"Association between dietary inflammatory index (DII) and risk of irritable bowel syndrome: a case-control study"

Background

Pathophysiology of IBS is not well recognized; however, several studies have shown the possible relationship between diet and risk of IBS. We assessed the ability of the dietary inflammatory index (DII) to predict the risk of IBS.

Methods

The subjects were 155 IBS cases and 310 age- and sex-matched healthy controls (aged ≥18 years). The participants were recruited from June, 2019 to March, 2020. IBS was recognized using the Rome IV criteria. DII score was computed based on dietary intake using a 168-item FFQ. The DII score was calculated based on energy-adjusted amounts of nutrients using residual method. Logistic regression models were used to estimate multivariable odds ratios (ORs).

Results

The mean DII score was significantly higher among IBS patients in comparison to healthy controls (0.78 ± 2.22 vs. − 0.39 ± 2.27). In crude model, increase in DII as continuous variable was associated with a significant increase in the risk of IBS (OR (95% CI): 1.26 (1.1–15.38)). Furthermore, the association remained significant even after adjusting for age and sex (OR (95% CI): 1.28 (1.1–17.41)) and after multivariate adjustment (OR (95% CI): 1.38 (1.2–1.56)). In crude, age and sex adjusted and multivariate-adjusted models subjects in fourth quartile of DII had higher OR in comparison to subjects in first quartile.

Conclusions

This study showed a possible positive association between a pro-inflammatory diet and the risk of IBS. Thus, encouraging intake of more anti-inflammatory dietary factors and reducing intake of pro-inflammatory factors may be a strategy for reducing risk of IBS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-021-00721-5.

Effect of green tea on glycemic control in patients with type 2 diabetes mellitus: A systematic review and meta-analysis

BACKGROUND AND AIMS

Several studies have investigated the potential beneficial effects of green tea in patients with type 2 diabetes mellitus (T2DM). Therefore, we aimed to perform a systematic review and meta-analysis of the randomized controlled trials (RCTs) that assessed the effect of supplementary intake of green tea on fasting plasma glucose (FPG), fasting insulin, hemoglobin A1c (HbA1c) and HOMA-IR in patients with T2DM.

METHODS

A systematic search was performed in Web of Science, PubMed and Scopus without any language and time restriction up to June 2019, to retrieve the related RCTs. Meta-analysis was carried out using both the random and fixed effects model where appropriate. I2 index was used to evaluate the heterogeneity.

RESULTS

Initial search yielded 780 publications. Fourteen articles were eligible. Our meta-analysis indicated that the supplementary intake of green tea had no significant effect on FPG, fasting insulin, HbA1c and HOMA-IR in patients with T2DM.

CONCLUSION

Results of the present systematic review and meta-analysis indicated that the supplementary intake of green tea had no significant effect on FPG, fasting insulin, HbA1c and HOMA-IR in patients with T2DM.

Effect of Green Tea on Anthropometric Indices and Body Composition in Patients with Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

AIM

Previous studies that investigated the effect of green tea/green tea extract on anthropometric indices among type 2 diabetes mellitus (T2DM) patients found inconsistent results. Thus, in order to clarify the efficacy of green tea supplementation on anthropometric indices and body composition, we conducted a systematic review and meta-analysis to sum up the evidence of randomized controlled trials.

METHODS

A systematic search was conducted in the Scopus, ISI Web of Science and PubMed to find the related articles, up to June 2019. Meta-analysis was performed using the random effects model, and the I2 index was used to evaluate the heterogeneity.

RESULTS

Eleven articles were eligible. Our meta-analysis indicated that green tea consumption significantly decreased body weight, body mass index (BMI), and body fat (BF). The beneficial effect of green tea intake was observed in long-term intervention (>8 weeks), at lower doses of green tea (dosage ≤800 mg/day), and in overweight patients.

CONCLUSION

This study revealed the beneficial effects of green tea consumption in reducing body weight, BMI, and BF in T2DM patients. It should be noted that green tea was effective in long-term intervention, at lower doses of green tea, and in overweight patients.

Effect of green tea extract on lipid profile in patients with type 2 diabetes mellitus: A systematic review and meta-analysis

BACKGROUND

Previous studies have indicated controversial results regarding the efficacy of green tea extract (GTE) in improving the lipid profile of type 2 diabetes mellitus (T2DM) patients. We aimed to conduct a systematic review and meta-analysis to pool data from randomized controlled trials (RCTs).

METHODS

A systematic search was performed in Web of Science, PubMed, and Scopus databases, without any language and time restriction until August 2019, to retrieve the RCTs which examined the effects of GTE on serum concentrations of high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglyceride (TG) or total cholesterol (TC) in T2DM patients. Meta-analyses were carried out using a random effects model. I2 index was used to evaluate the heterogeneity.

RESULTS

Initial search yielded 780 publications. Of these, seven studies were eligible. The supplementary intake of GTE improved lipid profile by reducing serum TG concentrations in patients with T2DM. Meanwhile, subgroup analyses based on duration of interventions (≤8 and > 8 weeks) and intervention dosage (≤800 and > 800 mg/day) showed that the GTE supplementation longer than 8 weeks and in doses >800 mg/day resulted in a significant decrease in serum TG concentrations. Furthermore, intervention longer than 8 weeks with doses lower than 800 mg/day resulted in a significant reduction in serum TC concentrations.

