The association of dietary nitrates/nitrites intake and the gut microbial metabolite trimethylamine N-oxide and kynurenine in adults: a population-based study

Background

Dietary nitrate and nitrite may affect the gut microbiota and its metabolites, such as trimethylamine N-oxide (TMAO) and kynurenine (KYN). However, this association and the exact mechanism are still unclear. Therefore, this study aimed to assess the association between dietary consumption of nitrite and nitrate on TMAO and KYN levels in adults.

Methods

This cross-sectional study was employed on a subsample baseline phase of the Tehran University of Medical Sciences (TUMS) Employee's Cohort Study (TEC). A total of 250 adults aged 18 years or older were included in the current analysis. Data on the dietary intakes were collected using a validated dish-based food frequency questionnaire (FFQ), and dietary intakes of nitrite and nitrate were estimated using the FFQ with 144 items. Serum profiles and TMAO and KYN were measured using a standard protocol.

Results

The findings of this study demonstrate a significant association between the intake of animal sources of nitrate and nitrite and the likelihood of having elevated levels of TMAO and KYN. Specifically, after adjustment, individuals with the highest intake adherence to nitrates from animal sources exhibited increased odds of having the highest level of TMAO (≥51.02 pg/ml) (OR = 1.51, 95% CI = 0.59-3.88, P = 0.03) and KYN (≥417.41 pg/ml) (OR = 1.75, 95% CI = 0.73-4.17, P = 0.02). Additionally, subjects with the highest animal intake from nitrite sources have 1.73 and 1.45 times higher odds of having the highest levels of TMAO and KYN. These results emphasize the potential implications of animal-derived nitrate and nitrite consumption on the levels of TMAO and KYN.

Conclusion

The present evidence indicates that a high level of nitrate and nitrite intake from animal sources can increase the odds of high levels of TMAO and KYN. Further studies suggest that we should better evaluate and understand this association.

Meal-specific dietary patterns and biomarkers of insulin resistance in a sample of Iranian adults: a cross-sectional study

Current research emphasizes the habitual dietary pattern without differentiating eating occasions. We aimed to assess meal-specific dietary patterns and insulin resistance indicators. This cross-sectional study was conducted on 825 Iranian adults. Dietary data were recorded by three 24-h dietary recalls. Dietary patterns were identified using principal component analysis (PCA) on main meals and an afternoon snack. Anthropometric measurements, blood pressure, and laboratory investigation, fasting plasma glucose (FPG), triglyceride, insulin, c-reactive protein (CRP) were done. Homeostatic model assessment for insulin resistance and sensitivity (HOMA-IR and HOMA-IS), Triglycerides and glucose (TyG-index), and Lipid accommodation product index were calculated. We used multivariate analysis of variance (MANOVA) analysis. Two major dietary patterns at the main meals and the afternoon were identified. Higher adherence to "Bread, vegetable, and cheese" dietary pattern at breakfast was related to lower FPG, and "Oil, egg, and cereals" showed a direct association with body mass index, FPG, and TyG-index at breakfast. The "Western" pattern in lunch and dinner directly related to waist circumference (WC) and body mass index, however, it was inversely related to HOMA-IS. This pattern at dinner was related to higher CRP. Higher adherence to "bread, cereals, and oil" pattern at afternoon snack was associated with a lower WC. These results indicated that unhealthy meal-specific dietary patterns are associated with a greater chance of obesity and insulin resistance risk. However, "Bread, vegetable, and cheese" dietary pattern at breakfast was related to lower FPG, and "bread, cereals, and oil" pattern in the afternoon was associated with lower WC.

Time-related meal patterns and breakfast quality in a sample of Iranian adults

BACKGROUND

Some evidence shows that meal timing is associated with diet quality. We aimed to investigate the relationship between meal timing and breakfast quality in a sample of Iranian adults.

METHODS

This cross-sectional study was conducted on 850 men and women living in Tehran, Iran. Dietary data was recorded by three non-consecutive 24-h dietary recalls. The Breakfast Quality Index (BQI) was calculated. Time-related meal patterns included the interval between the first and last meal (eating and fasting window), frequency of meals, length of sleep, and time of first and last eating occasion. The multiple linear regression analysis was used to identify the relationships between time-related meal patterns and BQI.

RESULTS

The mean (95% CI) of BQI was 4.52 (4.45-4.65) and the maximum was 8. Bread, cheese, vegetables, fruits, energy, and carbohydrate intake showed positive associations with BQI scores. Longer fasting time showed a positive association with fruits (β (CI 95%)) (0.11 (0.0003-0.005), and vegetable consumption (0.12 (0.009-0.07)) and BQI score (0.39 (0.001-0.06)). Time of first eating occasions indicated a negative association with protein and fat intake and BQI score. Time of last eating occasions showed a positive association with vegetables consumption and BQI score. The longer length of sleep was associated with a higher BQI score. The frequency of meals was significantly and positively related to energy and macronutrients intake and BQI.

