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Effect of Calorie Restriction and Intermittent Fasting Regimens on Brain-Derived Neurotrophic Factor Levels and Cognitive Function in Humans: A Systematic Review.
Alkurd, R, Mahrous, L, Zeb, F, Khan, MA, Alhaj, H, Khraiwesh, HM, Faris, ME
Medicina (Kaunas, Lithuania). 2024;60(1)
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Brain-derived neurotrophic factor (BDNF) is a protein that plays a crucial role in brain development, cognition and metabolism. Intermittent fasting (IF) is a promising therapeutic strategy for managing metabolic disorders and improving cognitive function. Therefore, this systematic review of sixteen experimental and observational studies investigated the effect of IF on BDNF production and improvements in cognition through the BDNF pathway in healthy adults and people with metabolic disorders. Included studies focused on different IF regimens such as calorie restriction (CR), alternate-day fasting (ADF), time-restricted eating (TRE) and Ramadan model of intermittent fasting (RIF) Future, well-controlled, long-term, robust studies are required to assess the effect of different IF regimens on the production of BDNF and cognitive function in people with metabolic disorders, as the current research is inconclusive. However, healthcare professionals can use the review to understand the potential beneficial effects of IF on cognition and metabolic health in humans.
Abstract
Background: The potential positive interaction between intermittent fasting (IF) and brain-derived neurotrophic factor (BDNF) on cognitive function has been widely discussed. This systematic review tried to assess the efficacy of interventions with different IF regimens on BDNF levels and their association with cognitive functions in humans. Interventions with different forms of IF such as caloric restriction (CR), alternate-day fasting (ADF), time-restricted eating (TRE), and the Ramadan model of intermittent fasting (RIF) were targeted. Methods: A systematic review was conducted for experimental and observational studies on healthy people and patients with diseases published in EMBASE, Scopus, PubMed, and Google Scholar databases from January 2000 to December 2023. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statements (PRISMA) for writing this review. Results: Sixteen research works conducted on healthy people and patients with metabolic disorders met the inclusion criteria for this systematic review. Five studies showed a significant increase in BDNF after the intervention, while five studies reported a significant decrease in BDNF levels, and the other six studies showed no significant changes in BDNF levels due to IF regimens. Moreover, five studies examined the RIF protocol, of which, three studies showed a significant reduction, while two showed a significant increase in BDNF levels, along with an improvement in cognitive function after RIF. Conclusions: The current findings suggest that IF has varying effects on BDNF levels and cognitive functions in healthy, overweight/obese individuals and patients with metabolic conditions. However, few human studies have shown that IF increases BDNF levels, with controversial results. In humans, IF has yet to be fully investigated in terms of its long-term effect on BDNF and cognitive functions. Large-scale, well-controlled studies with high-quality data are warranted to elucidate the impact of the IF regimens on BDNF levels and cognitive functions.
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Impact of probiotics on muscle mass, muscle strength and lean mass: a systematic review and meta-analysis of randomized controlled trials.
Prokopidis, K, Giannos, P, Kirwan, R, Ispoglou, T, Galli, F, Witard, OC, Triantafyllidis, KK, Kechagias, KS, Morwani-Mangnani, J, Ticinesi, A, et al
Journal of cachexia, sarcopenia and muscle. 2023;14(1):30-44
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Sarcopenia is a progressive skeletal muscle disorder involving accelerated loss of muscle mass, strength and function. It generally occurs in older age groups but can also be seen in younger people. Multiple factors contribute to the development of the condition. Besides nutritional management strategies, probiotics have recently caught the interest of researchers. As probiotics promote metabolic building activity, aid digestion and absorption and reduce muscle breakdown by favourably managing inflammation, they present great potential for the management of sarcopenia. This systematic review and meta-analysis explored the impact of probiotic supplementation on muscle mass, total lean mass and muscle strength in human adults. The review included 24 studies, with probiotics mainly from the Bifidobacteria or Lactobacilli family. The analysis concluded that probiotic supplementation improved muscle mass in comparison to placebos. It also significantly increased overall muscle strength in 6 randomized controlled trials, which was most obvious in age groups of 50 and above. However, no changes were seen concerning total lean mass. It appeared that longer studies, of >12 weeks or more, showed better outcomes in this review. Furthermore, Bifidobacteria species seemed to exhibit more favourable effects, and the authors also noted the beneficial results were more significant in Asian populations. Further research is needed to understand more about the underlying mechanism, best probiotics strains and the specifics of different demographic groups. This article yields a concise overview of sarcopenia, the nutritional aspects of the disease and how probiotics may be beneficial in disease management, strengthened with data from the review.
