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Circulation May 2022Despite substantial research highlighting the importance of exogenous dietary cholesterol intake and endogenous serum cholesterol level in human health, a thorough... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Despite substantial research highlighting the importance of exogenous dietary cholesterol intake and endogenous serum cholesterol level in human health, a thorough evaluation of the associations is lacking. Our study objective was to examine overall and cause-specific mortality in relation to dietary and serum cholesterol, as well as egg consumption, and conduct an updated meta-regression analysis of cohort studies.
METHODS
We conducted a prospective analysis of 27 078 men in the ATBC Study (Alpha-Tocopherol, Beta-Carotene Cancer Prevention). Multivariable-controlled cause-specific Cox proportional hazards regression models were used to calculate hazard ratios and 31-year absolute mortality risk differences. A systematic review and meta-analysis of cohort studies was also performed (PROSPERO [URL: https://www.crd.york.ac.uk/prospero/; Unique identifier: CRD42021272756]).
RESULTS
Based on 482 316 person-years of follow-up, we identified 22 035 deaths, including 9110 deaths from cardiovascular disease (CVD). Greater dietary cholesterol and egg consumption were associated with increased risk of overall and CVD-related mortality. Hazard ratios for each additional 300 mg cholesterol intake per day were 1.10 and 1.13 for overall and CVD-related mortality, respectively; for each additional 50-g egg consumed daily, hazard ratios were 1.06 and 1.09, respectively, for overall and CVD-related mortality (all values<0.0001). After multivariable adjustment, higher serum total cholesterol concentrations were associated with increased risk of CVD-related mortality (hazard ratios per 1 SD increment, 1.14; <0.0001). The observed associations were generally similar across cohort subgroups. The updated meta-analysis of cohort studies on the basis of 49 risk estimates, 3 601 401 participants, and 255 479 events showed consumption of 1 additional 50-g egg daily was associated with significantly increased CVD risk (pooled relative risk, 1.04 [95% CI, 1.00-1.08]; I=80.1%). In the subgroup analysis of geographic regions (=0.02), an increase of 50-g egg consumed daily was associated with a higher risk of CVD in US cohorts (pooled relative risk, 1.08 [95% CI, 1.02-1.14]) and appeared related to a higher CVD risk in European cohorts with borderline significance (pooled relative risk, 1.05), but was not associated with CVD risk in Asian cohorts.
CONCLUSIONS
In this prospective cohort study and updated meta-analysis, greater dietary cholesterol and egg consumption were associated with increased risk of overall and CVD-related mortality. Our findings support restricted consumption of dietary cholesterol as a means to improve long-term health and longevity.
Topics: Cardiovascular Diseases; Cause of Death; Cholesterol, Dietary; Eggs; Humans; Male; Prospective Studies; Risk Factors
PubMed: 35360933
DOI: 10.1161/CIRCULATIONAHA.121.057642 -
The American Journal of Clinical... Nov 2018High dietary intake or blood concentrations (as biomarkers of dietary intake) of vitamin C, carotenoids, and vitamin E have been associated with reduced risk of... (Meta-Analysis)
Meta-Analysis
Dietary intake and blood concentrations of antioxidants and the risk of cardiovascular disease, total cancer, and all-cause mortality: a systematic review and dose-response meta-analysis of prospective studies.
BACKGROUND
High dietary intake or blood concentrations (as biomarkers of dietary intake) of vitamin C, carotenoids, and vitamin E have been associated with reduced risk of cardiovascular disease, cancer, and mortality, but these associations have not been systematically assessed.
OBJECTIVE
We conducted a systematic review and meta-analysis of prospective studies of dietary intake and blood concentrations of vitamin C, carotenoids, and vitamin E in relation to these outcomes.
DESIGN
We searched PubMed and Embase up to 14 February 2018. Summary RRs and 95% CIs were calculated with the use of random-effects models.
RESULTS
Sixty-nine prospective studies (99 publications) were included. The summary RR per 100-mg/d increment of dietary vitamin C intake was 0.88 (95% CI: 0.79, 0.98, I2 = 65%, n = 11) for coronary heart disease, 0.92 (95% CI: 0.87, 0.98, I2 = 68%, n = 12) for stroke, 0.89 (95% CI: 0.85, 0.94, I2 = 27%, n = 10) for cardiovascular disease, 0.93 (95% CI: 0.87, 0.99, I2 = 46%, n = 8) for total cancer, and 0.89 (95% CI: 0.85, 0.94, I2 = 80%, n = 14) for all-cause mortality. Corresponding RRs per 50-μmol/L increase in blood concentrations of vitamin C were 0.74 (95% CI: 0.65, 0.83, I2 = 0%, n = 4), 0.70 (95% CI: 0.61, 0.81, I2 = 0%, n = 4), 0.76 (95% CI: 0.65, 0.87, I2 = 56%, n = 6), 0.74 (95% CI: 0.66, 0.82, I2 = 0%, n = 5), and 0.72 (95% CI: 0.66, 0.79, I2 = 0%, n = 8). Dietary intake and/or blood concentrations of carotenoids (total, β-carotene, α-carotene, β-cryptoxanthin, lycopene) and α-tocopherol, but not dietary vitamin E, were similarly inversely associated with coronary heart disease, stroke, cardiovascular disease, cancer, and/or all-cause mortality.
