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Advances in Nutrition (Bethesda, Md.) Mar 2022Vitamin B-12 deficiency is a major public health problem affecting individuals across the lifespan, with known hematological, neurological, and obstetric consequences.... (Review)
Review
Vitamin B-12 deficiency is a major public health problem affecting individuals across the lifespan, with known hematological, neurological, and obstetric consequences. Emerging evidence suggests that vitamin B-12 may have an important role in other aspects of human health, including the composition and function of the gastrointestinal (gut) microbiome. Vitamin B-12 is synthesized and utilized by bacteria in the human gut microbiome and is required for over a dozen enzymes in bacteria, compared to only 2 in humans. However, the impact of vitamin B-12 on the gut microbiome has not been established. This systematic review was conducted to examine the evidence that links vitamin B-12 and the gut microbiome. A structured search strategy was used to identify in vitro, animal, and human studies that assessed vitamin B-12 status, dietary intake, or supplementation, and the gut microbiome using culture-independent techniques. A total of 22 studies (3 in vitro, 8 animal, 11 human observational studies) were included. Nineteen studies reported that vitamin B-12 intake, status, or supplementation was associated with gut microbiome outcomes, including beta-diversity, alpha-diversity, relative abundance of bacteria, functional capacity, or short-chain fatty acids (SCFA) production. Evidence suggests that vitamin B-12 may be associated with changes in bacterial abundance. While results from in vitro studies suggest that vitamin B-12 may increase alpha-diversity and shift gut microbiome composition (beta-diversity), findings from animal studies and observational human studies were heterogeneous. Based on evidence from in vitro and animal studies, microbiome outcomes may differ by cobalamin form and co-intervention. To date, few prospective observational studies and no randomized trials have been conducted to examine the effects of vitamin B-12 on the human gut microbiome. The impact of vitamin B-12 on the gut microbiome needs to be elucidated to inform screening and public health interventions.
Topics: Animals; Humans; Gastrointestinal Microbiome; Vitamin B 12; Microbiota; Eating; Bacteria; Vitamins; Observational Studies as Topic
PubMed: 34612492
DOI: 10.1093/advances/nmab123 -
Reproductive Biology and Endocrinology... Jan 2023Metformin is the gold standard insulin sensitizer, which is widely used to treat insulin resistance in polycystic ovary syndrome (PCOS). However, metformin may induce... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Metformin is the gold standard insulin sensitizer, which is widely used to treat insulin resistance in polycystic ovary syndrome (PCOS). However, metformin may induce gastrointestinal side effects.
OBJECTIVE
Inositols have long been debated as a potential alternative for metformin in treating PCOS. Therefore, the present systematic review aimed to evaluate the efficacy and safety of inositols in treating PCOS.
METHODS
The present systematic search was performed in CENTRAL, MEDLINE, and Embase from the inception until October 20th, 2021. Eligible randomized controlled trials (RCTs) included women diagnosed with PCOS and compared any inositols with metformin or placebo. Our primary outcome was cycle normalization, whereas secondary outcomes were body mass index (BMI), parameters of carbohydrate metabolism and clinical and laboratory hyperandrogenism. Results are reported as risk ratios or mean differences (MDs) with 95% confidence intervals (CIs).
RESULTS
Twenty-six RCTs were identified, including data of 1691 patients (806 inositol, 311 with placebo, and 509 metformin groups). In patients treated with inositols, the risk (CI: 1.13; 2.85) of having a regular menstrual cycle was found by 1.79 higher than in the case of placebo. Moreover, the inositols showed non-inferiority compared to metformin in this outcome. In the case of BMI (MD = -0.45; CI: -0.89; -0.02), free testosterone (MD = -0,41, CI: -0.69; -0.13), total testosterone (MD = -20.39, CI: -40.12; -0.66), androstenedione (MD = -0.69, CI: -1,16; -0.22), glucose (MD = -3.14; CI: -5.75; -0.54) levels and AUC insulin (MD = -2081.05, CI: -2745.32; -1416.78) inositol treatment induced greater decrease compared to placebo. Inositol increased sex-hormone-binding globulin significantly compared to placebo (MD = 32.06, CI:1.27; 62.85).
CONCLUSION
Inositol is an effective and safe treatment in PCOS. Moreover, inositols showed non-inferiority in most outcomes compared to the gold standard treatment; metformin.
TRIAL REGISTRATION
PROSPERO registration number: CRD42021283275.
