Dietary patterns and micronutrients in respiratory infections including COVID-19: a narrative review.

BACKGROUND: COVID-19 is a pandemic caused by nCoV-2019, a new beta-coronavirus from Wuhan, China, that mainly affects the respiratory system and can be modulated by nutrition. METHODS: This review aims to summarize the current literature on the association between dietary intake and serum levels of micronutrients, malnutrition, and dietary patterns and respiratory infections, including flu, pneumonia, and acute respiratory syndrome, with a focus on COVID-19. We searched for relevant articles in various databases and selected those that met our inclusion criteria. RESULTS: Some studies suggest that dietary patterns, malnutrition, and certain nutrients such as vitamins D, E, A, iron, zinc, selenium, magnesium, omega-3 fatty acids, and fiber may have a significant role in preventing respiratory diseases, alleviating symptoms, and lowering mortality rates. However, the evidence is not consistent and conclusive, and more research is needed to clarify the mechanisms and the optimal doses of these dietary components. The impact of omega-3 and fiber on respiratory diseases has been mainly studied in children and adults, respectively, and few studies have examined the effect of dietary components on COVID-19 prevention, with a greater focus on vitamin D. CONCLUSION: This review highlights the potential of nutrition as a modifiable factor in the prevention and management of respiratory infections and suggests some directions for future research. However, it also acknowledges the limitations of the existing literature, such as the heterogeneity of the study designs, populations, interventions, and outcomes, and the difficulty of isolating the effects of single nutrients from the complex interactions of the whole diet.

Relationship between caffeine intake and small for gestational age and preterm birth: a dose-response meta-analysis.

Our meta-analysis aimed to determine the dose-response relationship between caffeine intake and risk of small for gestational age (SGA) and preterm birth (PB). A systematic search of PubMed, Web of science and Scopus was done from inception to January 2023 using relevant keywords. All case-control and cohort studies reported in English were included if the exposure of interest was caffeine intake during pregnancy, the outcome of interest was spontaneous SGA and PB, and multivariable-adjusted odds ratios (ORs) or risk ratios were provided or could be calculated. In all, 22 studies (15 cohort studies and seven case-control studies) were included in this review. Examining the association of caffeine intake with risk of PB, no significant relationship was found (Pooled ES: 1.04; 95% CI: 0.95 to 1.14, P = 0.019). Findings from this meta-analysis demonstrated that caffeine intake had a significantly higher risk of SGA respectively (Pooled ES: 1.28; 95% CI: 1.16 to 1.41, P < 0.001). A dose-response analysis proposed that an increase of 100 mg caffeine per day was associated with a 13% greater risk of SGA. This study confirmed that caffeine intake raises the risk of SGA. However, the risk of PB was not found to be reliably associated with maternal caffeine consumption.

Maternal caffeine consumption during pregnancy and risk of low birth weight: a dose-response meta-analysis of cohort studies.

BACKGROUND & OBJECTIVES: Earlier published studies on maternal caffeine intake during pregnancy in relation to the risk of low birth weight (LBW) (birth weight <2500 g) have indicated conflicting findings. Therefore, the present systematic review and meta-analysis was conducted to examine the association between maternal caffeine intake and risk of LBW. METHODS: We searched for relevant articles published up to Jan 2021 through PubMed and Scopus. For this purpose, we used MESH (Medical Subject Heading) and non-MESH keywords. Cohort studies that considered maternal caffeine intake as the exposure variable and LBW as the main outcome variable were included in the systematic review. Finally, seven cohort studies were considered in this systematic review and meta-analysis. RESULTS: Combining seven effect sizes, we found a significant positive association between maternal caffeine intake and risk of LBW (RR: 1.70; 95% CI: 1.19-2.43). We also found that each additional 100-mg per day of maternal caffeine intake was significantly associated with an increased risk of LBW (RR: 1.12; 95% CI: 1.03-1.22; Pheterogeneity = 0.020). In addition, nonlinear dose-response analysis showed a significant relationship (Pnonlinearity < 0.001) between maternal caffeine intake and risk of LBW. CONCLUSIONS: In this systematic review and meta-analysis, we found a significant positive association between maternal caffeine intake and risk of LBW.

Zinc supplementation and immune factors in adults: a systematic review and meta-analysis of randomized clinical trials.

