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Effect of probiotics or prebiotics on thyroid function: A meta-analysis of eight randomized controlled trials.
Shu, Q, Kang, C, Li, J, Hou, Z, Xiong, M, Wang, X, Peng, H
PloS one. 2024;19(1):e0296733
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The gut microbiome is thought to play a role in thyroid disorders, mediated by regulating iodine uptake, degradation and enterohepatic cycling of thyroid hormones, and differences in microbiome composition between patients with thyroid disorders and healthy individuals have been observed. The aim of this systematic review and meta-analysis was to evaluate the effect of pro-, pre- and synbiotics on thyroid function (thyroid stimulating hormone (TSH), free thyroxine (fT4) and free triiodothyronine (fT3) and thyroid stimulating hormone receptor antibody (TRAb)) in patients with and without thyroid disorders. 8 randomised controlled trials including 367 participants were included in the review and meta-analysis. Neither pro-, pre- nor synbiotics had a significant effect on TSH, fT4 or fT3 but pre- and probiotics lead to a significant reduction in TRAb in patients with Graves’ disease.
Abstract
BACKGROUND Microbiome-directed therapies are increasingly utilized to optimize thyroid function in both healthy individuals and those with thyroid disorders. However, recent doubts have been raised regarding the efficacy of probiotics, prebiotics, and synbiotics in improving thyroid function. This systematic review aimed to investigate the potential relationship between probiotics/prebiotics and thyroid function by analyzing the impact on thyroid hormone levels. METHODS We conducted a comprehensive systematic review and meta-analysis of randomized controlled trials that investigated the effects of probiotics, prebiotics, and synbiotics on free triiodothyronine (fT3), free thyroxine (fT4), thyroid stimulating hormone (TSH), and thyroid stimulating hormone receptor antibody (TRAb) levels. We searched for articles from PubMed, Scopus, Web of Science, and Embase up until April 1st, 2023, without any language restriction. Quantitative data analysis was performed using a random-effects model, with standardized mean difference (SMD) and 95% confidence interval as summary statistics. The methods and results were reported according to the PRISMA2020 statement. RESULTS A total of eight articles were included in this review. The meta-analysis showed no significant alterations in TSH (SMD: -0.01, 95% CI: -0.21, 0.20, P = 0.93; I2: 0.00%), fT4 (SMD: 0.04, 95% CI: -0.29, 0.21, P = 0.73; I2: 0.00%) or fT3 (SMD: 0.45, 95% CI: -0.14, 1.03, P = 0.43; I2: 78.00%), while a significant reduction in TRAb levels was observed (SMD: -0.85, 95% CI: -1.54, -0.15, P = 0.02; I2: 18.00%) following probiotics/prebiotics supplementation. No indication of publication bias was found. CONCLUSIONS Probiotics/prebiotics supplementation does not influence thyroid hormone levels, but may modestly reduce TRAb levels in patients with Graves' disease.
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Are probiotics, prebiotics, and synbiotics beneficial in primary thyroid diseases? A systematic review with meta-analysis.
Zawadzka, K, Kałuzińska, K, Świerz, MJ, Sawiec, Z, Antonowicz, E, Leończyk-Spórna, M, Abadi, AK, Trofimiuk-Müldner, M, Bała, MM
Annals of agricultural and environmental medicine : AAEM. 2023;30(2):217-223
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Irregularities in intestinal microbial composition are thought to be correlated with thyroid dysfunction. Supplementation of prebiotics, probiotics and synbiotics are gaining momentum in recent times in improving health in general. This systematic review of randomised controlled trials was conducted to summarise the up-to-date evidence on the therapeutic potential of prebiotics, probiotics and synbiotics in the treatment of thyroid disease. The meta-analysis did not show beneficial effects on thyroid hormone balance, BMI or levothyroxine dosage reduction. Supplementation with Lactobacillus and Bifidobacterium resulted in improvement in constipation and a statistically non-significant reduction in thyroid-stimulating hormone in adult participants with hypothyroidism. Further robust long-term studies are required to evaluate the efficacy of prebiotics, probiotics and synbiotics in thyroid disease treatment as the availability of the number of studies included in this systematic review was limited. However, healthcare professionals can use the review to understand the current evidence in this area and the correlation between gut microbial alterations and thyroid disease.