Topics: Female; Humans; Polycystic Ovary Syndrome; Inositol; Hypoglycemic Agents; Randomized Controlled Trials as Topic; Metformin; Testosterone; Insulins
PubMed: 36703143
DOI: 10.1186/s12958-023-01055-z -
Nutrients Feb 2022Dementia is a syndrome characterized by progressive cognitive impairment that interferes with independent function in daily activities. Symptoms of dementia depend on... (Review)
Review
BACKGROUND
Dementia is a syndrome characterized by progressive cognitive impairment that interferes with independent function in daily activities. Symptoms of dementia depend on its cause and vary greatly between individuals. There is extensive evidence supporting a relationship between diet and cognitive functions. This systematic review studies the efficacy of using vitamin supplements in the diet as a solution to nutritional deficiencies and the prevention of dementia and mild cognitive impairment.
METHODS
An intensive search of different databases (PubMed, Web of Science, and Cochrane CENTRAL) was performed. Articles that were published between 2011 and November 2021 were retrieved using the mentioned search strategy. This systematic review has been conducted according to the PRISMA statement.
RESULTS
Folic acid supplementation proved to have better outcomes on cognitive tests than their respective control groups. The combined supplementation of folic acid and vitamin B12 showed some discrepancies between studies. Thiamine as supplementation did not only prove to have a positive impact on cognitive performance when given alone but also when given in combination with folic acid. Regarding vitamin D supplementation, the results observed were not so encouraging. A concomitant supplementation of low-dose vitamin E and vitamin C was also not associated with an improvement of cognitive function.
CONCLUSIONS
The findings of this systematic review suggest that supplementation of B Complex vitamins, especially folic acid, may have a positive effect on delaying and preventing the risk of cognitive decline. Ascorbic acid and a high dose of vitamin E, when given separately, also showed positive effects on cognitive performance, but there is not sufficient evidence to support their use. The results of vitamin D supplementation trials are not conclusive in assessing the potential benefits that vitamin D might have on cognition.
Topics: Cognition Disorders; Dementia; Dietary Supplements; Humans; Vitamin B 12; Vitamins
PubMed: 35268010
DOI: 10.3390/nu14051033 -
Nutrients Mar 2021Vitamin B12 is often used to improve cognitive function, depressive symptoms, and fatigue. In most cases, such complaints are not associated with overt vitamin B12... (Meta-Analysis)
Meta-Analysis
Vitamin B12 is often used to improve cognitive function, depressive symptoms, and fatigue. In most cases, such complaints are not associated with overt vitamin B12 deficiency or advanced neurological disorders and the effectiveness of vitamin B12 supplementation in such cases is uncertain. The aim of this systematic review and meta-analysis of randomized controlled trials (RCTs) is to assess the effects of vitamin B12 alone (B12 alone), in addition to vitamin B12 and folic acid with or without vitamin B6 (B complex) on cognitive function, depressive symptoms, and idiopathic fatigue in patients without advanced neurological disorders or overt vitamin B12 deficiency. Medline, Embase, PsycInfo, Cochrane Library, and Scopus were searched. A total of 16 RCTs with 6276 participants were included. Regarding cognitive function outcomes, we found no evidence for an effect of B12 alone or B complex supplementation on any subdomain of cognitive function outcomes. Further, meta-regression showed no significant associations of treatment effects with any of the potential predictors. We also found no overall effect of vitamin supplementation on measures of depression. Further, only one study reported effects on idiopathic fatigue, and therefore, no analysis was possible. Vitamin B12 supplementation is likely ineffective for improving cognitive function and depressive symptoms in patients without advanced neurological disorders.
Topics: Cognition; Depression; Dietary Supplements; Fatigue; Humans; Vitamin B 12; Vitamins
PubMed: 33809274
DOI: 10.3390/nu13030923 -
BMJ Clinical Evidence Mar 2014More than half of pregnant women suffer from nausea and vomiting, which typically begins by the fourth week and disappears by the 16th week of pregnancy. The cause of... (Review)
Review
INTRODUCTION
More than half of pregnant women suffer from nausea and vomiting, which typically begins by the fourth week and disappears by the 16th week of pregnancy. The cause of nausea and vomiting in pregnancy is unknown, but may be due to the rise in human chorionic gonadotrophin concentration. In 1 in 200 women, the condition progresses to hyperemesis gravidarum, which is characterised by prolonged and severe nausea and vomiting, dehydration, and weight loss.