PURPOSE: This systematic review and meta-analysis aimed to investigate the effect of zinc supplementation on immune factors in randomized controlled trials. METHODS: A comprehensive search was done in PubMed, Scopus, Web of Science, Embase, and Cochrane databases up to December 2020. We used standard and weighted mean differences and 95% confidence intervals for net changes in selected parameters of immune responses. Subgroup analysis was used to find heterogeneity. RESULT: Overall, 35 RCTs comprising 1995 participants were eligible for this meta-analysis. There was a significant reduction of circulating CRP (WMD: -32.4; 95% CI: -44.45 to -19.62, p < 0.001), hs-CRP (WMD: -0.95; 95% CI: -1.01 to -0.89, p < 0.001), Neutrophil levels (SMD: -0.46; 95% CI: -0.90 to -0.01, p = 0.043), following zinc supplementation. CD4 level also increased significantly, (WMD: 1.79; 95% CI: 0.57 to 3, p = 0.004). Zinc supplementation had no significant effect on WBC (SMD: -0.66; 95% CI: -1.67 to 0.36, p = 0.204), lymphocyte (WMD: 1.86; 95% CI: -0.86 to 4.58, p = 0.181), monocyte levels (SMD: -0.16; 95% CI: -0.07 to 0.39, p = 0.167), CD3 (SMD: 0.37; 95% CI: -0.49 to 1.22, p = 0.399). CONCLUSION: Zinc supplementation decreased the CRP, hs-CRP and TNF-α, IL-6, neutrophil and increased CD3 and CD4 level significantly.

Association between overweight/obesity with depression, anxiety, low self-esteem, and body dissatisfaction in children and adolescents: a systematic review and meta-analysis of observational studies.

PURPOSE: Childhood and Adolescent overweight and obesity may be associated with psychological problems. We aimed to conduct a systematic review and summarize published articles on the association between overweight/obesity with risk of depression, anxiety, low self-esteem, and body dissatisfaction among children and adolescents. METHODS: PubMed and Scopus databases were used to conduct a comprehensive search and identify eligible literature published prior to July 2020. The random-effects models (DerSimonian-Laird method) were applied to pool the effect sizes. Subgroup analysis was performed to find potential sources of heterogeneity. RESULTS: 28 studies (3 prospective cohorts and 25 cross-sectional) were included in the current systematic review and meta-analysis. The total sample sizes ranged from 244 to 60252. A positive significant association was found between overweight (pooled risk estimate: 1.15, 95% CI: 1.00-1.31, P = 0.04) and obesity (pooled risk estimate: 1.53, 95% CI: 1.16-2.02, P = 0.003) with risk of low self-esteem, respectively. A significant positive association was found between obesity and risk of body dissatisfaction (pooled risk estimate: 4.05, 95% CI: 2.34-7.023, P = 0.0001). Moreover, no association was found between overweight and risk of body dissatisfaction among children and adolescents. Also, no association was observed between overweight/obesity and risk of depression and anxiety. CONCLUSIONS: Findings showed a positive association between obesity and the risk of body dissatisfaction and low self-esteem among children and adolescents. Moreover, there was a significant positive association between overweight and the risk of low self-esteem.

Vegetarian diet and the risk of depression, anxiety, and stress symptoms: a systematic review and meta-analysis of observational studies.

Previous studies reported inconsistent findings regarding the consumption of a vegetarian diet with mental health outcomes, specifically depression, anxiety and stress. A systematic review was conducted to summarize the current state of literature regarding our understanding of the association between a vegetarian diet and depression, anxiety and stress. A literature search was completed using Scopus, PubMed, and the Web of Science for relevant articles published prior to July 2020. Prospective cohort and cross-sectional studies conducted on adults reporting risk estimates for the consumption of a vegetarian diet, depression, anxiety, and stress were selected. A fixed effects or a random effects model was performed to pool effect sizes. Results from 13 publications (four cohort studies and nine cross-sectional studies) assessing the relationship between the consumption of a vegetarian diet and depression, anxiety and stress were included. The pooled effect size from 10 studies indicated no association between the consumption of a vegetarian diet and depression (pooled effect size: 1.02, 95% CI: 0.84-1.25, p = 0.817). Further, the pooled effect size from four studies suggests that a vegetarian diet is not associated with anxiety (pooled effect size: 1.09, 95% CI: 0.71-1.68, p = 0.678). Due to insufficient data for stress, we were not able to pool the results. Together, no significant associations were observed between the consumption of a vegetarian diet and depression or anxiety. Future cohort studies are needed to further investigate the effects of a vegetarian diet on these mental health outcomes.

