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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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Effects of Intermittent Energy Restriction Compared with Those of Continuous Energy Restriction on Body Composition and Cardiometabolic Risk Markers - A Systematic Review and Meta-Analysis of Randomized Controlled Trials in Adults.
Schroor, MM, Joris, PJ, Plat, J, Mensink, RP
Advances in nutrition (Bethesda, Md.). 2024;15(1):100130
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Intermittent energy restriction (IER) diets, such as the 5:2 diet, time-restricted eating (TRE), and alternate-day fasting (ADF), are gaining popularity. According to previous research, IER protocols effectively manage obesity and may have many other health benefits, including improving metabolic health. This systematic review and meta-analysis of twenty-eight parallel-design randomised controlled trials looked at the benefits of IER protocols, such as ADF, TRE, and the 5:2 diet, and the effects of continuous energy restriction (CER) on anthropometric and cardiometabolic outcomes. The results of this systematic review and meta-analysis showed that both the IER and CER are equally beneficial. However, IER protocols showed greater but clinically insignificant improvements in fat-free mass and waist circumference in healthy adults. IER and CER protocols were not different in improving the lipid profile, glucose and insulin levels and blood pressure. Different IER diets showed different positive effects on metabolic parameters. Future robust studies are required to assess the effects of these energy-restriction diets on metabolic and anthropometric parameters because of the high variability in the included studies. However, healthcare professionals can use the results of this review to understand the potential clinical utility of various energy-restriction diets.
Abstract
The interest in intermittent energy restriction (IER) diets as a weight-loss approach is increasing. Different IER protocols exist, including time-restricted eating (TRE), alternate-day fasting (ADF), and the 5:2 diet. This meta-analysis compared the effects of these IER diets with continuous energy restriction (CER) on anthropometrics and cardiometabolic risk markers in healthy adults. Twenty-eight trials were identified that studied TRE (k = 7), ADF (k = 10), or the 5:2 diet (k = 11) for 2-52 wk. Energy intakes between intervention groups within a study were comparable (17 trials), lower in IER (5 trials), or not reported (6 trials). Weighted mean differences (WMDs) were calculated using fixed- or random-effects models. Changes in body weight [WMD: -0.42 kg; 95% confidence interval (CI): -0.96 to 0.13; P = 0.132] and fat mass (FM) (WMD: -0.31 kg; 95% CI: -0.98 to 0.36; P = 0.362) were comparable when results of the 3 IER diets were combined and compared with those of CER. All IER diets combined reduced fat-free mass (WMD: -0.20 kg; 95% CI: -0.39 to -0.01; P = 0.044) and waist circumference (WMD: -0.91 cm; 95% CI: -1.76 to -0.06; P = 0.036) more than CER. Effects on body mass index [BMI (kg/m2)], glucose, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), serum lipid and lipoprotein concentrations, and blood pressure did not differ. Further, TRE reduced body weight, FM, and fat-free mass more than CER, whereas ADF improved HOMA-IR more. BMI was reduced less in the 5:2 diet compared with CER. In conclusion, the 3 IER diets combined did not lead to superior improvements in anthropometrics and cardiometabolic risk markers compared with CER diets. Slightly greater reductions were, however, observed in fat-free mass and waist circumference. To what extent differences in energy intakes between groups within studies may have influenced these outcomes should be addressed in future studies.
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A systematic review and meta-analysis of the correlation between polycystic ovary syndrome and irritable bowel syndrome.
Wei, Z, Chen, Z, Xiao, W, Wu, G
Gynecological endocrinology : the official journal of the International Society of Gynecological Endocrinology. 2023;39(1):2239933
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The pathophysiology of polycystic ovarian syndrome (PCOS) and irritable bowel syndrome (IBS) remains elusive, the correlation between IBS and PCOS has been validated. This study's aim was to quantify the relationship between IBS and PCOS by estimating the odds ratio of IBS in PCOS patients. This study was a systematic review and meta-analysis of six studies in qualitative synthesis and five studies in quantitative synthesis. Results showed approximately 2.2 times elevated IBS risk in PCOS patient. Among six studies involved in this systematic review, a case-control study reported a negative relationship between IBS and PCOS, while most studies reported a positive association, which confirmed the pooled estimates results. Authors concluded that their study found a significant association between increased odds of IBS and PCOS.