Expert Review
Conflicts of interest:
None
Take Home Message:
- This was a well-conducted meta-analysis based on its methodological approach that demonstrated that Lactobacillus and Bifidobacterium probiotic supplementation may contribute to improved muscle mass in younger adults and improved muscle strength in older adults.
- Bifidobacterium probiotic supplementation was associated with enhanced muscle mass in younger adults, a potential focus for those considering probiotic supplements.
- The duration of probiotic therapy matters, with longer-term (12 weeks or more) supplementation showing improvements in muscle mass and strength..
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
This systematic review and meta-analysis evaluated the effect of probiotics on muscle mass, total lean mass and muscle strength in both young and older adults.
Methods
- The search encompassed PubMed, Scopus, Web of Science, and Cochrane Library databases, from inception up to June 2022; studies included spanned a period from 2013 to June 2022.
- The study adhered to Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines and included the Risk-of-Bias tool to assess study quality.
- The study focused on changes in muscle mass, total lean mass, and muscle strength.
- Inclusion criteria: randomised controlled trials (RCTs) with adult participants (>18 years); interventions involving any probiotics, and a control group receiving either no treatment or a placebo.
Results
- 24 RCTs were included (709 participants), with studies conducted in Europe, USA, and Asia. Intervention durations: ranged from 3 weeks to 12 months.
- Participants included overweight, untrained healthy and resistance-trained individuals, and those with specific conditions like metabolic syndrome and frailty.
- Body composition assessments were conducted using bioelectrical impedance (BIA) and/or dual-energy X-ray absorptiometry (DXA).
- Probiotic strains employed in the included studies varied, with Lactobacillus the most common, followed by Bifidobacterium; some combined both. 5 of 24 studies also used additional strains.
- Dosages: ranged from 2 × 10^9 to 11.2 × 10^10 colony-forming units (CFU).
- 4 out of 24 studies used fermented food products like cheese and noodles as sources of probiotics.
- 22 RCTs measured muscle mass and total lean mass; 6 RCTs measured global muscle strength.
- Probiotic supplementation (≥12 weeks) moderately increased muscle mass, with a standardised mean difference (SMD) of 0.42. This significant effect (95% CI: 0.10–0.74, P=0.009) was observed only in younger Asian adults (<50 years) after Bifidobacterium supplementation, based on a meta-analysis of 10 studies.
- Probiotic supplementation (≥12 weeks) significantly increased global muscle strength in older adults (>50 years; SMD: 0.69, 95% CI: 0.33–1.06, P = 0.0002).
- Probiotic supplementation showed no significant impact on lean mass (SMD: -0.03, 95% CI: 0.19 – 0.13, P = 0.69).
Conclusion
Probiotic supplementation, especially Lactobacillus and Bifidobacterium may have a positive impact on muscle mass and global strength
Clinical practice applications:
- Consumption of probiotics, mainly Lactobacillus and Bifidobacterium may contribute to improved muscle strength in older individuals (>50y).
- Consumption of Bifidobacterium strains was associated with improved muscle mass in younger individuals (<50y) in Asian countries, in a low number of studies (k=2).
- Bifidobacterium breve B-3 was associated with an improvement in muscle mass in older overweight individuals, although a causal relationship was not established.
- Probiotics may enhance muscle mass or strength by enhancing protein digestion and amino acid absorption for muscle synthesis and function.
- Considering an individual’s goals, a practitioner could consider probiotic supplementation as a complementary intervention when aiming to enhance muscle mass or strength .
Considerations for future research:
- Future research could focus on pinpointing which specific probiotic strains are most effective for muscle strength or muscle mass to tailor more precise interventions.
- Most studies did not exceed 12 weeks, highlighting the need for long-term research on probiotics sustained muscle impact.
- Future research could investigate the effects of probiotics across diverse demographic groups including different ages, sexes, and ethnic backgrounds to understand the impact in different populations.
- Delving deeper into the mechanisms by which probiotics influence muscle health could lead to targeted probiotic therapies that address specific physiological pathways.
- Finally, future research could explore how probiotics can be combined with other interventions, such as exercise or nutritional modifications, to synergistically improve muscle health and function.
