Potato Consumption and Risk of Site-Specific Cancers in Adults: A Systematic Review and Dose-Response Meta-Analysis of Observational Studies.

The etiology of cancer type may vary significantly due to anatomy, embryology, and physiology of the cancer site. Although the association between potato consumption and colorectal cancer (CRC) was summarized in a 2018 meta-analysis of 5 cohort studies, to the best of our knowledge, no meta-analysis has evaluated potato consumption in relation to multiple cancer sites in adults. Medline/PubMed, ISI Web of Knowledge, Scopus, and the Cochrane Database of Systematic Reviews were searched for relevant publications through August 2020. We selected cohort or case-control studies conducted in adults that reported risk estimates (relative risk [RRs], HRs, and ORs) of potato intake for any cancer type. Random effects meta-analyses compared high and low intake categories. Twenty prospective cohort studies (total n = 785,348) including 19,882 incident cases, and 36 case-control studies (21,822 cases; 66,502 controls) were included. Among cohort studies, we did not find an association between high versus low intake of total potato (white and yellow) consumption and overall cancers: 1.04 (95% CI: 0.96, 1.11; tau2 = 0.005, n = 18). We found no relation between total potato consumption (high compared with low intake) and risk of CRC, pancreatic cancer, colon, gastric, breast, prostate, kidney, lung, or bladder cancer in cohort or case-control studies. We did not find an association between high versus low consumption of potato preparations (boiled/fried/mashed/roasted/baked) and risk of gastrointestinal-, sex-hormone-, or urinary-related cancers in cohort or case-control studies. Certainty of the evidence was low for total cancer, CRC, colon, rectal, renal, pancreatic, breast, prostate, and lung cancer and very low for gastric and bladder cancer. In conclusion, potato intake or potato preparations were not associated with multiple cancer sites when comparing high and low intake categories. This finding was consistent with the findings from the 2018 meta-analysis regarding potato intake and risk of CRC.

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.

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.

The association of red meat consumption and mental health in women: A cross-sectional study.

OBJECTIVES: Previous studies have shown that red meat consumption has beneficial effects on health. The purpose of this study was to determine the relationship between red meat consumption and depression, anxiety and psychological distress in Tehrani women. METHODS: In this cross-sectional study, 482 women aged 20-50 years old referred to the health centers of Tehran University of Medical Sciences in 2018 were selected by multistage cluster sampling. The usual dietary intake was evaluated using a semi-quantitative food frequency questionnaire containing 168 items that its validity and reliability were approved previously. The red meat category was defined as the sum of red meats (beef, lamb), and organ meats (beef liver, kidney, and heart, ruminant meat). Psychological disorders were assessed using a validated Depression, Anxiety, Stress Scales (DASS) questionnaires with 21-items. In the logistic regression analysis, the results were adjusted to the confounding factors. RESULTS: The mean age of the study participants was 31.87 ± 7.6 years. The prevalence of depressive symptoms, anxiety and psychological distress among participants was 34%, 40% and 42%, respectively. After controlling for potential confounders, women in the highest quartile of red meat had a highest prevalence of depressive symptoms (OR: 2.51; 95% CI: 1.32-4.76; p = 0.002), anxiety (OR: 1.82; 95% CI: 1.00-3.29; p = 0.034) and stress (OR: 3.47; 95% CI: 1.88-6.42; p < 0.001) compared with those in the lowest quartile. CONCLUSIONS: We found a significant association between red meat intake and mental health in women. Prospective studies are needed to confirm these findings.

Association of dietary acid-base load and psychological disorders among Iranian women: A cross-sectional study.

