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The American Journal of Clinical... Jan 2023Selenium is an essential trace element with both beneficial and detrimental effects on health depending on dose and chemical form. Currently, there is debate on... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Selenium is an essential trace element with both beneficial and detrimental effects on health depending on dose and chemical form. Currently, there is debate on recommendations for selenium supplementation as a public health measure to improve immune function and reduce infectious disease susceptibility.
OBJECTIVES
We performed a systematic review and meta-analysis of experimental studies assessing the effect of selenium supplementation on immunity-related outcomes in healthy people.
METHODS
We undertook a search of published and unpublished studies in literature databases such as PubMed/MEDLINE, Embase, and clinicaltrials.gov up to 17 October, 2022, and performed a meta-analysis comparing the effects on immunity-related outcomes between Se-supplemented versus control arms. Whenever possible we assessed the nonlinear relation using a dose-response approach.
RESULTS
9 trials were included, 5 in North America, and 4 in Europe, with a duration between 8 and 48 weeks and supplementation of both inorganic and organic selenium forms. Selenium supplementation did not substantially affect immunoglobulin or white blood cell concentrations, and the dose-response meta-analysis indicated that an increase in plasma selenium concentrations above 100 μg/L did not further increase IgA levels nor T cells. An inverted U-shaped relation emerged for NK cell count, with a lower number of these cells both below and above 120 μg/L. The only beneficial effect of selenium supplementation was the increased activity for NK lysis, but the available data did not permit dose-response analysis. Cytokine levels were substantially unaffected by selenium supplementation.
CONCLUSIONS
Although some of the data suggested beneficial effects of selenium supplementation on immune function, the overall picture appears to be inconsistent and heterogeneous due to differences in trial duration and interventions, plus evidence of null and even detrimental effects. Overall, the evidence that we extracted from the literature in this systematic review does not support the need to supplement selenium beyond the recommended dietary intake to obtain beneficial effects on immune function. This trial was registered at PROSPERO (CRD42022312280).
Topics: Humans; Selenium; Trace Elements; Dietary Supplements; Immunity; Europe
PubMed: 36789948
DOI: 10.1016/j.ajcnut.2022.11.007 -
Acta Obstetricia Et Gynecologica... Oct 2022Preeclampsia is associated with adverse maternal and neonatal outcomes. It is unclear whether multivitamin use reduces the risk of preeclampsia. This systematic review... (Meta-Analysis)
Meta-Analysis Review
INTRODUCTION
Preeclampsia is associated with adverse maternal and neonatal outcomes. It is unclear whether multivitamin use reduces the risk of preeclampsia. This systematic review and meta-analysis aimed to evaluate the association between multivitamin use and the risk of preeclampsia.
MATERIAL AND METHODS
We searched PubMed, Embase and the Cochrane Library from database inception to July 2021. Randomized controlled trials (RCTs), case-control and cohort studies assessing the association between multivitamin use and risk of preeclampsia were eligible. Studies of treatment with a single micronutrient were excluded. Relative risks and 95% confidence intervals (95% CI) were calculated using random-effects models. RoB2, the Newcastle Ottawa Scale and GRADE were used to assess risk of bias and quality of evidence. The protocol was registered in PROSPERO (no. CRD42021214153).
RESULTS
Six studies were included (33 356 women). Only two RCTs were found, both showing a significantly decreased risk of preeclampsia in multivitamin users. These studies were not compatible for meta-analysis due to clinical heterogeneity. A meta-analysis of observational studies using a random-effects model showed an unchanged risk of preeclampsia following multivitamin use (relative risk 0.85, 95% CI 0.69-1.03). The quality of evidence according to GRADE was very low.
CONCLUSIONS
Very weak evidence suggests that multivitamin use might reduce the risk of preeclampsia; however, more research is needed. Large RCTs should be prioritized. The results of this review do not allow any final conclusions to be drawn regarding a preventive effect of multivitamin use in relation to preeclampsia.