Abstract
Probiotics have shown potential to counteract sarcopenia, although the extent to which they can influence domains of sarcopenia such as muscle mass and strength in humans is unclear. The aim of this systematic review and meta-analysis was to explore the impact of probiotic supplementation on muscle mass, total lean mass and muscle strength in human adults. A literature search of randomized controlled trials (RCTs) was conducted through PubMed, Scopus, Web of Science and Cochrane Library from inception until June 2022. Eligible RCTs compared the effect of probiotic supplementation versus placebo on muscle and total lean mass and global muscle strength (composite score of all muscle strength outcomes) in adults (>18 years). To evaluate the differences between groups, a meta-analysis was conducted using the random effects inverse-variance model by utilizing standardized mean differences. Twenty-four studies were included in the systematic review and meta-analysis exploring the effects of probiotics on muscle mass, total lean mass and global muscle strength. Our main analysis (k = 10) revealed that muscle mass was improved following probiotics compared with placebo (SMD: 0.42, 95% CI: 0.10-0.74, I2 = 57%, P = 0.009), although no changes were revealed in relation to total lean mass (k = 12; SMD: -0.03, 95% CI: -0.19 - 0.13, I2 = 0%, P = 0.69). Interestingly, a significant increase in global muscle strength was also observed among six RCTs (SMD: 0.69, 95% CI: 0.33-1.06, I2 = 64%, P = 0.0002). Probiotic supplementation enhances both muscle mass and global muscle strength; however, no beneficial effects were observed in total lean mass. Investigating the physiological mechanisms underpinning different ageing groups and elucidating appropriate probiotic strains for optimal gains in muscle mass and strength are warranted.
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The efficacy of fermented foods in the treatment and management of diarrhoeal diseases: A systematic review and meta-analysis.
Olayanju, A, Mellor, D, Khatri, Y, Pickles, N
Nutrition and health. 2023;29(1):71-83
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According to World Health Organisation (WHO), diarrhoeal disease is the second leading cause of death among children under the age of 5 in the world. The WHO’s recommendation for the treatment of diarrhoea is oral rehydration solution (ORS), consisting of a solution of clean water, sugar and salt along with a 10-14 day supplemental treatment course of dispersible 20 mg zinc tablets. The aim of this study was to evaluate the available evidence with respect to the efficacy of fermented foods and beverages in comparison with unfermented or heat-treated products, including dairy and cereal products, focussing on the treatment of diarrhoea in infants. This study is a systematic review and meta-analysis of seven randomised controlled trials. Results show that administering fermented foods during an episode of diarrhoea in infants under five years of age, may reduce the duration of the disease in comparison to the control groups. There was no clear effect on daily stool frequency, but duration of hospitalisation was reduced following administration of fermented foods. Authors conclude that fermented foods may be helpful in the treatment of diarrhoea in infants up to the age of five. Thus, more good quality trials are required to investigate the complex matrix of fermented food products, other than dairy foods, in the management, particularly treatment of gastrointestinal diseases such as diarrhoea.
Abstract
Background: Diarrhoeal disease is a major cause of global infant mortality, and compromises the ability of many countries with respect to achieving sustainable development goals. The WHO's recommendation of Oral Rehydration Solution (ORS) and zinc in the management of this disease, may not be readily available. Consideration and assessment of cultural practices in its management has been an area of increased interest over the last decade. Aim: This study aims to systematically evaluate efficacy of the consumption of traditional fermented foods as functional products for the treatment and management of diarrhoea. Methods: Following PRISMA guidelines, a systematic review was conducted of electronic databases (Cochrane Library, Ovid Medline and Pubmed) databases with no restrictions on language and publication date for RCTs that investigated the effect of consumption of fermented foods on the treatment of diarrhoea in children under five years of age. Results: Seven RCTs were included. Meta-analysis showed that compared to control, consumption of fermented foods significantly reduced mean duration of diarrhoea, -0.61 days; (95% CI, -1.04, -0.18); length of hospitalization, -0.35 days (95% CI, -0.69, -0.02); but not mean daily frequency of stool -2.00 (95% CI,-7.03, 3.04). Conclusion: Limited available evidence suggests that consumption of fermented foods may help reduce duration and severity of symptoms as a treatment of diarrhoea. More high quality research needs to be undertaken to investigate the efficacy of fermented food as an effective alternative to ORS as a potential WHO recommendation for management of diarrhoeal disease.
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The effects of dietary patterns and food groups on symptomatic osteoarthritis: A systematic review.
Zeng, J, Franklin, DK, Das, A, Hirani, V
Nutrition & dietetics: the journal of the Dietitians Association of Australia. 2023;80(1):21-43
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Osteoarthritis is a chronic joint disease that can lead to disability, characterised by the deterioration and loss of joint cartilage, inflammation, pain, aches, and stiffness. Research has shown a positive association between osteoarthritis progression and pro-inflammatory diets, such as Western diets, and a negative association with anti-inflammatory diets, such as the DASH and Mediterranean diets. This systematic review evaluated the evidence from the literature to show the positive and negative associations between osteoarthritis and diet. The Prudent diet, Mediterranean diet, and increased fibre intake were effective in reducing the progression of osteoarthritis and alleviating its symptoms, while the Western diet increased the progression of symptomatic osteoarthritis. The Prudent diet was found to be particularly effective in alleviating symptomatic osteoarthritis. The beneficial effects of anti-inflammatory diets and increased fibre intake are thought to be due to the reduction and suppression of inflammatory cytokines, while inflammatory diets have the opposite effect. Although there is high heterogeneity between the studies, healthcare professionals can use the results of this systematic review to understand the therapeutic clinical utility of anti-inflammatory diets and high-fibre intake in reducing the progression of symptomatic osteoarthritis in people above the age of 45 years. Further robust studies are needed to evaluate the effectiveness of other therapeutic dietary strategies.
