Effects of dietary nitrate on inflammation and immune function, and implications for cardiovascular health

Beet supplementation mitigates post-exercise inflammation

Objectives

This study investigated the efficacy of a mixed beet-based supplement (BEET) versus placebo (PL) in countering inflammation during recovery from 2.25 h of intensive cycling in 20 male and female cyclists. A multi-omics approach was used that included untargeted proteomics and a targeted oxylipin panel.

Methods

A randomized, placebo-controlled, double-blind, crossover design was used with two 2-week supplementation periods and a 2-week washout period. Supplementation periods were followed by a 2.25 h cycling bout at close to 70%VO2max. The BEET supplement provided 212 mg of nitrates per day, 200 mg caffeine from green tea extract, 44 mg vitamin C from Camu Camu berry, B-vitamins from quinoa sprouts (40% Daily Value for thiamin, riboflavin, niacin, and vitamin B6), and 2.5 g of a mushroom blend containing Cordyceps sinensis and Inonotus obliquus. Six blood samples were collected before and after supplementation (overnight fasted state), immediately post-exercise, and at 1.5 h-, 3 h-, and 24 h-post-exercise.

Results

The 2.25 h cycling bout increased plasma levels of 41 of 67 oxylipins detected. BEET supplementation significantly increased plasma nitrate (NO3 -) and nitrite (NO2 -) (sum, NO3 - + NO2 -) concentrations (interaction effect, p < 0.001) and two anti-inflammatory oxylipins [18-hydroxyeicosapentaenoic acid (18-HEPE) and 4-hydroxy-docosahexanoic acid (4-HDoHE)]. The untargeted proteomics analysis identified 616 proteins (458 across all times points), and 2-way ANOVA revealed a cluster of 45 proteins that were decreased and a cluster of 21 that were increased in the BEET versus PL trials. Functional enrichment supported significant BEET-related reductions in inflammation-related proteins including several proteins related to complement activation, the acute phase response, and immune cell adhesion, migration, and differentiation.

Discussion

Intake of a BEET-based supplement during a 2-week period was linked to higher plasma levels of NO3 - + NO2 -, elevated post-exercise levels of two anti-inflammatory oxylipins, and a significant decrease in a cluster of proteins involved in complement activation and inflammation. These data support that 2-weeks intake of nitrate from a mixed beet-based supplement moderated protein biomarkers of exercise-induced inflammation in athletes.

Increased nitrate intake from beetroot juice over 4 weeks affects nitrate metabolism, but not vascular function or blood pressure in older adults with hypertension

The decline in vascular function and increase in blood pressure with aging contribute to an increased cardiovascular disease risk. In this randomized placebo-controlled crossover study, we evaluated whether previously reported cardiovascular benefits of plant-derived inorganic nitrate via nitric oxide (NO) translate into improved vascular function and blood pressure-lowering in 15 men and women (age range: 56-71 years) with treated hypertension. We investigated the effects of a single ∼400 mg-dose at 3 hours post-ingestion (3H POST) and the daily consumption of 2 × ∼400 mg of nitrate through nitrate-rich compared with nitrate-depleted (placebo) beetroot juice over 4 weeks (4WK POST). Measurements included nitrate and nitrite in plasma and saliva; endothelial-dependent and -independent forearm blood flow (FBF) responses to acetylcholine (FBFACh) and glyceryltrinitrate (FBFGTN); and clinic-, home- and 24-hour ambulatory blood pressure. Compared to placebo, plasma and salivary nitrate and nitrite increased at 3H and 4WK POST following nitrate treatment (P < 0.01), suggesting a functioning nitrate-nitrite-NO pathway in the participants of this study. There were no differences between treatments in FBFACh and FBFGTN-area under the curve (AUC) ratios [AUC ratios after (3H POST, 4WK POST) compared with before (PRE) the intervention], or 24-hour ambulatory blood pressure or home blood pressure measures (P > 0.05). These findings do not support the hypothesis that an increased intake of dietary nitrate exerts sustained beneficial effects on FBF or blood pressure in hypertensive older adults, providing important information on the efficacy of nitrate-based interventions for healthy vascular aging. This study was registered under ClinicialTrials.gov (NCT04584372).

