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Nutrition Reviews Nov 2023A bidirectional relationship between gut microbiota (GM) and circadian rhythms has been proposed. (Meta-Analysis)
Meta-Analysis
CONTEXT
A bidirectional relationship between gut microbiota (GM) and circadian rhythms has been proposed.
OBJECTIVE
The aim of this study was to analyze the efficacy of probiotic or prebiotic intervention on sleep quality and quantity.
DATA SOURCES
A systematic review and meta-analysis were conducted using the databases PubMed (MEDLINE), Embase, CINAHL, and Web of Science. Only randomized clinical trials written in English or Spanish were considered.
DATA EXTRACTION
The initial search resulted in 219 articles. Following the removal of duplicates and consideration of the selection criteria, 25 articles were selected for the systematic review and 18 articles for the meta-analysis.
DATA ANALYSIS
Microbiota modulation was not demonstrated to be associated with significant improvement in sleep quality in the present meta-analysis (P = 0.31). In terms of sleep duration, the meta-analysis found no improvement due to GM modulation (P = 0.43).
CONCLUSION
The results of this meta-analysis indicate that there is still insufficient evidence to support the relationship between GM modulation and improved sleep quality. While several studies assume that including probiotics in the diet will undoubtedly improve sleep quality, more research is needed to fully understand this phenomenon.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO registration no. CRD42021245118.
Topics: Humans; Gastrointestinal Microbiome; Probiotics; Prebiotics; Microbiota; Sleep
PubMed: 37023468
DOI: 10.1093/nutrit/nuad027 -
Nutrients May 2024Understanding the relationship between the intake of sugars and diet quality can inform public health recommendations. This systematic review synthesized recent... (Review)
Review
Understanding the relationship between the intake of sugars and diet quality can inform public health recommendations. This systematic review synthesized recent literature on associations between sugar intake and diet quality in generally healthy populations aged 2 years or older. We searched databases from 2010 to 2022 for studies of any design examining associations between quantified sugar intake in the daily diet and dietary indexes (DIs) or micronutrient intakes. Different sugar types and diet quality measures were analyzed separately. We converted DI results to Pearson's correlations and grouped indexes with or without a free or added sugar component to facilitate cross-study comparisons. Meta-analysis was deemed inappropriate. From 13,869 screened records, we included 27 cross-sectional studies. NUQUEST risk of bias ratings were neutral ( = 18 studies) or poor ( = 9), and strength of evidence by the GRADE approach was very low due to study design. Most studies reported negative associations for added and free sugars with diet quality indexes ( ranging from -0.13 to -0.42) and nutrients of public health concern (fiber, vitamin D, calcium, potassium), while associations with total sugars were mixed. Due to cross-sectional study designs, the clinical relevance of these findings is unclear. Prospective studies are needed to minimize confounding and inform causal relationships.
Topics: Humans; Dietary Sugars; Diet; Cross-Sectional Studies; Female; Adult; Male; Diet, Healthy; Child; Middle Aged; Adolescent; Micronutrients; Child, Preschool; Young Adult; Aged
PubMed: 38892483
DOI: 10.3390/nu16111549 -
Journal of Medical Microbiology Sep 2023Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that affects the quality of life of numerous people worldwide. The therapeutic role of gut... (Meta-Analysis)
Meta-Analysis
Efficacy of probiotics, prebiotics and synbiotics in irritable bowel syndrome: a systematic review and meta-analysis of randomized, double-blind, placebo-controlled trials.
Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that affects the quality of life of numerous people worldwide. The therapeutic role of gut microbiota modulation in IBS remains controversial. We aimed to assess the efficacy of probiotics, prebiotics or synbiotics in patients with IBS. We searched MEDLINE and EMBASE up to 1 August 2023, to identify the randomized, double-blind, placebo-controlled trials investigating the effectiveness of probiotics, prebiotics or synbiotics among patients with IBS. Pooled analyses of the effects of probiotics in relieving IBS symptoms were calculated using a random-effects model. Further subgroup analyses were performed by different genera, doses and duration of treatment. Our final analysis included 52 trials involving 6289 IBS patients. Probiotics significantly increased the overall response rate (RR:1.64; <0.00001), subjective relief rate (RR:1.50; =0.0002) and abdominal pain relief rate (RR:1.69; <0.00001). As for specific genera, mixed probiotics (RR:1.41; =0.0001), (RR:1.76; <0.00001), (RR:1.97; =0.0004) and (RR:1.31; =0.0004) markedly relieved IBS symptoms. Mixed probiotics (RR:1.31; =0.005), (RR:2.22; =0.04) and (RR:1.62; <0.0001) elevated patients' subjective relief rate. Besides, probiotics effectively relieved the abdominal pain in IBS patients (RR:1.69; <0.00001). Probiotics appeared to show a remarkable beneficial role at a dose of 10 c.f.u./day or above (RR:1.662; <0.0001) and started to work at 4 weeks (RR 1.72; <0.00001). Efficacy of prebiotics and synbiotics in IBS remained uncertain, due to the deficiency of available RCTs. Probiotics have a therapeutic role in IBS. However, the effect of different probiotics varies. The minimal effective dose of probiotics may be 10 c.f.u./day. With appropriate probiotic formula, the therapeutic effect can occur at 4 weeks. These data provide a basis for further research on the optimal probiotic therapy in IBS.
Topics: Humans; Prebiotics; Synbiotics; Irritable Bowel Syndrome; Quality of Life; Probiotics; Lactobacillus; Abdominal Pain; Randomized Controlled Trials as Topic
PubMed: 37772692
DOI: 10.1099/jmm.0.001758 -
Journal of Affective Disorders Dec 2023Anxiety can adversely affect human well-being. This meta-analysis aimed to evaluate the effects of interventions that alter the gut microbes (including probiotics,... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Anxiety can adversely affect human well-being. This meta-analysis aimed to evaluate the effects of interventions that alter the gut microbes (including probiotics, prebiotics, and synbiotics) on anxiety.
METHODS
A systematic meta-analysis of the effects of probiotics, prebiotics, and synbiotics on anxiety was conducted by searching randomized controlled trials (RCTs) in 13 databases. The primary outcomes were the pre- and post-intervention anxiety scores in the intervention and placebo groups. Anxiety scores were extracted as standard mean differences (SMDs) and pooled based on a random effects model. Subgroup analyses of anxiety scales, health status, gastrointestinal symptoms, flora strains, treatment type, probiotic dose, region, and treatment duration were also performed.
RESULTS
29 RCTs (2035 participants) were included, revealing that both probiotics and synbiotics significantly reduced anxiety scores. Additionally, anxiety scores did not significantly reduce when comparing prebiotics and placebos.
LIMITATIONS
Owing to the small combined effect size of probiotic/prebiotic/synbiotic treatments and the relatively few studies on prebiotics and synbiotics included in the analysis, the findings of probiotic/prebiotic/synbiotic treatments are preliminary.
CONCLUSIONS
Our study indicated that probiotics and synbiotics can reduce anxiety scores; however, it might be premature to conclude their clinical efficacy in alleviating anxiety due to the small effect size. There is no consensus regarding the optimal dose, treatment duration, treatment type, or probiotic strain to improve anxiety. Moreover, the mechanisms by which probiotics and synbiotics improve anxiety remain unclear. More RCTs are needed to determine the mechanisms of action and to identify appropriate markers to clarify their effects.
Topics: Humans; Synbiotics; Prebiotics; Randomized Controlled Trials as Topic; Probiotics; Anxiety
PubMed: 37734624
DOI: 10.1016/j.jad.2023.09.018 -
The American Journal of Clinical... Jun 2024Older adults living in residential care facilities are commonly given laxatives to treat constipation; however, these may not always provide full relief, and side...
BACKGROUND
Older adults living in residential care facilities are commonly given laxatives to treat constipation; however, these may not always provide full relief, and side effects include diarrhea. Dietary fiber effectively prevents constipation, and international guidelines recommend 25 g/d for optimal laxation. Older adults in residential care rely on the facility menu to provide their nutritional requirements, including adequate dietary fiber. Little is known about how much dietary fiber is provided and consumed.
