The effect of vegetarian diets on iron status in adults: A systematic review and meta-analysis

Background: Vegetarian diets exclude meat, seafood, and products containing these foods. Although the vegetarian lifestyle could lead to a better health status in adults, it may also bear risks for certain nutritional deficiencies. Cross-sectional studies and narrative reviews have shown that the iron status of vegetarians is compromised by the absence of highly bioavailable haem-iron in meatless diets and the inhibiting effect of certain components present in plant foods on non-haem iron bioavailability.

Methods: The databases Pubmed, Scopus, Embase, and Cochrane CentralRegister of Controlled Trials were searched for studies comparing serum ferritin, as the major laboratory parameter for iron status of adult vegetarians with non-vegetarian control groups. A qualitative review was conducted as well as an inverse-variance random-effects meta-analysis to pool available data. In addition the effect of vegetarian diets according to gender was investigated with a subgroup analysis. The results were validated using a sensitivity analysis.

Results: A total of 27 cross-sectional studies and three interventional studies were selected for the systematic review. The meta-analysis which combined data of 24 cross-sectional studies showed that adult vegetarians have significantly lower serum ferritin levels than their non-vegetarian controls (?29.71 µg/L, 95% CI [?39.69, ?19.73], p < 0.01). Inclusion of semi-vegetarian diets did not change the results considerably (?23.27 µg/L, 95% CI [?29.77, ?16.76], p < 0.01). The effects were more pronounced in men (?61.88 µg/L, 95% CI [?85.59, ?38.17], p < 0.01) than in both premenopausal women (?17.70 μg/L, 95% CI [?29.80, ?5.60], p < 0.01) and all women (?13.50 μg/L, 95% CI [?22.96, ?4.04], p < 0.01), respectively.

Conclusions: In conclusion our results showed that vegetarians are more likely to have lower iron stores compared with non-vegetarians. However, since high iron stores are also a risk factor for certain non-communicable diseases, such as type 2 diabetes, it is recommended that not only vegetarians but also non-vegetarians should regularly control their iron status and improve their diet regarding the content and bioavailability of iron by consuming more plants and less meat.     

Effects of local anesthetic or systemic analgesia on pain associated with cautery disbudding in calves: A systematic review and meta-analysis

Disbudding is a common management procedure performed on dairy farms and, when done without pain mitigation, is viewed as a key welfare issue. Use of pain control has increased in recent years, but full adoption of anesthesia and analgesia by veterinarians or dairy producers has not been achieved. This may in part be due to the lack of a consistent recommendations of treatment protocols between studies examining pain control methods for disbudding. The objective of this systematic review was to examine the effects of these pain control practices for the most common method of disbudding, cautery, on outcomes associated with disbudding pain in calves. The outcomes were plasma cortisol concentrations, pressure sensitivity of the horn bud area, and validated pain behaviors (ear flick, head shake, head rub, foot stamp, and vocalization). Intervention studies describing cautery disbudding in calves 12 wk of age or younger were eligible, provided they compared local anesthesia, nonsteroidal anti-inflammatory drug (NSAID), or local anesthesia and NSAID to 1 or more of local anesthesia, NSAID, or no pain control. The search strategy used the Agricola, Medline (via OvidSP), and Web of Science databases, as well as the Searchable Proceedings of Animal Conferences (S-PAC), ProQuest Dissertations and Theses Database, and Open Access Theses and Dissertations. Meta-analysis was performed for all outcomes measured at similar time points with more than 2 studies. Local anesthetic was associated with reduced plasma cortisol until 2 h postdisbudding; however, a rise in cortisol was observed in the meta-analysis of studies reporting at 4 h postdisbudding. Heterogeneity was present in several of the analyses for this comparison. The addition of NSAID to local anesthetic showed reduction in plasma cortisol at 4 h, and a reduction in pressure sensitivity and pain behaviors in some analyses between 3 and 6 h postdisbudding. Heterogeneity was present in some meta-analyses, including several using pain behavior outcomes. This may reflect the variation in measurement time periods for behavioral measures between studies, as well as differences among NSAID treatments. Overall, a protective effect of local anesthetic was seen for the acute pain of cautery disbudding, and the delayed rise in cortisol was mitigated by the addition of an NSAID, which also reduced other signs of pain, including pressure sensitivity and pain behaviors. Based on these findings, we recommend use of local anesthetic and an NSAID as best practices for pain mitigation for cautery disbudding of calves 12 wk of age or less. The magnitude and duration of the effect of NSAID treatment was not possible to deduce from the literature because wide variation existed between studies. We recommend consideration of more standardized outcome measurements, especially for pain behaviors. Adherence to reporting guidelines by authors would help ensure more transparent and complete information is available to end users.     

