The effect of curcumin with piperine supplementation on pro-oxidant and antioxidant balance in patients with non-alcoholic fatty liver disease: a randomized, double-blind, placebo-controlled trial.

Background The main causes of the progression of non-alcoholic fatty liver disease (NAFLD) are enhanced levels of reactive oxygen species and lipid peroxidation products. Therefore, the usage of antioxidant agents for the prevention and remedy of this disorder was recommended. Curcumin is proposed to treat NAFLD due to its high antioxidative activity. The aim of this study was to examine the effect of curcumin with piperine supplementation on oxidative stress in subjects with NAFLD. Methods In this double-blind, placebo-controlled trial, 55 subjects were randomly divided into two groups (curcumin with piperine and placebo). The participants received administrations of curcumin (500 mg) in combination with piperine (5 mg) and placebo daily for 8 weeks. Oxidative stress was assessed by measuring serum pro-oxidant and antioxidant balance (PAB) assay before and after the intervention. Results The serum PAB values did not significantly change between the treatment group vs. age and gender-matched placebo group after 8 weeks of supplementation. Also, curcumin in combination with piperine did not show a significant decrease (p = 0.06) in PAB levels compared to baseline. Conclusions The present study demonstrated that a dose of curcumin, co-supplied with piperine might be less than a dose in which curcumin can significantly decrease PAB values in these patients.

A pilot study of the effect of phospholipid curcumin on serum metabolomic profile in patients with non-alcoholic fatty liver disease: a randomized, double-blind, placebo-controlled trial.

BACKGROUND/OBJECTIVES: Curcumin, a natural polyphenol compound in the spice turmeric, has been found to have potent anti-oxidative and anti-inflammatory activity. Curcumin may treat non-alcoholic fatty liver disease (NAFLD) through its beneficial effects on biomarkers of oxidative stress (OS) and inflammation, which are considered as two feature of this disease. However, the effects of curcumin on NAFLD have been remained poorly understood. This investigation evaluated the effects of administrating curcumin on metabolic status in NAFLD patients. SUBJECTS/METHODS: Fifty-eight NAFLD patients participated in a randomized, double-blind, placebo-controlled parallel design of study. The subjects were allocated randomly into two groups, which either received 250 mg phospholipid curcumin or placebo, one capsule per day for a period of 8 weeks. Fasting blood samples were taken from each subject at the start and end of the study period. Subsequently, metabolomics analysis was performed for serum samples using NMR. RESULTS: Compared with the placebo, supplementing phospholipid curcumin resulted in significant decreases in serum including 3- methyl-2-oxovaleric acid, 3-hydroxyisobutyrate, kynurenine, succinate, citrate, α-ketoglutarate, methylamine, trimethylamine, hippurate, indoxyl sulfate, chenodeoxycholic acid, taurocholic acid, and lithocholic acid. This profile of metabolic biomarkers could distinguish effectively NAFLD subjects who were treated with curcumin and placebo groups, achieving value of 0.99 for an area under receiver operating characteristic curve (AUC). CONCLUSIONS: Characterizing the serum metabolic profile of the patients with NAFLD at the end of the intervention using NMR-based metabolomics method indicated that the targets of curcumin treatment included some amino acids, TCA cycle, bile acids, and gut microbiota.

Effect of conjugated linoleic acid on blood inflammatory markers: a systematic review and meta-analysis on randomized controlled trials.