METHODS AND OUTCOMES
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatment for nausea and vomiting in early pregnancy? What are the effects of treatments for hyperemesis gravidarum? We searched: Medline, Embase, The Cochrane Library, and other important databases up to September 2013 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
RESULTS
We found 32 studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
CONCLUSIONS
In this systematic review we present information relating to the effectiveness and safety of the following interventions: acupressure; acupuncture; corticosteroids; ginger; metoclopramide; ondansetron; prochlorperazine; promethazine; and pyridoxine (vitamin B6).
Topics: Acupressure; Acupuncture Therapy; Adrenal Cortex Hormones; Antiemetics; Female; Zingiber officinale; Humans; Nausea; Pregnancy; Pyridoxine; Vomiting
PubMed: 24646807
DOI: No ID Found -
Journal of the American College of... Dec 2022Healthy dietary patterns are rich in micronutrients, but their influence on cardiovascular disease (CVD) risks has not been systematically quantified.
BACKGROUND
Healthy dietary patterns are rich in micronutrients, but their influence on cardiovascular disease (CVD) risks has not been systematically quantified.
OBJECTIVES
The goal of this study was to provide a comprehensive and most up-to-date evidence-based map that systematically quantifies the impact of micronutrients on CVD outcomes.
METHODS
This study comprised a systematic review and meta-analysis of randomized controlled intervention trials of micronutrients on CVD risk factors and clinical events.
RESULTS
A total of 884 randomized controlled intervention trials evaluating 27 types of micronutrients among 883,627 participants (4,895,544 person-years) were identified. Supplementation with n-3 fatty acid, n-6 fatty acid, l-arginine, l-citrulline, folic acid, vitamin D, magnesium, zinc, α-lipoic acid, coenzyme Q10, melatonin, catechin, curcumin, flavanol, genistein, and quercetin showed moderate- to high-quality evidence for reducing CVD risk factors. Specifically, n-3 fatty acid supplementation decreased CVD mortality (relative risk [RR]: 0.93; 95% CI: 0.88-0.97), myocardial infarction (RR: 0.85; 95% CI: 0.78-0.92), and coronary heart disease events (RR: 0.86; 95% CI: 0.80-0.93). Folic acid supplementation decreased stroke risk (RR: 0.84; 95% CI: 0.72-0.97), and coenzyme Q10 supplementation decreased all-cause mortality events (RR: 0.68; 95% CI: 0.49-0.94). Vitamin C, vitamin D, vitamin E, and selenium showed no effect on CVD or type 2 diabetes risk. β-carotene supplementation increased all-cause mortality (RR: 1.10; 95% CI: 1.05-1.15), CVD mortality events (RR: 1.12; 95% CI: 1.06-1.18), and stroke risk (RR: 1.09; 95% CI: 1.01-1.17).
CONCLUSIONS
Supplementation of some but not all micronutrients may benefit cardiometabolic health. This study highlights the importance of micronutrient diversity and the balance of benefits and risks to promote and maintain cardiovascular health in diverse populations. (Antioxidant Supplementation in the Prevention and Treatment of Cardiovascular Diseases; CRD42022315165).
Topics: Humans; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Risk Factors; Heart Disease Risk Factors; Vitamin D; Folic Acid; Stroke
PubMed: 36480969
DOI: 10.1016/j.jacc.2022.09.048 -
Diabetes & Metabolic Syndrome Oct 2022Metformin-treated type 2 diabetes mellitus (T2DM) patients are at higher risk of vitamin B deficiency and more severe neuropathy symptoms. There is still no guideline... (Review)
Review
The efficacy of vitamin B supplementation for treating vitamin B deficiency and peripheral neuropathy in metformin-treated type 2 diabetes mellitus patients: A systematic review.
BACKGROUND AND AIMS
Metformin-treated type 2 diabetes mellitus (T2DM) patients are at higher risk of vitamin B deficiency and more severe neuropathy symptoms. There is still no guideline suggesting vitamin B supplementation for this population. This study aimed to analyze the efficacy of vitamin B supplementation in this population.
METHOD
Studies reporting the efficacy of vitamin B supplementation in metformin-treated T2DM patients were systematically searched in PubMed, Cochrane, EBSCOHost, and Scopus following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Additional relevant studies were searched manually through citations. Study quality and risk of bias were assessed using suitable tools.