CONCLUSION

Earlier first and last meal, longer sleep length, longer fasting window, and a greater meal frequency were associated with a better breakfast quality.

The Potential Effect of Blueberry on Cognitive Health and Mood State based on Human Intervention Studies: Systematic Review and Mini Meta-Analysis

BACKGROUND

Blueberries are known for their high content of several bioactive compounds, specifically anthocyanin, which are the most beneficial of the flavonoid family in terms of neuroprotection. Several human interventional studies have been conducted to assess the effects of blueberry intake on cognitive performance; however, the results of clinical trials are inconclusive. Therefore, this systematic review and meta-analysis evaluated the effect of blueberry supplementation on some aspects of cognitive performance and mood parameters using data from clinical trials based on existing evidence.

METHODS

Relevant studies, published in April 2021, were searched through PubMed/Medline, Scopus, Embase, and Google Scholar. The random effect size was used to estimate the pooled effect size. Heterogeneity between studies was evaluated by the Cochrane Q test and I-squared (I²). To detect the potential source of heterogeneity, a subgroup analysis was conducted.

RESULTS

Fourteenrandomized trials were included in the quantitative analysis, and six were pooled for statistical analysis. Blueberry intervention resulted in no significant change in mood state score (WMD = 0.03; 95% CI: -0.80 to 0.87, P = 0.16). Moreover, no significant effect of blueberry intake was shown in attention task reaction time (WMD = -1.50 ms; 95% CI: -24.75 to -21.75, P = 0.9), percentages of attention task accuracy (WMD = 0.85; 95% CI: -2.57 to 0.86, P = 0.3), one-back test accuracy (WMD = 0.03; 95% CI: -0.04 to 0.09, P = 0.4). Significant effect was indicated (WMD = 0.08; 95% CI: 0.02 to 0.13, P = 0.005) in two-back test accuracy.

CONCLUSION

We found a significant effect of blueberry consumption on two-back test accuracy as a cognitive outcome. More high-quality clinical trials according to the challenges mentioned seem to indicate the use of blueberry as a supplement for cognitive and mood health efficiently.

A multi-centre survey on hospital malnutrition: result of PNSI study

Background

Disease-related malnutrition is associated with adverse outcomes such as increased rates of morbidity and mortality, prolonged hospital stay, and extra costs of health care. This study was conducted to assess nutritional status among patients and to determine the risk factors for malnutrition in Iran university f.

Methods

Persian Nutritional Survey In Hospitals (PNSI) was a cross-sectional study that conducted in 20 university hospitals across Iran. All the patients with age range of 18 to 65 years, who were admitted or discharged, were assessed by subjective global assessment (SGA).

Results

In total, 2109 patients were evaluated for malnutrition. Mean values of age and body mass index were 44.68 ± 14.65 years and 25.44 ± 6.25 kg/m², respectively. Malnutrition (SGA-B & C) was identified in 23.92% of the patients, 26.23 and 21% of whom were among the admitted and discharged patients, respectively. The highest prevalence of malnutrition was in burns (77.70%) and heart surgery (57.84%) patients. Multivariate analysis presented male gender (OR = 1.02, P < 0.00), malignant disease (OR = 1.40, P < 0.00), length of hospital stay (OR = 1.20, P < 0.00), and polypharmacy (OR = 1.06, P < 0.00) as independent risk factors for malnutrition. Malnutrition was not associated with age (P = 0.10).

Conclusion

This study provides an overall and comprehensive illustration of hospital malnutrition in Iran university hospitals, finding that one out of four patients were malnourished; thus, appropriate consideration and measures should be taken to this issue.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-021-00741-1.

Probiotic Supplementation and Micronutrient Status in Healthy Subjects: A Systematic Review of Clinical Trials

Micronutrient deficiencies are a worldwide public health concern. Emerging evidence supports the ability of probiotics to enhance micronutrient status, which could aid in the prevention of non-communicable disease-associated malnutrition. This systematic review evaluated evidence of the efficacy of probiotic supplementation to improve micronutrient status in healthy subjects. The authors searched for published English language peer-reviewed journal articles in PubMed, Scopus, Embase, and Google Scholar databases from inception to July 2020 using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The quality of eligible studies was assessed using the Revised Cochrane Risk-of-Bias tool (RoB)2 and Risk of Bias in Non-Randomized Studies of Interventions tool (ROBINS-I tool). Fourteen original studies out of 2790 met the inclusion criteria. The results indicated that, despite varying degrees of efficacy, the intake of certain probiotics in healthy subjects was associated with a positive impact on the status of certain micronutrients (vitamin B12, calcium, folate, iron and zinc). A limitation was that studies were widely heterogeneous in terms of participant age, probiotic strain, species, dosage, intervention duration, and form of administration. Additional clinical trials are warranted to determine the most effective strains of probiotics, doses and durations of interventions.