Associations between mother-child dyad dietary patterns and child anthropometric measures among 6-year-old children.

The goals of this study were to study relationships between maternal and children's dietary patterns (DPs) and to assess how children's DP was associated with child anthropometry. This cross-sectional study included 788 pairs of 6-year-old girls and mothers in health centers in Tehran, Iran. Information on dietary intake was collected with a 168-item food frequency questionnaire. Principal component factor analysis was performed to label different data-driven dietary patterns. Three different binary logistic regression models were used to evaluate the associations between child's DPs and child anthropometry. A positive correlation was found between all maternal patterns and child's Western DP (p < 0.001). Maternal prudent and Western DPs were correlated with child's high-protein DP (p < 0.001). Children's high-protein DP was negatively correlated with maternal high fat DP (p < 0.001). Maternal prudent and high fat DPs were correlated with prudent DP in children (p < 0.001). In adjusted models, a child being in the highest compared to the first quartile of the high-protein DP was associated with decreased odds of underweight and wasting (OR 0.43; 95% CI 0.23-0.80).Conclusion: The present study showed inverse associations between a high-protein DP in children and being underweight and wasted. Also, a positive correlation was found between all maternal DPs and children's Western DPs. This correlation should be taken into account while managing child nutrition by means of educating parents on the influence of their own dietary pattern on their children. Moreover, getting enough protein through a balanced diet should be considered in children. What is Known: • Some research exists on the intake of specific foods in relation to risk of abnormal growth in children. • Less is known about the relationship between mothers' and children's food intake. What is New: • Better adherence to a high-protein dietary pattern was significantly associated with lower risk of being both underweight and wasted. • This study suggests that correlation between mothers' and their children's dietary patterns exists, which should be taken into consideration when managing child nutrition.

Association between Ultraprocessed Food Intake and Overweight, Obesity, and Malnutrition among Children in Tehran, Iran.

Childhood is a critical period for susceptibility to malnutrition. The consumption of ultraprocessed foods (UPFs) has been increasing among children. The objective of this study was to evaluate the relationship between UPF intake and overweight/obesity and malnutrition in children. 788 children aged 6 years were included in a population-based cross-sectional study in Tehran. A 168-item semiquantitative food frequency questionnaire was used to evaluate dietary intake. UPFs were detected using the NOVA classification system. Logistic regression analyses were used, and results were reported as odds ratios (ORs) and 95% confidence interval (CI) of obesity and malnutrition across the tertiles of UPFs adjusted for energy intake, socioeconomic status, and physical activity. The mean weight, height, BMI, and total energy intake of participants were 20.85 ± 2.35 kg, 113.75 ± 2.00 cm, 16.12 + 1.84 kg/m2, and 1014.74 ± 259.16 (kcal/d), respectively. There were no significant associations between UPF intake and obesity (OR = 0.97; 95% CI 0.31 to 3.01; P-trend = 0.98), wasting (OR = 0.94; 95% CI 0.30 to 2.87; P-trend = 0.87), overweight/obesity (OR = 0.86; 95% CI 0.59 to 1.25; P-trend = 0.45), underweight/wasting (OR = 0.69; 95% CI 0.40 to 1.17; P-trend = 0.17), marginal-stunting (OR = 1.16; 95% CI 0.71 to 1.89; P-trend = 0.53), or marginal-stunting/overweight/obesity (OR = 1.25; 95% CI 0.62 to 2.54; P-trend = 0.47). There was no evidence of an association between intake of UPFs and risk of overweight, obesity, and malnutrition in children.

Dietary Inflammatory Index in relation to Type 2 Diabetes: A Meta-Analysis.