Abstract
INTRODUCTION AND OBJECTIVE A number of studies indicate the presence of a thyroid-gut axis and the important influence of the gut microbiota on thyroid function. As prebiotics, probiotics and synbiotics show therapeutic potential in the treatment of intestinal dysbiosis, the aim of this review is to evaluate the efficacy of their supplementation in primary thyroid diseases. REVIEW METHODS Electronic databases (Ovid MEDLINE, Embase, CENTRAL), registers of clinical trials, and grey literature up to 6 October 2022 were searched for randomised controlled trials (RCTs) meeting pre-specified inclusion criteria. The protocol was registered in PROSPERO (CRD42021235054). BRIEF DESCRIPTION OF THE STATE OF KNOWLEDGE After screening 1,721 references, two RCTs were identified, which included 136 hypothyroid participants in total. Meta-analysis of the results after eight weeks of supplementation with predominantly Lactobacillus and Bifidobacterium strains indicated a clinically and statistically nonsignificant decrease in TSH (MD -0.19 mIU/L; 95% CI -0.43 to 0.06; I2= 0%), and no effect on fT3 levels (MD 0.01 pg/mL; 95% CI-0.16 to 0.18; I2= 0%). Data from single studies indicated no significant change in the levels of fT4, thyroid auto-antibodies, BMI, levothyroxine doses, and severity of symptoms measured with validated scales. Only constipation scores showed significant improvement (MD -8.71 points in the Faecal Incontinence Questionnaire; 95% CI -15.85 to -1.57; I2= 0%). SUMMARY Low-certainty evidence from two randomised trials, suggests that routine administration of probiotics, prebiotics or synbiotics may result in little to no benefit in patients with primary hypothyroidism.
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The effect of synbiotic supplementation on hypothyroidism: A randomized double-blind placebo controlled clinical trial.
Ramezani, M, Reisian, M, Sajadi Hezaveh, Z
PloS one. 2023;18(2):e0277213
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Despite the increased awareness and the improvements in medical management of hypothyroidism; depression, mood disturbance and poor health-related quality of life (QoL) is common among hypothyroid patients. Synbiotics have been advocated as being beneficial to patients with metabolic diseases. Synbiotics are a mixture of probiotics and prebiotics that beneficially affect the host by improving the survival and stimulating the growth of advantageous and health promoting microbial species in the gastrointestinal tract. The aim of this study was to examine whether synbiotic supplementation could enhance depression, QoL, and blood pressure, as well as thyroid hormones in hypothyroid patients. This study is a 10-week parallel design randomised placebo-controlled trial. Participants – adults with hypothyroidism - were randomly assigned to the synbiotic (n = 28) or the placebo (n = 28) group. Results show that following 10 weeks supplementation with synbiotics (500 mg of 10⁹ CFU/g probiotics plus fructo-oligosaccharide) in comparison to placebo does not affect serum thyroid stimulating hormone level and depression. However, it significantly improved blood pressure levels and various domains and areas of QoL. Authors conclude that further clinical trials are needed to assess the effectiveness of a synbiotic supplementation along with the current routine treatment for hypothyroid patients.
Abstract
OBJECTIVE We hypothesize that synbiotic supplementation could modulate the intestinal microbiota and subsequently, improve the condition of hypothyroid patients. METHODS Fifty-six adult hypothyroid patients were recruited to this double-blind, placebo-controlled, randomized clinical trial. The intervention was 10 weeks of synbiotic (500 mg of 109 CFU/g probiotics plus fructo-oligosaccharide, n = 28) compared to placebo (lactose, magnesium stearate, talc, and silicon dioxide, n = 28). Randomization and allocation to trial groups were carried out using random number sequences drawn from https://sealedenvelope.com/. Primary outcomes were serum thyroid stimulating hormone (TSH) and free thyroxine (FT4), and secondary outcomes were depression, quality of life, and blood pressure (BP). P-values< 0.05 were considered statistically significant. RESULTS Analysis on 51 patients who completed the trial showed that TSH and depression (p> 0.05) did not change significantly, while serum FT4 significantly increased in both groups (p = 0.03 and p = 0.02 in symbiotic and placebo respectively). A significant decrease in systolic BP occurred only in the synbiotic group (p = 0.05). Significant improvements occurred regarding different domains and areas of quality of life in the crude and adjusted analysis, including perceived mental health (p = 0.02), bodily pain (p = 0.02), general health perception (p = 0.002), and wellbeing (p = 0.002), which were significantly higher in the synbiotic group. CONCLUSIONS Ten-week supplementation with synbiotic had no favorable effect on depression and TSH, but it improved blood pressure and quality of life in patients with hypothyroidism. More trials are needed to support or reject these findings. TRIAL REGISTRATION IRCT20210926052583N1, Iranian Registry of Clinical Trials (IRCT), registered October 1st, 2021.