Association between vitamin D and dry eye disease: A systematic review and meta-analysis of observational studies

PurposeA number of studies have examined the association between vitamin D and dry eye disease in different populations, but findings are inconclusive. Herein, available observational studies were systematically reviewed to elucidate the overall relationship between vitamin D and dry eye disease among adult population.MethodsPubMed, Scopus, Google scholar and ISI web of science databases were searched until January 2020 for studies assessing the association between vitamin D and dry eye disease. The Newcastle-Ottawa Quality Assessment Scale was used to examine the quality of each study.ResultsA total of 14 studies out of 252 met the inclusion criteria and were included in this systematic review and meta-analysis. Serum 25(OH) D3 was lower in dry eye disease subjects compared to healthy ones (WMD −5.93; 95 % CI, −7.47 to −4.40; P < 0.001) with evidence of significant heterogeneity (I² = 94.6 % p < 0.001). Also, in final analysis, vitamin D correlated significantly with ocular surface disease index (Fisher’s Z: −0.26; 95 % CI, −0.48 to −0.04; P = 0.018), with significant heterogeneity between studies (I² = 59.3 %, P = 0.043).ConclusionIt was found that serum vitamin D had a significantly lower level in dry eye disease patients, and correlated with ocular surface disease index but no other dry eye disease parameter. The findings add to the existing literature supporting the concept that nutrition especially vitamin D plays an important role in human eye health. Prospective studies are needed to confirm this relationship     

Lycopene and tomato and risk of cardiovascular diseases: A systematic review and meta-analysis of epidemiological evidence

Background and aims: Worldwide, cardiovascular diseases (CVDs) remains as the main cause of mortality. Observational studies supports an association between intake of tomato products or lycopene with a reduced CVDs risk. Our aim was to undertake a systematic review and meta-analysis of the evidence on the topic.

Methods: Medline, Web of Science, and Scopus were searched from inception until July 2017. We included longitudinal and cross-sectional studies reporting associations between lycopene and tomato consumption and cardiovascular morbidity and mortality among adult subjects. Random-effects models were used to determine the pooled effect sizes.

Results: Twenty-eight publications met our inclusion criteria and 25 studies provided quantitative data for meta-analysis. Results showed that individuals in the highest consumption category of, or with the highest serum concentration of, lycopene had significantly lower risk of stroke (hazard ratio (HR) 0.74, 0.62–0.89, p = 0.02; I² = 32) and CVDs (HR 0.86, 0.77–0.95, p = 0.003; I² = 0). In addition, individuals categorised in the highest serum concentration of lycopene also had significantly lower risk of mortality (HR 0.63, 0.49–0.81, p<0.001; I² = 46). Lycopene was not significantly associated with myocardial infarction, while scarce evidence on the association of lycopene with atherosclerosis, congestive heart failure, or atrial fibrillation was evident. Evidence from three studies suggested that higher intakes of tomato were associated with non-significantly lower stroke, CVDs and CHD.

Conclusions: This comprehensive meta-analysis suggests that high-intakes or high-serum concentration of lycopene are associated with significant reductions in the risk of stroke (26%), mortality (37%) and CVDs (14%).     