CONCLUSIONS
Higher dietary intake and/or blood concentrations of vitamin C, carotenoids, and α-tocopherol (as markers of fruit and vegetable intake) were associated with reduced risk of cardiovascular disease, total cancer, and all-cause mortality. These results support recommendations to increase fruit and vegetable intake, but not antioxidant supplement use, for chronic disease prevention.
Topics: Antioxidants; Ascorbic Acid; Cardiovascular Diseases; Carotenoids; Cause of Death; Diet; Feeding Behavior; Humans; Neoplasms; Nutritional Status; Vitamin E; alpha-Tocopherol
PubMed: 30475962
DOI: 10.1093/ajcn/nqy097 -
Nutrients Feb 2022Recently, it has been discovered that anti-inflammatory and anti-oxidative pathways play a role in depression and anxiety. Lower serum levels of antioxidants, such as... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Recently, it has been discovered that anti-inflammatory and anti-oxidative pathways play a role in depression and anxiety. Lower serum levels of antioxidants, such as vitamin E, have been implicated in both depression and anxiety.
METHODS
This PROSPERO-registered systematic review (Reference: CRD42021260058) is reported according to PRISMA guidelines. PubMed, EMBASE, CENTRAL, PsycINFO, and CINAHL were searched from inception to June 2021.
RESULTS
Twelve studies were included in this systematic review, and nine in meta-analysis of vitamin E versus placebo. For depression, meta-analysis of 354 participants showed a standardised mean difference of -0.88 (95% CI: -1.54, -0.21; I2 = 87%) favouring vitamin E. For anxiety, meta-analysis of 306 participants showed a standardised mean difference of -0.86 (95% CI: -2.11, 0.40; I2 = 95%) favouring vitamin E. Three of the studies involved a pure comparison of vitamin E against placebo, while others included constituents such as omega-3 fatty acids. Nine of the studies were at low risk of bias, two had some concerns, and one was at high risk of bias.
CONCLUSION
Vitamin E supplementation has shown inconclusive results in ameliorating both depression and anxiety. Containing a reassuring safety profile and low cost, future studies would be of promise, and they would benefit from both larger sample sizes and from excluding other constituents, such as omega-3 fatty acids, from experimental and comparator arms.
Topics: Anxiety; Anxiety Disorders; Depression; Humans; Vitamin E; alpha-Tocopherol
PubMed: 35277015
DOI: 10.3390/nu14030656 -
The Cochrane Database of Systematic... Nov 2018Vitamins and minerals have many functions in the nervous system which are important for brain health. It has been suggested that various different vitamin and mineral... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Vitamins and minerals have many functions in the nervous system which are important for brain health. It has been suggested that various different vitamin and mineral supplements might be useful in maintaining cognitive function and delaying the onset of dementia. In this review, we sought to examine the evidence for this in people who already had mild cognitive impairment (MCI).
OBJECTIVES
To evaluate the effects of vitamin and mineral supplementation on cognitive function and the incidence of dementia in people with mild cognitive impairment.
SEARCH METHODS
We searched ALOIS, the Cochrane Dementia and Cognitive Improvement Group's (CDCIG) specialised register, as well as MEDLINE, Embase, PsycINFO, CENTRAL, CINAHL, LILACs, Web of Science Core Collection, ClinicalTrials.gov, and the WHO Portal/ICTRP, from inception to 25 January 2018.
SELECTION CRITERIA
We included randomised or quasi-randomised, placebo-controlled trials which evaluated orally administered vitamin or mineral supplements in participants with a diagnosis of mild cognitive impairment and which assessed the incidence of dementia or cognitive outcomes, or both. We were interested in studies applicable to the general population of older people and therefore excluded studies in which participants had severe vitamin or mineral deficiencies.