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Polyphenol Intake in Pregnant Women on Gestational Diabetes Risk and Neurodevelopmental Disorders in Offspring: A Systematic Review.
Salinas-Roca, B, Rubió-Piqué, L, Montull-López, A
Nutrients. 2022;14(18)
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In Europe, gestational diabetes affects approximately 10.9% of pregnant women. According to previous research, the cardiometabolic health of the mother and the mother's dietary habits during pregnancy may affect the foetus' neurodevelopment. Taking polyphenol supplements and eating foods rich in polyphenols is beneficial for promoting health across generations. In this systematic review, fourteen studies were included in order to evaluate the effects of polyphenols on gestational diabetes and mental health in the offspring. A higher prevalence of neurodevelopmental diseases in offspring is associated with gestational diabetes. The results of this systematic review revealed that polyphenol intake during pregnancy might have a beneficial effect on improving cardiometabolic health, reducing inflammation, DNA methylation and oxidative stress, thus reducing the risk of developing fetal neurodevelopmental disorders, such as attention deficit hyperactivity disorder, autism spectrum disorder and learning disorders. There is a need for further robust research, as the existing evidence regarding the safety of long-term polyphenol supplementation and its effects on gestational diabetes and fetal neurodevelopment is very limited. In spite of this, healthcare professionals can use the findings of this systematic review to learn more about the positive health benefits of polyphenols in pregnant women.
Abstract
The intake of foods containing polyphenols can have a protective role to avoid comorbidities during pregnancy and, at the same time, promote transgenerational health. This review aims to describe the effect of polyphenol intake through supplements or polyphenol-rich foods during pregnancy on the incidence and evolution of gestational diabetes mellitus (GDM), as well as the link with the neurodevelopment of the fetus. Using PRISMA procedures, a systematic review was conducted by searching in biomedical databases (PubMed, Cinahl and Scopus) from January to June 2022. Full articles were screened (n = 419) and critically appraised. Fourteen studies were selected and were divided into two different thematic blocks considering (i) the effect of polyphenols in GDM and (ii) the effect of GDM to mental disorders in the offspring. A positive relationship was observed between the intake of polyphenols and the prevention and control of cardiometabolic complications during pregnancy, such as GDM, which could be related to thwarted inflammatory and oxidative processes, as well as neuronal factors. GDM is related to a greater risk of suffering from diseases related to neurodevelopment, such as attention deficit hyperactivity disorder, autism spectrum disorder and learning disorder. Further clinical research on the molecule protective mechanism of polyphenols on pregnant women is required to understand the transgenerational impact on fetal neurodevelopment.
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Nutritional intervention for diabetes mellitus with Alzheimer's disease.
Li, Z, Li, S, Xiao, Y, Zhong, T, Yu, X, Wang, L
Frontiers in nutrition. 2022;9:1046726
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Diabetes Mellitus (DM) affects more than 463 million people worldwide. Similarly, the number of deaths related to Alzheimer’s disease (AD) has increased by 145%. There are several common risk factors for Type 2 Diabetes and AD, including obesity, insulin resistance, and ageing, as well as common pathological mechanisms, including altered insulin signalling, oxidative stress, neuroinflammation, mitochondrial dysfunction, formation of glycated proteins and metabolic syndrome. This review aims to summarize the therapeutic effects of different nutritional therapy strategies on the reduction of DM and AD risk. Controlling blood sugar levels and reducing calorie intake is crucial to preventing diabetes and Alzheimer's disease. The low-carbohydrate, ketogenic, and Mediterranean diets have been found to improve glucose control in people with Type 2 diabetes (T2D). In addition, MIND (Mediterranean-DASH Diet Intervention for Neurodegenerative Delay) and a ketogenic diet may improve cognition in AD patients. Lactobacillus, Bifidobacterium probiotics, and prebiotics, such as inulin, may inhibit the progression of T2D and AD diseases by suppressing inflammation and modulating gut microbes. In addition, vitamins A, C, D, E, B6, B12, folate, long-chain polyunsaturated fatty acids, zinc, magnesium, and polyphenols may improve cognitive decline, homocysteine levels, and insulin resistance in AD and T2D patients. Healthcare professionals can use the results of this review to understand the beneficial effects of dietary strategies and multi-nutrient supplementation on DM and AD. However, further robust studies are required to investigate the risk factors and underlying mechanisms behind DM-combined AD progression.