Topics: Case-Control Studies; Cohort Studies; Female; Humans; Infant, Newborn; Micronutrients; Pre-Eclampsia; Pregnancy
PubMed: 35388472
DOI: 10.1111/aogs.14356 -
Nutricion Hospitalaria Oct 2023Objective: to explore the association between serum vitamin D level and the occurrence and pathological grade of gastric cancer. Material a nd methods: search PubMed,... (Meta-Analysis)
Meta-Analysis
Objective: to explore the association between serum vitamin D level and the occurrence and pathological grade of gastric cancer. Material a nd methods: search PubMed, Embase, Web of Science, Cochrane and Chinese database; all articles about the association between serum vitamin D levels and gastric cancer published before July 2021. Results: 10 trials with 1159 cases of gastric cancer patients and 33,387 cases of regular control patients were analyzed. The serum vitamin D level of the gastric cancer group (15.56 ± 7.46 ng/ml) was lower than in the control group (17.60 ± 1.61 ng/ml), and the difference was statistically significant. The patients with gastric cancer, clinical stage III/IV (16.19 ± 8.04 ng/ml) had lower vitamin D levels than those with stage I/II (19.61 ± 9.61 ng/ml), and the patients with low differentiation of gastric cancer (17.5 ± 9.5 ng/ml) had lower levels than those with well- or moderately-differentiated cancer (18.04 ± 7.92 ng/ml). The patients with lymph node metastasis (19.41 ± 8.63 ng/ml) had lower vitamin D levels than the patients without lymph node metastasis (20.65 ± 7.96 ng/ml), and the difference was statistically significant. Conclusion: vitamin D levels were negatively associated with gastric cancer. Vitamin D levels were significantly associated with different clinical stages, degrees of differentiation, and lymph node metastasis, suggesting that low vitamin D levels might predict poor prognosis in gastric cancer.
Topics: Humans; Vitamin D; Lymphatic Metastasis; Stomach Neoplasms; Neoplasm Staging; Vitamins
PubMed: 37334809
DOI: 10.20960/nh.04410 -
Nutrition Reviews Feb 2013Micronutrient status during pregnancy influences maternal and fetal health, birth outcomes, and the risk of chronic disease in offspring. Research reporting dietary... (Meta-Analysis)
Meta-Analysis Review
Micronutrient status during pregnancy influences maternal and fetal health, birth outcomes, and the risk of chronic disease in offspring. Research reporting dietary intake during pregnancy in nationally representative population samples, however, is limited. This review summarizes the micronutrient intakes of pregnant women from developed countries and compares them with relevant national recommendations. A systematic search without date limits was conducted. All studies reporting the micronutrient intakes of pregnant women were considered, irrespective of design. Two authors independently identified studies for inclusion and assessed methodological quality. Nutritional adequacy was summarized, with confounding factors considered. Meta-analysis data are reported for developed countries collectively, by geographical region, and by dietary methodology. Pregnant women in developed countries are at risk of suboptimal micronutrient intakes. Folate, iron, and vitamin D intakes were consistently below nutrient recommendations in each geographical region, and calcium intakes in Japan were below the Japanese recommendations and the average intake levels in other developed countries. Research examining the implications of potential nutrient insufficiency on maternal and offspring health outcomes is needed along with improvements in the quality of dietary intake reporting.
Topics: Developed Countries; Female; Humans; Maternal Nutritional Physiological Phenomena; Micronutrients; Nutrition Policy; Nutritional Requirements; Pregnancy; Pregnancy Complications; Prenatal Nutritional Physiological Phenomena
PubMed: 23356639
DOI: 10.1111/nure.12003 -
Nutrients Nov 2023Adults with Crohn's disease (CD) may be at risk of micronutrient insufficiency in clinical remission through restrictive eating, malabsorption, abnormal losses or... (Review)
Review
Adults with Crohn's disease (CD) may be at risk of micronutrient insufficiency in clinical remission through restrictive eating, malabsorption, abnormal losses or inflammation. This systematic review synthesises the literature on micronutrient insufficiency in CD in clinical remission in terms of the prevalence of low circulating micronutrient concentrations and as a comparison against a healthy control (HC). Studies were included if the population was predominantly in remission. A total of 42 studies met the inclusion criteria; 12 were rated as low quality, leaving 30 studies covering 21 micronutrients of medium/high quality that were included in the synthesis. Vitamins D and B12 were the most frequently reported nutrients (8 and 11); there were few eligible studies for the remaining micronutrients. The prevalence studies were consistent in reporting individuals with low Vitamins A, B6, B12 and C, β-carotene, D, Magnesium, Selenium and Zinc. The comparator studies were inconsistent in finding differences with CD populations; Vitamin D, the most reported nutrient, was only lower than the HC in one-quarter of the studies. Adult CD populations are likely to contain individuals with low levels of one or more micronutrients, with the most substantial evidence for Vitamins D and B12. The studies on other micronutrients are of insufficient number, standardisation and quality to inform practice.