Background and Aims: Epidemiologic studies show a strong association between chronic inflammation and type 2 diabetes (T2D). Diet may also affect the risk of T2D by modulating inflammation. This meta-analysis aimed to assess the relation of dietary inflammatory index (DII) and risk of T2D. Methods: PubMed and Scopus were systematically searched from their inception to September 2020 to identify relevant studies. Relative risks, hazard ratios, or odds ratios (OR), with their corresponding 95% confidence intervals (95% CI), were calculated and pooled using a random-effects model. Results: A total of 48 different studies, with a total sample size of 1,687,424 participants, were eligible to be included in this meta-analysis. In the overall analysis, no significant association was observed between DII and risk of T2D (OR = 1.03, 95% CI: 0.91 to 1.15), with significant evidence for heterogeneity (I 2 = 96.5%, P < 0.001); however, higher DII was identified as being significantly related to increased risk of T2D in high quality studies (OR = 1.58, 95% CI: 1.15 to 2.17). In the stratified analysis by the dietary assessment tool, background disease, and sex of participants, DII showed no significant association with T2D. Conclusions: Higher DII might be associated with an increased risk of T2D. Additional well-designed studies are required to confirm this finding.

The effects of magnesium supplementation on obesity measures in adults: a systematic review and dose-response meta-analysis of randomized controlled trials.

Previous studies reported inconsistent findings regarding the effects of magnesium supplementation on obesity measures. This study was done to quantify the effect of magnesium supplementation on body weight, Body Mass Index (BMI), Waist Circumference (WC), Body Fat (BF) percentage and Waist to Hip Ratio (WHR). Four online databases (Scopus, PubMed, Google Scholar and Cochrane library) were searched until March 2020 using relevant keywords. Random-effects model was used to pool effect sizes; Cochran's Q-test and I2 index assessed heterogeneity. Sensitivity analysis and Egger test were used to check the robustness of findings and the possibility of publication bias, respectively. Thirty-two RCTs including different dosage of magnesium (48-450 mg/d), and duration (6-24 weeks) were entered to this study. Magnesium supplementation resulted in a great reduction in BMI [Weighted Mean Difference (WMD): -0.21 kg/m2, 95% CI: -0.41, -0.001, P = 0.048, I2 = 89.5%, n = 22], which was mainly driven by the effect among those with magnesium deficiency, insulin resistance related disorders, and obesity at baseline. No significant change was observed in bodyweight, WC, BF percentage and WHR as compared to controls. However, the change in body weight, and WC was significant in subgroups of participants with insulin resistance related disorders, hypertension, obesity, magnesium deficiency at baseline, and females. We found a significant reduction in BMI following magnesium supplementation. The change in body weight and WC were evident in certain subgroups.

Associations between dietary intake of B-vitamins and psychological disorders among Iranian women: a cross-sectional study.

OBJECTIVE: B-vitamins affect brain function through multiple pathways. Given limited evidence on the relationship between dietary intake of these vitamins and psychological disorders, we examined dietary intake of vitamin B6-9-12 in relation to psychological disorders among Iranian women. DESIGN: Cross-sectional study. Dietary intake was assessed using a valid and reliable FFQ. To assess psychological disorders, we used a version of the Depression Anxiety Stress Scale-21 validated in Iran. SETTING: Ten public health centres in southern Tehran, Iran. PARTICIPANTS: A total of 447 female participants aged 20-50 years. RESULTS: The median values of vitamin B6 (pyridoxine), B9 (folate) and B12 (cobalamin) were 1·30 mg/d, 313·89 µg/d and 3·99 µg/d, respectively. After adjustment for potential confounders, dietary vitamin B6 intake was associated with lower odds of depression (OR: 0·54; 95 % CI: 0·31, 0·95; Ptrend: 0·03). However, there was a positive association between dietary vitamin B12 intake with the odds of depression (OR: 2·05; 95 % CI: 1·17, 3·60; Ptrend: 0·01) and psychological distress (OR: 2·00; 95 % CI: 1·17, 3·41; Ptrend: 0·01). No association was found between vitamin B9 with any psychological disorders. CONCLUSIONS: Women with higher dietary intakes of vitamin B6 had lower likelihood of depression. However, women with higher dietary intake of vitamin B12 had higher odds of depression and psychological distress. Future prospective studies in different populations are needed to clarify whether B-vitamin deficiency is a cause or consequence of psychological disorders.

Associations between dietary intake of B vitamins and cardiovascular risk factors in elderly men: A cross-sectional study.