RESULTS
Seven clinical trials with a total of 506 participants were included. Using the Cochrane's Risk of Bias 2 tools for clinical trials, 4 studies were assessed to have high risk of bias and 3 studies had low risk of bias. There were 5 studies that measured changes in serum vitamin B level, all of which reported a statistically significant increase after supplementation. Significant reductions in homocysteine after supplementation were found in 2 studies. Its effect on neuropathy symptoms was still unclear, with 2 studies reporting a significant improvement and 1 study reporting no significant effect.
CONCLUSIONS
The results of this systematic review support the implementation of vitamin B supplementation for metformin-treated T2DM to prevent or treat vitamin B deficiency and neuropathy. More high-quality clinical studies are required to generate quantitative analysis and to encourage supplementation in available guidelines.
Topics: Humans; Metformin; Diabetes Mellitus, Type 2; Vitamin B 12; Hypoglycemic Agents; Vitamin B 12 Deficiency; Peripheral Nervous System Diseases; Homocysteine; Dietary Supplements; Vitamins
PubMed: 36240684
DOI: 10.1016/j.dsx.2022.102634 -
Nutrients Aug 2020Fibromyalgia (FM) is a multifactorial syndrome of unknown etiology, characterized by widespread chronic pain and various somatic and psychological manifestations. The...
Fibromyalgia (FM) is a multifactorial syndrome of unknown etiology, characterized by widespread chronic pain and various somatic and psychological manifestations. The management of FM requires a multidisciplinary approach combining both pharmacological and nonpharmacological strategies. Among nonpharmacological strategies, growing evidence suggests a potential beneficial role for nutrition. This review summarizes the possible relationship between FM and nutrition, exploring the available evidence on the effect of dietary supplements and dietary interventions in these patients. Analysis of the literature has shown that the role of dietary supplements remains controversial, although clinical trials with vitamin D, magnesium, iron and probiotics' supplementation show promising results. With regard to dietary interventions, the administration of olive oil, the replacement diet with ancient grains, low-calorie diets, the low FODMAPs diet, the gluten-free diet, the monosodium glutamate and aspartame-free diet, vegetarian diets as well as the Mediterranean diet all appear to be effective in reducing the FM symptoms. These results may suggest that weight loss, together with the psychosomatic component of the disease, should be taken into account. Therefore, although dietary aspects appear to be a promising complementary approach to the treatment of FM, further research is needed to provide the most effective strategies for the management of FM.
Topics: Acetylcarnitine; Ascorbic Acid; Chlorella; Diet, Vegan; Dietary Supplements; Fibromyalgia; Nutrition Therapy; Nutritional Physiological Phenomena; Syndrome; Ubiquinone; Vitamin E
PubMed: 32825400
DOI: 10.3390/nu12092525 -
The Cochrane Database of Systematic... Mar 2018Vitamin B deficiency is common, and the incidence increases with age. Most people with vitamin B deficiency are treated in primary care with intramuscular (IM) vitamin... (Review)
Review
BACKGROUND
Vitamin B deficiency is common, and the incidence increases with age. Most people with vitamin B deficiency are treated in primary care with intramuscular (IM) vitamin B. Doctors may not be prescribing oral vitamin B formulations because they may be unaware of this option or have concerns regarding its effectiveness.
OBJECTIVES
To assess the effects of oral vitamin B versus intramuscular vitamin B for vitamin B deficiency.
SEARCH METHODS
We searched CENTRAL, MEDLINE, Embase, and LILACS, as well as the WHO ICTRP and ClinicalTrials.gov. The latest search date was 17 July 2017. We applied no language restrictions. We also contacted authors of relevant trials to enquire about other published or unpublished studies and ongoing trials.
SELECTION CRITERIA
Randomised controlled trials (RCTs) comparing the effect of oral versus IM vitamin B for vitamin B deficiency.
DATA COLLECTION AND ANALYSIS
We used standard methodological procedures expected by Cochrane. Our primary outcomes were serum vitamin B levels, clinical signs and symptoms of vitamin B deficiency, and adverse events. Secondary outcomes were health-related quality of life, acceptability to patients, haemoglobin and mean corpuscular volume, total homocysteine and serum methylmalonic acid levels, and socioeconomic effects. We used GRADE to assess the quality of the evidence for important outcomes. We did not perform meta-analyses due to the small number of included trials and substantial clinical heterogeneity.