Vegetarian,vegan diets and multiple health outcomes: A systematic review with meta-analysis of observational studies

Background: Beneficial effects of vegetarian and vegan diets on health outcomes have been supposed in previous studies. Objectives: Aim of this study was to clarify the association between vegetarian, vegan diets, risk factors for chronic diseases, risk of all-cause mortality, incidence, and mortality from cardio-cerebrovascular diseases, total cancer and specific type of cancer (colorectal, breast, prostate and lung), through meta-analysis. Methods: A comprehensive search of Medline, EMBASE, Scopus, The Cochrane Library, and Google Scholar was conducted. Results: Eighty-six cross-sectional and 10 cohort prospective studies were included. The overall analysis among cross-sectional studies reported significant reduced levels of body mass index, total cholesterol, LDL-cholesterol, and glucose levels in vegetarians and vegans versus omnivores. With regard to prospective cohort studies, the analysis showed a significant reduced risk of incidence and/or mortality from ischemic heart disease (RR 0.75; 95% CI, 0.68 to 0.82) and incidence of total cancer (RR 0.92; 95% CI 0.87 to 0.98) but not of total cardiovascular and cerebrovascular diseases, all-cause mortality and mortality from cancer. No significant association was evidenced when specific types of cancer were analyzed. The analysis conducted among vegans reported significant association with the risk of incidence from total cancer (RR 0.85; 95% CI, 0.75 to 0.95), despite obtained only in a limited number of studies. Conclusions: This comprehensive meta-analysis reports a significant protective effect of a vegetarian diet versus the incidence and/or mortality from ischemic heart disease (?25%) and incidence from total cancer (?8%). Vegan diet conferred a significant reduced risk (?15%) of incidence from total cancer.     

Evidence that mastitis can cause pregnancy loss in dairy cows: A systematic review of observational studies

The objective of this study was to conduct a systematic review to identify and assess evidence and knowledge gaps in published observational studies that have investigated the relationship between mastitis and pregnancy loss (PL) in dairy cows. PubMed and ScienceDirect were used to search pertinent peer-reviewed research reports of interest. Screening of research reports was conducted at 3 levels: titles, abstracts, and full-text articles. The search identified 651 records for initial screening. The final screening process identified 8 qualified articles for review after removing 10 duplicate records, 582 titles, 31 abstracts, and 20 full-text articles. Two studies produced strong epidemiologic evidence indicating that (1) exposure to clinical mastitis during early gestation (first 45 d of gestation) is associated with subsequent PL during the following 90 d; and (2) subclinical mastitis 1 to 30 d before artificial insemination (AI) is associated with subsequent PL at 35 to 41 d of gestation. An additional study showed that exposure to clinical mastitis during early lactation in combination with low body condition can increase the risk of PL in dairy cows; however, the interaction effect between clinical mastitis and low body condition on PL was considered weak. Four other studies produced inconclusive evidence indicating that mastitis is a predisposing factor for PL in dairy cows, as the exposure risk period for mastitis overlapped with the follow-up period for diagnosis of PL in dairy cows. Finally, one study failed to identify a relationship between mastitis and PL in dairy cows. Further research is needed to (1) support the hypothesis that mastitis in combination with low body condition score (or other exposure factors) can increase the risk of PL, (2) compare the effect of clinical versus subclinical mastitis on PL, (3) compare the effect of mastitis before breeding and during gestation on PL, and (4) compare the effect of mastitis on PL in dairy cows during different lactations.     

