated sex/ethnicity associations with COVID-19 status. RESULTS There was over-representation of men and BAME ethnicities in the COVID-19 positive group. BAME individuals had, on average, poorer cardiometabolic profile, lower 25(OH)-vitamin D, greater material deprivation, and were more likely to live in larger households and in flats/apartments. Male sex, BAME ethnicity, higher BMI, higher Townsend deprivation score and household overcrowding were independently associated with significantly greater odds of COVID-19. The pattern of association was consistent for men and women; cardiometabolic, socio-demographic and behavioural factors did not attenuate sex/ethnicity associations. CONCLUSIONS In this study, sex and ethnicity differential pattern of COVID-19 was not adequately explained by variations in cardiometabolic factors, 25(OH)-vitamin D levels or socio-economic factors. Factors which underlie ethnic differences in COVID-19 may not be easily captured, and so investigation of alternative biological and genetic susceptibilities as well as more comprehensive assessment of the complex economic, social and behavioural differences should be prioritised.
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Effect of Supplemental Parenteral Nutrition Versus Enteral Nutrition Alone on Clinical Outcomes in Critically Ill Adult Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Alsharif, DJ, Alsharif, FJ, Aljuraiban, GS, Abulmeaty, MMA
Nutrients. 2020;12(10)
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For individuals who are critically ill and cannot eat, the use of a tube through the mouth is the preferred way to ensure nutrition needs are met. However, complications such as diarrhoea and vomiting often means that these individuals still do not achieve optimal nutrition. In these instances, giving individuals nutrients directly into a vein alongside the feeding tube is an option to ensure they do not become nutrient deficient. This is known as a combination of enteral and parenteral nutrition. However, studies on the use of this combination are limited. This systematic review and meta-analysis of 5 studies aimed to determine the effects of a combination of enteral and parenteral feeding on clinical outcomes compared to a feeding tube alone. The results showed that compared to enteral feeding alone the combination decreased infections and intensive care unit (ICU) mortality. There was a very small effect on duration of ventilation and no effects were seen on length of hospital stay nor length of ICU stay. It was concluded that enteral feeding alone is insufficient to meet the nutritional needs of critically ill patients. Supplementing in parenteral nutrition may be of benefit to these individuals and help decrease infections and improve ICU mortality. This study could be used by healthcare professionals to understand that the health of patients who are being fed through a tube may be compromised through malnutrition and that supplemental ways of getting more nutrients into these individuals is of importance.
Abstract
Enteral nutrition (EN) is considered the first feeding route for critically ill patients. However, adverse effects such as gastrointestinal complications limit its optimal provision, leading to inadequate energy and protein intake. We compared the clinical outcomes of supplemental parenteral nutrition added to EN (SPN + EN) and EN alone in critically ill adults. Electronic databases restricted to full-text randomized controlled trials available in the English language and published from January 1990 to January 2019 were searched. The risk of bias was evaluated using the Jadad scale, and the meta-analysis was conducted using the MedCalc software. A total of five studies were eligible for inclusion in the systematic review and meta-analysis. Compared to EN alone, SPN + EN decreased the risk of nosocomial infections (relative risk (RR) = 0.733, p = 0.032) and intensive care unit (ICU) mortality (RR = 0.569, p = 0.030). No significant differences were observed between SPN + EN and EN in the length of hospital stay, hospital mortality, length of ICU stay, and duration of mechanical ventilation. In conclusion, when enteral feeding fails to fulfill the energy requirements in critically ill adult patients, SPN may be beneficial as it helps in decreasing nosocomial infections and ICU mortality, in addition to increasing energy and protein intakes with no negative effects on other clinical outcomes.
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Comparing eating behaviours, and symptoms of depression and anxiety between Spain and Greece during the COVID-19 outbreak: Cross-sectional analysis of two different confinement strategies.