DATA COLLECTION AND ANALYSIS
We sought data on our primary outcomes of dementia incidence and overall cognitive function and on secondary outcomes of episodic memory, executive function, speed of processing, quality of life, functional performance, clinical global impression, adverse events, and mortality. We conducted data collection and analysis according to standard Cochrane systematic review methods. We assessed the risk of bias of included studies using the Cochrane 'Risk of bias' assessment tool. We grouped vitamins and minerals according to their putative mechanism of action and, where we considered it to be clinically appropriate, we pooled data using random-effects methods. We used GRADE methods to assess the overall quality of evidence for each comparison and outcome.
MAIN RESULTS
We included five trials with 879 participants which investigated B vitamin supplements. In four trials, the intervention was a combination of vitamins B6, B12, and folic acid; in one, it was folic acid only. Doses varied. We considered there to be some risks of performance and attrition bias and of selective outcome reporting among these trials. Our primary efficacy outcomes were the incidence of dementia and scores on measures of overall cognitive function. None of the trials reported the incidence of dementia and the evidence on overall cognitive function was of very low-quality. There was probably little or no effect of B vitamins taken for six to 24 months on episodic memory, executive function, speed of processing, or quality of life. The evidence on our other secondary clinical outcomes, including harms, was very sparse or very low-quality. There was evidence from one study that there may be a slower rate of brain atrophy over two years in participants taking B vitamins. The same study reported subgroup analyses based on the level of serum homocysteine (tHcy) at baseline and found evidence that B vitamins may improve episodic memory in those with tHcy above the median at baseline.We included one trial (n = 516) of vitamin E supplementation. Vitamin E was given as 1000 IU of alpha-tocopherol twice daily. We considered this trial to be at risk of attrition and selective reporting bias. There was probably no effect of vitamin E on the probability of progression from MCI to Alzheimer's dementia over three years (HR 1.02; 95% CI 0.74 to 1.41; n = 516; 1 study, moderate-quality evidence). There was also no evidence of an effect at intermediate time points. The available data did not allow us to conduct analyses, but the authors reported no significant effect of three years of supplementation with vitamin E on overall cognitive function, episodic memory, speed of processing, clinical global impression, functional performance, adverse events, or mortality (five deaths in each group). We considered this to be low-quality evidence.We included one trial (n = 256) of combined vitamin E and vitamin C supplementation and one trial (n = 26) of supplementation with chromium picolinate. In both cases, there was a single eligible cognitive outcome, but we considered the evidence to be very low-quality and so could not be sure of any effects.
AUTHORS' CONCLUSIONS
The evidence on vitamin and mineral supplements as treatments for MCI is very limited. Three years of treatment with high-dose vitamin E probably does not reduce the risk of progression to dementia, but we have no data on this outcome for other supplements. Only B vitamins have been assessed in more than one RCT. There is no evidence for beneficial effects on cognition of supplementation with B vitamins for six to 24 months. Evidence from a single study of a reduced rate of brain atrophy in participants taking vitamin B and a beneficial effect of vitamin B on episodic memory in those with higher tHcy at baseline warrants attempted replication.
Topics: Aged; Aged, 80 and over; Ascorbic Acid; Cognition; Cognition Disorders; Dementia; Dietary Supplements; Executive Function; Humans; Memory, Episodic; Middle Aged; Mortality; Picolinic Acids; Quality of Life; Randomized Controlled Trials as Topic; Trace Elements; Vitamin B Complex; Vitamins; alpha-Tocopherol
PubMed: 30383288
DOI: 10.1002/14651858.CD011905.pub2 -
Nutrients May 2022Vitamin E deficiency (VED) is associated with clinical repercussions in preterm newborns (PTN), but low levels are also found in full-term newborns (TN). As this... (Review)
Review
Vitamin E deficiency (VED) is associated with clinical repercussions in preterm newborns (PTN), but low levels are also found in full-term newborns (TN). As this inadequacy can compromise neurogenesis in childhood, studies are needed to assess whether there is a difference in vitamin E status among newborns according to gestational age to provide support for neonatal monitoring protocols. This systematic review presents a synthesis of the available information on the vitamin E status among PTN and TN. The review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Observational studies that evaluated alpha-tocopherol levels were searched in the databases reported in the protocol registered in PROSPERO (CRD42021165152). The Newcastle-Ottawa Scale was used to assess the methodological quality. Overall, 1809 articles were retrieved; 10 were included in the systematic review. In the PTN, the alpha-tocopherol levels ranged from 3.9 to 8.5 mmol/L, while in TN, they were 4.9 to 14.9 mmol/L, and VED ranged from 19% to 100% in newborns. Despite substantial heterogeneity in research methodology and VED classification, the results suggest that the alpha-tocopherol levels among preterm and full-term newborns is below the recommended levels. Our findings demonstrate that further investigations are needed to standardize this classification and to monitor vitamin E status in birth and postnatal with adequate bias control.