Metabolic effects of aspartame in adulthood: A systematic review and meta-analysis of randomized clinical trials

Data about harms or benefits associated with the consumption of aspartame, a nonnutritive sweetener worldwide consumed, are still controversial. This systematic review and meta-analysis of randomized controlled clinical trials aimed to assess the effect of aspartame consumption on metabolic parameters related to diabetes and obesity. The search was performed on Cochrane, LILACS, PubMed, SCOPUS, Web of Science databases, and on a gray literature using Open Grey, Google Scholar, and ProQuest Dissertations &; Theses Global. Searches across all databases were conducted from the earliest available date up to April 13, 2016, without date and language restrictions. Pooled mean differences were calculated using a random or fixed-effects model for heterogeneous and homogenous studies, respectively. Twenty-nine articles were included in qualitative synthesis and twelve, presenting numeric results, were used in meta-analysis. Fasting blood glucose (mmol/L), insulin levels (μU/mL), total cholesterol (mmol/L), triglycerides concentrations (mmol/L), high-density lipoprotein cholesterol (mmol/L), body weight (kg), and energy intake (MJ) were considered as the main outcomes in subjects that consumed aspartame, and results were presented as mean difference; % confidence interval, range. Aspartame consumption was not associated with alterations on blood glucose levels compared to control (?0.03 mmol/L; 95% CI, ?0.21 to 0.14) or to sucrose (0.31 mmol/L; 95% CI, ?0.05 to 0.67) and on insulin levels compared to control (0.13 μU/mL; 95% CI, ?0.69 to 0.95) or to sucrose (2.54 μU/mL; 95% CI, ?6.29 to 11.37). Total cholesterol was not affected by aspartame consumption compared to control (?0.02 mmol/L; 95% CI, ?0.31 to 0.27) or to sucrose (?0.24 mmol/L; 95% CI, ?0.89 to 0.42). Triglycerides concentrations were not affected by aspartame consumption compared to control (0.00 mmol/L; 95% CI, ?0.04 to 0.05) or to sucrose (0.00 mmol/L; 95% CI, ?0.09 to 0.09). High-density lipoprotein cholesterol serum levels were higher on aspartame compared to control (?0.03 mmol/L; 95% CI, ?0.06 to ?0.01) and lower on aspartame compared to sucrose (0.05 mmol/L; 95% CI, 0.02 to 0.09). Body weight did not change after aspartame consumption compared to control (5.00 kg; 95% CI, ?1.56 to 11.56) or to sucrose (3.78 kg; 95% CI, ?2.18 to 9.74). Energy intake was not altered by aspartame consumption compared to control (?0.49 MJ; 95% CI, ?1.21 to 0.22) or to sucrose (?0.17 MJ; 95% CI, ?2.03 to 1.69). Data concerning effects of aspartame on main metabolic variables associated to diabetes and obesity do not support a beneficial related to its consumption.     

Systematic review and meta-analysis of anti-hyperglycaemic effects of Pu-erh tea

Pu-erh tea was presumed to have anti-hyperglycaemic effects with limited evidence. This study uses meta-analysis to investigate anti-hyperglycaemic effect of Pu-erh tea. Five English databases and three Chinese ones were systematically searched up to July 31, 2018. Those databases were searched to identify studies containing keywords of ‘Pu-erh’, ‘Pu'er’, ‘blood sugar’, ‘blood glucose’ and ‘hyperglycaemia’. RevMan 5 and Stata were then utilized to conduct meta-analysis. Systematic reviews collected two mice studies with sixteen records for meta-analysis. Meta-analysis results showed that Pu-erh tea has significant anti-hyperglycaemic effect on mice. Pooled weight mean difference of blood sugar on mice studies were 71 and 116 mg dL⁻¹ at 21st day and 28th day respectively. Meta-regression disclosed over a longer intervention period showed that Pu-erh tea can reduce fasting blood glucose. Secondly, a higher dose of Pu-erh is shown to lower fasting blood glucose more significantly.     