Abstract
The combined disease burden of diabetes mellitus (DM) and Alzheimer's disease (AD) is increasing, and the two diseases share some common pathological changes. However, the pharmacotherapeutic approach to this clinical complexity is limited to symptomatic rather than disease-arresting, with the possible exception of metformin. Whether nutritional intervention might extend or synergize with these effects of metformin is of interest. In particular, dietary patterns with an emphasis on dietary diversity shown to affect cognitive function are of growing interest in a range of food cultural settings. This paper presents the association between diabetes and AD. In addition, the cross-cultural nutritional intervention programs with the potential to mitigate both insulin resistance (IR) and hyperglycemia, together with cognitive impairment are also reviewed. Both dietary patterns and nutritional supplementation showed the effects of improving glycemic control and reducing cognitive decline in diabetes associated with AD, but the intervention specificity remained controversial. Multi-nutrient supplements combined with diverse diets may have preventive and therapeutic potential for DM combined with AD, at least as related to the B vitamin group and folate-dependent homocysteine (Hcy). The nutritional intervention has promise in the prevention and management of DM and AD comorbidities, and more clinical studies would be of nutritional scientific merit.
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White common bean extract remodels the gut microbiota and ameliorates type 2 diabetes and its complications: A randomized double-blinded placebo-controlled trial.
Feng, Y, Zhu, J, Wang, Q, Cao, H, He, F, Guan, Y, Li, D, Yan, J, Yang, J, Xia, Y, et al
Frontiers in endocrinology. 2022;13:999715
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Patients with type 2 diabetes (T2D) have a higher risk of macrovascular complications. Intensive glycaemic control reduces microvascular complications and exerts a modest improved effect on macrovascular outcomes. The main aim of this study was to explore the effects of white common bean extract (WCBE) on glucose metabolism and diabetic complications in patients with T2D. This study was a randomised double-blind placebo-controlled trial which enrolled ninety-six patients with T2D aged between 35 and 75 years. Participants were randomly assigned in a 1:2 ratio to the control group and WCBE group. Results showed that WCBE alleviated glucose metabolism dysbiosis and diabetic complication indices. In fact, after 2 months of an intense intervention with a WCBE treatment and in the following two-month maintenance period, the improvements to glycaemic metabolism were preserved. Furthermore, there was notable improvement of the structure of the gut microbiota, especially the enrichment of short-chain fatty acid-producing bacteria and inhibition of opportunistic pathogens. Authors conclude that WCBE may be considered as a novel prebiotic antidiabetic agent for the regulation of glucose metabolism and gut microbiota homeostasis and may slightly ameliorate diabetic complications in patients with T2D.