Impact of Dietary Nitrate on the Recovery of Therapy-related Vascular Health Impairments Following Standard Periodontal Aftercare Therapy: a Hypothesis-generating Subanalysis

This follow-up study assessed the impact of a nitrate-rich diet on salivary nitrate/nitrite levels and the recovery of therapy-induced vascular impairments in a cohort of 39 periodontitis patients treated by standard subgingival mechanical plaque removal (PMPR). At baseline, saliva samples for nitrate/nitrite analysis were collected, and peripheral/central blood and augmentation pressure was documented using the Arteriograph recording system. Immediately after, PMPR vascular parameters were reassessed. All study patients received a randomly allocated supply of a lettuce beverage to be consumed for 14 days, containing either a daily dosage of 200 mg nitrate (test group, n = 20) or being void of nitrate (placebo group, n = 19). At day 14, salivary and vascular parameters were reassessed. Initial salivary and vascular parameters did not differ significantly between the groups. PMPR impaired all vascular parameters in both groups with no differences between the groups. At day 14, salivary nitrate/nitrite levels of the test group were significantly elevated compared to baseline. All vascular parameters had significantly recovered from the impairment inflicted by PMPR. In the placebo group, by contrast, salivary parameters did not differ significantly from baseline, and the recovery of impaired vascular parameters was restricted to a significant improvement of diastolic blood pressure. Correlation analysis identified a significant inverse correlation between salivary nitrate/nitrite sum and central/peripheral blood pressure and augmentation pressure. In conclusion, the data of this subanalysis suggest that increasing salivary nitrate/nitrite levels by a diet rich in nitrate may improve recovery of therapy-induced vascular impairments after PMPR.

Altered Gastric Microbiota and Inflammatory Cytokine Responses in Patients with Helicobacter pylori-Negative Gastric Cancer

The role of the gastric mucosal microbiome in Helicobacter pylori-negative gastric cancer (GC) remains unclear. Therefore, we aimed to characterize the microbial alterations and host inflammatory cytokine responses in H. pylori-negative GC. Gastric mucosal samples were obtained from 137 H. pylori-negative patients with GC (n = 45) and controls (chronic gastritis or intestinal metaplasia, n = 92). We performed 16S rRNA gene sequencing (n = 67), a quantitative reverse transcription-polymerase chain reaction to determine the relative mRNA expression levels of TNF (tumor necrosis factor), IL1B (interleukin 1 beta), IL6 (interleukin 6), CXCL8 (C-X-C motif chemokine ligand 8), IL10 (interleukin 10), IL17A (interleukin 17A), TGFB1 (transforming growth factor beta 1) (n = 113), and the correlation analysis between sequencing and expression data (n = 47). Gastric mucosal microbiota in patients with GC showed reduced diversity and a significantly different composition compared to that of the controls. Lacticaseibacillus was significantly enriched, while Haemophilus and Campylobacter were depleted in the cancer group compared to the control group. These taxa could distinguish the two groups in a random forest algorithm. Moreover, the combined relative abundance of these taxa, a GC microbiome index, significantly correlated with gastric mucosal IL1B expression, which was elevated in the cancer group. Overall, altered gastric mucosal microbiota was found to be associated with increased mucosal IL1B expression in H. pylori-negative GC.

Red, white, and processed meat consumption related to inflammatory and metabolic biomarkers among overweight and obese women

BACKGROUND

Considering that a high meat intake is directly associated with obesity, it is critical to address the relationship between consuming different types of meat with inflammation and metabolism in overweight and obese cohorts. Thus, we evaluated the association between red, white, and processed meat consumption with inflammatory and metabolic biomarkers in overweight and obese women.

METHODS

The current cross-sectional study was conducted on 391 overweight and obese Iranian women. Dietary intake was obtained from a food frequency questionnaire (FFQ) with 147 items. The anthropometric measurements, serum lipid profile, and inflammatory markers were measured by standard protocols. All associations were assessed utilizing one-way analysis of variance (ANOVA), analysis of covariance (ANCOVA), and linear regression models.

RESULTS

In the adjusted model, it was established that higher intake of processed meat had a significant positive association with leptin levels (β: 0.900, 95% CI: 0.031;1.233, p = 0.015). Moreover, after considering the confounders, a significant positive association between processed meat and macrophage inflammatory protein (MCP-1) levels was observed (β: 0.304, 95% CI:0.100;1.596, p = 0.025). Positive significant associations between high-sensitivity C-reactive protein (hs-CRP) (β:0.020, 95% CI:0.000;0.050, P = 0.014) and plasminogen activator inhibitor 1 (PAI-1) (β:0.263, 95% CI:0.112;0.345, p = 0.053) and MCP-1 (β:0.490, 95% CI: 0.175;1.464, p = 0.071) levels with red meat were also shown; while there was a significant negative association between red meat and the homeostasis model assessment of insulin resistance (HOMA-IR) (β: -0.016, 95% CI: -0.022, -0.001, p = 0.033). Furthermore, a significant negative association were established following confounding adjustment between Galectin-3 (Gal-3) (β: -0.110, 95% CI: -0.271;0.000, p = 0.044), MCP-1 (β: -1.933, 95% CI: -3.721;0.192, p = 0.022) and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) (β: -0.011, 95% CI: -0.020,0.000, p = 0.070) levels with high adherence of white meat intake. In contrast, a significant marginally positive association between PAI-1 levels and high adherence to white meat intake (β: -0.340, 95% CI: -0.751;0.050, p = 0.070) has been shown.