Metabolic acidosis, which can be affected by dietary acid-base load, seems to be associated with psychological disorders through different pathways. Given limited evidence on dietary acid-base load, we aimed to examine the association of dietary acid-base load with psychological disorders in Iranian women. This cross-sectional study was performed on 447 female subjects (20-50 years old). Dietary intake was assessed using a valid food frequency questionnaire for Iran. Dietary acid-base load was calculated through different indices including potential renal acid load (PRAL), net endogenous acid production (NEAP), and dietary acid load (DAL). To assess psychological disorders, an Iranian validated version of depression, anxiety, and stress scale (DASS-21) was used. The mean value of PRAL, NEAP, and DAL were -8.87mEq/da, 37.94mEq/day, and 30.77mEq/day, respectively. Considering a wide range of confounding variables, compared with the first tertile, a significant positive association was observed between dietary acid-base load and depression (ORPRAL: 3.63; 95 %CI:1.97, 6.71; Ptrend = 0.0001) (ORNEAP:3.42; 95 %CI: 1.87, 6.23; Ptrend = 0.0001) (ORDAL: 3.02; 95 %CI: 1.64, 5.58; Ptrend = 0.0001). Women in the high dietary acid-base load category had higher anxiety (ORPRAL: 3.31; 95 %CI: 1.81, 6.06; Ptrend = 0.0001) (ORNEAP:3.47; 95 %CI: 1.90, 6.33; Ptrend = 0.0001) (ORDAL: 3.25; 95 %CI: 1.76, 5.98; Ptrend = 0.0001). Moreover, there was a strong positive relationship between dietary acid-base load and psychologicaldistress (ORPRAL: 3.79; 95 %CI: 2.09, 6.90; Ptrend = 0.0001) (ORNEAP: 3.67; 95 %CI: 2.04, 6.58; Ptrend = 0.0001) (ORDAL: 3.00; 95 %CI: 1.66, 5.43; Ptrend = 0.0001). Women with higher dietary acid-base load score had greater odds for depression, anxiety, and psychological distress compared to lower ones.

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.

Dietary intake of fish, n-3 polyunsaturated fatty acids, and risk of inflammatory bowel disease: a systematic review and meta-analysis of observational studies.

PURPOSE: Fish consumption and dietary intake of n-3 polyunsaturated acids (PUFAs) may be associated with inflammatory bowel disease (IBD). We aimed to conduct a systematic review and summarize published articles on the association between fish consumption and dietary intake of n-3 PUFAs with the risk of IBD. METHODS: PubMed, Scopus, and Web of Science databases were used to conduct a comprehensive search and identify eligible literature published prior to January 2019. Fixed-effects model or random-effects models (DerSimonian-Laird method) were applied to pool the effect sizes. Cochrane Q test was used to trace the potential source of heterogeneity across studies. RESULTS: 12 studies (5 prospective and 7 case-control) were included in the systematic review, which ten of them were eligible for inclusion in the meta-analysis. Studies were included a total sample size of 282610 participants which 2002 of them were cases of IBD [1061 Crohn's disease (CD) and 937 ulcerative colitis (UC)]. A negative association was found between fish consumption and the incidence of CD (pooled effect size: 0.54, 95%CI: 0.31-0.96, P = 0.03). There was no relationship between total dietary n-3 PUFAs intake and IBD (pooled effect size: 1.17, 95%CI: 0.80-1.72, P = 0.41). A significant inverse association was observed between dietary long-chain n-3 PUFAs and the risk of UC (pooled effect size: 0.75, 95%CI: 0.57-0.98, P = 0.03). Moreover, no association was found between α-Linolenic acid (ALA) and IBD (pooled effect size: 1.17, 95%CI: 0.63-2.17, P = 0.62). CONCLUSIONS: Findings showed a negative association between fish consumption and the risk of CD. Moreover, there was a significant inverse association between dietary long-chain n-3 PUFAs and the risk of UC.

The effects of psyllium supplementation on body weight, body mass index and waist circumference in adults: A systematic review and dose-response meta-analysis of randomized controlled trials.