OBJECTIVES
We aimed to determine the provision and consumption of dietary fiber for older adults living in residential care facilities.
METHODS
We systematically searched available literature for studies reporting the analysis of residential care menus and meals consumed by residents aged over 65 y. A meta-analysis was performed on the studies that provided the mean amount of dietary fiber provided and consumed by residents. A random effect model was applied due to the heterogeneity of study methodologies.
RESULTS
The literature search yielded 4406 publications, but only 28 studies were eligible for our meta-analysis. The study sample comprised 4817 residents. The mean amount of fiber provided to residents was 21.4 g/d [standard error (SE): 1.2; 95% confidence interval: 18.8, 24.2 g/d], the mean amount of fiber consumed by residents was 15.8 g/d (SE: 0.6; 95% confidence interval: 14.7, 16.9 g/d).
CONCLUSIONS
Older adults living in care facilities are provided with dietary fiber below the recommended guidelines. Compounding this is that residents consume much less than what is provided and do not meet the recommendations for dietary fiber consumption. There is scope to improve dietary fiber provision, promote consumption to residents to aid laxation, and potentially reduce laxative use and the unwanted side effects of diarrhea. This trial was registered at PROSPERO as CRD42023427265.
PubMed: 38851635
DOI: 10.1016/j.ajcnut.2024.05.026 -
The Journal of Nutritional Biochemistry Jul 2024Globally, neurodegeneration and cerebrovascular disease are common and growing causes of morbidity and mortality. Pathophysiology of this group of diseases encompasses... (Review)
Review
Globally, neurodegeneration and cerebrovascular disease are common and growing causes of morbidity and mortality. Pathophysiology of this group of diseases encompasses various factors from oxidative stress to gut microbial dysbiosis. The study of the etiology and mechanisms of oxidative stress as well as gut dysbiosis-induced neurodegeneration in Alzheimer's disease, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis, autism spectrum disorder, and Huntington's disease has recently received a lot of attention. Numerous studies lend credence to the notion that changes in the intestinal microbiota and enteric neuroimmune system have an impact on the initiation and severity of these diseases. The prebiotic role of polyphenols can influence the makeup of the gut microbiota in neurodegenerative disorders by modulating intracellular signalling pathways. Metabolites of polyphenols function directly as neurotransmitters by crossing the blood-brain barrier or indirectly via influencing the cerebrovascular system. This assessment aims to bring forth an interlink between the consumption of polyphenols biotransformed by gut microbiota which in turn modulate the gut microbial diversity and biochemical changes in the brain. This systematic review will further augment research towards the association of dietary polyphenols in the management of gut dysbiosis-associated neurodegenerative diseases.
Topics: Polyphenols; Dysbiosis; Gastrointestinal Microbiome; Humans; Neurodegenerative Diseases; Animals; Oxidative Stress; Phytotherapy; Prebiotics; Diet
PubMed: 38490348
DOI: 10.1016/j.jnutbio.2024.109622 -
Nutrition Reviews Nov 2023Ramadan fasting (RF) is associated with various physiological and metabolic changes among fasting Muslims. However, it remains unclear whether these effects are...
CONTEXT
Ramadan fasting (RF) is associated with various physiological and metabolic changes among fasting Muslims. However, it remains unclear whether these effects are attributable to changes in meal timing or changes in dietary energy and macronutrient intakes. Furthermore, the literature on the associations between RF, meal timing, and energy and macronutrient intakes is inconclusive.
OBJECTIVES
This systematic review aimed to estimate the effect sizes of RF on energy and macronutrient intakes (carbohydrates, protein, fats, dietary fiber, and water) and determine the effect of different moderators on the examined outcomes.
DATA SOURCES
The Cochrane, CINAHL, EMBASE, EBSCOhost, Google Scholar, PubMed/MEDLINE, ProQuest Medical, Scopus, ScienceDirect, and Web of Science databases were searched from inception to January 31, 2022.
