Gaba-producing lactobacilli boost cognitive reactivity to negative mood without improving cognitive performance: A human Double-Blind Placebo-Controlled Cross-Over study.

BACKGROUND: Psychobiotic bacteria are probiotics able to influence stress-related behavior, sleep, and cognitive outcomes. Several in vitro and human studies were performed to assess their physiological potential, to find strains having psychotropic activity in humans, and to elucidate the metabolic pathways involved. In our previous in vitro study, we identified two strains Levilactobacillus brevis P30021 and Lactiplantibacillus plantarum P30025, able to produce GABA and acetylcholine, being promising candidates to provide an effect on mood and cognitive performance. AIM: To investigate the effects of probiotics in the alleviation on the cognitive performance of moderately stressed healthy adults. Secondary outcomes were related to mood improvement, production of GABA, glutamate, acetylcholine, and choline and modification of the microbiota composition. METHODS: A 12-week randomized, double-blind, placebo-controlled, cross-over study investigated the effects of a probiotic formulation (Levilactobacillus brevis P30021 and Lactiplantibacillus plantarum P30025) on psychological, memory, and cognition parameters in 44 (Probiotic = 44, Placebo = 43) adults with a mean age of 29 ± 5.7 years old by CogState Battery test. Subjects-inclusion criteria was a mild-moderate (18.7 ± 4.06) stress upon diagnosis using the DASS-42 questionnaire. RESULTS: Probiotic treatment had no effect on subjective stress measures. The probiotic formulation showed a significant beneficial effect on depressive symptoms by reducing cognitive reactivity to sad mood (p = 0.034). Rumination significantly improved after intake of the probiotic (p = 0.006), suggesting a potential benefit in reducing the negative cognitive effects associated with depression and improving overall mental health. When stratifying the treated subjects according to the response, we found an increase in the abundance of the probiotic genera in the gut microbiota of positive responders (p = 0.009 for Lactiplantibacillus and p = 0.004 for L.brevis). No relevant correlations were observed between the neurotransmitter concentration in the faecal sample, scores of LEIDS, DASS-42, and cognitive tests. CONCLUSION: We highlight the potential of this probiotic preparation to act as psycobiotics for the relief of negative mood feelings. The assessment of the psychotropic effects of dietary interventions in human participants has many challenges. Further interventional studies investigating the effect of these psychobiotic bacteria in populations with stressed-related disorders are required including longer period of intervention and larger sample size in order to verify the effects of the treatment on further stress-related indicators.

Recent advances in bio-based extraction processes for the recovery of bound phenolics from agro-industrial by-products and their biological activity.

Usually found bound to other complex molecules (e.g., lignin, hemicellulose), phenolic compounds (PC) are widely present in agro-industrial by-products, and their extraction is challenging. In recent times, research is starting to highlight the bioactive roles played by bound phenolics (BPC) in human health. This review aims at providing a critical update on recent advances in green techniques for the recovery of BPC, focusing on enzymatic-assisted (EAE) and fermentation-assisted extraction (FAE) as well as in the combination of technologies, showing variable yield and features. The present review also summarizes the most recent biological activities attributed to BPC extracts until now. The higher antioxidant activity of BPC-compared to FPC-coupled with their affordable by-product source make them medicinally potent and economically viable, promoting their integral upcycling and generating new revenue streams, business, and employment opportunities. In addition, EAE and FAE can have a biotransformative effect on the PC itself or its moiety, leading to improved extraction outcomes. Moreover, recent research on BPC extracts has reported promising anti-cancer and anti-diabetic activity. Yet further research is needed to elucidate their biological mechanisms and exploit the true potential of their applications in terms of new food products or ingredient development for human consumption.

Psychobiotics, gut microbiota and fermented foods can help preserving mental health.

Psychobiotics include a novel class of probiotic microorganisms that convey benefit upon the host's mental health via the dynamic microbiota-gut-brain crosstalk. Research is bolstering the concept that gut bacteria are involved in the transmission of information between the gut and the brain, engaging neural, immune, and endocrine pathways. Factors such as diet, stress and aging can shape the microbiota composition in a process that may also influence the onset and development of mental diseases. This review aims to provide an outline of the link between the microbiota and brain function focusing on preclinical and clinical evidence of the potential application of psychobiotics in the context of the cognitive process and performance. The occurrence of metabolic precursors of neurotransmitters in foods that can be converted by the gut microbiota and play a role in the gut-brain axis is discussed. The understanding of the molecular mechanisms by which communication occurs is still at its infancy; however clinical studies have shown that dietary interventions based on psychobiotics might be a novel nutritional approach targeting gut microbiota for managing cognitive performance and preventing memory decline across the lifespan.