Fruit consumption and adiposity status in adults: A systematic review of current evidence

The aim of this review was to update current understanding of the potential association between fruit consumption and adiposity status in adult populations. Electronic databases were searched from January 1, 1997 to the search date of August 15, 2014, retrieving 4382 abstracts that were reviewed for eligibility: randomized controlled trial (RCT) or prospective cohort (PC), published in English, assessing the effect of whole fruit or fruit juice consumption on adiposity in healthy adult populations. Quality ratings for the 11 included RCTs were either positive (n = 2), neutral (n = 8), or negative (n = 1), while the six included PCs were either positive (n = 4) or neutral (n = 2). Consumption of whole fruit was found to contribute to a reduced risk for long-term weight gain in middle-aged adults. Experimental trials suggest this beneficial effect of whole fruit is mediated by a reduction in total energy intake. Fruit juice, however, had an opposing effect, promoting weight gain over the long term. This review reinforces national food-based dietary guidelines, encouraging the consumption of whole fruits and replacing fruit juices with plain water, as part of a broader set of dietary strategies to reduce total dietary energy intake in adult populations.     

The effects of quercetin supplementation on lipid profiles and inflammatory markers among patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized controlled trials

Abstract

Aims: This systematic review and meta-analysis of randomized controlled trials (RCTs) was performed to determine the effect of quercetin administration on lipid profiles and inflammatory markers among patients with metabolic syndrome (MetS) and related disorders.

Methods: We searched systematically online databases including Cochrane Library, EMBASE, MEDLINE, and Web of Science to identify the relevant RCTs until November 2018. Q-test and I² statistics were applied to assess heterogeneity among included studies. Data were combined using fixed- or random-effects model and presented as standardized mean difference (SMD) with 95% confidence interval (CI).

Results: Out of 591 citations, 16 RCTs were included in the meta-analysis. The pooled findings showed that quercetin consumption significantly decreased total-cholesterol (SMD = ?0.98; 95% CI, ?1.48, ?0.49; p?<?0.001; I²: 94.0), LDL-cholesterol (SMD = ?0.88; 95% CI, ?1.35, ?0.41; p?<?0.001; I²: 92.7) and C-reactive protein (CRP) levels (?0.64; 95% CI, ?1.03, ?0.25; p?=?0.001; I²: 90.2). While, quercetin supplementation did not significantly affect triglycerides (TG) (SMD = ?0.32; 95% CI, ?0.68, 0.04; p?=?0.08; I²: 84.8), HDL-cholesterol (SMD = 0.20; 95% CI, ?0.20, 0.24; p?=?0.84; I²: 70.6), interleukin 6 (IL-6) (SMD = ?0.69; 95% CI, ?1.69, 0.31; p?=?0.17; I²: 94.5) and tumor necrosis factor-alpha (TNF-α) levels (SMD = ?0.06; 95% CI, ?0.25, 0.14; p?=?0.58; I²: 35.6)

Conclusions: In summary, the current meta-analysis demonstrated that quercetin supplementation significantly reduced total-cholesterol, LDL-cholesterol, and CRP levels, yet did not affect triglycerides, HDL-cholesterol, IL-6 and TNF-α among patients with MetS and related disorders.     

Dietary intake of fish,n-3 polyunsaturated fatty acids and risk of hip fracture: A systematic review and meta-analysis on observational studies

Previous studies have shown that fish consumption and dietary intake of n-3 polyunsaturated fatty acids (n-3 PUFAs) are associated with hip fracture; however, findings were conflicting. The present review aimed to summarize the current evidence on the association of fish consumption and dietary intake of n-3 PUFAs with hip fracture. The online databases of PubMed, ISI Web of Science, Scopus, ProQuest, Science Direct and Embase were searched until August 2017 for related publications using relevant keywords. To pool data, either a fixed-effects model or random-effects models were used. Cochran's Q tests were used to assess heterogeneity between studies. In total, 10 studies (7 prospective and 3 case-control studies) were included in this systematic review, and 9 studies with total sample size of 292657 participants were included in the meta-analysis. The age of participants was 20 years or older. Combining 8 effect sizes from 4 prospective studies and 2 case-control studies revealed a significant inverse association between fish consumption and risk of hip fracture (pooled effect size: 0.88, 95% CI: 0.79-0.98, P = 0.02). Although this relationship became non-significant in prospective studies, a significant inverse association was found in prospective studies with sample size of 10000 individuals or more, and studies that considered body mass index as a covariate. Furthermore, dietary intake of n-3 PUFAs was inversely associated with risk of hip fracture (pooled effect size: 0.89, 95% CI: 0.80-0.99, P = 0.02). Also, such relationship was seen after excluding one case-control study and combining effect sizes only from prospective studies (pooled effect size: 0.88, 95% CI: 0.80-0.98, P = 0.02). In conclusion, we found that fish consumption and dietary intake of n-3 PUFAs might have protective effects on bone health and decline the risk of hip fracture.     