Topics: Adult; Humans; Micronutrients; Crohn Disease; Trace Elements; Vitamins; Vitamin A; Cholecalciferol
PubMed: 38004171
DOI: 10.3390/nu15224777 -
The Cochrane Database of Systematic... Feb 2024Pressure ulcers are localized injuries to the skin or the underlying tissue, or both, and are common in older and immobile people, people with diabetes, vascular... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Pressure ulcers are localized injuries to the skin or the underlying tissue, or both, and are common in older and immobile people, people with diabetes, vascular disease, or malnutrition, as well as those who require intensive or palliative care. People with pressure ulcers often suffer from severe pain and exhibit social avoidance behaviours. The prevention and treatment of pressure ulcers involves strategies to optimize hydration, circulation, and nutrition. Adequate nutrient intake can reduce the risk factor of malnutrition and promote wound healing in existing pressure ulcers. However, it is unclear which nutrients help prevent and treat pressure ulcers. This is an update of an earlier Cochrane Review.
OBJECTIVES
To evaluate the benefits and harms of nutritional interventions (special diets, supplements) for preventing and treating pressure ulcers in people with or without existing pressure ulcers compared to standard diet or other nutritional interventions.
SEARCH METHODS
We used extensive Cochrane search methods. The latest search was in May 2022.
SELECTION CRITERIA
We included randomized controlled trials (RCTs) in people with or without existing pressure ulcers, that compared nutritional interventions aimed at preventing or treating pressure ulcers with standard diet or other types of nutritional interventions.
DATA COLLECTION AND ANALYSIS
We used standard Cochrane methods. Our primary outcome for prevention studies was the proportion of participants who developed new (incident) pressure ulcers. For treatment studies, our primary outcomes were time to complete pressure ulcer healing, number of people with healed pressure ulcers, size and depth of pressure ulcers, and rate of pressure ulcer healing. Secondary outcomes were side effects, costs, health-related quality of life and acceptability. We used GRADE to assess certainty of evidence for each outcome.
MAIN RESULTS
We included 33 RCTs with 7920 participants. Data for meta-analysis were available from 6993 participants. Pressure ulcer prevention Eleven studies (with 12 arms) compared six types of nutritional interventions for the prevention of pressure ulcers. Compared to standard diet, energy, protein and micronutrient supplements may result in little to no difference in the proportion of participants developing a pressure ulcer (energy, protein and micronutrient supplements 248 per 1000, standard diet 269 per 1000; RR 0.92, 95% CI 0.71 to 1.19; 3 studies, 1634 participants; low-certainty evidence). Compared to standard diet, protein supplements may result in little to no difference in pressure ulcer incidence (protein 21 per 1000, standard diet 28 per 1000; RR 0.75, 95% CI 0.49 to 1.14; 4 studies, 4264 participants; low-certainty evidence). The evidence is very uncertain about the gastrointestinal side effects of these supplements (protein 109 per 1000, standard diet 155 per 1000; RR 0.70, 95% CI 0.06 to 7.96; 2 studies, 140 participants, very low-certainty evidence). The evidence is very uncertain about the effects of protein, arginine, zinc and antioxidants; L-carnitine, L-leucine, calcium, magnesium and vitamin D; EPA, GLA and antioxidants; disease-specific supplements on pressure ulcer incidence when compared to standard diet (1 study each; very low-certainty evidence for all comparisons). Pressure ulcer treatment Twenty-four studies (with 27 arms) compared 10 types of nutritional interventions or supplements for treatment of pressure ulcers. Compared to standard diet, energy, protein and micronutrient supplements may slightly increase the number of healed pressure ulcers (energy, protein and micronutrients 366 per 1000, standard diet 253 per 1000; RR 1.45, 95% CI 1.14 to 1.85; 3 studies, 577 participants, low-certainty evidence). The evidence is very uncertain about the effect of these supplements on gastrointestinal side effects. Compared to standard diet, the evidence is very uncertain about the effect of protein, arginine, zinc and antioxidant supplements on pressure ulcer healing (pressure ulcer area: mean difference (MD) 2 cm² smaller, 95% CI 4.54 smaller to 0.53 larger; 2 studies, 71 participants, very low-certainty evidence). The evidence on side effects of these supplements is very uncertain. Compared to standard diet, supplements with arginine and micronutrients may not increase the number of healed pressure ulcers, but the evidence suggests a slight reduction in pressure ulcer area (MD 15.8% lower, 95% CI 25.11 lower to 6.48 lower; 2 studies, 231 participants, low-certainty evidence). The evidence is very uncertain about changes in pressure ulcer scores, acceptability, and side effects of these supplements. Compared to placebo, collagen supplements probably improve the mean change in pressure ulcer area (MD 1.81 cm² smaller, 95% CI 3.36 smaller to 0.26 smaller; 1 study, 74 participants, moderate-certainty evidence). The evidence is very uncertain about the effect of these supplements on side effects. The evidence is very uncertain about the effects of vitamin C, different doses of arginine; EPA, GLA (special dietary fatty acids) and antioxidants; protein; a specialized amino acid mixture; ornithine alpha-ketoglutarate and zinc supplements on pressure ulcer healing (1 or 2 studies each; very low-certainty evidence).