Abstract
AIM: To systematically review current literature to determine the association between symptomatic osteoarthritis and dietary patterns, diet quality and food groups in adults aged ≥45 years. METHODS The review was registered on PROSPERO (CRD42021270891). Cochrane Central Library, Cumulative Index of Nursing and Allied Health Literature, Embase, Medline and Web of Science databases were searched. A total of 3816 records were identified. Eligible articles involved populations aged ≥45 years with symptomatic osteoarthritis, assessing dietary patterns, diet quality or food groups, with pain in joints as outcomes. The Joanna Briggs Institute Critical Appraisal Checklists were used for quality assessment. Grading of Recommendations, Assessment, Development and Evaluation was used to assess the certainty of evidence. RESULTS Six cohort studies were included. The Prudent dietary pattern and the Mediterranean dietary pattern reduced the progression of osteoarthritis symptoms. The Western dietary pattern increased symptomatic osteoarthritis progression. Increased total fibre consumption reduced symptomatic osteoarthritis progression and pain worsening, but the effects of fibre from each food group were inconclusive. Diet with high inflammatory potential increased risk of new onset symptomatic osteoarthritis, but the effects of overall diet quality were inconclusive. CONCLUSIONS The Prudent dietary pattern showed the highest protection on symptomatic osteoarthritis in adults aged 45 years and over. The body of evidence is limited, suggesting that further research is needed to corroborate the estimated effect at a high certainty of evidence, and to incorporate previously unstudied dietary patterns and food groups. Identifying the most beneficial dietary pattern may inform future guidelines for reducing symptomatic osteoarthritis in middle aged and older adults.
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Modulating the Gut Microbiome in Multiple Sclerosis Management: A Systematic Review of Current Interventions.
Tsogka, A, Kitsos, DK, Stavrogianni, K, Giannopapas, V, Chasiotis, A, Christouli, N, Tsivgoulis, G, Tzartos, JS, Giannopoulos, S
Journal of clinical medicine. 2023;12(24)
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Multiple sclerosis (MS) is an autoimmune disease caused by the altered immune system mistakenly attacking the central nervous system. While genetics play a leading causative role in the manifestation of this disease, other contributing environmental factors can also exist, such as a disruption in the intestinal microbial composition. Previous research has shown that the bidirectional communication between the brain's and gut's health, also known as the gut-brain axis, may contribute to the prognosis of MS. Modulating gut microbial composition can be a therapeutic strategy in MS patients to manage symptoms and prevent disease progression. This systematic review assessed different protocols for modulating gut microbial composition, including dietary modifications, probiotic use, intermittent fasting, and faecal microbial transplantation. The review included thirteen studies that compared the effects of the above gut microbial modulation intervention protocols in MS patients with healthy participants. While different dietary modification strategies improved MS symptoms, probiotic supplementations and intermittent fasting reduced inflammation, and faecal microbial transplantation showed promising positive effects in a few reports. Due to the methodological limitations of the included studies, further robust studies are required to evaluate the beneficial effects of gut microbial modulation strategies in reducing the symptoms of MS patients. However, healthcare professionals can use the results of this study to understand the benefits of gut microbial modulation in MS patients.
Abstract
This review attempted to explore all recent clinical studies that have investigated the clinical and autoimmune impact of gut microbiota interventions in multiple sclerosis (MS), including dietary protocols, probiotics, fecal microbiota transplantation (FMT), and intermittent fasting (IF). Methods: Thirteen studies were held between 2011 and 2023 this demonstrated interventions in gut microbiome among patients with MS and their impact the clinical parameters of the disease. These included specialized dietary interventions, the supply of probiotic mixtures, FMT, and IF. Results: Dietary interventions positively affected various aspects of MS, including relapse rates, EDSS disability scores, MS-related fatigue, and metabolic features. Probiotic mixtures showed promising results on MS-related fatigue, EDSS parameters, inflammation; meanwhile, FMT-though a limited number of studies was included-indicated some clinical improvement in similar variables. IF showed reductions in EDSS scores and significant improvement in patients' emotional statuses. Conclusions: In dietary protocols, clinical MS parameters, including relapse rate, EDSS, MFIS, FSS, and MSQoL54 scales, were significantly improved through the application of a specific diet each time. Probiotic nutritional mixtures promote a shift in inflammation towards an anti-inflammatory cytokine profile in patients with MS. The administration of such mixtures affected disability, mood levels, and quality of life among patients with MS. FMT protocols possibly demonstrate a therapeutic effect in some case reports. IF protocols were found to ameliorate EDSS and FAMS scores. All interventional means of gut microbiome modulation provided significant conclusions on several clinical aspects of MS and highlight the complexity in the relationship between MS and the gut microbiome.
