Association of nutritional status and diet with the gut microbiome in acutely ill hospitalised older adults / Associação do estado nutricional e da dieta com o microbioma intestinal em idosos hospitalizados agudamente enfermos

Introduction - Ageing is characterised by changes associated with an increased risk of developing chronic diseases and syndromes, of which malnutrition is one of the most common in older adults. The gut microbiota has an important role in the hosts health and is determined by several factors, including nutritional status and diet. Therefore, the gut microbiota may be associated with malnutrition and dietary intake in acutely ill older adults. Objectives - to identify- 1) the prevalence of malnutrition; 2) the association of malnutrition with the composition and metabolic potential of the gut microbiota and its impact on clinical outcomes; 3) the effect of habitual diet on the gut microbiota of acutely ill hospitalised older adults according to the nutritional status. Methods - a longitudinal analysis secondary to a prospective cohort was performed on 108 participants aged 65+ years old admitted to the hospital due to acute conditions. Clinical, demographic, nutritional, and anthropometric data and rectal swab samples were collected at admission and after 72 hours of hospitalisation. The food intake was estimated using the dietary history and the nutritional status diagnosed using the Global Leadership Initiative on Malnutrition (GLIM) criteria, preceded by the Mini-Nutritional Assessment Short-form (MNA-SF). Rectal swab samples were obtained to analyse the gut microbiota via 16S rRNA gene sequencing. The microbiota diversity, overall composition and differential abundances were calculated and compared between well-nourished and malnourished groups. Microbiome features potentially associated with malnutrition were selected by penalised models and confirmed by additive models. The prediction of clinical outcomes was investigated from the "malnourished microbiota" using decision trees. The dietary intake was explored through multivariate methods and investigated with the microbiota using tests of association and mediation analysis. Results - Malnourished patients (51%) had a different overall microbiota composition compared to well-nourished during hospitalisation (R= 0.079, p= 0.003). Severely malnourished (32.4%) showed a poorer diversity at admission (Shannon p= 0.012, Simpson p= 0.018) and after 72 hours (Shannon p= 0.023, Chao1 p= 0.008). Subdoligranulum, Lachnospiraceae NK4A136 group and Faecalibacterium prausnitzii, short-chain fatty acids producers, had significantly lower abundance and negative association with malnutrition, while Fusobacterium, Corynebacterium and Ruminococcaceae Incertae Sedis were highly increased and positively associated with malnutrition. Corynebacterium, Ruminococcaceae Incertae Sedis and the overall composition were important predictors of critical care in malnourished during hospitalisation. Malnourished patients had a significantly lower intake of plant protein, carbohydrates, dietary fibre, Fe, Mn, folate, campesterol, beta-sitosterol, and -linolenic acid, and higher intake of Vitamin D. There were no significant correlations of nutrients, foods or food groups with the microbiota structure, but for individual taxa and -diversity metrics. Mediation analysis revealed a significant indirect effect of the nutritional status on the differential abundance of several bacterial taxa partially mediated in a positive direction by dietary fibre, plant-based protein, onions, and olive oil, and negative by vitamin D. Conclusion - Malnourished patients had a significantly lower intake of key dietary compounds and substantial gut microbial disturbances during hospitalisation, pronounced in the severe stage. Some plant-based compounds might confer beneficial effects on the gut microbiota profile. A "malnourished microbiota" may be able to predict critical illness in hospitalised malnourished older patients. Bench-to-bedside investigations are necessary to confirm these findings.