Abstract
OBJECTIVE Excessive carbohydrate intake is a high risk factor for increased morbidity of type 2 diabetes (T2D). A novel regimen for the dietary care of diabetes that consists of a highly active α-amylase inhibitor derived from white common bean extract (WCBE) and sufficient carbohydrates intake was applied to attenuate T2D and its complications. Furthermore, the role of gut microbiota in this remission was also investigated. METHODS We conducted a 4-month randomized double-blinded placebo-controlled trial. During the intense intervention period, ninety subjects were randomly assigned to the control group (Group C) and WCBE group (Group W). Subjects in Group C were supplemented with 1.5 g of maltodextrin as a placebo. Subjects in Group W took 1.5 g of WCBE half an hour before a meal. Fifty-five participants continued the maintenance intervention receiving the previous dietary intervention whereas less frequent follow-up. The variation in biochemical, vasculopathy and neuropathy indicators and the structure of the fecal microbiota during the intervention was analyzed. RESULT Glucose metabolism and diabetic complications showed superior remission in Group W with a 0.721 ± 0.742% decline of glycosylated hemoglobin after 4 months. The proportion of patients with diabetic peripheral neuropathy (Toronto Clinical Scoring System, TCSS ≥ 6) was significantly lower in Group W than in Group C. Both the left and right sural sensory nerve conduction velocity (SNCV-left sural and SNCV-right sural) slightly decreased in Group C and slightly increased in Group W. Additionally, the abundances of Bifidobacterium, Faecalibacterium and Anaerostipes were higher in Group W, and the abundances of Weissella, Klebsiella, Cronobacter and Enterobacteriaceae_unclassified were lower than those in Group C at month 2. At the end of month 4, Bifidobacterium remained more abundant in Group W. CONCLUSION To our knowledge, this is the first report of improvement to diabetes complications by using a dietary supplement in such a short-term period. The enrichment of SCFA-producing bacteria might be responsible for the attenuation of T2D and its complications. CLINICAL TRIAL REGISTRATION NUMBER http://www.chictr.org.cn/edit.aspx?pid=23309&htm=4, identifier ChiCTR-IOR-17013656.
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Effect of Probiotics on Metabolic Outcomes in Pregnant Women with Gestational Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Taylor, BL, Woodfall, GE, Sheedy, KE, O'Riley, ML, Rainbow, KA, Bramwell, EL, Kellow, NJ
Nutrients. 2017;9(5)
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The gut microbiota is an important ecosystem consisting of both residential and pathogenic bacteria. The microbiota produce bioactive compounds shown to benefit host metabolism. A variety of factors influence the gut microbiome, including host genetics, illness, antibiotic use, dietary patterns, weight loss and pregnancy. Throughout pregnancy the gut microbiota undergoes significant changes. The aim of this study is to determine the effect of 6-8-week probiotic supplementation versus placebo on glucose homeostasis, lipid levels and gestational weight gain in pregnant women diagnosed with gestational diabetes mellitus. This study is a systemic review based on four randomised controlled trials involving 288 participants. All studies included healthy pregnant women, age range between 18 – 40 years, who were diagnosed with gestational diabetes mellitus at 24 – 30 weeks gestation by oral glucose tolerance test. The study found that a 6 – 8-week probiotic intervention did not improve fasting blood glucose or LDL-cholesterol levels. However, probiotic supplementation in women with gestational diabetes mellitus was associated with significant reductions in insulin resistance. Authors conclude that while probiotic supplementation resulted in a significant reduction in insulin resistance in pregnant women with gestational diabetes mellitus, there was no significant effect on fasting blood glucose or LDL-cholesterol.
Abstract
The metabolic effects of probiotic administration in women with gestational diabetes mellitus (GDM) is unknown. The objective of this review was to investigate the effect of probiotics on fasting plasma glucose (FPG), insulin resistance (HOMA-IR) and LDL-cholesterol levels in pregnant women diagnosed with GDM. Seven electronic databases were searched for RCTs published in English between 2001 and 2017 investigating the metabolic effects of a 6-8 week dietary probiotic intervention in pregnant women following diagnosis with GDM. Eligible studies were assessed for risk of bias and subjected to qualitative and quantitative synthesis using a random effects model meta-analyses. Four high quality RCTs involving 288 participants were included in the review. Probiotic supplementation was not effective in decreasing FBG (Mean Difference = -0.13; 95% CI -0.32, 0.06, p = 0.18) or LDL-cholesterol (-0.16; 95% CI -0.45, 0.13, p = 0.67) in women with GDM. However, a significant reduction in HOMA-IR was observed following probiotic supplementation (-0.69; 95% CI -1.24, -0.14, p = 0.01). There were no significant differences in gestational weight gain, delivery method or neonatal outcomes between experimental and control groups, and no adverse effects of the probiotics were reported. Probiotic supplementation for 6-8 weeks resulted in a significant reduction in insulin resistance in pregnant women diagnosed with GDM. The use of probiotic supplementation is promising as a potential therapy to assist in the metabolic management of GDM. Further high quality studies of longer duration are required to determine the safety, optimal dose and ideal bacterial composition of probiotics before their routine use can be recommended in this patient group.