SCIENTIFIC INSIGHTS
Intestine: our “second brain”
Have you ever heard of the gut referred to as our "second brain"? This definition—first introduced in 1999 in the book by neurobiologist Michael D. Gershon, a professor of Pathology and Cell Biology at the Columbia University, often called the "father of neuro-gastroenterology"—stems from the fact that within our gut there is a network of neurons identical to those in the brain, forming the so-called enteric nervous system, which interacts with both the central and autonomic nervous systems.
In simple terms, the gut and the brain constantly communicate and influence each other. This is why we talk about the gut-brain axis.
In scientific research, the connection between the enteric nervous system and mental well-being has led to focus on "psychobiotics." What are they?
Intestine and emotional well-being: psychobiotics
Psychobiotics are defined as probiotics beneficial for mood, meaning they can positively influence mental functions. The study of their mechanisms of action is at the forefront of research, and we already have several interesting insights. For example, probiotics play a role in countering inflammatory processes, which underlie many health conditions, including mental disorders, as they disrupt the functionality of affected organs.
Moreover, psychobiotics produce substances in the gut that act on the brain, such as serotonin, the so-called "happiness hormone," and gamma-aminobutyric acid (GABA), an important neurotransmitter involved in modulating responses to stress-related anxiety. These substances can activate intestinal cells, which in turn release molecules that stimulate brain function and influence behaviour.
In short, psychobiotics are indeed very promising for emotional well-being. To learn more, below are some studies on the psychobiotics we have selected for ProbioGea Mente.
Scientific insights
A patented probiotic mix: Limosilactobacillus reuteri PBS072, Bifidobacterium breve BB077
Nobile V, Giardina S, Puoci F. The Effect of a Probiotic Complex on the Gut-Brain Axis: A Translational Study. Neuropsychobiology. 2022;81(2):116-126. doi: 10.1159/000518385. Epub 2021 Aug 30. PMID: 34515196.
This study investigated some mechanisms of action of the probiotic complex through in vitro tests. It was found that those probiotic strains, by processing certain metabolic agents, reduce levels of LSD1 - an enzyme present in neurons that is expressed during stress - and converts stress stimuli into anxious behaviour. Additionally, one test revealed that the metabolites derived from the probiotic strains in the mix not only restored but also significantly increased GABA concentration after stress induction (remember that GABA, or gamma-aminobutyric acid, is a crucial neurotransmitter for modulating responses, particularly to stress-related anxiety). Finally, in an in vitro test on intestinal cells exposed to cortisol (a stress agent), it was observed that cortisol-induced reductions in serotonin levels (another important neurotransmitter, the lack of which is linked to depressive states) were almost completely restored by the strains of the probiotic mix.
This same study includes an interesting clinical trial involving 30 students aged between 18 and 30, selected on the basis of self-reported stress levels during exam preparation. Results suggest that during stressful situations, the administered probiotics promote attention, concentration, and mental flexibility (problem-solving). They enhance intellectual responsiveness, improving short-term memory, and have a positive effect on the quality of life, as evidenced by improvements in sleep quality and anxiety perception.
Nobile V, Puoci F. Effect of a Multi-Strain Probiotic Supplementation to Manage Stress during the COVID-19 Pandemic: A Randomized, Double-Blind, Placebo-Controlled, Cross-Over Clinical Trial. Neuropsychobiology. 2023;82(2):61-71. doi: 10.1159/000527956. Epub 2023 Jan 12. PMID: 36634645; PMCID: PMC9843736.
Another significant placebo-controlled clinical trial tested the use of the probiotic mix on 33 healthy male and female subjects (aged 25 to 60) experiencing typical work-related stress. Sleep quality and mood state were monitored, and various psychophysical parameters (anger, tension, depression, fatigue, confusion, and vigour) were assessed through a questionnaire. The study demonstrated a positive modulation of the mood of the tested subjects, with a significant reduction in both anger and nervous tension, as well as a significant improvement in sleep quality.
Vicariotto F, Malfa P, Torricelli M, Lungaro L, Caio G, De Leo V. Beneficial Effects of Limosilactobacillus reuteri PBS072 and Bifidobacterium breve BB077 on Mood Imbalance, Self-Confidence, and Breastfeeding in Women during the First Trimester Postpartum. Nutrients. 2023 Aug 9;15(16):3513. doi: 10.3390/nu15163513. PMID: 37630704; PMCID: PMC10458832.
Another important area of application for the probiotic complex is supporting women during the postpartum and breastfeeding periods, when anxiety and depressive states related to the new and demanding role can frequently arise. This interesting multicentre clinical study involved a total of 200 new mothers (within the first three months postpartum) aged between 18 and 50, who were breastfeeding, randomly divided into a test group and a placebo group. The first group took the probiotic mix for 90 days, while the second group received an inert product. The mood and quality of life of the new mothers, the breastfeeding quality, and the baby's crying were monitored.
The probiotic mix has been shown to significantly support the mood of mothers compared to the placebo. Additionally, there was a notable improvement in breastfeeding performance among the new mothers, maintaining a positive trend throughout the treatment, with a 24% increase compared to the control group. There was also an improvement in the baby's response to breastfeeding, with a significant reduction in the incidence of crying episodes (-80% in the probiotic group compared to -40% in the control group). This is likely because, in the first six months of life, changes in the composition of breast milk—mediated by the intestinal and skin microbiota—can positively influence the baby's gut microbiota, leading to reduced gas production and, consequently, fewer crying episodes.