DATA EXTRACTION
The studies that assessed energy, carbohydrate, protein, fat, fiber, and water intakes pre- and post-fasting were extracted.
DATA ANALYSIS
Of the 4776 identified studies, 85 relevant studies (n = 4594 participants aged 9-85 y) were selected. The effect sizes for the studied variables were as follows: energy (number of studies [K] = 80, n = 3343 participants; mean difference [MD]: -142.45; 95% confidence interval [CI]: -215.19, -69.71), carbohydrates (K = 75, n = 3111; MD: -23.90; 95% CI: -36.42, -11.38), protein (K = 74, n = 3108; MD: -4.21; 95% CI: -7.34, -1.07), fats (K = 73, n = 3058; MD: -2.03; 95% CI: -5.73, 1.67), fiber (K = 16, n = 1198; MD: 0.47; 95% CI: -1.44, 2.39), and water (K = 17, n = 772; MD: -350.80; 95% CI: -618.09, 83.50). Subgroup analyses showed age significantly moderated the 6 dietary outcomes, and physical activity significantly moderated water intake. There were significant reductions in energy, carbohydrate, and protein intakes during RF.
CONCLUSIONS
The change in meal timing rather than quantitative dietary intake may explain various physiological and health effects associated with RF.
PubMed: 37986623
DOI: 10.1093/nutrit/nuad141 -
Frontiers in Nutrition 2023Poor dietary structure plays a pivotal role in the development and progression of type 2 diabetes and is closely associated with dysbiosis of the gut microbiota. Thus,...
BACKGROUND
Poor dietary structure plays a pivotal role in the development and progression of type 2 diabetes and is closely associated with dysbiosis of the gut microbiota. Thus, the objective of this systematic review was to assess the impact of dietary interventions on improving gut microbiota and metabolic levels in patients with type 2 diabetes.
METHODS
We conducted a systematic review and meta-analysis following the PRISMA 2020 guidelines.
RESULTS
Twelve studies met the inclusion criteria. In comparison to baseline measurements, the high-fiber diet produced substantial reductions in FBG (mean difference -1.15 mmol/L; 95% CI, -2.24 to -0.05; I = 94%; = 0.04), HbA1c (mean difference -0.99%; 95% CI, -1.93 to -0.03; I = 89%; = 0.04), and total cholesterol (mean difference -0.95 mmol/L; 95% CI, -1.57 to -0.33; I = 77%; = 0.003); the high-fat and low-carbohydrate diet led to a significant reduction in HbA1c (mean difference -0.98; 95% CI, -1.50 to -0.46; I = 0%; = 0.0002). Within the experimental group (intervention diets), total cholesterol (mean difference -0.69 mmol/L; 95% CI, -1.27 to -0.10; I = 52%; = 0.02) and LDL-C (mean difference -0.45 mmol/L; 95% CI, -0.68 to -0.22; I = 0%; < 0.0001) experienced significant reductions in comparison to the control group (recommended diets for type 2 diabetes). However, no statistically significant differences emerged in the case of FBG, HbA1c, HOMA-IR, and HDL-C between the experimental and control groups. The high dietary fiber diet triggered an augmented presence of short-chain fatty acid-producing bacteria in the intestines of individuals with T2DM. In addition, the high-fat and low-carbohydrate diet resulted in a notable decrease in Bacteroides abundance while simultaneously increasing the relative abundance of Eubacterium. Compared to a specific dietary pattern, personalized diets appear to result in the production of a greater variety of beneficial bacteria in the gut, leading to more effective blood glucose control in T2D patients.
CONCLUSION
Dietary interventions hold promise for enhancing metabolic profiles in individuals with T2D through modulation of the gut microbiota. Tailored dietary regimens appear to be more effective than standard diets in improving glucose metabolism. However, given the limited and highly heterogeneous nature of the current sample size, further well-designed and controlled intervention studies are warranted in the future.