Introdução - O envelhecimento é caracterizado por mudanças associadas a uma maior chance de desenvolver síndromes e doenças crônicas, das quais a desnutrição é uma das mais comuns em idosos. A microbiota intestinal tem um papel importante na saúde e é determinada por vários fatores, incluindo o estado nutricional e a dieta. Portanto, a microbiota intestinal pode estar associada à desnutrição e à ingestão alimentar em idosos gravemente doentes. Objetivos - identificar- 1) a prevalência de desnutrição; 2) a associação da desnutrição com a composição e o potencial metabólico da microbiota intestinal e seu impacto nos desfechos clínicos; 3) o efeito da dieta habitual sobre a microbiota intestinal de idosos hospitalizados com doenças agudas de acordo com o estado nutricional. Métodos - uma análise longitudinal secundária a uma coorte prospectiva foi realizada em 108 participantes com mais de 65 anos de idade admitidos no hospital devido a condições agudas. Foram coletados dados clínicos, demográficos, nutricionais, antropométricos e swab retal na admissão e após 72 horas de internação. O consumo alimentar foi estimado por meio do histórico alimentar e o estado nutricional foi diagnosticado pelos critérios da Iniciativa de Liderança Global sobre Desnutrição (GLIM), precedido da triagem pela Mini-Avaliação Nutricional versão curta (MAN-SF). Amostras de swab retal foram obtidas para analisar a microbiota intestinal via sequenciamento do gene 16S rRNA. A diversidade da microbiota, composição geral e a abundâncias diferenciais foram calculadas e comparadas entre os grupos bem nutrido e desnutrido. Variáveis do microbioma potencialmente associadas à desnutrição foram selecionadas por modelos penalizados e confirmadas por modelos aditivos. A predição para os desfechos clínicos foi investigada a partir da "microbiota desnutrida" utilizando árvores de decisão. O consumo alimentar foi explorado por meio de métodos multivariados e investigado com a microbiota por meio de testes de associação e análise de mediação. Resultados - Os pacientes desnutridos (51%) apresentaram composição geral da microbiota diferente comparado com os bem nutridos durante a hospitalização (R= 0,079, p= 0,003). Os sevemente desnutridos (32,4%) apresentaram menor diversidade na admissão (Shannon p= 0,012, Simpson p= 0,018) e após 72 horas (Shannon p = 0,023, Chao1 p= 0,008). Subdoligranulum, Lachnospiraceae NK4A136 e Faecalibacterium prausnitzii, produtores de ácidos graxos de cadeia curta, tiveram abundância significativamente menor e associação negativa com a desnutrição, enquanto Fusobacterium, Corynebacterium e Ruminococcaceae Incertae Sedis tiveram maior abundância e associação positiva. Corynebacterium, Ruminococcaceae Incertae Sedis e a composição geral foram importantes preditores de cuidados intensivos em desnutridos durante a hospitalização. Pacientes desnutridos tiveram ingestão significativamente menor de proteína vegetal, carboidratos, fibra dietética, Fe, Mn, folato, campesterol, beta-sitosterol e ácido -linolênico, e maior de vitamina D. Não houve correlações significativas entre nutrientes, alimentos ou grupos de alimentos com a estrutura da microbiota, mas sim para táxons individuais e métricas da -diversidade. A análise de medição revelou um efeito indireto significativo do estado nutricional sobre a abundância diferencial de vários táxons bacterianos parcialmente mediada em uma direção positiva pela fibra alimentar, proteína vegetal, cebola, e azeite de oliva, e negativa pela vitamina D. Conclusão - Pacientes desnutridos tiveram menor ingestão de compostos dietéticos chaves e distúrbios microbianos intestinais substanciais durante a hospitalização, pronunciados no estágio grave. Alguns compostos de origem vegetal podem conferir efeitos benéficos no perfil da microbiota intestinal. A "microbiota desnutrida" pode ser capaz de predizer doenças críticas em idosos desnutridos hospitalizados. Investigações pré-clínicas e translacionais são necessárias para confirmar esses achados.

Applicability of the GLIM criteria for the diagnosis of malnutrition in older adults in the emergency ward: A pilot validation study.