OBJECTIVE: Low intake of B vitamins can lead to hyperhomocysteinaemia, which is reported as a risk factor for cardiovascular disease (CVD). However, little is known about this relationship. Therefore, we decided to examine the association between dietary intake of B vitamins and cardiovascular risk factors in elderly men. METHODS: The present cross-sectional study consisted of 357 elderly men. Dietary intake was assessed using a validated and reliable food frequency questionnaire. All biochemical factors [fasting blood sugar (FBS), triglyceride (TG), high-sensitivity C-reactive protein (hs-CRP), interleukin 6 (IL-6) and tumour necrosis factor-α (TNF-α)], waist circumference (WC) and blood pressure (BP) were assessed using standard methods. RESULTS: A significant inverse association was observed between high dietary intake of total B vitamins (ORTotal B vitamins : 0.30; 95% CI: 0.10, 0.86; P = .01) and vitamin B9 (ORvitamin B9 : 0.20; 95% CI: 0.02, 0.52; P = .002) with high WC. Furthermore, an inverse association was observed between high dietary intake of vitamin B6 (ORvitamin B6 : 0.28; 95% CI: 0.08, 1.00; P = .05) and vitamin B9 (ORvitamin B9 : 0.20; 95% CI: 0.06, 0.70; P = .01) with hs-CRP level. CONCLUSIONS: In elderly men, a high dietary intake of total B vitamins and vitamin B9 was associated with lower odds of having a high WC. Similarly, high dietary intake of vitamin B6 and B9 was associated with lower odds of having a high hs-CRP level.

Glycemic index, but not glycemic load, is associated with an increased risk of metabolic syndrome: Meta-analysis of observational studies.

BACKGROUND: Diets with high glycemic index (GI) or high glycemic load (GL) have been linked to important risk factors associated with the development of metabolic syndrome (MetS), such as dyslipidemia, higher blood glucose, and insulin concentrations. However, the role of GI and GL in relation to Mets is still understudied and controversial. This review, therefore, assessed whether high GI or GL contribute to development of Mets. METHODS: A systematic search of four bibliographic databases was conducted (MEDLINE/PubMed, EMBASE, Web of Sciences, and Scopus) from inception to January 2020 for observational studies assessing GI/GL in relation to MetS. Risk estimates were pooled using random-effect models for the highest versus lowest intake categories, and assessed for heterogeneity using subgroup analysis. The dose-response nature of the relationship was also investigated. Sensitivity analysis and Egger test were used to check the robustness of findings and the possibility of publication bias, respectively. RESULTS: Data from 12 publications (one cohort study and eleven cross-sectional studies) with a total sample size of 36,295 subjects are included. The pooled effect sizes from the nine studies indicated high versus low dietary GI was associated with increased risk of MetS (OR = 1.05, 95% CI: 1.01 to 1.09) (I2  = 58.1, P = .004). This finding was supported by all subgroup analyses except where studies used 24-h recalls for dietary assessment. Additionally, a linear dose-response investigation revealed that each 5-point increment in GI was associated with 2% increase in the risk of MetS (OR = 1.02, 95% CI: 1.01 to 1.02); non-linear pattern was insignificant, however (p-nonlinearity = 0.63). Moreover, pooled effect sizes from ten studies suggested that no association was found between the GL and MetS with results remaining consistent in all subgroup analyses. CONCLUSION: A diet with lower GI may protect against MetS. Nutrition policy and clinical practices should encourage a diet with low GI. Future studies should include both GI and GL and different criteria of MetS to provide a better comparison.

Food quality score and anthropometric status among 6-year-old children: A cross-sectional study.

OBJECTIVE: Weight status and growth during childhood are indicative of healthy development throughout the lifespan. It is well understood that dietary patterns and overall quality of diet can prevent disease, improve health status and optimise growth and development. The current study investigates the relationship between overall diet quality and measures of childhood development including body mass index and height-for-age in 6-year-old children. METHODS: This cross-sectional study was conducted across 788 6-year-old children from Tehran, Iran, in 2018. Food quality score (FQS) was used to assess overall diet quality, in addition to a modified food-based diet quality score specific to children (modified FQS) developed by our group. RESULTS: Participants in the highest tertile using the modified FQS had the highest height-for-age z-score (HAZ) (-0.509 ± 0.028 vs -0.605 ± 0.028; P = .048). In contrast, participants in the highest tertile assessed using the original FQS had a higher BMI for age z-score (BAZ) compared to participants in the first tertile (0.391 ± 0.072 vs 0.266 ± 0.072; P = .023). Children within the highest tertile, according to the original FQS, compared to those within the lowest tertile were 49% less likely to be categorised as severely underweight (OR: 0.51; 95% CI: 0.47-0.98). CONCLUSIONS: Findings presented in this study demonstrate that FQS was significantly associated with participants characterised as severely underweight; however, FQS was not associated with other anthropometric parameters. Therefore, future well-designed cohort studies are required to address limitations of the current study.

