Brain functions are influenced by the presence, activity, and metabolism of the gut microbiota through the gut-microbiota-brain (GMB) axis. The consumption of a fiber-rich diet increases the content of short-chain fatty acids (SCFAs) from bacterial fermentation in the colon. Among SCFAs, butyrate stands out because of its wide array of biological functions, such as ability to influence brain functions. Pharmacologically, sodium butyrate (NaB) regulates gene expression in the brain, where it has several beneficial effects ranging from neurodegenerative diseases to behavioral disorders through inhibitors of histone deacetylases (HDACis). In this context, we review the mechanisms of action of the two types of butyrate on brain functions, with an emphasis on the epigenetic approach. Both types of butyrate are potentially interesting for the prevention and adjuvant therapy of neurological and psychological disorders due to their neuroprotective functions. However, further studies are needed to investigate the possible neuroepigenetic effects of butyrate derived from bacterial fermentation.

Folate, vitamin B6, and vitamin B12 intake can be important regulators for obesity development. Thus, we investigated the possible association between the intake of these vitamins and the excess body weight or obesity prevalence in the participants of the Cohort of Universities in Minas Gerais (CUME project). This study analyzed cross-sectional data of 2695 graduates and postgraduates from universities in the state of Minas Gerais (801 men, 1894 women, ages 36.2 ± 9.4). The first step consisted of collecting data online, and the second step consisted of blood collecting in the subsample living in the city of Viçosa and its region (Minas Gerais). Excess body weight and obesity prevalence were 38.1% and 10.1%, respectively. Inadequate intake of folate, B6, and B12 were 12, 6.3, and 11.1%, respectively. Beans/lentils and French bread presented the highest contribution to folate intake (23.45% and 10.01%, respectively). Those individuals in the third tertile for folate intake (≥511.12 μg/d) had a lower excess body weight [prevalence ratio (PR): 0.79, confidence interval (CI): 0.71–0.8] and obesity prevalence (PR: 0.60, CI: 0.45–0.78). These associations were maintained when the sample was categorized by sex. In addition, serum folate was positively associated with dietary folate (p for trend = 0.032) and negatively associated with serum homocysteine (p for trend = 0.003) in the subsample. Dietary folate intake was negatively associated with excess body weight and obesity in CUME participants, indicating the relevance of this vitamin dietary assessment.

Melatonin is an important hormone in the regulation of circadian rhythms and has great antioxidant power. Recent studies have demonstrated the benefits of its supplementation in the metabolic profile. Food sources have also been studied for complementary therapies. However, information on the bioavailability of food sources of melatonin is still scarce. Thus, the objective of this review is to gather in the literature studies that evaluate the relationship between food consumption and improvements in circulating melatonin in humans. In total, 178 studies were found, of which 11 were included in this review. The results show increases in the excretion of the melatonin metabolite (6‑sulfatoxymelatonin) or circulating melatonin for foods such as cherries, grapes, bananas, pineapples, dark green vegetables, Japanese vegetables and beer. Significant increases in melatonin were observed even after ingesting cultivars with low concentrations of this hormone. It was possible to assume that other nutrients that precede their synthesis (serotonin and tryptophan) could also have led to this increase. Although consumption of the foods found is beneficial in increasing circulating melatonin, further confirmatory studies are needed.

Background and aim: We aimed to systematically review observational studies that evaluated the potential association of the dietary total antioxidant capacity (dTAC) with common mental disorders (depression and anxiety) and sleep disorders.Methods: Studies with an observational design that evaluated the association between the dTAC and common mental disorders and sleep disorders were identified using the PubMed and Scopus databases. The Meta-analysis Guideline of Observational Studies in Epidemiology and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis were used to conduct and report the data of this systematic review.Results: Of the 439 records, seven studies were included in this review. There was a sample variation of 41–3,297 participants. We highlight that five of the studies analyzed were conducted in the Iranian population. Four studies analyzed only women, and three studies were conducted with postmenopausal or climacteric women. Four cross-sectional studies showed inverse associations between the dTAC and depression, anxiety, and sleep disorders in Iranians.Conclusions: The consumption of a diet rich in antioxidants, characterized by high dTAC scores, seems to be inversely associated with depression, anxiety, and sleep disorders. However, further studies with different populations and designs are necessary for a better understand this relationship.Relevance to patients: This review assesses the association of the dTAC with common mental disorders (depression and anxiety) and sleep disorders. These knowledge will help guide further studies on the relationship between diet and mental disorders and sleep disorders. Knowledge about these relationships is essential for the creation of non-pharmacological practices for the prevention of these disorders.

Resumo Objetivo associar o nível de ativação com a qualidade de vida relacionada à saúde de pessoas que realizam o tratamento hemodialítico. Método estudo quantitativo, transversal e correlacional com 162 pessoas em tratamento hemodialítico. Os dados foram coletados por meio da aplicação de questionários para a caracterização sociodemográfica, socioeconômica e clínica do Kidney Disease Quality of Life Short Form e da escala Patient Activation Measure. Os dados secundários foram coletados por meio do prontuário médico. Para a análise dos dados, utilizaram-se a estatística descritiva e a regressão logística. Resultados a ativação do paciente em hemodiálise associou-se positivamente com os domínios sintomas, funcionamento físico, saúde geral, bem-estar emocional, energia/fadiga e o componente mental da qualidade de vida relacionada à saúde. Conclusão e implicação para a prática como a ativação apresenta relação com a qualidade de vida relacionada à saúde, na prática assistencial, essa métrica deve ser considerada ao implementar medidas que visem a aumentar a qualidade de vida relacionada à saúde das pessoas em hemodiálise.

This study aims to evaluate the association between Dietary Total Antioxidant Capacity (dTAC) and Total Antioxidant Capacity of food groups (fgTAC) with the incidence of depression in Brazilian graduates participating in the Cohort of Universities of Minas Gerais (CUME Study). The sample consisted of 2572 participants without a medical diagnosis of depression at baseline who responded to at least one follow-up questionnaire from the CUME Project. The Ferric Reducing Antioxidant Power assay was used to determine dTAC. Incidence of depression was estimated by self-reported medical diagnosis of depression during the years of cohort follow-up. Cox regression models were used to relate dTAC and fgTAC to the incidence of depression. The mean follow-up time was 2·96 (1·00) years, and 246 cases of depression were observed (32·3/1000 person-years). The mean dTAC was 11·03 (4·84) mmol/d. We found no associations between higher dTAC and lower risk of developing depression after adjusting for possible confounders. The incidence of depression was inversely associated with fgTAC of the beans and lentils group (hazard ratio (HR): 0·61; 95 % CI 0·41, 0·90). The fgTAC of the junk food group was positively associated with higher incidence of depression after all adjustments (HR: 1·57; 95 % CI 1·08, 2·26). Our findings do not support an association between dTAC and the incidence of depression in a highly educated Brazilian population. However, associations of fgTAC show the importance of analysing the food matrix in which these antioxidants are inserted. We highlight the need for more prospective studies with different nationalities to confirm these results.