Irritable bowel syndrome is a highly prevalent gastrointestinal disorder that threatens the quality of life of millions and poses a substantial financial burden on healthcare systems around the world. Intense research into the human microbiome has led to fascinating discoveries which directly and indirectly implicate the diversity and function of this occult organ in irritable bowel syndrome (IBS) pathophysiology. The benefit of manipulating the gastrointestinal microbiota with diet and probiotics to improve symptoms has been demonstrated in a wealth of both animal and human studies. The positive and negative mechanistic roles bacteria play in IBS will be explored and practical probiotic and dietary choices offered.
Migraine is a common and disabling neurological condition with a complex etiology. Recent advances in the understanding of the gut microbiome have shown the role of gut micro-organisms in disease outcomes for distant organs—including the brain. Interventions targeting the gut microbiome have been shown to be effective in multiple neurological diagnoses, but there is little research into the role of the microbiome in migraine. This systematic review seeks to assess the current research landscape of randomized placebo controlled trials utilizing probiotic interventions as migraine prophylaxis. Searches were conducted of scientific databases including PubMed, MEDLINE, and the Cochrane Library, following PRISMA guidelines. Of 68 screened studies, 2 were eligible for analysis. Due to methodological differences, meta-analysis was not possible. Qualitative comparison of the studies demonstrated a dichotomy of results—one trial reported no significant change in migraine frequency and intensity, while the second trial reported highly significant improvements. No clear ‘gold standard’ currently exists for microbiome research, let alone for migraine-related microbiome research. The heterogeneity of outcome measures used in the two trials included in this systematic review shows the need for a standardization of outcome measures, therefore a series of recommendations for future probiotic–migraine research are included.
The gut–brain axis refers to the bidirectional biochemical pathways linking the central nervous system with the gastrointestinal tract. Research suggests that changes in the micro-organisms found in the GI tract (the gut microbiota) can affect the brain's physiological, behavioural and cognitive functions. And through this so-called microbiota gut–brain axis it has been suggested that multiple neurological and psychiatric diagnoses (including Parkinson's disease, Alzheimer's disease, anxiety, depression and migraine) may be influenced by the micro-organisms of the gut. Migraine is a common and frequently debilitating condition. It has a global prevalence of approximately 15% and is responsible for millions of lost school and work days globally every month. Migraine is characterised by repeated, severe and protracted headaches, often preceded or accompanied by nausea, sensory hypersensitivity and visual disturbances. Migraine can be managed with analgesic and prophylactic drugs, although these are not always effective and can frequently have significant side effects. Some promising phase I/II studies suggest that certain combinations of probiotics could reduce the frequency and severity of migraine symptoms, with consequent reductions in medication use. Although research into microbiome-related treatments for migraine are in their infancy, further research into the field, including larger, phase III trials, could provide many millions of migraine patients with an alternative to traditional pharmacological means of managing migraine symptoms.
The human microbiome plays a vital role in patients' susceptibility to infections. A change to the composition of the microbiome-be it a change in the presence or abundance of microbial species or the introduction of new pathogens-may result in dysbiosis, which has been identified in patients with acute gastroenteritis (AGE) and antibiotic-associated diarrhoea (AAD). Probiotics can ameliorate dysbiosis, and there is extensive research into their use in AGE and AAD. Recently, national and international bodies-inlcuding the European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) and the National Institute for Health and Care Excellence (NICE) Clinical Knowledge Summaries (CKS)-have recommended the use of probiotics in the treatment of AGE and the prevention of AAD and Clostridium difficile infections (CDI). Also, there is emerging evidence suggesting that the perioperative use of probiotics in elective surgery can reduce rates of surgical infections (SI) and reduce the need for postoperative antibiotics. A growing body of evidence suggests that probiotics should be considered as an adjunct to standard protocols in AGE, AAD, CDI and SI, and this review summarises recent developments in probiotic research in these conditions.
AimsThe aim of this proof-of-concept study was to understand the effect of daily intake of a 14-strain probiotic on mood, reward learning and emotional and cognitive processing in adults with low mood in the absence of prescribed medication. Salivary cortisol was measured as a marker for physiological stress.MethodsIn this parallel-group double-blind, placebo-controlled trial, 80 healthy adults with self-identified low mood were randomised to receive either the 14-strain probiotic or placebo for a duration of 4 weeks. Data were collected from participants at baseline (week 0) and post-intervention (week 4).ResultsProbiotic intake significantly reduced depression scores (by 50%) compared to baseline, as measured by the Patient Health Questionnaire-9 (PHQ-9) scale (p < 0.05). Analysis of individual items in the PHQ-9 revealed that participants taking probiotics reported improved concentration relative to baseline (+ 51%, p < 0.05) and felt less tired compared to placebo (−21%, p < 0.01).Regarding emotional processing, the probiotic group was more accurate at recognising facial expressions compared to those receiving placebo (facial emotion recognition test, +12%, p < 0.05). Furthermore, the probiotic group performed less well at the reward learning task relative to the placebo group (probabilistic instrumental learning task, p < 0.05) and was less vigilant to emotional cues compared neutral cues (dot-probe unmasked test, −8%, P < 0.05). The probiotic group also showed increased susceptibility to emotional interference during a cognitive learning task, relative to placebo (auditory visual learning task, −18% p < 0.05).The study also revealed a downward trend in salivary cortisol in the probiotic group over 4 weeks.Together, these results suggest that probiotics may work via a different psychological mechanism to that of conventional antidepressants. In other words, probiotics may work by reducing emotional salience across all emotions whereas conventional antidepressants are thought to work by increasing bias to positive emotional cues and decreasing bias to negative ones.ConclusionThese data suggest that intake of Bio-Kult® Advanced has an effect on mood and that this is achieved in ways distinct from the effects of pharmacological antidepressants. While more research is needed, these results suggest that certain probiotics could form part of an ‘early intervention’ strategy for people experiencing low mood. A second randomised controlled trial (currently recruiting) will provide data on this intervention in patients with a formal diagnosis of depression undergoing concurrent pharmacological treatment.ClinicalTrials.gov Identifier: NCT03801655
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.