Abstract
BACKGROUND Research on the prevalence of irritable bowel syndrome (IBS) among polycystic ovary syndrome (PCOS) patients has gained significant momentum over the years. However, it remains unclear whether PCOS is related to a higher prevalence of IBS. The objective of this systematic review and meta-analysis was to fully study IBS correlation with PCOS. METHODS From inception until October 16th, 2022, all observational studies documenting IBS prevalence in PCOS patients were collected from the China national knowledge infrastructure(CNKI), China Science and Technology Journal Database(VIP), Wanfang database, PubMed, Embase, Web of Science, and Cochrane databases. The quality of case-control studies was assessed with Newcastle-Ottawa Scale. Review Manager 5.3 was used to determine the pooled odds ratio (OR) and 95% confidence interval (CI). RESULTS 5 case-control studies involving 1268 individuals and one cross-sectional study involving 291 participants were included in our qualitative analysis. The quantitative analysis was conducted based on five case-control studies. Four case-control studies involving 1063 participants showed a higher prevalence of IBS in PCOS This meta-analysis revealed an almost twice higher risk of IBS in comparison with controls (OR = 2.23, 95%CI:1.58-3.14, p < 0.001; I2=41%, p = 0.150). Four sensitivity analyses validated the consistency of the aggregated findings. CONCLUSION This meta-analysis and systematic review demonstrated a significant association between PCOS and increased odds of IBS. However, more high-quality and well-controlled research is essential to increase the robustness of our conclusions.
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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.
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Effect of supplementation with probiotics or synbiotics on cardiovascular risk factors in patients with metabolic syndrome: a systematic review and meta-analysis of randomized clinical trials.
Chen, T, Wang, J, Liu, Z, Gao, F
Frontiers in endocrinology. 2023;14:1282699
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Metabolic syndrome (metS) is characterised by insulin resistance, dyslipidaemia, central obesity and/or high blood pressure and is a significant risk factor for cardiovascular disease and type 2 diabetes mellitus. MetS is associated with an imbalanced microbiome and some but not all studies have shown benefits of supplementation with probiotics. The aim of this systematic review and meta-analysis of randomised controlled trials was to evaluate the effects of pro- or synbiotics on cardiovascular risk factors (body mass index, LDL cholesterol, fasting blood glucose and systolic blood pressure) in patients with metS. 11 studies were included in the review of which 7 were judged to have a low risk of bias, whilst risk of bias was unclear in 4 articles. The meta-analysis found that pro- or synbiotics have a positive effect on body mass index, LDL cholesterol and fasting blood glucose but not on systolic blood pressure. Subgroup analysis of pro- and synbiotics separately also found no effects on systolic blood pressure.
Abstract
PURPOSE The effectiveness of probiotics or synbiotics in adults with metabolic syndromes (MetS) remains controversial, this meta-analysis will further analyze the effects of probiotics or synbiotics on cardiovascular factors in adults with MetS. METHODS We searched Web of Science, PubMed, Embase, Cochrane Library and other databases for randomized controlled trials (RCTs) on the effects of probiotics or synbiotics on MetS in adults up to July 2023, and used RevMan 5.4.0 software for statistical analysis. RESULTS This analysis included eleven RCTs (n = 608 participants), and the results showed that compared with the control group, supplementation with probiotics or synbiotics reduced body mass index (weighted mean difference, WMD = -0.83, 95% CI = [-1.21, -0.44], P <0.0001, n = 9), low-density lipoprotein (LDL-c) (standard mean difference, SMD = -0.24, 95% CI = [-0.41, -0.08], P = 0.004, n = 10), fasting blood glucose (FBG)(SMD = -0.17, 95% CI = [-0.33, -0.01], P = 0.03, n = 11), but had no beneficial effect on systolic blood pressure (SBP) (WMD = 1.24, 95% CI = [-2.06, 4.54], P = 0.46, n = 8) in MetS patients. CONCLUSION Supplementation with probiotics or synbiotics can reduce BMI, LDL-c, FBG in patients with MetS, but our findings did not demonstrate a favorable effect on reducing SBP. Future studies with larger samples and longer intervention periods are needed.