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Advancements in Nutritional Strategies for Gestational Diabetes Management: A Systematic Review of Recent Evidence.
Sánchez-García, JC, Saraceno López-Palop, I, Piqueras-Sola, B, Cortés-Martín, J, Mellado-García, E, Muñóz Sánchez, I, Rodríguez-Blanque, R
Journal of clinical medicine. 2023;13(1)
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Gestational Diabetes Mellitus (GDM) causes hyperglycaemia due to the deficit of insulin during pregnancy. Dietary and lifestyle management plays a vital role in maintaining glycaemic control in women with GDM to avoid health risks to the mother and baby. Therefore, this systematic review of fourteen randomised controlled trials evaluated the latest research advancements to identify effective nutritional strategies for managing hyperglycaemia in women with GDM. Among all the dietary strategies implemented in the included randomised controlled trials, probiotic supplementation and supplementation of probiotics and vitamin D were most effective in GDM. Further robust studies are required to evaluate the potential effectiveness of different nutritional strategies for managing GDM. Healthcare professionals can use the results of this systematic review to understand the latest evidence supporting nutritional strategy for women with GDM and the need for personalised support for managing hyperglycaemia in GDM.
Abstract
Gestational diabetes mellitus (GDM) is defined as hyperglycaemia first detected at any time during pregnancy with values lower than those determined by the WHO for diabetes diagnosis in adults. This pathology, with a worldwide prevalence of 13.4%, causes significant maternal and foetal risks. The first line of treatment consists of maintaining normo-glycaemia through an adequate diet and lifestyle changes. The aim is to synthesize the scientific evidence updating the nutritional recommendations for the effective management of GDM. A systematic review of the scientific literature was conducted following the PRISMA guidelines. Randomized clinical trials published within the last five years and providing information on nutritional recommendations to achieve an effective management of gestational diabetes were selected. The databases searched were PubMed, the WOS Core Collection, SCOPUS, and CINAHL, using the MeSH terms: "Diabetes, Gestational"; "Nutrition Assessment (nutrition*)"; "Diet"; "Eating"; and "Food"; with the Boolean operators "AND" and "OR". The PEDro scale (Physiotherapy Evidence Database) was used to assess the scientific quality of the studies, with a mean score of 8.9, indicating an average good scientific quality. Results: A total of 809 papers were collected, of which, after applying the inclusion and exclusion criteria, 14 randomized clinical trials were selected. Probiotic supplementation and co-supplementation with vitamin D have been found to be the most beneficial options for both mothers with GDM and neonates, but the most effective regimens are not known. Diets enriched with extra virgin olive oil (EVOO) and oat bran, as well as some recommendations focused on carbohydrates also seem effective, as well as diets designed for this group of women with GDM such as "CHOICE". Conclusions: Although there are numerous proposals that have been published in recent years focused on the diet of women with GDM in order to improve their results and those of their children, it is the supplementation with probiotics and the co-supplementation with vitamin D that is most agreed upon as beneficial; however, more research is needed into which protocols are most effective. Other proposals that could also be beneficial should be further studied.
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Effects of Probiotics in Adults with Gastroenteritis: A Systematic Review and Meta-Analysis of Clinical Trials.
Mitra, AK, Asala, AF, Malone, S, Mridha, MK
Diseases (Basel, Switzerland). 2023;11(4)
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Gastroenteritis is a major cause of morbidity and mortality globally and symptoms can range from mild to life-threatening. Some studies have suggested benefits of probiotics in the treatment of gastroenteritis in children whilst in adults, results are inconsistent. The aim of this systematic review and meta-analysis was to evaluate the effects of probiotics on acute and chronic gastroenteritis in adults. 35 clinical trials were included in the systematic review and 22 in the meta-analysis. Of these, 23 dealt with inflammatory bowel disease, 5 with pouchitis, 3 with antibiotic-induced diarrhoea, 2 with Helicobacter pylori infection and one each with diverticulitis and acute watery diarrhoea. 27 (77%) of studies showed some benefits of probiotic administration. The meta-analysis of 22 studies did not show a statistically significant benefit of probiotics. Although statistical analysis showed the studies to be homogenous, the authors point out that studies differed widely in aetiologies and probiotics used. A subgroup analysis of 8 studies in patients with ulcerative colitis also showed no benefit. In all studies, probiotics were well tolerated and no adverse side effects were reported. The authors concluded that further research is needed to help identify the most appropriate use of probiotics for the different types of gastroenteritis.