Topics: Gestational Age; Humans; Infant; Infant, Newborn; Vitamin E; Vitamin E Deficiency; alpha-Tocopherol
PubMed: 35684057
DOI: 10.3390/nu14112257 -
The British Journal of Nutrition Mar 2016Demand for organic milk is partially driven by consumer perceptions that it is more nutritious. However, there is still considerable uncertainty over whether the use of... (Meta-Analysis)
Meta-Analysis Review
Higher PUFA and n-3 PUFA, conjugated linoleic acid, α-tocopherol and iron, but lower iodine and selenium concentrations in organic milk: a systematic literature review and meta- and redundancy analyses.
Demand for organic milk is partially driven by consumer perceptions that it is more nutritious. However, there is still considerable uncertainty over whether the use of organic production standards affects milk quality. Here we report results of meta-analyses based on 170 published studies comparing the nutrient content of organic and conventional bovine milk. There were no significant differences in total SFA and MUFA concentrations between organic and conventional milk. However, concentrations of total PUFA and n-3 PUFA were significantly higher in organic milk, by an estimated 7 (95 % CI -1, 15) % and 56 (95 % CI 38, 74) %, respectively. Concentrations of α-linolenic acid (ALA), very long-chain n-3 fatty acids (EPA+DPA+DHA) and conjugated linoleic acid were also significantly higher in organic milk, by an 69 (95 % CI 53, 84) %, 57 (95 % CI 27, 87) % and 41 (95 % CI 14, 68) %, respectively. As there were no significant differences in total n-6 PUFA and linoleic acid (LA) concentrations, the n-6:n-3 and LA:ALA ratios were lower in organic milk, by an estimated 71 (95 % CI -122, -20) % and 93 (95 % CI -116, -70) %. It is concluded that organic bovine milk has a more desirable fatty acid composition than conventional milk. Meta-analyses also showed that organic milk has significantly higher α-tocopherol and Fe, but lower I and Se concentrations. Redundancy analysis of data from a large cross-European milk quality survey indicates that the higher grazing/conserved forage intakes in organic systems were the main reason for milk composition differences.
Topics: Animals; Cattle; Dairying; Dietary Fats, Unsaturated; Evidence-Based Practice; Fatty Acids, Omega-3; Food, Organic; Humans; Iodine; Iron, Dietary; Linoleic Acids, Conjugated; Livestock; Milk; Nutritive Value; Selenium; alpha-Tocopherol
PubMed: 26878105
DOI: 10.1017/S0007114516000349 -
Archives of Medical Research Feb 2023Gastric cancer (GC) is often diagnosed at an advanced stage and thus patients have a poor prognosis. This implies that early detection of this cancer will improve... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Gastric cancer (GC) is often diagnosed at an advanced stage and thus patients have a poor prognosis. This implies that early detection of this cancer will improve patient prognosis and survival. This systematic review explored the association of circulating protein and metabolite biomarkers with GC development.
METHODS
A literature search was conducted until November 2021 on Medline, Embase, Cochrane library, and Web of Science databases. Studies were included if they assessed circulating proteins and metabolites in blood, urine, or saliva and determined their association with GC risk. Quality of identified studies was determined using the Newcastle-Ottawa scale for cohort studies. Random and fixed effects meta-analyses were performed to calculate pooled odds ratio.
RESULTS
A total of 53 studies were included. High levels of anti-Helicobacter pylORi IgG levels, pepsinogen I (PGI) <30 µg/L and serum pepsinogen I/ pepsinogen II (PGI/II) ratio<3 were positively associated with risk of developing GC (pooled odds ratio (OR): 2.70; 95% CI: 1.44-5.04, 5.96, 95% CI: 2.65-13.42 and 4.43; 95% CI: 3.04-6.47). In addition, an inverse relationship was found between ferritin, iron and transferrin levels and risk of developing GC (OR: 0.62; 95% CI: 0.38-1,0.97; 95% CI: 0.94-1 and 0.85; 95% CI: 0.76-0.94). However, there was no association between levels of glucose, cholesterol, vitamin C, vitamin B12, vitamin A, α-Carotene, β-Carotene, α-Tocopherol, γ-Tocopherol, and GC risk.
CONCLUSION
The pooled analysis demonstrated that high levels of anti-Helicobacter pylORi IgG, PGI<30µg/L and serum PGI/II ratio <3 and low levels of ferritin, iron and transferrin were associated with risk of GC.