Effects of quercetin supplementation on lipid profile: A systematic review and meta-analysis of randomized controlled trials

Background: In spite of promising experimental findings, randomized controlled trials (RCTs) have yielded mixed results on the impact of quercetin supplementation on plasma lipid levels.

Aim: The present study aimed to quantify the effects of quercetin on plasma lipids using a meta-analysis of RCTs.

Methods: A systematic literature search of Medline was conducted for RCTs that investigated the efficacy of quercetin supplementation on plasma lipids comprising total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated for net changes in lipid concentrations using a random-effects model. Meta-regression analysis was conducted to assess the effect of quercetin dose and duration of supplementation as moderators on the calculated effect measures.

Results: Five RCTs totaling 442 subjects (221 in the quercetin and 221 in the control group) fulfilled the eligibility criteria and selected for analyses. Combined estimate of effect size for the impact of quercetin on plasma LDL-C (WMD: 1.43 mg/dL, 95% CI: ?0.92–3.78, p = 0.23), HDL-C (WMD: 0.26 mg/dL, 95% CI: ?0.74–1.25, p = 0.61) and triglycerides (WMD: ?9.42 mg/dL, 95% CI: ?27.80–8.96, p = 0.32) was not statistically significant. However, a borderline significant but clinically non-relevant increase in total cholesterol was observed (WMD: 3.13 mg/dL, 95% CI: ?0.01–6.27, p = 0.05). When the analysis was confined to the subgroups of studies with quercetin doses ≥500 mg/day and follow-up of ≥ 4 weeks, a significant increase in total cholesterol (WMD: 3.57 mg/dL, 95% CI: 0.21–6.92, p = 0.04) and a decline in triglycerides (WMD: ?24.54 mg/dL, 95% CI: ?33.09 to ?15.99, p < 0.00001) was observed, but LDL-C and HDL-C concentrations remained unchanged (p > 0.05). Changes in plasma triglycerides, but not other indices of lipid profile, were significantly associated with quercetin dose (slope: ?0.057; 95% CI: ?0.103 to ?0.010; p = 0.02) and duration of supplementation (slope: ?5.314; 95% CI: ?9.482 to ?1.147; p = 0.01).

Conclusion: Available evidence from RCTs does not suggest any clinically relevant effect of quercetin supplementation on plasma lipids, apart from a significant reduction of triglycerides at doses above 50 mg/day.     

Effect of vegetarian diets on zinc status: a systematic review and meta‐analysis of studies in humans

Plant‐based diets contain less saturated fat and cholesterol and more folate, fibre and phytochemicals than omnivorous diets, but some micronutrients, especially zinc, are poorly bioavailable. The findings of studies exploring the zinc intake and zinc status in populations that habitually consume vegetarian diets are inconsistent. This study aims to investigate the effects of plant‐based diets on dietary zinc intake and status in humans using systematic review and meta‐analysis techniques. Thirty‐four studies were included in the systematic review. Of these, 26 studies (reporting 48 comparisons) compared males and/or females consuming vegetarian diets with non‐vegetarian groups and were included in meta‐analyses. Dietary zinc intakes and serum zinc concentrations were significantly lower (?0.88 ± 0.15 mg day^?1, P < 0.001 and ?0.93 ± 0.27 µmol L^?1, P = 0.001 respectively; mean ± standard error) in populations that followed habitual vegetarian diets compared with non‐vegetarians. Secondary analyses showed greater impact of vegetarian diets on the zinc intake and status of females, vegetarians from developing countries and vegans. Populations that habitually consume vegetarian diets have low zinc intakes and status. Not all vegetarian categories impact zinc status to the same extent, but a lack of consistency in defining vegetarian diets for research purposes makes dietary assessment difficult. Dietary practices that increase zinc bioavailability, the consumption of foods fortified with zinc or low‐dose supplementation are strategies that should be considered for improving the zinc status of vegetarians with low zinc intakes or serum zinc concentrations at the lower end of the reference range. © 2013 Society of Chemical Industry     