Papandreou, C, Arija, V, Aretouli, E, Tsilidis, KK, Bulló, M
European eating disorders review : the journal of the Eating Disorders Association. 2020;28(6):836-846
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Stress and mental health problems which may be induced by restrictions imposed during the Covid-19 pandemic can lead to unhealthy eating habits. Restrictions have varied amongst countries and this cross-sectional analysis aimed to compare eating behaviours and symptoms of stress experienced by 1841 individuals in countries with differing lockdown measures. The results showed that individuals in the country with higher lockdown measures showed lower restraint in eating, they were more likely to overeat if they saw or smelt food and reported increased anxiety. However, they did not display depression or overeating when experiencing negative feelings. It was concluded that both countries had a high frequency of depression and anxiety. Higher restrictions were associated with greater anxiety, lower restraint and overeating when confronted with food. This paper could be used by healthcare professionals to recognise the need to include dietary advice when dealing with patients who are reporting anxiety during the current Covid-19 pandemic.
Abstract
OBJECTIVE We compared eating behaviours, and depressive and anxiety symptoms in two countries with different confinement strictness strategies and different levels of COVID-19 pandemic. METHOD A web-based cross-sectional survey was administered during and shortly after the COVID-19 related lockdown in Spain and Greece. Multivariable linear regression analyses were performed to identify country differences associated with eating behaviour, and symptoms of depression and anxiety. RESULTS This study included 1,002 responders in Spain and 839 in Greece. The mean ± SD of restraint, emotional and external eating was 2.5 ± 0.79, 2.1 ± 0.81 and 2.6 ± 0.65 in Spain, whereas 2.7 ± 0.85, 2.3 ± 0.99 and 2.9 ± 0.74 in Greece. Spanish participants had lower average scores of restraint and external eating compared to Greek participants (p < .001), but no difference was seen for emotional eating. In Spain, 13.6%, and 12.3% of the survey respondents reported moderate to severe depressive and anxiety symptoms, respectively, whereas in Greece the respective values were 18.8 and 13.2%. After adjusting for several risk factors, a higher prevalence of anxiety symptoms was observed in Spain compared to Greece (p = .001), but no difference was seen for depressive symptoms. CONCLUSIONS This study demonstrated high scores of inappropriate eating behaviours and a high frequency of depressive and anxiety symptoms in two Mediterranean countries during the COVID-19 outbreak. Our findings revealed that compared to Greek participants, Spanish participants, that faced more severe COVID-19 pandemic and stricter lockdown measures, were associated with lower restraint and external eating and increased anxiety symptoms, but not with depressive symptoms or emotional eating.
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Systematic review and meta-analysis of the associations of vegan and vegetarian diets with inflammatory biomarkers.
Menzel, J, Jabakhanji, A, Biemann, R, Mai, K, Abraham, K, Weikert, C
Scientific reports. 2020;10(1):21736
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A growing trend towards vegetarianism and veganism has emerged in the past few years. Evidence has led to the assumption that these diets may protect against chronic disease, and one potential mechanism is through the modulation of inflammatory biomarkers. The aim of this review was to investigate the associations of veganism and vegetarianism with inflammatory markers. From the 21 cross-sectional studies included in this study, both vegan and vegetarian diets were associated with lower levels of CRP compared to omnivores. There was no association with all other inflammatory markers. Based on these findings, the authors conclude there is evidence for both vegan and vegetarian diets reducing CRP, a major marker of low-grade inflammation. More research is needed as most inflammatory markers have only been investigated in single studies thus far.