CONCLUSION

In conclusion, present systematic review and meta-analysis revealed that the supplementary intake of GTE may improve lipid profile by reducing serum concentrations of TG in patients with T2DM. Furthermore, the results of our stratified analyses suggested that long-term GTE intervention may reduce serum concentrations of TG and TC.

Serum Levels of Chemerin, Apelin, and Adiponectin in Relation to Clinical Symptoms, Quality of Life, and Psychological Factors in Irritable Bowel Syndrome

BACKGROUND

Adipokines have endocrine roles in metabolism and immunity. Dysregulation of adipokine levels is associated with several diseases with chronic inflammation. We aimed to assess the serum concentrations of chemerin, apelin, and adiponectin in irritable bowel syndrome (IBS). Furthermore, we evaluated the possible association of these adipokines with clinical symptoms, quality of life (QoL), and psychological factors.

MATERIALS AND METHODS

In this case-control study, 114 male and female IBS patients were recruited from outpatient clinics. Along with the IBS patients, 114 sex and age-matched healthy volunteers were recruited. Patients filled in the questionnaires of the IBS severity scoring system (IBSSS), gastrointestinal (GI) and somatic symptoms, IBS specific QoL (IBS-QoL), and psychological disorders, and went to the lab for blood sampling.

RESULTS

Serum levels of both adiponectin and apelin were significantly (P=0.04, 0.03, respectively) lower, whereas chemerin was significantly (P=0.01) higher in IBS patients. Chemerin was higher in IBS-D compared with both IBS-C and IBS-A, while apelin and adiponectin were not different between subtypes. After adjustments for confounders only, chemerin had a positive association with IB severity scoring system and GI symptoms. Furthermore, chemerin had positive associations, whereas apelin and adiponectin had inverse associations with somatic symptoms and psychological factors. There were no significant associations between adipokines including chemerin, apelin, and adiponectin, and IBS-QoL.

CONCLUSIONS

Chemerin had significant associations with both the severity of clinical symptoms and psychological factors in IBS; thus, it could be considered as a potential therapeutic target in these patients; however, further studies are needed.

Effect of Vitamins C and E Co-Supplementation on Serum C-Reactive Protein Level: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Studies assessing the effect of vitamin C and E co-supplementation on levels of circulating C-reactive protein (CRP) show contradictory results. We carried out a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the effect of vitamin C and E co-supplementation on CRP. A systematic search was carried out using PubMed, Scopus, Ovid, Cochrane, Embase, and the Web of Science without any language or time restriction (until 31 March 2019) to retrieve RCTs that examined the effect of vitamin C and E co-supplementation on CRP. A meta-analysis was carried out using a random effects model, and I² indexes were used to evaluate the heterogeneity. The search yielded 5,134 publications, including 8 eligible RCTs. The results indicate that vitamin C and E co-supplementation does not significantly impact levels of serum CRP [weighted mean difference and 95% confidence interval with random effects model analysis: −0.22 mg/L (−0.85, 0.41), P=0.5]. Subgroup analysis demonstrated that vitamin C and E co-supplementation significantly reduced serum CRP in participants ≥30 years of age, but significantly increased serum CRP in participants <30 years of age. The results of this meta-analysis indicate beneficial effects of vitamins C and E co-supplementation on CRP in participants ≥30 years of age, and not in younger participants. To confirm these results, further well-designed RCTs are needed.

The effect of green tea on C-reactive protein and biomarkers of oxidative stress in patients with type 2 diabetes mellitus: A systematic review and meta-analysis

INTRODUCTION

The beneficial effects of green tea on regulating insulin sensitivity and preventing the development of type 2 diabetes mellitus (T2DM) have been identified.

OBJECTIVES

We aimed to investigate the effect of green tea on serum levels of C-reactive protein (CRP) and biomarkers of oxidative stress in patients with T2DM.

METHODS

A systematic search was performed in the ISI Web of science, PubMed and Scopus to find articles related to the effect of the green tea on CRP, malondealdehyde (MDA) and total antioxidant capacity (TAC) in T2DM patients, up to June 2019. There was no language and time limitation. Meta-analyses were performed using both the random and fixed effects model where appropriate, and I2 index was used to evaluate the heterogeneity.

RESULTS

Initial search yielded 780 publications. Eight articles with 614 T2DM patients were eligible. Following green tea consumption, CRP levels significantly decreased (weighted mean difference (WMD): -5.51 mg/dl, 95% CI: -9.18 to -1.83, p = 0.003) compared with the controlled group. Green tea consumption had no significant effect on plasma levels of TAC and MDA (0.02 mg/dl, CI: -0.06 to 0.10; -0.14 mg/dl, CI: -0.40 to 0.12; respectively).

CONCLUSION

This systematic review and meta-analysis indicated that green tea significantly reduced the circulating levels of CRP, whereas, it had no significant effect on MDA and TAC. Overall, green tea can be considered as a healthy drink to reduce CRP levels in T2DM patients.