Expert Review
Conflicts of interest:
None
Take Home Message:
- For chronic inflammatory gastroenteritis conditions in adults, probiotics were effective in treating and preventing relapse
- In ulcerative colitis, probiotics were not effective and adverse events outweighed the benefits
- No safety concerns were found for probiotic use in any studies
- Aetiologies, disease severity and duration as well as the type of probiotics used were widely diverse.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
To date, evidence has been mixed for probiotic effectiveness in gastrointestinal syndromes associated with gastroenteritis. The aim of this study was to review current evidence on the effect of probiotics on gastroenteritis in adults.
Methods
This was a systematic review (n=35; total sample size 4577, median 44) and meta-analysis (n=22) of randomised controlled trials. Quality was assessed using CADIMA as per a rating scale (0 to 4) and standards of critical appraisal.
Results
All 35 studies on gastroenteritis included participants with chronic diarrhoea of diverse aetiologies such as IBD, antibiotic-associated, except one which had acute watery diarrhoea.
51% (n=18) of studies assessed the effects of probiotics in the treatment of ulcerative colitis (UC) and Crohn's disease (CD). 60% (n=21) used multiple strains of probiotics while the rest used single strains. Lactobacilli, Bifidobacteria, Escherichia and Streptococcus were the most common and only a few studies administered probiotics with another conventional treatment.
19 studies (55%) rated highly in terms of quality while 15 (43%) scored moderately. The majority (63%) of the 27 studies where probiotics were shown to be effective were of high quality.
Systematic review results:
- 27/53 studies (77%) showed a favourable response after using probiotics (resolution, improvement, remission or no relapse), mostly in patients with IBDs
- 7 studies (20%) found probiotics to be ineffective
- 1 study was inconclusive
- Multiple strain probiotics (VSL #3) was found to be most effective in IBD
- All administered probiotics were well tolerated with no adverse side effects although caution in immunocompromised patients was mentioned in several studies.
The meta-analysis results:
- Overall effectiveness for 22 studies (p=0.37) highlighted there was not enough evidence that the intervention was more protective than controls.
- Probiotics were not effective in UC (p = 0.28), and adverse events caused by probiotics may outweigh the benefits in studies with UC patients.
Conclusion
While benefits of effectiveness were found for probiotic use in gastroenteritis in adults, results from the systematic review and meta-analysis showed a mixed effect.
Clinical practice applications:
- Based on the systematic review, probiotics may be an effective treatment or adjuvant treatment for gastroenteritis but ineffective for around 20% of patients
- It is worth noting that combined therapy with standard treatment showed effective results
- Beneficial effects of probiotics in other key clinical outcomes including disease prevention, relapse, quality of life, morbidity were found
- While the results are interesting it is difficult to apply them in practice as the type of probiotics used were widely different as were the causes, severity and duration of gastroenteritis.
Considerations for future research:
- Further and larger studies would be beneficial to understand the benefits of probiotics in terms of single therapy or in combination with standard treatment particularly for UC, CDs, gastroenteritis not due to viral infection
- Individual-level data instead of aggregated data could give a better idea of effectiveness of probiotics in the future
- In this study aetiologies and the type, dosage, duration of probiotics used were widely diverse therefore systematic reviews and meta-analysis on specific conditions, specific probiotic strains and combinations would be beneficial.
Abstract
Probiotics have been widely used in gastroenteritis due to acute and chronic illnesses. However, evidence supporting the effectiveness of probiotics in different health conditions is inconclusive and conflicting. The aim of this study was to review the existing literature on the effects of probiotics on gastroenteritis among adults. Only original articles on clinical trials that demonstrated the effects of probiotics in adults with gastroenteritis were used for this analysis. Multiple databases, such as PubMed, Google Scholar, MEDLINE and Scopus databases, were searched for the data. The study followed standard procedures for data extraction using a PRISMA flow chart. A quality appraisal of the selected studies was conducted using CADIMA. Finally, a meta-analysis was performed. Thirty-five articles met the selection criteria; of them, probiotics were found effective in the treatment and/or prevention of chronic inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease in 17 (49%), and the treatment of pouchitis in 4 (11.4%), antibiotic-induced diarrhea in 3 (8.6%), Helicobacter pylori infection in 2 (5.7%) and diverticulitis in 1 (2.9%), while the remaining 7 (20%) were ineffective, and 1 study's results were inconclusive. The meta-analysis did not demonstrate any significant protective effects of probiotics. Having a τ2 value of zero and I2 of 6%, the studies were homogeneous and had minimum variances. Further studies are suggested to evaluate the beneficial effects of probiotics in IBDs and other chronic bowel diseases.