Abstract
Plant-based diets like vegetarian or vegan diets might influence circulating levels of inflammatory biomarkers, thereby reducing the risk of chronic diseases. This systematic review and meta-analysis aimed to investigate the associations of veganism and vegetarianism with circulating inflammatory biomarkers in comparison to omnivores. Literature search was conducted in Pubmed and EMBASE until April 2020 and mean differences of biomarkers were assessed for: C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-18 (IL-18), interleukin-1 receptor antagonist (IL-1 RA), tumor necrosis factor-alpha (TNF-ɑ), E-selectin, intercellular adhesion molecule-1 (ICAM-1), monocyte chemoattractant protein-1 (MCP-1), adiponectin, omentin-1 and resistin. Of initially identified 1073 publications, 21 cross-sectional studies met the inclusion criteria and were included in the systematic review and meta-analysis. Vegan diet was associated with lower levels of CRP compared to omnivores [mean difference - 0.54 mg/l, 95%-CI: - 0.79 to - 0.28, p < 0.0001]. This association was less pronounced in vegetarians [mean difference - 0.25 mg/l, 95%-CI: - 0.49 to 0.00, p = 0.05]. In patients with impaired kidney function, the association between vegetarian nutrition and CRP was much stronger with - 3.91 mg/l (95%-CI: - 5.23 to - 2.60; p < 0.0001). No substantial effects were observed for all other inflammatory biomarkers. Despite strong associations between CRP and a vegan or vegetarian diet were seen, further research is needed, as most inflammatory biomarkers were investigated only in single studies so far.
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Bariatric and metabolic surgery during and after the COVID-19 pandemic: DSS recommendations for management of surgical candidates and postoperative patients and prioritisation of access to surgery.
Rubino, F, Cohen, RV, Mingrone, G, le Roux, CW, Mechanick, JI, Arterburn, DE, Vidal, J, Alberti, G, Amiel, SA, Batterham, RL, et al
The lancet. Diabetes & endocrinology. 2020;8(7):640-648
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Bariatric surgery has been proven for weight loss in people with severe obesity. However, during the covid-19 pandemic, surgery has been postponed for many individuals. Under normal conditions, patients who are awaiting bariatric surgery are prioritised based on weight, however this does not necessarily reflect severity of their condition. This review paper aimed to develop new criteria in order to help prioritise individuals who are awaiting bariatric surgery. The authors began by reviewing the reasons for delaying bariatric surgery and the need for beds, the risks of covid-19 transmission during the procedure and the severe covid-19 complications that individuals with obesity can experience were discussed. A recommendation was made that all patients having bariatric surgery be tested for Covid-19. Solutions were proposed for those awaiting surgery such as diets, exercise, optimal blood sugar control and the potential use of weight loss medications. Prioritisation of surgery should focus on clinical need; it should be accessible and minimise harm from delays. Individuals with obesity and type 2 diabetes should be prioritised based on those who have an increased risk of death, determined by whether the individual; has poor blood sugar control despite maximal use of medications to control it, uses insulin, has previous heart disease, has liver disease or if they have other risk factors. It was concluded that weight alone is inadequate to prioritise candidates for bariatric surgery. Disease severity should be at the centre of decisions, especially when access to surgery is reduced, as is during the Covid -19 pandemic. This paper could be used by healthcare professionals to understand how to prioritise their obese and type 2 diabetic patients who are awaiting bariatric surgery.
Abstract
The coronavirus disease 2019 pandemic is wreaking havoc on society, especially health-care systems, including disrupting bariatric and metabolic surgery. The current limitations on accessibility to non-urgent care undermine postoperative monitoring of patients who have undergone such operations. Furthermore, like most elective surgery, new bariatric and metabolic procedures are being postponed worldwide during the pandemic. When the outbreak abates, a backlog of people seeking these operations will exist. Hence, surgical candidates face prolonged delays of beneficial treatment. Because of the progressive nature of obesity and diabetes, delaying surgery increases risks for morbidity and mortality, thus requiring strategies to mitigate harm. The risk of harm, however, varies among patients, depending on the type and severity of their comorbidities. A triaging strategy is therefore needed. The traditional weight-centric patient-selection criteria do not favour cases based on actual clinical needs. In this Personal View, experts from the Diabetes Surgery Summit consensus conference series provide guidance for the management of patients while surgery is delayed and for postoperative surveillance. We also offer a strategy to prioritise bariatric and metabolic surgery candidates on the basis of the diseases that are most likely to be ameliorated postoperatively. Although our system will be particularly germane in the immediate future, it also provides a framework for long-term clinically meaningful prioritisation.