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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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Effects of Probiotics on Glycemic Control and Metabolic Parameters in Gestational Diabetes Mellitus: Systematic Review and Meta-Analysis.
Yefet, E, Bar, L, Izhaki, I, Iskander, R, Massalha, M, Younis, JS, Nachum, Z
Nutrients. 2023;15(7)
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The prevalence of gestational diabetes is increasing worldwide. Gestational diabetes mellitus (GDM) increases obesity and future development of type 2 diabetes in mother and child. Previous research has looked at the beneficial effects of probiotics in reducing metabolic diseases, however, these specific benefits on women with GDM are not fully understood yet. This systematic review and meta-analysis of fourteen randomised controlled trials assessed the beneficial effects of probiotics on glycemic control and metabolic parameters in women with GDM. This study separately assessed probiotic bacterial strains such as Lactobacillus acidophilus, Bifidobacterium bifidum, and Lactobacillus casei to understand their beneficial effects on metabolic parameters. This meta-analysis and systematic review suggest that probiotic supplementation could help improve glycemic control, insulin resistance and lipid levels in women diagnosed with GDM. All probiotic strains showed improvements in metabolic parameters when assessed separately. Further robust studies are required to assess the effect of probiotic supplementation on post- and pre-prandial glycemic control in women with GDM. Healthcare professionals can employ the results of this study to understand the therapeutic benefits of probiotics for improving GDM.
Abstract
OBJECTIVES To assess the effects of probiotic supplements on glycemic control and metabolic parameters in women with gestational diabetes mellitus (GDM) by performing a systematic review and meta-analysis of randomized controlled trials. The primary outcome was glycemic control, i.e., serum glucose and insulin levels. Secondary outcomes were maternal weight gain, neonatal birth weight, and lipid parameters. Weighted mean difference (WMD) was used. Cochrane's Q test of heterogeneity and I2 were used to assess heterogeneity. RESULTS Of the 843 papers retrieved, 14 (n = 854 women) met the inclusion criteria and were analyzed. When compared with placebo, women receiving probiotic supplements had significantly lower mean fasting serum glucose, fasting serum insulin, homeostatic model assessment for insulin resistance (HOMA-IR), triglycerides, total cholesterol, and VLDL levels. Decreased neonatal birth weight was witnessed in supplements containing Lactobacillus acidophilus. CONCLUSION Probiotic supplements may improve glycemic control and lipid profile and reduce neonatal birth weight in women with GDM.
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Diabetes mellitus, prediabetes and the risk of Parkinson's disease: a systematic review and meta-analysis of 15 cohort studies with 29.9 million participants and 86,345 cases.
Aune, D, Schlesinger, S, Mahamat-Saleh, Y, Zheng, B, Udeh-Momoh, CT, Middleton, LT
European journal of epidemiology. 2023;38(6):591-604
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Diabetes mellitus and prediabetes may increase an individual’s risk for Parkinson’s disease (PD), however the research completed to date has been controversial. This meta-analysis of 15 observational studies with 86,345 individuals with PD aimed to update the research on PD risk for individuals with diabetes or prediabetes and determine possible reasons for the ambiguity of previous research. The results showed that compared to people without diabetes, those with, were at a 27% increased relative risk of PD and a 4% increase amongst those with prediabetes. Individuals with a history of complications alongside diabetes were at a higher risk than those without. It was concluded that the risk of developing PD is increased amongst individuals with diabetes. This study could be used by healthcare professionals to understand that individuals with diabetes may be at an increased risk for PD and should be monitored. However, as this is based on observational studies, there is a chance that PD increases the risk for diabetes and not the reverse.