Bifidobacterium longum
Boehme M, Rémond-Derbez N, Lerond C, et al. Bifidobacterium longum subsp. longum Reduces Perceived Psychological Stress in Healthy Adults: An Exploratory Clinical Trial. Nutrients. 2023 Jul 13;15(14):3122. doi: 10.3390/nu15143122. PMID: 37513541; PMCID: PMC10383821.
This study examined the effects of a 6-week intake of Bifidobacterium longum on stress-related psychological and physiological parameters in 45 healthy adults (aged 25 to 65) experiencing mild to moderate stress. The main findings showed that the probiotic supplement significantly reduced perceived stress and improved subjective sleep quality compared to the placebo. Statistical analysis also indicated that the significant reduction in perceived stress was correlated with decreased anxiety, depression, and cortisol awakening response. These findings support the hypothesis that treatments with specific probiotics can positively influence perceived stress and its psychological and physical impacts on individual well-being.
Wang H, Braun C, Murphy EF, Enck P. Bifidobacterium longum 1714™ Strain Modulates Brain Activity of Healthy Volunteers During Social Stress. Am J Gastroenterol. 2019 Jul;114(7):1152-1162. doi: 10.14309/ajg.0000000000000203. PMID: 30998517; PMCID: PMC6615936.
The study evaluated the effects of Bifidobacterium longum on neural responses to social stress, induced by the "Cyberball game" (a paradigm for social stress). Forty healthy volunteers received either B. longum or a placebo for 4 weeks. B. longum was found to modulate resting neural activity, inducing increased vitality and reduced mental fatigue. Additionally, the probiotic positively influenced neural responses during social stress, which may be involved in activating brain centres that regulate negative emotions.
Lactobacillus helveticus
Kazemi A, Noorbala AA, Azam K, Eskandari MH, Djafarian K. Effect of probiotic and prebiotic vs placebo on psychological outcomes in patients with major depressive disorder: A randomized clinical trial. Clin Nutr. 2019 Apr;38(2):522-528. doi: 10.1016/j.clnu.2018.04.010. Epub 2018 Apr 24. PMID: 29731182.
For a better understanding of the results of this study, it's important to recall that kynurenine is a substance produced during stress and is a metabolite of tryptophan, the precursor of serotonin. When a person experiences high levels of stress, tryptophan is degraded to kynurenine. Hence, a higher kynurenine-to-tryptophan ratio indicates a more significant physiological stress state. In this interesting clinical study, the effects of probiotic and prebiotic supplementation were compared to a placebo in 81 volunteers with depressive disorders (mean age 36.5 ± 8 years) for 8 weeks. Individuals who took a probiotic mix containing Lactobacillus helveticus and Bifidobacterium longum (both present in ProbioGea Mente) showed a nearly 50% reduction in clinical scores compared to the placebo. Additionally, improvements were observed in the kynurenine/tryptophan and tryptophan/amino acids ratios.
Messaoudi M, Lalonde R, Violle N, et al. Assessment of psychotropic-like properties of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in rats and human subjects. Br J Nutr. 2011 Mar;105(5):755-64. doi: 10.1017/S0007114510004319. Epub 2010 Oct 26. PMID: 20974015.
In this clinical study involving 55 healthy male and female volunteers, a probiotic mix consisting of Lactobacillus helveticus and Bifidobacterium longum was administered for 30 days, compared to a placebo. Participants were assessed at the beginning and end of the treatment using several scales: the Hopkins Symptom Checklist (HSCL-90), which analyses a wide range of psychopathological disorders; the Hospital Anxiety and Depression Scale (HADS), which measures psychological distress in individuals with somatic or psychosomatic disorders; the Perceived Stress Scale (PSS), which evaluates how recent life situations are perceived as stressful; the Coping Checklist (CCL), which measures five types of strategies for coping with adverse events (problem-solving, avoidance with wishful thinking, seeking social support, positive reappraisal, and self-blame); and urinary free cortisol over 24 hours (UFC).
The administration of the probiotic mix alleviated psychological distress in the volunteers, significantly improving parameters on the HSCL-90 (for global severity index, somatization, depression, and anger-hostility), the HADS (for overall score and anxiety), and the CCL (problem-solving), while also reducing urinary cortisol levels (UFC). Therefore, the combination of L. helveticus and B. longum demonstrates anxiolytic-like activity and beneficial psychological effects.
Inulin from chicory
Qin YQ, Wang LY, Yang XY, et al. Inulin: properties and health benefits. Food Funct. 2023 Apr 3;14(7):2948-2968. doi: 10.1039/d2fo01096h. PMID: 36876591.
This review of studies focuses on the function of inulin and its health benefits. In addition to highlighting its recognized prebiotic activity and its contribution to the balance of the gut microbiota, the review mentions many other benefits of inulin, including its positive effects in alleviating depressive states.
Hughes RL, Alvarado DA, Swanson KS, Holscher HD. The Prebiotic Potential of Inulin-Type Fructans: A Systematic Review. Adv Nutr. 2022 Mar;13(2):492-529. doi: 10.1093/advances/nmab119. Epub 2023 Feb 10. PMID: 34555168; PMCID: PMC8970830.
This review of studies confirms the prebiotic effect of inulin on the gut microbiota - where it promotes levels of bifidobacteria and lactobacilli - as well as its beneficial action for intestinal barrier function.
DISCLAIMER
Our texts are for informational purposes only and should not be considered as indications for diagnosis and treatment of pathological conditions. They cannot replace your physician’s advice.
I nostri testi hanno scopo divulgativo, non vanno intesi come indicazione di diagnosi e cura di stati patologici e non vogliono sostituirsi in alcun modo al parere del Medico.