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Enriched Marine Oil Supplements Increase Peripheral Blood Specialized Pro-Resolving Mediators Concentrations and Reprogram Host Immune Responses: A Randomized Double-Blind Placebo-Controlled Study.
Souza, PR, Marques, RM, Gomez, EA, Colas, RA, De Matteis, R, Zak, A, Patel, M, Collier, DJ, Dalli, J
Circulation research. 2020;126(1):75-90
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Specialized pro-resolving mediators (SPM) are derived from essential fatty acids and promote resolution of inflammation. The main aim of this study was to establish the relationship(s) between supplement dose, peripheral blood SPM concentrations, and cellular responses using a novel enriched marine oil preparation. This study is a double-blind, randomized, crossover, dose escalation placebo-controlled study in healthy volunteers. Participants (n=22) were randomised to one of eight groups. Results show supplementation with refined marine oils lead to a rapid upregulation of peripheral blood SPM concentrations and reprograming of peripheral blood cell responses to sterile and infectious stimuli, changes that were found to persist after SPM concentrations returned to baseline. Authors conclude that enriched marine oil supplementation leads to a dose-and time-dependent increase of plasma SPM concentrations.
Abstract
RATIONALE Specialized pro-resolving mediators (SPM-lipoxins, resolvins, protectins, and maresins) are produced via the enzymatic conversion of essential fatty acids, including the omega-3 fatty acids docosahexaenoic acid and n-3 docosapentaenoic acid. These mediators exert potent leukocyte directed actions and control vascular inflammation. Supplementation of animals and humans with essential fatty acids, in particular omega-3 fatty acids, exerts protective actions reducing vascular and systemic inflammation. Of note, the mechanism(s) activated by these supplements in exerting their protective actions remain poorly understood. OBJECTIVE Given that essential fatty acids are precursors in the biosynthesises of SPM, the aim of the present study was to establish the relationship between supplementation and peripheral SPM concentrations. We also investigated the relationship between changes in plasma SPM concentrations and peripheral blood platelet and leukocyte responses. METHODS AND RESULTS Healthy volunteers were enrolled in a double-blinded, placebo-controlled, crossover study, and peripheral blood was collected at baseline, 2, 4, 6, and 24 hours post administration of placebo or one of 3 doses of an enriched marine oil supplement. Assessment of plasma SPM concentrations using lipid mediator profiling demonstrated a time- and dose-dependent increase in peripheral blood SPM concentration. Supplementation also led to a regulation of peripheral blood cell responses. Here we found a dose-dependent increase in neutrophil and monocyte phagocytosis of bacteria and a decrease in the diurnal activation of leukocytes and platelets, as measured by a reduction in adhesion molecule expression. In addition, transcriptomic analysis of peripheral blood cells demonstrated a marked change in transcript levels of immune and metabolic genes 24 hours post supplementation when compared with placebo. CONCLUSIONS Together, these findings demonstrate that supplementation with an enriched marine oil leads to an increase in peripheral blood SPM concentrations and reprograms peripheral blood cells, indicating a role for SPM in mediating the immune-directed actions of this supplement. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT03347006.
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Gut feelings: A randomised, triple-blind, placebo-controlled trial of probiotics for depressive symptoms.
Chahwan, B, Kwan, S, Isik, A, van Hemert, S, Burke, C, Roberts, L
Journal of affective disorders. 2019;253:317-326
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Depression is a debilitating psychiatric disorder that is the leading cause of disability world-wide. Multiple causes of depression have been identified, including genetic, neurological, inflammatory, personality, cognitive, and environmental factors. The aim of this study was to investigate the effectiveness of the multispecies probiotic Ecologic® Barrier for reducing symptoms in adults with mild to severe levels of depression. The study was a triple-blinded parallel, placebo-controlled randomised clinical trial. Participants were randomly allocated into two groups; probiotic and placebo. 71 participants with depressive symptoms were recruited and allocated sequentially over 12 months. Results indicate that all participants across both probiotic and placebo groups exhibited a reduction in depressive symptoms over the time-period of the trial. Thus, the routine involved with daily preparation and consumption of the probiotic and scheduled appointments, as well as involvement in these behaviours with the aim of seeking improvement in depressive symptoms had positive impacts on mood, irrespective of whether the probiotic or placebo was consumed. Authors conclude that their findings offer evidence to indicate that probiotic consumption can exert change on cognitive patterns associated with depression.