Abstract
A diagnosis of diabetes mellitus and prediabetes has been associated with increased risk of Parkinson's disease (PD) in several studies, but results have not been entirely consistent. We conducted a systematic review and meta-analysis of cohort studies on diabetes mellitus, prediabetes and the risk of PD to provide an up-to-date assessment of the evidence. PubMed and Embase databases were searched for relevant studies up to 6th of February 2022. Cohort studies reporting adjusted relative risk (RR) estimates and 95% confidence intervals (CIs) for the association between diabetes, prediabetes and Parkinson's disease were included. Summary RRs (95% CIs) were calculated using a random effects model. Fifteen cohort studies (29.9 million participants, 86,345 cases) were included in the meta-analysis. The summary RR (95% CI) of PD for persons with diabetes compared to persons without diabetes was 1.27 (1.20-1.35, I2 = 82%). There was no indication of publication bias, based on Egger's test (p = 0.41), Begg's test (p = 0.99), and inspection of the funnel plot. The association was consistent across geographic regions, by sex, and across several other subgroup and sensitivity analyses. There was some suggestion of a stronger association for diabetes patients reporting diabetes complications than for diabetes patients without complications (RR = 1.54, 1.32-1.80 [n = 3] vs. 1.26, 1.16-1.38 [n = 3]), vs. those without diabetes (pheterogeneity=0.18). The summary RR for prediabetes was 1.04 (95% CI: 1.02-1.07, I2 = 0%, n = 2). Our results suggest that patients with diabetes have a 27% increased relative risk of developing PD compared to persons without diabetes, and persons with prediabetes have a 4% increase in RR compared to persons with normal blood glucose. Further studies are warranted to clarify the specific role age of onset or duration of diabetes, diabetic complications, glycaemic level and its long-term variability and management may play in relation to PD risk.
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Associations between plant-based dietary patterns and risks of type 2 diabetes, cardiovascular disease, cancer, and mortality - a systematic review and meta-analysis.
Wang, Y, Liu, B, Han, H, Hu, Y, Zhu, L, Rimm, EB, Hu, FB, Sun, Q
Nutrition journal. 2023;22(1):46
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According to the World Health Organization, type 2 diabetes (T2D), cardiovascular disease (CVD), and cancer account for nearly one in every two deaths globally. These diseases have significant clinical and public health implications. This study's aim was to assess the association of adherence to plant-based dietary patterns and changes in them with risks of major chronic diseases, including T2D, CVD, and cancer, and mortality. This study was a systematic review and meta-analysis of 55 prospective studies. Results showed that greater adherence to a plant-based dietary pattern was inversely associated with risks of T2D, CVD, cancer and all-cause mortality. Associations for T2D, CVD, and cancer were strengthened when the plant-based diets further emphasised healthful plant-based foods, such as vegetables, fruits, whole grains, and legumes. Authors concluded that their findings support the current recommendations that emphasise consuming high-quality plant-based foods for achieving optimal health.
Abstract
BACKGROUND Plant-based dietary patterns are gaining more attention due to their potential in reducing the risk of developing major chronic diseases, including type 2 diabetes (T2D), cardiovascular disease (CVD), cancer, and mortality, while an up-to-date comprehensive quantitative review is lacking. This study aimed to summarize the existing prospective observational evidence on associations between adherence to plant-based dietary patterns and chronic disease outcomes. METHODS We conducted a systematic review and meta-analysis of evidence across prospective observational studies. The data sources used were PubMed and MEDLINE, Embase, Web of Science, and screening of references. We included all prospective observational studies that evaluated the association between adherence to plant-based dietary patterns and incidence of T2D, CVD, cancer, and mortality among adults (≥ 18 years). RESULTS A total of 76 publications were identified, including 2,230,443 participants with 60,718 cases of incident T2D, 157,335 CVD cases, 57,759 cancer cases, and 174,435 deaths. An inverse association was observed between higher adherence to a plant-based dietary pattern and risks of T2D (RR, 0.82 [95% CI: 0.77-0.86]), CVD (0.90 [0.85-0.94]), cancer (0.91 [0.87-0.96]), and all-cause mortality (0.84 [0.78-0.92]) with moderate to high heterogeneity across studies (I2 ranged: 47.8-95.4%). The inverse associations with T2D, CVD and cancer were strengthened when healthy plant-based foods, such as vegetables, fruits, whole grains, and legumes, were emphasized in the definition of plant-based dietary patterns (T2D: 0.79 [0.72-0.87]; CVD: 0.85 [0.80-0.92]; cancer: 0.86 [0.80-0.92]; I2 ranged: 53.1-84.1%). Association for mortality was largely similar when the analyses were restricted to healthy plant-based diets (0.86 [0.80-0.92], I2 = 91.9%). In contrast, unhealthy plant-based diets were positively associated with these disease outcomes. Among four studies that examined changes in dietary patterns, increased adherence to plant-based dietary patterns was associated with a significantly reduced risk of T2D (0.83 [0.71-0.96]; I2 = 71.5%) and a marginally lower risk of mortality (0.95 [0.91-1.00]; I2 = 0%). CONCLUSIONS Better adherence to plant-based dietary patterns, especially those emphasizing healthy plant-based foods, is beneficial for lowering the risks of major chronic conditions, including T2D, CVD, cancer, as well as premature deaths. REGISTRATION OF REVIEW PROTOCOL This review was registered at the PROSPERO International Prospective Register of Systematic Reviews ( https://www.crd.york.ac.uk/PROSPERO/ ) with the registration number CRD42022290202.