BACKGROUND/OBJECTIVES: Conjugated linoleic acid (CLA) is a polyunsaturated fatty acid with attractive biological activities. Numerous studies have been conducted on the inflammation-lowering effects of CLA in in vitro and animal models. However, the effects of CLA treatment on the inflammatory markers in humans are controversial. Therefore, the objective of this study was to perform a systematic review and meta-analysis on controlled clinical trials (RCT) assessing the effects of CLA supplementation on the circulating inflammatory markers, including C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). SUBJECTS/METHODS: The literature search of RCTs was performed using Pubmed/Medline, Scopus, ScienceDirect, Web of science, Cochrane, and Google Scholar databases from inception to March 2017. Weighted mean differences were estimated and the pooled effect size was calculated by a random effects model. RESULTS: Of the 427 identified studies, eleven RCTs, including 420 subjects were included in the statistical analysis. Findings suggested that CLA supplementation increased blood levels of CRP by 0.89 mg/l (95% CI: 0.11, 1.68; P = 0.025) and TNF-α levels by 0.39 pg/ml (95% CI: 0.23, 0.55; P < 0.0001). However, blood IL-6 levels were marginally decreased by 0.32 pg/ml (95% CI: -0.71, 0.07; P = 0.11) following CLA supplementation. There was a significant heterogeneity for the impact of CLA on CRP and IL-6, but not TNF-α. CONCLUSIONS: This meta-analysis showed that CLA supplementation may increase inflammatory markers (CRP and TNF-α). There are concerns about using CLA supplementation as an anti-obesity agent among the obese population for at least a short duration.

Effect of green tea on plasma leptin and ghrelin levels: A systematic review and meta-analysis of randomized controlled clinical trials.

OBJECTIVE: The purpose of this study was to conduct a meta-analysis of randomized controlled trials (RCTs) to assess the effect of green tea on serum leptin and ghrelin concentrations. METHODS: We searched PubMed, ISI Web of Science, Scopus, and Google scholar databases up to December 2016. The searches included RCTs conducted in human adults, and studies on the effect of green tea and green tea extract on serum leptin and ghrelin concentrations as outcome variables. Weighted mean differences (WMDs) and standard errors (SEs) of changes in serum ghrelin and leptin levels were calculated. The random effects model was used to derive the summary mean estimates with their corresponding SEs. RESULTS: Eleven RCTs were eligible to be included in the systematic review and the meta-analysis. Our analysis indicated that green tea did not significantly affect leptin and ghrelin concentrations in comparison to placebo (WMD = 1.28 ng/mL, 95% confidence interval: -0.49 to 3.05; P = 0.156, and WMD = 21.49 pg/mL, 95% confidence interval: -40.86 to 83.84; P = 0.499, respectively). However, green tea was associated with an increase in leptin concentration in studies that lasted for more than 12 wk and an increase in ghrelin in women and non-Asians. CONCLUSIONS: Green tea or green tea extract might not be able to change circulatory leptin and ghrelin levels, especially with short-term interventions. More RCTs with longer duration of treatment and higher doses are necessary to assess green tea's effect on fat mass and obesity hormones.

Effect of Green Tea on Plasma Adiponectin Levels: A Systematic Review and Meta-analysis of Randomized Controlled Clinical Trials.

OBJECTIVE: Our objective was to perform a systematic review and meta-analysis on randomized controlled trials (RCTs) assessing the effect of green tea on serum adiponectin concentration. METHOD: We searched PubMed, ISI Web of Science, Scopus, and the Google Scholar databases up to November 2016. RCTs conducted among human adults studied the effects of green tea and green tea extract on serum adiponectin concentrations as an outcome variable was included. The weighted mean differences and standard deviations (SD) of change in serum adiponectin levels were calculated. The random effects model was used for deriving a summary of mean estimates with their corresponding SDs. The protocol was registered with PROSPERO (No. CRD42017057716). RESULT: Fourteen RCTs were eligible to be included in the systematic review and the meta-analysis. Our analysis showed that green tea did not significantly affect adiponectin concentrations in comparison with placebo (weighted mean difference = -0.02 µg/ml, 95% confidence interval [CI], -0.41, 0.38; p = 0.936). There was a substantial heterogeneity between studies (I2 = 91.7%; p < 0.0001). Subgroup analyses based on sex, type of intervention, continent, and body mass index (BMI) could not explain the sources of heterogeneity. Metaregression analyses revealed that the dose and duration of green tea ingestion did not have any effect on adiponectin concentrations. CONCLUSION: Green tea could not change the circulatory adiponectin levels. The dose and duration of green tea could not change the result. RCTs with longer follow-up periods and higher doses are needed to replicate our results.