Association between Circulating Irisin and C-Reactive Protein Levels: A Systematic Review and Meta-Analysis

BACKGROUND

Although previous studies have demonstrated that irisin plays an anti-inflammatory role in the body, conflicting results have been reported regarding the correlation between serum levels of irisin and C-reactive protein (CRP). The present meta-analysis was conducted to further investigate the correlation between irisin and CRP levels.

METHODS

We systematically searched PubMed, the Cochrane Library, Web of Science, Embase, SCOPUS, and Ovid to retrieve studies assessing the correlation between irisin and CRP levels. Meta-analyses were performed using a random-effects model, and the I² index was used to evaluate heterogeneity.

RESULTS

Of the 428 studies that were initially found, 14 studies with 2,530 participants met the inclusion criteria for the meta-analysis. The pooled effect size was calculated as 0.052 (95% confidence interval, -0.047 to 0.152; P=0.302). Subgroup analyses identified s ignificant, positive, but weak correlations between CRP and irisin levels in cohort studies, studies conducted among healthy participants, studies in which the male-to-female ratio was less than 1, in overweight or obese subjects, and in studies with a sample size of at least 100 participants.

CONCLUSION

The present meta-analysis found no overall significant correlation between irisin and CRP levels, although a significant positive correlation was found in overweight or obese subjects. Well-designed studies are needed to verify the results of the present meta-analysis.

Sex-Related Differences in Clinical Symptoms, Quality of Life, and Biochemical Factors in Irritable Bowel Syndrome

BACKGROUND

Due to the sex differences in physiological and psychological factors, it can be speculated that clinical presentation of symptoms in male and female patients with irritable bowel syndrome (IBS) might be different.

AIM

To evaluate sex-related differences in clinical symptoms, quality of life, and biochemical factors in IBS.

METHODS

Ninety IBS patients (29 men, 61 women (45 premenopausal, 16 postmenopausal)) were recruited from the outpatient clinic of the University Hospital. All the patients met the Rome III Diagnostic Criteria. The IBS severity score system (IBS-SSS), gastrointestinal (GI) symptoms, IBS specific quality of life (IBS-QoL), and biochemical factors (IL-17, IL-10, TNFα, malondialdehyde (MDA), total antioxidant capacity (TAC)) were assessed.

RESULTS

Diarrhea predominant IBS (IBS-D) was more common in men (44.8%), whereas constipation-predominant IBS (IBS-C) and alternating bowel habits IBS (IBS-A) were more common in women (39.3, 42.6%, respectively). The women had a greater severity of abdominal distention, rumbling, flatulence, and dissatisfaction with bowel habits as compared with men. The scores of IBS-QoL in women were significantly (P < 0.05) lower than those in men. Moreover, pro-inflammatory cytokines (IL-17, TNFα) increased, and anti-inflammatory cytokine (IL-10) decreased in women versus men. In addition, there was no significant difference (P > 0.05) between pre- and postmenopausal women in the severity of symptoms. All of the GI symptoms and IBS-SSS have a significant negative correlation with IBS-QoL in both men and women.

CONCLUSIONS

Female with IBS reports a greater severity of IBS symptoms, increased inflammatory cytokines, and has an impaired quality of life compared with male.

Inflammatory cytokines and oxidative stress biomarkers in irritable bowel syndrome: Association with digestive symptoms and quality of life

A growing body of evidence suggests a possible role for low-grade inflammation in the pathogenesis of irritable bowel syndrome (IBS). The objectives of this study were to measure serum levels of tumor necrosis factor (TNF)-α, interleukin (IL)-17, interleukin (IL)-10, malondialdehyde (MDA) and total antioxidant capacity (TAC) in IBS patients and healthy controls (HCs), and to evaluate possible correlations of such markers with gastrointestinal (GI) symptoms and quality of life (QoL). Ninety Rome III positive IBS patients and 90 sex and age matched HCs were recruited. GI symptoms, IBS-QoL, IBS severity score system (IBSSS), and the serum levels of inflammatory cytokines and oxidative stress biomarkers were evaluated. In IBS patients, TNFα, IL-17 and MDA cytokines were significantly (P<0.05) higher, and IL-10 cytokine and TAC were significantly (P<0.05) lower vs. HCs. When comparing IBS subtypes, TNFα and IL-17 were significantly (P<0.05) higher, and IL-10 was significantly (P<0.05) lower in diarrhea predominant IBS (IBS-D) compared to HCs, whereas the inflammatory cytokine profile of other subtypes more closely resembled that of HCs. The serum levels of MDA and TAC were significantly different (P<0.05) in all the subtypes vs. HCs. All the inflammatory cytokines had significant (P<0.05) correlations with GI symptoms, IBSSS and IBS-QoL, whereas no significant association was found between oxidative stress biomarkers and these symptoms. IBS-D patients display increased pro-inflammatory cytokines and decreased anti-inflammatory cytokines. Present study demonstrated a correlation between inflammatory cytokines and both IBS symptoms and QoL.