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The effect of selenium supplementation in pregnant women on maternal, fetal, and newborn outcomes: a systematic review and meta-analysis.
McDougall, AR, Dore, G, Aboud, L, Makama, M, Nguyen, PY, Mills, K, Sanderson, B, Hastie, R, Ammerdorffer, A, Vogel, JP
American journal of obstetrics & gynecology MFM. 2023;5(11):101160
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Observational data show preterm birth risk is increased with low maternal selenium serum levels. Selenium is routinely included in supplements marketed to pregnant women, although studies have drawn conflicting findings about whether it provides benefit. The aim of this study was to identify and analyse the available interventional and observational evidence of the effect of selenium supplementation during pregnancy on preterm birth (PTB) prevention. This study was a systematic review of thirty-two studies - 5 observational studies and 27 randomised trials. Results showed that there was no association between selenium supplementation and any clinical outcome. Authors concluded that since there was insufficient evidence in all outcomes, selenium supplementation during pregnancy cannot be recommended as a part of routine antenatal care.
Abstract
OBJECTIVE Low maternal selenium status has been associated with poor pregnancy outcomes, including preterm birth. This study aimed to evaluate available evidence of the effects of selenium supplementation during pregnancy on preterm birth and related maternal, fetal, and newborn outcomes. DATA SOURCES MEDLINE, Embase, CINAHL, Global Index Medicus, and the Cochrane Library were systematically searched on June 23, 2022, without language or time restrictions. STUDY ELIGIBILITY CRITERIA Randomized controlled trials and nonrandomized interventional studies were included if they compared the effects of selenium supplementation with placebo or no treatment among pregnant women. The review protocol was registered in the International Prospective Register of Systematic Reviews (identification number: CRD42022383669). METHODS For outcomes reported by ≥1 study, a meta-analysis was conducted. Because of the small number of studies and high clinical heterogeneity between populations, random-effects models were used. The Risk of Bias 2 and Risk Of Bias In Non-randomized Studies - of Interventions tools were used to assess study quality, and Grading of Recommendations Assessment, Development, and Evaluation analysis was used to determine the certainty of evidence for each outcome. RESULTS Literature searches identified 5105 unique records, and 32 studies met the eligibility criteria. Of note, 11 reports were not included for analysis following research integrity assessments. Moreover, 10 trials and 3 observational studies met the inclusion criteria; however, only 8 trials (1851 women) and 1 prospective cohort study (71,728 women) reported on at least 1 review outcome. Our results could not determine the effect of selenium supplementation on preterm birth at <37 weeks of gestation (relative risk, 0.65; 95% confidence interval, 0.26-1.63; very low certainty evidence) and <34 weeks of gestation (relative risk, 1.05; 95% confidence interval, 0.59-1.44; very low certainty evidence). CONCLUSION There is limited evidence on the effects of selenium supplementation during pregnancy. Further trials, with larger sample sizes, more representative populations, and reliable assessment of maternal selenium status at trial entry, are required.