AUTHORS' CONCLUSIONS
The benefits of nutritional interventions with various compositions for pressure ulcer prevention and treatment are uncertain. There may be little or no difference compared to standard nutrition or placebo. Nutritional supplements may not increase gastrointestinal side effects, but the evidence is very uncertain. Larger studies with similar nutrient compositions would reduce these uncertainties. No study investigated the effects of special diets (e.g. protein-enriched diet, vegetarian diet) on pressure ulcer incidence and healing.
Topics: Humans; Aged; Pressure Ulcer; Antioxidants; Vitamins; Zinc; Malnutrition; Arginine
PubMed: 38345088
DOI: 10.1002/14651858.CD003216.pub3 -
Nutrients Aug 2021Micronutrient deficiencies are a worldwide public health concern. Emerging evidence supports the ability of probiotics to enhance micronutrient status, which could aid... (Review)
Review
Micronutrient deficiencies are a worldwide public health concern. Emerging evidence supports the ability of probiotics to enhance micronutrient status, which could aid in the prevention of non-communicable disease-associated malnutrition. This systematic review evaluated evidence of the efficacy of probiotic supplementation to improve micronutrient status in healthy subjects. The authors searched for published English language peer-reviewed journal articles in PubMed, Scopus, Embase, and Google Scholar databases from inception to July 2020 using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The quality of eligible studies was assessed using the Revised Cochrane Risk-of-Bias tool (RoB)2 and Risk of Bias in Non-Randomized Studies of Interventions tool (ROBINS-I tool). Fourteen original studies out of 2790 met the inclusion criteria. The results indicated that, despite varying degrees of efficacy, the intake of certain probiotics in healthy subjects was associated with a positive impact on the status of certain micronutrients (vitamin B12, calcium, folate, iron and zinc). A limitation was that studies were widely heterogeneous in terms of participant age, probiotic strain, species, dosage, intervention duration, and form of administration. Additional clinical trials are warranted to determine the most effective strains of probiotics, doses and durations of interventions.
Topics: Bacteria; Gastrointestinal Microbiome; Healthy Volunteers; Humans; Malnutrition; Micronutrients; Minerals; Nutritional Status; Probiotics; Trace Elements; Vitamins
PubMed: 34578878
DOI: 10.3390/nu13093001 -
Nutrients Aug 2023Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder, the prevalence of which has increased in children and adolescents over the years. Studies point to... (Review)
Review
Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder, the prevalence of which has increased in children and adolescents over the years. Studies point to deficiency of trace elements as one of the factors involved in the etiology of the disorder, with zinc being one of the main trace elements investigated in individuals with ASD. The aim of this review is to summarize scientific evidence about the relationship between zinc status and ASD in children and adolescents. This review has been registered in the International Prospective Register of Systematic Reviews (registration number CRD42020157907). The methodological guidelines adopted were in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Studies were selected from an active investigation of the PubMed, Scopus, LILACS, and Google databases to search for observational studies. Fifty-two studies from twenty-two countries were included. The sample sizes ranged from 20 to 2635, and the participants ranged from 2 to 18 years old. Nine types of biological matrices were used, with hair, serum, and plasma being the most frequently used in the evaluation of zinc concentrations. Significant differences in zinc concentrations between the ASD and control groups were observed in 23 studies, of which 19 (36%) showed lower zinc concentrations in the ASD group. The classification of studies according to methodological quality resulted in high, moderate, and low quality in 10, 21, and 21 studies, respectively. In general, we did not observe a significant difference between zinc concentrations of children and adolescents with ASD compared to controls; however, studies point to an occurrence of lower concentrations of Zn in individuals with ASD. This review reveals that more prospective studies with greater methodological rigor should be conducted in order to further characterize this relation.