Topics: Humans; Stomach Neoplasms; Pepsinogen A; Biomarkers; Pepsinogen C; Immunoglobulin G; Ferritins; Iron; Transferrins; Helicobacter Infections
PubMed: 36759293
DOI: 10.1016/j.arcmed.2022.12.012 -
Cureus Jun 2021Vitamin E is a fat-soluble vitamin and an antioxidant that prevents the peroxidation of lipid in vitro. The antioxidant role of vitamin E in preventing adverse... (Review)
Review
Vitamin E is a fat-soluble vitamin and an antioxidant that prevents the peroxidation of lipid in vitro. The antioxidant role of vitamin E in preventing adverse cardiovascular outcomes is controversial as some studies support it, while others reject it. Therefore, this review aims to determine whether there is an association between vitamin E and cardiovascular diseases (CVDs). An electronic search was done to find out relevant articles. Papers were shortlisted after the initial title and abstract screen. A full-text study was done, and inclusion and exclusion criteria were applied before the quality assessment of each paper was done. Only high-quality papers were selected for analysis. Full-text articles of the last ten years were included, while non-English articles, gray literature, and animal studies were excluded. The majority of the papers, including 75% of the total population in this review, suggested no role of vitamin E in preventing CVD and CVD mortality. Some studies also suggested that a high level of vitamin E can be associated with adverse cardiovascular outcomes. Thus, one should be prudent about taking vitamin E supplementation for cardiovascular risk prevention.
PubMed: 34277234
DOI: 10.7759/cureus.15616 -
International Journal For Vitamin and... Dec 2015The purpose of this study is to systematically review the published literature reporting vitamin E intake levels and serum concentrations in order to obtain a global...
The purpose of this study is to systematically review the published literature reporting vitamin E intake levels and serum concentrations in order to obtain a global overview of α-tocopherol status. Articles published between 2000 and 2012 were considered; 176 articles referring to 132 single studies were included. Applying an RDA (recommended daily allowance) of 15 mg/day and EAR (estimated average requirement) of 12 mg/day to all populations with a minimum age of 14 years, 82 and 61 % of mean and median data points were below the RDA and the EAR, respectively. Regarding serum concentrations, globally 13 % of the included data points were below the functional deficiency threshold concentration of 12 µmol/L, mostly for newborns and children. Several prospective observational studies suggest that a serum α-tocopherol concentration of ≥30 µmol/L has beneficial effects on human health. Of the reported study populations and subpopulations, only 21 % reached this threshold globally. This systematic review suggests that the α-tocopherol status is inadequate in a substantial part of the studied populations.
PubMed: 27414419
DOI: 10.1024/0300-9831/a000281 -
Journal of Research in Medical Sciences... 2021Food frequency questionnaires (FFQs) are inexpensive, easy to administer, and practical tools for dietary assessment in epidemiological studies. Several studies have... (Review)
Review
BACKGROUND
Food frequency questionnaires (FFQs) are inexpensive, easy to administer, and practical tools for dietary assessment in epidemiological studies. Several studies have investigated the validity and reproducibility of FFQs for the Iranian population. This systematic review aimed to assess the developed and validated FFQs for use in the Iranian population and compare their features and the validation studies in this regard.
MATERIALS AND METHODS
A comprehensive search was conducted in ISI Web of Knowledge, PubMed, Scopus, and Iranian databases without time constraints to retrieve the relevant English and non-English publications. Studies would be included if they were focused on the design and validation of FFQs in Iran.
RESULTS
In total, 782 articles were found, 22 of which met the eligibility criteria and evaluated 18 FFQs. Validation studies had been conducted on 18 out of 20 FFQs. The median of the correlation coefficients for the comparison of the FFQ intakes and the dietary reference method by nutrients varied within the range of 0.19-0.65, indicating reasonable validity. The median of the correlation coefficients for the comparison of two FFQs by nutrients was 0.28-0.85, showing appropriate reproducibility. However, low validity was observed in some nutrients and food groups, such as egg, legumes, iron, folate, and α-tocopherol. In seven studies, biomarkers were used for the assessment of nutrient intake using an FFQ with the median correlation coefficient of -0.07-0.42. In addition, the quality of methodology was evaluated in the FFQ validation studies, with 18 out of 20 studies reporting good and excellent quality.
CONCLUSION
Although the FFQs used to assess the dietary intake of the Iranian population have different features, they have acceptable validity and reproducibility. Nevertheless, some food groups and nutrients have poor validity and must be considered attentively.
PubMed: 34484382
DOI: 10.4103/jrms.JRMS_652_20