MAIN RESULTS
Three RCTs met our inclusion criteria. The trials randomised 153 participants (74 participants to oral vitamin B and 79 participants to IM vitamin B). Treatment duration and follow-up ranged between three and four months. The mean age of participants ranged from 38.6 to 72 years. The treatment frequency and daily dose of vitamin B in the oral and IM groups varied among trials. Only one trial had low or unclear risk of bias across all domains and outcome measures. Two trials reported data for serum vitamin B levels. The overall quality of evidence for this outcome was low due to serious imprecision (low number of trials and participants). In two trials employing 1000 μg/day oral vitamin B, there was no clinically relevant difference in vitamin B levels when compared with IM vitamin B. One trial used 2000 μg/day vitamin B and demonstrated a mean difference of 680 pg/mL (95% confidence interval 392.7 to 967.3) in favour of oral vitamin B. Two trials reported data on adverse events (very low-quality evidence due to risk of performance bias, detection bias, and serious imprecision). One trial stated that no treatment-related adverse events were seen in both the oral and IM vitamin B groups. One trial reported that 2 of 30 participants (6.7%) in the oral vitamin B group left the trial early due to adverse events. Orally taken vitamin B showed lower treatment-associated costs than IM vitamin B in one trial (low-quality evidence due to serious imprecision). No trial reported on clinical signs and symptoms of vitamin B deficiency, health-related quality of life, or acceptability of the treatment scheme.
AUTHORS' CONCLUSIONS
Low quality evidence shows oral and IM vitamin B having similar effects in terms of normalising serum vitamin B levels, but oral treatment costs less. We found very low-quality evidence that oral vitamin B appears as safe as IM vitamin B. Further trials should conduct better randomisation and blinding procedures, recruit more participants, and provide adequate reporting. Future trials should also measure important outcomes such as the clinical signs and symptoms of vitamin B deficiency, health related-quality of life, socioeconomic effects, and report adverse events adequately, preferably in a primary care setting.
Topics: Administration, Oral; Aged; Humans; Injections, Intramuscular; Randomized Controlled Trials as Topic; Vitamin B 12; Vitamin B 12 Deficiency; Vitamin B Complex
PubMed: 29543316
DOI: 10.1002/14651858.CD004655.pub3 -
Cephalalgia : An International Journal... Feb 2022Burning mouth syndrome is a chronic idiopathic intractable intraoral dysaesthesia that remains a challenge to clinicians due to its poorly understood pathogenesis and... (Review)
Review
BACKGROUND
Burning mouth syndrome is a chronic idiopathic intractable intraoral dysaesthesia that remains a challenge to clinicians due to its poorly understood pathogenesis and inconsistent response to various treatments.
AIM
This review aimed to study the short- (≤3 months) and long-term (>3 months) effectiveness and sustainable benefit of different burning mouth syndrome treatment strategies and the associated side effects.
MATERIALS AND METHODS
Randomised controlled trials of burning mouth syndrome treatment compared with placebo or other interventions with a minimum follow up of 2 months were searched from the PubMed, Embase and Cochrane database (published to July 2020).
RESULTS
Twenty-two studies were selected based on the inclusion and exclusion criteria and analysed. Nine categories of burning mouth syndrome treatment were identified: Anticonvulsant and antidepressant agents, phytomedicine and alpha lipoic acid supplements, low-level laser therapy, saliva substitute, transcranial magnetic stimulation, and cognitive behaviour therapy. Cognitive behaviour therapy, topical capsaicin and clonazepam, and laser therapy demonstrated favourable outcome in both short- and long-term assessment. Phytomedicines reported a short-term benefit in pain score reduction. The pooled effect of alpha lipoic acid (ALA) pain score improvement was low, but its positive effects increased in long term assessment.
CONCLUSION
A more significant volume in terms of sample size, multi-centres, and multi-arm comparison of therapeutic agents with placebo and longitudinal follow-up studies is recommended to establish a standardised burning mouth syndrome treatment protocol. Further studies are required to assess the analgesic benefits of topical clonazepam and capsaicin, alternative medicines with neurodegenerative prevention capability and psychology support in treating burning mouth syndrome and reducing systemic adverse drug reactions. International Prospective Register of Systematic Reviews (PROSPERO):Protocol ID - CRD42020160892.
Topics: Burning Mouth Syndrome; Capsaicin; Clonazepam; Humans; Pain; Thioctic Acid
PubMed: 34404247
DOI: 10.1177/03331024211036152