Effects of garlic supplementation on oxidative stress and antioxidative capacity biomarkers: A systematic review and meta-analysis of randomized controlled trials.

Evidence suggests that garlic supplementation may have an effect on oxidative stress by augmenting the rate of enzymatic and non-enzymatic antioxidants and diminishing pro-oxidant enzymes. Given inconsistencies across studies, we aimed to systematically review the current literature and quantify the effects of garlic supplementation on oxidative stress. We conducted a systematic search with multiple databases (Scopus, PubMed, and Web of Science) to find relevant articles published prior to October 2020. Results were reported as bias-corrected standardized mean difference (Hedges' g) with 95% confidence intervals (CI) using random-effects models. Cochrane's Q and I squared (I2 ) tests were used to determine heterogeneity among the studies included. Twelve randomized controlled trials (RCTs) were included. Garlic doses ranged from 80 to 4,000 mg/day, and intervention duration varied between 2 and 24 weeks. Garlic supplementation increased serum level of total antioxidant capacity (TAC) (Hedges' g: 2.77, 95% CI: 1.37 to 4.17, p < 0.001) and superoxide dismutase (SOD) (Hedges' g: 13.76, 95% CI: 4.24 to 23.29, p = 0.004), while it reduced the malondialdehyde serum level (MDA) (Hedges' g: -1.94, 95% CI: -3.17 to -0.70, p = 0.002). Due to limited data available, glutathione (GSH) was not considered for the current meta-analysis. The nonlinear dose-response effect of garlic supplementation was not observed with regard to serum TAC and MDA levels (TAC: p-nonlinearity = 0.398; MDA: p-nonlinearity = 0.488). Garlic supplementation appears to improve serum levels of TAC, MDA, and SOD. Garlic supplementation may be useful to reduce oxidative stress and related diseases. Future studies with large sample sizes and longer duration are required to confirm these findings.

The association between Healthy Beverage Index and anthropometric measures among children: a cross-sectional study.

PURPOSE: Several studies evaluated the associations between specific beverages and cardio-metabolic risks among children. However, the evidence on the association between patterns of the beverage consumption and children's anthropometric indices is rare. Therefore, this study was conducted to examine the association between Healthy Beverage Index (HBI) and anthropometric measures among 6-year-old girl children. METHODS: In this cross-sectional study, 788 children selected from health centers in Tehran, Iran. Data on beverage intake, socio-demographic, physical activity, and anthropometric characteristics were evaluated using reliable and validated standard protocols. The predefined HBI was calculated based on the previous research. RESULTS: After controlling for several confounders [mother age, mother body mass index, mother physical activity, socioeconomic status, children physical activity and energy intake, total oils (all kinds of oils like animal and plant oils), and total sweet foods (sweet foods except sweetened beverages)], being in the third compared to the first tertile of HBI among children was associated with increased odds of wasting (OR: 5.16; 95% CI 1.5-17.79) and underweight/wasting (OR: 1.81; 95% CI 1.07-3.07). Among the HBI components, just being in the third compared to the first tertile of high-fat milk was inversely associated with decreased odds of wasting (OR: 0.18; 95% CI 0.04-0.73). CONCLUSIONS: The HBI among children was associated with higher odds of wasting and underweight/wasting. In addition, high-fat milk consumption decreased the odds of wasting among children. Further prospective studies need to confirm these results. LEVEL OF EVIDENCE: Level V, descriptive cross-sectional study.

Ultra-processed food and the risk of overweight and obesity: a systematic review and meta-analysis of observational studies.