Background: Previous studies reported inconsistent findings regarding the effects of psyllium supplementation on obesity measures. This systematic review and meta-analysis was performed to summarize data from available randomized clinical trials (RCTs) on the effect of psyllium supplementation on body weight, body mass index (BMI), and waist circumference (WC) in adults.Methods: PubMed, SCOPUS, Cochrane Library, and Google Scholar were searched to identify relevant articles up to August 2018. The effect sizes were presented as weighted mean difference (WMD) and 95% confidence intervals (CI) by using random effects model. To detect dose-response relationships, we used fractional polynomial modeling.Results: A total of 22 RCTs were included. Meta-analysis did not find any significant effect of psyllium supplementation on body weight (MD: -0.28 kg, 95% CI: -0.78, 0.21, p = 0.268), BMI (MD: -0.19 kg/m2, 95% CI: -0.55, 0.15, p = 0.27) and WC (MD: -1.2 cm, 95% CI: -2.6, 0.2, p = 0.09). Subgroup analysis showed that psyllium dosage, kind of psyllium administration, duration of trial, study design, sample size, and gender were potential sources of heterogeneity. Moreover, there was nonlinear association between duration of psyllium consumption, BMI and WC.Conclusion: Psyllium supplementation does not reduce body weight, BMI, and WC significantly.

Effect of magnesium supplementation on endothelial function: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND AND AIMS: Findings of past studies are inconsistent regarding the effects of magnesium (Mg) supplementation on endothelial function (EF). We performed this meta-analysis to examine the effects of magnesium supplementation on flow-mediated dilation (FMD) and carotid intima media thickness (CIMT) as markers of EF. METHODS: Literature searches of English publications in MEDLINE and EMBASE databases were conducted up to November 2017. Results are reported as weighted mean difference (MD) with 95% confidence intervals (CI) using random effects model (DerSimonian-Laird method). Cochrane's Q test and I-squared (I2) were used to determine heterogeneity among included studies. To determine potential sources of heterogeneity, subgroup analysis was conducted for pre-defined criteria. Funnel plot and Egger's regression test were used to assess publication bias. RESULTS: Seven RCTs with 306 participants were included. Mg supplementation significantly increased FMD (MD: 2.97; 95% CI: 0.23 to 5.70%, p = 0.033). Between studies heterogeneity was high and subgroup analysis could not identify the sources of heterogeneity. Magnesium supplementation had no significant effect on CIMT (MD: -0.13 mm; 95% CI: 0.27, 0.01; p = 0.077) with high heterogeneity. Mg dose, duration of treatment, healthy status, baseline CIMT and sample size were the potential sources of heterogeneity. Mg supplementation could decrease CIMT to a greater extent in hemodialysis (HD) patients; lower doses of Mg, higher sample size and follow up duration and subjects with higher baseline CIMT also reduced the heterogeneity to some degree (p < 0.001). CONCLUSIONS: Magnesium supplementation may improve endothelial function without affecting carotid intima media thickness.

Dietary Total Antioxidant Capacity and Cardiovascular Disease Risk Factors: A Systematic Review of Observational Studies.

OBJECTIVE: Measurement of dietary total antioxidant capacity (DTAC) is considered a new holistic dietary approach and assesses total antioxidants present in the overall diet. Our aim was to perform a comprehensive review of the literature on the association between DTAC and cardiovascular disease (CVD) risk factors. METHODS: PubMed, Web of Science, and Scopus were used to conduct a comprehensive search for articles published on this topic through September 2017. There was no limit on earliest year of publication. The search was based on the following keywords: dietary total antioxidant capacity, nonenzymatic antioxidant capacity, total radical-trapping antioxidant parameter, ferric reducing ability of plasma, oxygen radical absorbance capacity, Trolox equivalent antioxidant capacity, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), total cholesterol (TC), waist circumference (WC), insulin resistance, homeostatic model assessment of insulin resistance (HOMA-IR), insulin, obesity, glucose, C-reactive protein (CRP), blood pressure (BP), and body mass index. In total, 16 papers were identified for inclusion in the present systematic review. RESULTS: Most well-designed studies that evaluated associations between DTAC and CVD risk factors showed inverse associations for fasting blood glucose, CRP, BP, and WC and positive associations for HDL-C. However, there was no association between DTAC and LDL-C or TC in any of the studies. Results regarding the association of DTAC with insulin, HOMA-IR, high-sensitivity CRP, and TG in the published literature were inconsistent. CONCLUSIONS: Findings indicated a substantial association between high DTAC and most CVD-related risk factors.