PubMed: 38260058
DOI: 10.3389/fnut.2023.1243095 -
Hepatology (Baltimore, Md.) Mar 2024The association between fiber or whole grain intakes and the risk of liver cancer remains unclear. We assessed the associations between fiber or whole grain intakes and...
BACKGROUND AND AIMS
The association between fiber or whole grain intakes and the risk of liver cancer remains unclear. We assessed the associations between fiber or whole grain intakes and liver cancer risk among 2 prospective studies, and systematically reviewed and meta-analyzed these results with published prospective studies.
APPROACH AND RESULTS
A total of 111,396 participants from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) and 26,085 men from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study were included. Intakes of total fiber and whole grains were estimated from validated food frequency questionnaires. Study-specific HRs and 95% CI with liver cancer risk were estimated using multivariable-adjusted Cox regression. We systematically reviewed existing literature, and studies were combined in a dose-response meta-analysis. A total of 277 (median follow-up = 15.6 y) and 165 (median follow-up = 16.0 y) cases of liver cancer were observed in Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial and Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, respectively. Dietary fiber was inversely associated with liver cancer risk in Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (HR 10g/day : 0.69; 95% CI: 0.55-0.86). No significant associations were observed between whole grain intakes and liver cancer risk in either study. Our meta-analysis included 2383 incident liver cancer cases (7 prospective cohorts) for fiber intake and 1523 cases (5 prospective cohorts) for whole grain intake; combined HRs for liver cancer risk were 0.83 (0.76-0.91) per 10 g/day of fiber and 0.92 (0.85-0.99) per 16 g/day (1 serving) of whole grains.
CONCLUSIONS
Dietary fiber and whole grains were inversely associated with liver cancer risk. Further research exploring potential mechanisms and different fiber types is needed.
PubMed: 38441973
DOI: 10.1097/HEP.0000000000000819 -
Cureus Oct 2023The prevalence and associated risk factors of irritable bowel syndrome (IBS) have been a significant area of focus in several studies conducted in Saudi Arabia. These... (Review)
Review
The prevalence and associated risk factors of irritable bowel syndrome (IBS) have been a significant area of focus in several studies conducted in Saudi Arabia. These studies have looked at varied populations, including school teachers, university students, and the general populace. The reported prevalence rates for IBS vary substantially across studies, ranging from 7.9% to an astounding 49.3%. The average prevalence noted across these studies is about 24%. The aim of this review is to collate, compare, and analyze data from these studies, hoping to shed light on the key risk factors and demographic trends associated with IBS in Saudi Arabia. This review encompasses data from 20 studies, aggregating information from 17,018 participants. The research methodologies adopted by each of these studies have been analyzed, especially focusing on their sample sizes, which vary significantly. Furthermore, the review incorporates details on the socio-demographic attributes of the participants, including age specifics, gender representation, and geographical distribution within Saudi Arabia. The results demonstrate a wide variability in IBS prevalence among different groups. The overall prevalence of IBS in Saudi Arabia based on the provided data is approximately 24%. Gender-based breakdown in some studies indicated varying prevalence among males and females, which indicated that females are more prone to the disease. The same for certain age groups, specifically between 51 and 60 years, which showed slightly higher rates. Factors such as educational discipline, living conditions, mental health, dietary habits, family history of IBS, and certain comorbidities such as diabetes mellitus were found to influence the occurrence of IBS in different cohorts. Moreover, lifestyle factors such as low water intake, lack of dietary fiber, stress, and even caffeine intake were associated with IBS. Socioeconomic aspects, including family income levels and academic performance, were also hinted to have a potential link with IBS prevalence. In light of the presented data, it is evident that IBS prevalence in Saudi Arabia is influenced by a multitude of factors, ranging from genetic and dietary to psychological and socioeconomic. The substantial variations in prevalence across different cohorts suggest the need for a more nuanced understanding of this condition, specifically tailored to the unique demographics and cultural contexts of Saudi Arabia. Early diagnosis and tailored interventions, considering these multifaceted determinants, are crucial for the effective management of IBS in the region.
PubMed: 38021554
DOI: 10.7759/cureus.47440