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Effects of Probiotics on Autism Spectrum Disorder in Children: A Systematic Review and Meta-Analysis of Clinical Trials.
He, X, Liu, W, Tang, F, Chen, X, Song, G
Nutrients. 2023;15(6)
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Autism spectrum disorder (ASD) is a developmental disability caused by differences in the brain and is characterized by a series of neurodevelopmental disorders, including language and social disorders, restricted interests, and repetitive stereotyped activities. The aim of this study was to explore whether probiotics could improve the overall severity of ASD symptoms in children. This study was a systematic review and meta-analysis of seven studies. Results showed that probiotic supplementation did not improve the associated behavioural symptoms in children with ASD. However, multiple-strain probiotic blend intervention exhibited a positive therapeutic effect on children with ASD and was more effective than single-strain probiotics in subgroup analyses. Authors concluded that to demonstrate the therapeutic effects of probiotics on children with ASD, randomised, double-blind, and placebo-controlled studies following strict trial guidelines are needed.
Abstract
Many studies have explored the efficacy of probiotics on autism spectrum disorder (ASD) in children, but there is no consensus on the curative effect. This systematic review and meta-analysis aimed to comprehensively investigate whether probiotics could improve behavioral symptoms in children with ASD. A systematic database search was conducted and a total of seven studies were included in the meta-analysis. We found a nonsignificant overall effect size of probiotics on behavioral symptoms in children with ASD (SMD = -0.24, 95% CI: -0.60 to 0.11, p = 0.18). However, a significant overall effect size was found in the subgroup of the probiotic blend (SMD = -0.42, 95% CI: -0.83 to -0.02, p = 0.04). Additionally, these studies provided limited evidence for the efficacy of probiotics due to their small sample sizes, a shorter intervention duration, different probiotics used, different scales used, and poor research quality. Thus, randomized, double-blind, and placebo-controlled studies following strict trial guidelines are needed to precisely demonstrate the therapeutic effects of probiotics on ASD in children.
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The Effects of Probiotics/Synbiotics on Glucose and Lipid Metabolism in Women with Gestational Diabetes Mellitus: A Meta-Analysis of Randomized Controlled Trials.
Mu, J, Guo, X, Zhou, Y, Cao, G
Nutrients. 2023;15(6)
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Women with gestational diabetes mellitus (GDM) are at an increased risk of complications during pregnancy and type 2 diabetes, pancreatic cancer, and heart disease after pregnancy. There is some controversy over the research surrounding current treatments of GDM and as such new treatment strategies are being researched and developed. Amongst these is the possibility of using probiotics and synbiotics to alleviate the driving factors of GDM, however the research is inconclusive as some studies have shown a benefit whereas others have not. This meta-analysis of 11 randomised control trials (RCTs) containing 779 participants aimed to determine the effect of probiotic/synbiotics on sugar and lipid levels in the blood. The results showed that amongst 8 of the RCTs, Lactobacillus was the most researched probiotic gut bacteria, with 6 species researched. In addition, Bifidobacterium bifidum and Streptococcus thermophilus were also used as a probiotic. 3 RCTs looked at synbiotics including 5 Lactobacillus species and 3 Bifidobacterium species. Supplementation with probiotics/synbiotics significantly improved blood sugar levels, measures of insulin resistance, and total cholesterol in pregnant women with GDM. Other blood lipids such as triglycerides, high density lipoprotein, low density lipoprotein, weight at the end of the trial, and weight gain during pregnancy were unaffected by supplementation. It was concluded that probiotics/synbiotics are of benefit to women with GDM especially if they contain L. acidophilus and B. bifidum. However, there may be more research required to better inform GDM management. This study could be used by healthcare professionals to understand that the gut microbiota may have a pivotal role in GDM. More research is required before this forms part of a regular management strategy.