BACKGROUND: Numerous studies have reported the association of ultra-processed foods with excess body weight; however, the nature and extent of this relation has not been clearly established. This systematic review was conducted to analyze the currently documented evidence regarding the association between ultra-processed food with overweight and obesity. METHODS: A literature search was performed using multiple literature databases for relevant articles published prior to November 2019. Random effects model, namely the DerSimonian-Laird method, was applied to pool effect sizes. The potential sources of heterogeneity across studies were explored using the Cochrane Q test. RESULTS: Fourteen studies (one cohort study and thirteen cross-sectional studies) were included in this review. A significant association was identified between ultra-processed food intake and overweight (pooled effect size: 1.02; 95% confidence interval (95% CI): 1.01, 1.03, p < 0.001) and obesity (pooled effect size: 1.26; 95% CI: 1.13, 1.41, p < 0.001). CONCLUSION: Our findings revealed a positive association between ultra-processed foods and excess body weight. Future studies with longitudinal designs and adequate control for confounding factors are required to clarify whether ultra-processed food intake alters anthropometric parameters and leads to obesity.

The effects of N-Acetylcysteine on serum level of inflammatory biomarkers in adults. Findings from a systematic review and meta-analysis of randomized clinical trials.

PURPOSE: Randomized Clinical Trials (RCTs) have provided varied and conflicting findings regarding the effect of N-acetylcysteine (NAC) on inflammatory biomarkers. This study was conducted to review existing literature to determine whether NAC supplementation can affect inflammatory biomarkers in adults. METHODS: Bibliographic databases of Scopus, and PubMed were used for relevant papers published until October 2019. Results were reported as weighted mean differences (WMD) with 95% confidence intervals (CI) using multi-level models. Cochrane's Q and I-squared (I2) tests were used to determine heterogeneity among studies. RESULTS: Twenty-four RCTs which include 1057 sample size were entered to analysis. NAC doses and intervention duration ranged from 400 to 2000 mg/d, and 1 to 80 weeks, respectively. Oral supplementation of NAC reduced serum level of C-reactive protein (CRP) [WMD: -0.61 mg/L, 95% CI: -1.18 to -0.03, P = 0.039, I2 = 79.6%], and interleukin-6 (IL-6) [WMD: -0.43 pg/mL, 95% CI: -0.69 to -0.17, P = 0.001, I2 = 89.3%]. However, the effect of oral NAC supplementation on other inflammatory biomarkers was nonsignificant. Dose-response investigation showed a non-linear association between oral NAC supplementation with CRP. CONCLUSION: Oral NAC supplementation reduced serum level of CRP and IL-6, but did not affect other inflammatory biomarkers. Nevertheless, more RCTs seems to be required to explore how NAC in different dosage and different routes of administration can affect inflammatory biomarkers.

The association between different types of amino acid intake and physical growth among children.

BACKGROUND & AIMS: Restricted linear growth and abnormal weight status are commonly observed among children in low-income countries, possibly due to inadequate protein intake. Considering the role of protein intake and amino acid (AA) synthesis in growth and development, it has been suggested that there may be an association between AA intake and physical growth. We aimed to investigate the association between different types of AA intake and physical growth among children. METHODS: A cross-sectional study including 780 six-year-old children referred to 10 health care centers for vaccination between October 2017 and March 2018 was conducted. Anthropometric data was collected using standard methods, and dietary intake was assessed using a validated food-frequency questionnaire (FFQ) in an interview by a trained technician. RESULTS: Children in the highest tertile (3rd) of branched-chain amino acids (BCAA) intake had a higher weight-for-age z-score (WAZ) (P = 0.02) and body mass index-for-age z-score (BAZ) (P = 0.001) compared to those in the lowest tertile (1st). Interestingly, BAZ was significantly associated with the highest tertile of acidic AA intake (P = 0.04), while an inverse association was observed between the highest tertile of aromatic AA (phenylalanine and tyrosine) intake and BAZ (P = 0.01) . No significant associations were observed between the highest tertile of sulfuric, aliphatic, or neutral AA and BAZ, height-for-age z-score (HAZ) or WAZ. Further, underweight was associated with the 3rd tertile of aromatic, alcoholic, aliphatic or neutral AA and BCAA intake. Aliphatic and neutral AA intake was also increased the risk of overweight. Finally, stunted growth patterns were associated with the highest tertile of acidic, alcoholic. CONCLUSION: Findings presented in this study showed that higher BAZ and WAZ are associated with 3rd tertiles of BCAA intake, but lower BAZ were associated with 3rd tertiles of aromatic AA (phenylalanine and tyrosine) intake. Future research in other populations are needed to confirm these findings.