BACKGROUND & AIMS: Acutely ill older adults are at higher risk of malnutrition. This study aimed to explore the applicability and accuracy of the GLIM criteria to diagnose malnutrition in acutely ill older adults in the emergency ward (EW). METHODS: We performed a retrospective secondary analysis, of an ongoing cohort study, in 165 participants over 65 years of age admitted to the EW of a Brazilian university hospital. Nutrition assessment included anthropometry, the Simplified Nutritional Assessment Questionnaire (SNAQ), the Malnutrition Screening Tool (MST), and the Mini-Nutritional Assessment (MNA). We diagnosed malnutrition using GLIM criteria, defined by the parallel presence of at least one phenotypic [nonvolitional weight loss (WL), low BMI, low muscle mass (MM)] and one etiologic criterion [reduced food intake or assimilation (RFI), disease burden/inflammation]. We used the receiver operating characteristic (ROC) curves and Cox and logistic regression for data analyses. RESULTS: GLIM criteria, following the MNA-SF screening, classified 50.3% of participants as malnourished, 29.1% of them in a severe stage. Validation of the diagnosis using MNA-FF as a reference showed good accuracy (AUC = 0.84), and moderate sensitivity (76%) and specificity (75.1%). All phenotypic criteria combined with RFI showed the best metrics. Malnutrition showed a trend for an increased risk of transference to intensive care unit (OR = 2.08, 95% CI 0.99, 4.35), and severe malnutrition for in-hospital mortality (HR = 4.23, 95% CI 1.2, 14.9). CONCLUSION: GLIM criteria, following MNA-SF screening, appear to be a feasible approach to diagnose malnutrition in acutely ill older adults in the EW. Nonvolitional WL combined with RFI or acute inflammation were the best components identified and are easily accessible, allowing their potential use in clinical practice.

Nutrition and Alzheimer Disease.

We gathered some theoretic and practical concepts related to the importance of nutrition in the prevention and management of Alzheimer disease (AD). Besides the role of nutrients in brain development and functioning, some nutrients exert special control in the development of AD, due to their participation in neurotransmitter synthesis, their modulation in epigenetics mechanisms, and as antioxidants. In addition, some non-nutrient food-derived substances have shown potential in the control of neuroinflammation and consequently in the prevention of AD. Finally, it is important to be aware of the nutritional status and food intake patterns of the patient with AD.

Nutritional Strategies in the Management of Alzheimer Disease: Systematic Review With Network Meta-Analysis.

BACKGROUND: Alzheimer disease (AD) is the major cause of dependency and disability in the elderly. Numerous studies have sought to achieve its prevention and/or management examining a role for modifiable risk factors, such as nutrition. This work aims to investigate the effects of food and/or nutrients in the management of AD at different stages. METHODS: Electronic databases were searched for clinical trials examining the effect of nutrient intervention in individuals with AD, compared with placebo, published up to 2014. The outcomes investigated were neuropsychological assessment scales, neuroimaging, and biomarkers. The Cochrane tool was employed to assess risk of bias. Pairwise meta-analyses were performed in a random-effect model by estimating the weighted mean differences with 95% confidence interval (CI) for each outcome measure. The Network meta-analysis was undertaken on cognitive outcome. RESULTS: Selected studies used antioxidants, B-vitamins, inositol, medium-chain triglyceride, omega-3, polymeric formulas, polypeptide, and vitamin D. AD outcome measurements were mainly restricted to cognitive state and functional abilities. Estimate treatment effects from pairwise meta-analyses showed large but nonsignificant effect in the supplementation with proline-rich polypeptide [weighted mean difference 6.93 (95% CI -3.04, 16.89); P = .17] and B-vitamins [weighted mean difference 0.52 (95% CI -0.05, 1.09); P = .07) on cognitive function measured by the Mini-Mental State Examination. The other nutrients supplementation did not show any significant effect on any outcome measures. CONCLUSIONS: Isolated nutrient supplementations show no convincing evidence of providing a significant benefit on clinical manifestations or neuropathology of AD. During the initial stages of AD, nutrient supplementation did not show any effect when delivered individually, probably because of their synergistic function on brain, at different domains.