Abstract
BACKGROUND Gestational diabetes mellitus (GDM) is prevalent with lasting health implications for the mother and offspring. Medical therapy is the foundation of GDM management, for achieving optimal glycemic control often requires treatment with insulin or metformin. Gut dysbiosis is a feature of GDM pregnancies, therefore, dietary manipulation of the gut microbiota may offer a new avenue for management. Probiotics are a relatively new intervention, which can reduce the mother's blood sugar levels and, furthermore, adjust glucose and lipid metabolism in both mother and offspring. OBJECTIVE The aim of this systematic review and meta-analysis is to explore the effect of probiotics/synbiotics on glucose and lipid metabolism in women with GDM. METHODS A systematic search of the literature was conducted using the electronic databases Cochrane Library, Web of Science, PubMed, and EBOSCO, published between 1 January 2012 and 1 November 2022. A total of 11 randomized controlled clinical trials (RCTs) were analyzed. The indicators included fasting plasma glucose (FPG), fasting serum insulin (FSI), the homoeostatic model assessment for insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), total cholesterol (TC), HDL cholesterol, LDL cholesterol and triglycerides (TG), the mean weight at end of trial, and gestational weight gain (GWG). RESULTS Compared with the placebo, probiotics/synbiotics were associated with a statistically significant improvement in FPG (MD = -2.33, 95% CI = -4.27, -0.40, p = 0.02), FSI (MD = -2.47 95% CI = -3.82, -1.12, p = 0.0003), HOMA-IR (MD = -0.40, 95% CI = -0.74, -0.06, p = 0.02), and TC (MD = -6.59, 95% CI = -12.23,--0.95, p = 0.02), while other factors had no significant difference. The subgroup analysis revealed that the kind of supplement led to heterogeneity for FPG and FSI, while heterogeneity was not found for others. CONCLUSION Probiotics/synbiotics could control glucose and lipid metabolism in pregnant women with GDM. There was a significant improvement in FPG, FSI, HOMA-IR, and TC. The use of specific probiotic supplementation may be a promising prevention and therapeutic strategy for GDM. However, due to the heterogeneity among existing studies, further studies are warranted to address the limitations of existing evidence and better inform the management of GDM.
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The effects of probiotics supplementation on glycaemic control among adults with type 2 diabetes mellitus: a systematic review and meta-analysis of randomised clinical trials.
Li, G, Feng, H, Mao, XL, Deng, YJ, Wang, XB, Zhang, Q, Guo, Y, Xiao, SM
Journal of translational medicine. 2023;21(1):442
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Type 2 diabetes mellitus (T2DM), an endocrine and metabolic disease, is influenced by host physiology and environmental factors. Recent studies have shown that the gut microbiota plays a key role in the maintenance of host homeostasis and pathogenesis of T2DM. The aim of this study was to evaluate the effects of a probiotic intervention on glycaemic control in T2DM patients and to evaluate the variations in these effects due to participant characteristics and intervention characteristics. This study was a systematic review and meta-analysis of thirty randomised-controlled studies including a total of 1,827 individuals. Results showed that probiotic supplementation had favourable effects on glycaemic control in T2DM patients. Bifdobacterium and food-type probiotics had greater glucose-lowering effects than other probiotic genera and types of vehicles used to deliver the probiotics. Authors concluded that the administration of probiotics may be a promising adjuvant therapy for glycaemic control in T2DM patients.
Abstract
OBJECTIVE This systematic review and meta-analysis study aimed to evaluate the effectiveness of probiotics supplementation on glycaemic control in patients with type 2 diabetes mellitus (T2DM) based on the data from the randomised clinical trials (RCTs). METHODS PubMed, Web of Sciences, Embase, and Cochrane Library were searched from the inception to October 2022, and RCTs about probiotics and T2DM were collected. The standardised mean difference (SMD) with 95% confidence interval (CI) was used to estimate the effects of probiotics supplementation on glycaemic control related parameters, e.g. fasting blood glucose (FBG), insulin, haemoglobin A1c (HbA1c), and homeostasis model of assessment of insulin resistance (HOMA-IR). RESULTS Thirty RCTs including 1,827 T2MD patients were identified. Compared with the placebo group, the probiotics supplementation group had a significant decrease in the parameters of glycaemic control, including FBG (SMD = - 0.331, 95% CI - 0.424 to - 0.238, Peffect < 0.001), insulin (SMD = - 0.185, 95% CI - 0.313 to - 0.056, Peffect = 0.005), HbA1c (SMD = - 0.421, 95% CI - 0.584 to - 0.258, Peffect < 0.001), and HOMA-IR (SMD = - 0.224, 95% CI - 0.342 to - 0.105, Peffect < 0.001). Further subgroup analyses showed that the effect was larger in the subgroups of Caucasians, high baseline body mass index (BMI ≥ 30.0 kg/m2), Bifidobacterium and food-type probiotics (Psubgroup < 0.050). CONCLUSION This study supported that probiotics supplementation had favourable effects on glycaemic control in T2DM patients. It may be a promising adjuvant therapy for patients with T2DM.