Consumer acceptance of reformulated food products: A systematic review and meta-analysis of salt-reduced foods

Food product reformulation is promoted as an effective strategy to reduce population salt intake and address the associated burden of chronic disease. Salt has a number of functions in food processing, including impacting upon physical and sensory properties. Manufacturers must ensure that reformulation of foods to reduce salt does not compromise consumer acceptability.

The aim of this systematic review is to determine to what extent foods can be reduced in salt without detrimental effect on consumer acceptability.

Fifty studies reported on salt reduction, replacement or compensation in processed meats, breads, cheeses, soups, and miscellaneous products. For each product category, levels of salt reduction were collapsed into four groups: <40%, 40–59%, 60–79% and ≥80%. Random effects meta-analyses conducted on salt-reduced products showed that salt could be reduced by approximately 40% in breads [mean change in acceptability for reduction <40% (?0.27, 95% confidence interval (CI) ?0.62, 0.08; p = 0.13)] and approximately 70% in processed meats [mean change in acceptability for reductions 60–69% (?0.18, 95% CI ?0.44, 0.07; p = 0.15)] without significantly impacting consumer acceptability. Results varied for other products.

These results will support manufacturers to make greater reductions in salt when reformulating food products, which in turn will contribute to a healthier food supply.     

Diet effects in the asthma treatment: A systematic review

Introduction: Obesity in asthmatic patients has important relationships with asthma control, pulmonary function, and quality of life. The objective of this study was to conduct a systematic review of the literature on the effect of diet on asthma management in adults. Methods: We searched PubMed, Embase, and Scopus (January 1948–October 2014) for randomized clinical trials that evaluated the effects of diet in adults with asthma. Results: Of 12,215 studies identified, 21 were included. A reduction in weight of at least 7.5% from baseline as a result of caloric restriction can be beneficial for improving disease control, quality of life, and pulmonary function in obese patients with asthma. A dietary pattern rich in foods with potential antioxidant effect had an impact in improving asthma control, but with little clinical significance. Studies involving antioxidant supplementation showed improvements in asthma control with magnesium supplementation and less decline in lung function with vitamin C supplementation. Studies of fatty acid supplementation demonstrated effects on weight loss and improvement of asthma control and lung function. Studies of supplementation with propolis and caffeine reported significant increases in FEV1. Conversely, studies of high dietary salt intake reported greater declines in lung function. Conclusions: The evidence shows that, for obese adults with asthma, the best dietary intervention seems to be caloric restriction, regardless of specific dietary components.     

Effect of vitamin A supplementation on iron status in humans: A systematic review and meta-analysis

Anemia is a worldwide public health problem that can be related to many causes, including vitamin A deficiency. The aim of this study was to assess and estimate the effect of vitamin A supplementation (VAS) on iron status biomarkers and anemia in humans. Six databases, including Cochrane, EMBASE, LILACS, Pubmed, Scopus and Web of Science, were searched for clinical trials and cohort studies that investigated the effect of vitamin A supplementation alone on iron status and anemia, without time-restriction. The search yielded 23 eligible studies, 21 clinical trials and 2 cohort studies, with children, teenagers, pregnant or lactating women. The meta-analysis of the clinical trials showed that VAS reduces the risk of anemia by 26% and raises hemoglobin levels, compared to non-treated group, independent of the life stage. VAS did not alter the prevalence of iron deficiency among the clinical trials conducted with children and teenagers (RR 0.82, 95% CI 0.60 to 1.12, p = 0.204), whereas a significant increase in serum ferritin levels was observed in trials conducted with pregnant and lactating women (WMD 6.61 μg/L; 95% CI 6.00 to 7.21 μg/L; p < 0.001). Therefore, vitamin A supplementation alone may reduce the risk of anemia, by improving hemoglobin and ferritin levels in individuals with low serum retinol levels.     