Expert Review
Conflicts of interest:
None
Take Home Message:
- This study offers evidence to indicate that probiotic consumption can exert change on cognitive patterns associated with depression.
- The study suggests that probiotics, rather than having a direct effect on depressive symptoms, potentially act on immune system activity, inflammation and gut barrier integrity which contribute to the expression of depression.
- Probiotics may be a useful adjunct to potentiate the effects of other therapies, such as CBT.
- This study points to the validity of managing physical health as part of mental health treatment.
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
With evidence suggesting that decreased gut barrier function and inflammation are correlated with depression, this study set out to determine the effect of consumption of probiotic supplements on depressive symptoms from a sample of 71 participants with depression. The study was a triple-blinded parallel, placebo-controlled randomised clinical trial conducted over 8 weeks in Australia. Pre and post intervention measures of symptoms and vulnerability markers of depression as well as gut microbiota were compared alongside psychological variables and gut microbiota composition to non-depressed, placebo and probiotic groups. All the clinical trial participants demonstrated an improvement in symptoms – participants in the probiotic group demonstrated a significantly greater reduction in cognitive reactivity compared with the placebo group. Probiotics did not significantly alter the microbiota of depressed individuals, however a significant correlation was found between Ruminococcus gnavus and one of the metrics for depression.
Clinical practice applications:
This study was small and carried out over a short period of time. While significant results were found, which signify potential considerations for clinical practice, the results from this study do not offer evidence that the probiotics used had a direct effect on depressive symptoms – they suggest that probiotics potentially act on cognitive processes contributing to depression which may include immune system activity, inflammation, and gut barrier integrity. Overall, this study offers evidence to indicate that probiotic consumption can exert change on cognitive patterns associated with depression. In clinical practice, probiotics may be a useful adjunct to potentiate the effects of therapies, such as CBT. Finally, the use of probiotics promotes the concept of managing physical health as part of mental health treatment.
Considerations for future research:
These preliminary results are promising and offer a number of future research and clinical avenues to build upon. The results do however, indicate that a longer trial may be needed to fully assess the effects of probiotics on mood and the mechanisms by which probiotics may be influencing this. The study also suggests that further research using a range of concentrations in a dose response study may be warranted to determine the optimal dose; a greater dose over a longer period may produce detectable changes in microbiota as well as further differences in psychological data.
Abstract
BACKGROUND Depression is the leading cause of disability worldwide; with evidence suggesting that decreased gut barrier function and inflammation are correlated with depressive symptoms. We conducted a clinical trial to determine the effect of consumption of probiotic supplements (Winclove's Ecologic® Barrier) on depressive symptoms in a sample of participants with mild to severe depression. METHOD 71 participants were randomly allocated to either probiotic or placebo, which was, consumed daily over eight weeks. Pre- and post-intervention measures of symptoms and vulnerability markers of depression as well as gut microbiota composition were compared. Clinical trial participants were also compared on psychological variables and gut microbiota composition to a non-depressed group (n = 20). RESULTS All clinical trial participants demonstrated improvement in symptoms, suggesting non-specific therapeutic effects associated with weekly monitoring visits. Participants in the probiotic group demonstrated a significantly greater reduction in cognitive reactivity compared with the placebo group, particularly in the mild/moderate subgroup. Probiotics did not significantly alter the microbiota of depressed individuals, however, a significant correlation was found between Ruminococcus gnavus and one depression metric. LIMITATIONS There was a high attrition rate, which may be attributed to weekly monitoring visits. Additionally, modulation of the gut microbiota may need more specific testing to distinguish subtle changes. CONCLUSIONS While microbiota composition was similar between all groups, probiotics did affect a psychological variable associated with susceptibility to depression. Further research is needed to investigate how probiotics can be utilised to modify mental wellbeing, and whether they can act as an adjunct to existing treatments.