Effects of curcuminoids on inflammatory and oxidative stress biomarkers and clinical outcomes in critically ill patients: A randomized double-blind placebo-controlled trial

Experimental studies have suggested the beneficial effects of curcuminoids as natural polyphenols against traumatic brain injury (TBI). The aim of this study was to investigate the effects of supplementation with curcuminoids on inflammatory and oxidative stress biomarkers, clinical outcomes and nutritional status in critically ill patients with TBI. A total of 62 ICU-admitted adult patients with TBI were randomly allocated to receive either a daily dose of 500 mg curcuminoids or matched placebo via enteral nutrition for 7 consecutive days based on stratified block randomization by age and sex. Inflammatory and oxidative stress as well as clinical outcomes and nutritional status of the patients were measured at baseline and at the end of the study. There were no overall group effects regarding to all dependent variables. Compared with baseline, serum levels of IL-6, TNF-α, MCP-1 and CRP were significantly reduced in patients receiving curcuminoids (p < .05) without any significant changes in placebo group; however, changes in the activities of GPx and SOD in serum were not significant between two groups. Moreover, APACHEII and NUTRIC score were significantly improved following curcuminoids consumption in comparison with placebo (p < .05). The findings of this study suggest that short-term supplementation with curcuminoids may have beneficial effects on inflammation, clinical outcomes and nutritional status of critically ill patients with TBI.

Assessment of nutritional status in maintenance hemodialysis patients: A multicenter cross-sectional study in Iran

INTRODUCTION

Protein-energy wasting (PEW) is common in hemodialysis patients and is linked with a high rate of morbidity and mortality. Regarding importance of nutrition in these patients, a recent study was administered to evaluate the nutritional status of hemodialysis patients.

MATERIALS

In this cross-sectional study 540 HD patients from 15 dialysis centers were evaluated. The nutritional status of the patients was determined by Subjective Global Assessment (SGA), Dialysis Malnutrition Score (DMS), and Malnutrition Inflammation Score (MIS). Their dietary intakes were assessed using a Food Frequency Questionnaire (FFQ).

RESULT

Based on DMS, 66.7% of HD patients were well nourished and the prevalence of mild-to-moderate and severe PEW were 32.4% and 0.9% in HD patients, respectively. Based on MIS, 65.2% of HD patients were well nourished and the prevalence of mild-to-moderate and severe PEW was 34.0%. The prevalence of mild-to-moderate and severe malnutrition based on SGA was 35.0% and 1.1%, respectively. Energy and protein intake in 85.6% and 80.6% of patients respectively were less than the minimum recommended amount.

CONCLUSION

HD patients are at risk of malnutrition and in this regard training the patient, periodic assessment of nutritional status, and referring them to a dietitian seems necessary.

Effects of L-citrulline supplementation on blood pressure: A systematic review and meta-analysis

OBJECTIVE

We aimed to conduct a systematic review and meta-analysis of clinical trials that examined the effects of L-citrulline supplementation on blood pressure (BP).

MATERIALS AND METHODS

We searched MEDLINE, SCOPUS, PUBMED and Google scholar databases from inception to November 16, 2017 and 811 papers were identified, of which 8 trials with 10 data sets met the inclusion criteria. Inclusion criteria were: (1) application of randomized clinical trial with either crossover or parallel designs; (2) studies conducted in adults (≥18 y); (3) oral supplementation with L-citrulline compared to control group; (4) expression of sufficient data about systolic and diastolic BP at baseline and at the end of the study in each group. BP effects were pooled by random-effects models, with trials weighted by inverse variance.

RESULTS

The included studies' sample size ranged between 12 and 34 subjects. The mean age of the participants in these trials ranged between 22 and 71 years. Dosage of L-citrulline supplementation varied from 3 to 9 g/day. Duration of the intervention ranged between 1 and 17 weeks. The pooled changes in systolic and diastolic BP were (MD, -4.10 mm Hg; 95% CI [-7.94, -0.26]; p=0.037) and (MD -2.08 mm Hg; 95% CI [-4.32, 0.16]; P=0.069), respectively. The subgroup analysis showed a significant diastolic BP reduction in studies that used doses of ≥6 g/day (MD -2.75 mm Hg; 95% CI [-5.37, -0.12]; p=0.04).

CONCLUSION

Our results suggest that L-citrulline supplementation may reduce systolic BP. A significant reduction in diastolic BP was observed only in the studies that used doses ≥ 6 g/day.