Peanut and cardiovascular disease risk factors: A systematic review and meta-analysis

Abstract

Several studies have been conducted on the effects of peanut consumption on cardiovascular diseases (CVD) risk factors. However, the findings are conflicting and appear inconsistent. The aim of this review is to summarize the findings on the effect of peanut consumption on the risk factors of CVDs. We used relevant keywords and searched through PubMed, Scopus and Web of Science for articles published studies up to November 2018. Randomized controlled trials (RCTs) were included in this meta-analysis. Random or fixed-effects meta-analysis method depending on the results of heterogeneity tests was used to estimate the effect size. Between-study heterogeneity was assessed by Q test and I² index. Subgroup analysis was conducted to find any excess relationship. Publication bias was checked by Egger’s test and funnel plot. Quality of studies was assessed by the Cochrane criteria. According to the results of 13 RCTs, peanuts has no significant effect on weight (WMD: ?0.11?kg, P?=?0.773), waist circumference (WMD: ?1.41?cm, P?=?0.139), body mass index (WMD: ?0.14?kg/m², P?=?0.428), systolic and diastolic blood pressure (WMD: ?0.09?mmHg, P?=?0.939 and WMD: 0.60?mmHg, P?=?0.652, respectively), low-density lipoprotein cholesterol (WMD: ?3.31?mg/dl, P?=?0.472), triglyceride (WMD: ?7.59?mg/dl, P?=?0.180), total cholesterol (WMD: 3.15?mg/dl, P?=?0.171), fasting blood sugar (WMD: 0.57?mg/dl, P?=?0.604) and serum insulin (WMD: ?0.40, P?=?0.582). Also, this meta-analysis showed that peanut had a positive significant effect on high-density lipoprotein cholesterol (HDL) (WMD: 2.72?mg/dl, P?=?0.001). Peanuts consumption has a positive significant effect on HDL especially at the type of peanut oil, high-oleic peanut and peanut sprout and in healthy subjects and for consumption more than 12?weeks, while has no significant effect on other CVD risk factors.     

Visualized nutrition education and dietary behavioral change: A systematic review and meta-analysis

Effectiveness of using visual approaches in health education and its influential factors were still in debate. This study aimed to asess the effects of visualized nutrition education on dietary knowledge and behavioral changes, and factors influencing them. A comprehensive search of PubMed, EMBASE, Scopus, and Cochrane Library was conducted. Eligible studies were trials assessed effects of visualized nutrition education on dietary knowledge or behavior changes, compared with non-visualized or no education group. Fourteen studies (n?=?7,259) were qualitatively analyzed and 7 of them were included in the meta-analysis. We found a higher fiber intake in both short term (1.59?g/1000 kcals, 95% CI 0.90–2.27) and long term (1.36?g/1000 kcals, 95% CI 0.64–2.09). A marginal advantage was shown in short-term fruits and vegetables consumption (F&V consumption) (standardized mean difference [SMD]?=?0.08, 95% CI ?0.00 to 0.16). The education effects were more pronounced when education was delivered in series (SMD_{F&V consumption}?=?0.09, 95% CI 0.00–0.17), avoiding loss-framing (SMD_{Fat intake}?=?0.31, 95% CI 0.10–0.51) and video modeling (SMD_{F&V consumption}?=?0.23, 95% CI 0.03–0.43), with short length plus cultural adaptation. Visualized nutrition education was overall promising in improving dietary behaviors. Delivering in series, short in length, with cultural adaptation were features tended to enlarge the benefits of visualized education while loss-framing and video modeling might be avoided.