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Effect of a Nutritional and Behavioral Intervention on Energy-Reduced Mediterranean Diet Adherence Among Patients With Metabolic Syndrome: Interim Analysis of the PREDIMED-Plus Randomized Clinical Trial.
Sayón-Orea, C, Razquin, C, Bulló, M, Corella, D, Fitó, M, Romaguera, D, Vioque, J, Alonso-Gómez, ÁM, Wärnberg, J, Martínez, JA, et al
JAMA. 2019;322(15):1486-1499
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Excess caloric intake and poor nutritional quality are associated with overweight and obesity. A traditional Mediterranean diet has been shown to reduce all-cause mortality, and in particular to reduce risk of cardiovascular disease, type 2 diabetes mellitus and overweight. The aim of this randomised, prospective, single-blinded study was to evaluate the effectiveness of an intensive lifestyle intervention programme in 6874 overweight or obese men and women with metabolic syndrome in Spain. The intervention group was advised on an energy-reduced Mediterranean diet and exercise and received behavioural support, with initial group sessions and interviews, and monthly follow-up phone calls for one year. The control group received advice on a Mediterranean diet and usual care, with 6 monthly follow-ups. After 12 months, the more intensively counselled patients showed a significantly better adherence to an energy-reduced Mediterranean diet than the control group. They had greater reductions in refined grains, pastries, red and processed meats and greater increases in vegetable, fruit and nut consumption than the control group. The intervention group had also better improvements in cardiovascular risk factors.
Abstract
Importance: High-quality dietary patterns may help prevent chronic disease, but limited data exist from randomized trials about the effects of nutritional and behavioral interventions on dietary changes. Objective: To assess the effect of a nutritional and physical activity education program on dietary quality. Design, Setting, and Participants: Preliminary exploratory interim analysis of an ongoing randomized trial. In 23 research centers in Spain, 6874 men and women aged 55 to 75 years with metabolic syndrome and no cardiovascular disease were enrolled in the trial between September 2013 and December 2016, with final data collection in March 2019. Interventions: Participants were randomized to an intervention group that encouraged an energy-reduced Mediterranean diet, promoted physical activity, and provided behavioral support (n = 3406) or to a control group that encouraged an energy-unrestricted Mediterranean diet (n = 3468). All participants received allotments of extra-virgin olive oil (1 L/mo) and nuts (125 g/mo) for free. Main Outcomes and Measures: The primary outcome was 12-month change in adherence based on the energy-reduced Mediterranean diet (er-MedDiet) score (range, 0-17; higher scores indicate greater adherence; minimal clinically important difference, 1 point). Results: Among 6874 randomized participants (mean [SD] age, 65.0 [4.9] years; 3406 [52%] men), 6583 (96%) completed the 12-month follow-up and were included in the main analysis. The mean (SD) er-MedDiet score was 8.5 (2.6) at baseline and 13.2 (2.7) at 12 months in the intervention group (increase, 4.7 [95% CI, 4.6-4.8]) and 8.6 (2.7) at baseline and 11.1 (2.8) at 12 months in the control group (increase, 2.5 [95% CI, 2.3-2.6]) (between-group difference, 2.2 [95% CI, 2.1-2.4]; P < .001). Conclusions and Relevance: In this preliminary analysis of an ongoing trial, an intervention that encouraged an energy-reduced Mediterranean diet and physical activity, compared with advice to follow an energy-unrestricted Mediterranean diet, resulted in a significantly greater increase in diet adherence after 12 months. Further evaluation of long-term cardiovascular effects is needed. Trial Registration: isrctn.com Identifier: ISRCTN89898870.