Impact of high prebiotic and probiotic dietary education in the SARS-CoV-2 era: improved cardio-metabolic profile in schizophrenia spectrum disorders

Altered gut microbiota and systemic immunity in Chinese patients with schizophrenia comorbid with metabolic syndrome

BACKGROUND

Metabolic syndrome (MetS) is highly prevalent in individuals with schizophrenia (SZ), leading to negative consequences like premature mortality. Gut dysbiosis, which refers to an imbalance of the microbiota, and chronic inflammation are associated with both SZ and MetS. However, the relationship between gut dysbiosis, host immunological dysfunction, and SZ comorbid with MetS (SZ-MetS) remains unclear. This study aims to explore alterations in gut microbiota and their correlation with immune dysfunction in SZ-MetS, offering new insights into its pathogenesis.

METHODS AND RESULTS

We enrolled 114 Chinese patients with SZ-MetS and 111 age-matched healthy controls from Zhejiang, China, to investigate fecal microbiota using Illumina MiSeq sequencing targeting 16 S rRNA gene V3-V4 hypervariable regions. Host immune responses were assessed using the Bio-Plex Pro Human Cytokine 27-Plex Assay to examine cytokine profiles. In SZ-MetS, we observed decreased bacterial α-diversity and significant differences in β-diversity. LEfSe analysis identified enriched acetate-producing genera (Megamonas and Lactobacillus), and decreased butyrate-producing bacteria (Subdoligranulum, and Faecalibacterium) in SZ-MetS. These altered genera correlated with body mass index, the severity of symptoms (as measured by the Scale for Assessment of Positive Symptoms and Scale for Assessment of Negative Symptoms), and triglyceride levels. Altered bacterial metabolic pathways related to lipopolysaccharide biosynthesis, lipid metabolism, and various amino acid metabolism were also found. Additionally, SZ-MetS exhibited immunological dysfunction with increased pro-inflammatory cytokines, which correlated with the differential genera.

CONCLUSION

These findings suggested that gut microbiota dysbiosis and immune dysfunction play a vital role in SZ-MetS development, highlighting potential therapeutic approaches targeting the gut microbiota. While these therapies show promise, further mechanistic studies are needed to fully understand their efficacy and safety before clinical implementation.

Nutraceuticals in Psychiatric Disorders: A Systematic Review

Correct nutrition and diet are directly correlated with mental health, functions of the immune system, and gut microbiota composition. Diets with a high content of some nutrients, such as fibers, phytochemicals, and short-chain fatty acids (omega-3 fatty acids), seem to have an anti-inflammatory and protective action on the nervous system. Among nutraceuticals, supplementation of probiotics and omega-3 fatty acids plays a role in improving symptoms of several mental disorders. In this review, we collect data on the efficacy of nutraceuticals in patients with schizophrenia, autism spectrum disorders, major depression, bipolar disorder, and personality disorders. This narrative review aims to provide an overview of recent evidence obtained on this topic, pointing out the direction for future research.

An Update on Prebiotics and on Their Health Effects

Prebiotic compounds were originally defined as "a nondigestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and thus improves host health"; however, a significant modulation of the definition was carried out in the consensus panel of The International Scientific Association for Probiotics and Prebiotics (ISAPP), and the last definition states that "prebiotics are substrates that are selectively utilized by host microorganisms conferring a health benefit". Health effects of prebiotics compounds attracted the interest of researchers, food companies and Regulatory Agencies, as inferred by the number of articles on Scopus for the keywords "prebiotic" and "health effects", that is ca. 2000, for the period January 2021-January 2024. Therefore, the aim of this paper is to contribute to the debate on these topics by offering an overview of existing knowledge and advances in this field. A literature search was performed for the period 2012-2023 and after the selection of the most relevant items, the attention was focused on seven conditions for which at least 8-10 different studies were found, namely colorectal cancer, neurological or psychiatric conditions, intestinal diseases, obesity, diabetes, metabolic syndrome, and immune system disorders. In addition, the analysis of the most recent articles through the software VosViewer version 1.6.20 pointed out the existence of five clusters or macro-categories, namely: (i) pathologies; (ii) metabolic condvitions; (iii) structure and use in food; (iv) immunomodulation; (v) effect on gut microbiota.

Nutritional Impact and Eating Pattern Changes in Schizophrenic Spectrum Disorders after Health Education Program on Symbiotic Dietary Modulation Offered by Specialised Psychiatric Nursing-Two-Arm Randomised Clinical Trial

Background: The traditional therapeutic approach has perceived the role of nutrition as a minor intervention in psychiatry. The microbiota−gut−brain axis theory evidences the influence of dietary and nutritional patterns on mental health. Aims: To evidence the impact of dietary advice on increasing symbiotic intake on nutritional status and dietary habits in individuals with schizophrenia spectrum disorders. Methods: Randomised clinical trial (two-arm, double-blind, balanced-block, six-month intervention) in 50 individuals diagnosed with schizophrenia spectrum disorders. The control group received conventional dietary advice on an individual basis. A personal nutritional education programme was established in the intervention group (IG) to increase prebiotic and probiotic intake through dietary advice (dairy and fermented foods, green leafy vegetables, high-fibre fruit, whole grains, etc.). Data on nutritional status and dietary habits were collected (baseline and six months). The degree of dietary adherence to the recommended patterns was recorded weekly. Anthropometric parameters were also analysed monthly. Results: Finally, 44 subjects completed the follow-up. All participants exceeded the dietary reference intakes. The overall and intra-group analysis showed a statistically significant (p < 0.05) reduction in macro and micronutrient intakes with a closer approximation to the recommended dietary intakes, except for polyunsaturated fatty acids, oligosaccharides, polysaccharides and dietary fibre. After six months of intervention, statistical differences (p < 0.001) were found in all variables of the anthropometric profile in the IG, as well as an increase in the consumption of foods with a high symbiotic content (at baseline and six months). Likewise, a reduction in eggs, meat, fish, sugars and ultra-processed foods was evident, leading to significant intra-group differences (p < 0.05). Conclusions: Implementing conventional nutritional education strategies and specific nutritional advice with a symbiotic effect improves the dietary-nutritional profile in patients with schizophrenia spectrum disorders. Furthermore, it highlights the nutritional impact on mental health, stating itself as adjuvant therapy for physical health and lifestyle improvement.