Topics: Humans; Adolescent; Child; Child, Preschool; Zinc; Trace Elements; Autism Spectrum Disorder; Prospective Studies; Databases, Factual
PubMed: 37630853
DOI: 10.3390/nu15163663 -
Nutrition (Burbank, Los Angeles County,... 2011This systematic review assessed the effects of micronutrient supplementation on adults recovering from critical illness. Primary outcomes included clinical endpoints... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
This systematic review assessed the effects of micronutrient supplementation on adults recovering from critical illness. Primary outcomes included clinical endpoints (mortality, infectious complications, length of intensive care unit and of hospital stay). Secondary outcomes included descriptions of practice issues, micronutrient status, morbidity, course of the acute-phase response, and oxidative stress.
METHODS
Electronic bibliographic databases, bibliographies of retrieved articles, and personal files were searched and reviewed. Randomized controlled trials (RCTs) of micronutrient supplementation in adult critically ill patients administered enterally and/or parenterally in addition to their routine care were included. Two authors independently extracted data and assessed trial quality. The random-effects model was used to estimate overall relative risk (RR)/mean difference and effect size. P<0.05 was considered statistically significant.
RESULTS
Fifteen (n=1714) and 18 (n=1849) RCTs were included for the primary and secondary objectives, respectively. Fourteen trials (n=1468) showed a statistically significant decrease in overall mortality (RR 0.78, 95% confidence interval 0.67-0.90, I2=0%, P=0.0009). Six RCTs (n=1194) indicated a statistically significant decrease in 28-d mortality (RR 0.75, 95% confidence interval 0.63-0.88, I2=0%, P=0.0006). Micronutrient supplementation was not associated with a decrease in infectious complications, length of intensive care unit, or length of hospital stay. In subgroup analyses, a sensitivity analysis of combined micronutrients indicated a significant decrease in mortality (RR 0.69, 95% confidence interval 0.54-0.90, I2=2%, P=0.006). The secondary outcomes confirmed that timing, duration, and dosing appear to be key factors to ensure optimal clinical benefit.
CONCLUSION
This review does suggest a potential benefit of micronutrient supplementation in critically ill adults by possibly being associated with a decrease in mortality.
Topics: Critical Illness; Dietary Supplements; Hospital Mortality; Humans; Micronutrients; Treatment Outcome
PubMed: 21679878
DOI: 10.1016/j.nut.2010.12.009 -
Advances in Nutrition (Bethesda, Md.) Jul 2015Pregnant and postpartum women with a history of bariatric surgery are at risk of micronutrient deficiencies as a result of the combination of physiologic changes related... (Review)
Review
Pregnant and postpartum women with a history of bariatric surgery are at risk of micronutrient deficiencies as a result of the combination of physiologic changes related to pregnancy and iatrogenic postoperative alterations in the absorption and metabolism of crucial nutrients. This systematic review investigates micronutrient deficiencies and related adverse clinical outcomes in pregnant and postpartum women after bariatric surgery. A systematic approach involving critical appraisal was conducted independently by 2 researchers to examine deficiencies of phylloquinone, folate, iron, calcium, zinc, magnesium, iodide, copper, and vitamins A, D, and B-12 in pregnant and postpartum women after bariatric surgery, together with subsequent outcomes in the neonates. The search identified 29 relevant cases and 8 cohort studies. The quality of reporting among the case reports was weak according to the criteria based on the CARE (CAse REporting) guidelines as was that for the cohort studies based on the criteria from the Cohort Study Quality Assessment list of the Dutch Cochrane Center. The most common adverse neonatal outcomes related to maternal micronutrient deficiencies include visual complications (vitamin A), intracranial hemorrhage (phylloquinone), neurological and developmental impairment (vitamin B-12), and neural tube defects (folate). On the basis of the systematically collected information, we conclude that the evidence on micronutrient deficiencies in pregnant and postpartum women after bariatric surgery and subsequent adverse neonatal outcomes remains weak and inconclusive.
Topics: Bariatric Surgery; Cohort Studies; Female; Folic Acid Deficiency; Humans; Infant, Newborn; Infant, Newborn, Diseases; Intracranial Hemorrhages; Micronutrients; Neural Tube Defects; Pregnancy; Pregnancy Complications; Pregnancy Outcome; Vision Disorders; Vitamin A Deficiency; Vitamin B 12 Deficiency
PubMed: 26178026
DOI: 10.3945/an.114.008086