CONCLUSIONS

Higher red and processed meat consumption were positively associated with inflammatory and metabolic markers in overweight and obese women. In contrast, negative relationships between high adherence to white meat and various inflammatory and metabolic parameters were established. Further studies are needed to confirm the causality of these associations and potential mediating pathways.

Utility of NO and H2S donating platforms in managing COVID-19: Rationale and promise

Viral infections are a continuing global burden on the human population, underscored by the ramifications of the COVID-19 pandemic. Current treatment options and supportive therapies for many viral infections are relatively limited, indicating a need for alternative therapeutic approaches. Virus-induced damage occurs through direct infection of host cells and inflammation-related changes. Severe cases of certain viral infections, including COVID-19, can lead to a hyperinflammatory response termed cytokine storm, resulting in extensive endothelial damage, thrombosis, respiratory failure, and death. Therapies targeting these complications are crucial in addition to antiviral therapies. Nitric oxide and hydrogen sulfide are two endogenous gasotransmitters that have emerged as key signaling molecules with a broad range of antiviral actions in addition to having anti-inflammatory properties and protective functions in the vasculature and respiratory system. The enhancement of endogenous nitric oxide and hydrogen sulfide levels thus holds promise for managing both early-stage and later-stage viral infections, including SARS-CoV-2. Using SARS-CoV-2 as a model for similar viral infections, here we explore the current evidence regarding nitric oxide and hydrogen sulfide's use to limit viral infection, resolve inflammation, and reduce vascular and pulmonary damage.

Impact of a Specific Collagen Peptide Food Supplement on Periodontal Inflammation in Aftercare Patients-A Randomised Controlled Trial

Background: This controlled clinical trial evaluated the impact of a specific collagen peptide food supplement on parameters of periodontal inflammation in aftercare patients. Methods: A total of 39 study patients were enrolled. At baseline, bleeding on probing (BoP; primary outcome), gingival index (GI), plaque control record (PCR), recession (REC) and probing pocket depth (PPD) for the calculation of the periodontal inflamed surface area (PISA) were documented. After subsequent professional mechanical plaque removal (PMPR), participants were randomly provided with a supply of sachets containing either a specific collagen peptide preparation (test group; n = 20) or a placebo (placebo group; n = 19) to be consumed dissolved in liquid once daily until reevaluation at day 90. Results: PMPR supplemented with the consumption of the specific collagen peptides resulted in a significantly lower mean percentage of persisting BoP-positive sites than PMPR plus placebo (test: 10.4% baseline vs. 3.0% reevaluation; placebo: 14.2% baseline vs. 9.4% reevaluation; effect size: 0.86). Mean PISA and GI values were also reduced compared to baseline, with a significant difference in favor of the test group (PISA test: 170.6 mm2 baseline vs. 53.7 mm2 reevaluation; PISA placebo: 229.4 mm2 baseline vs. 184.3 mm2 reevaluation; GI test: 0.5 baseline vs. 0.1 reevaluation; GI placebo: 0.4 baseline vs. 0.3 reevaluation). PCR was also significantly decreased in both experimental groups at revaluation, but the difference between the groups did not reach the level of significance. Conclusions: The supplementary intake of specific collagen peptides may further enhance the anti-inflammatory effect of PMPR in periodontal recall patients.

Nitrate Metabolism and Ischemic Cerebrovascular Disease: A Narrative Review

Inorganic and organic nitrates are present in vivo and in vitro. Inorganic nitrate is considered a pool of nitric oxide (NO), but it can be converted into nitrite and NO through various mechanisms. It plays an important role in the regulation of complex physiological and biochemical reactions, such as anti-inflammatory processes and the inhibition of platelet aggregation, which are closely related to the pathology and treatment of cerebrovascular disease. Ischemic cerebrovascular disease is characterized by high incidence, recurrence, and disability rates. Nitrate, nitrite, and NO were recently found to be involved in cerebrovascular disease. In this review, we describe the relationship between cerebrovascular disease and nitrate metabolism to provide a basis for further advances in laboratory and clinical medicine.

Effects of chronic dietary nitrate supplementation on longevity, vascular function and cancer incidence in rats

RATIONALE

Dietary nitrate and nitrite have a notoriously bad reputation because of their proposed association with disease, in particular cancer. However, more recent lines of research have challenged this dogma suggesting that intake of these anions also possess beneficial effects after in vivo conversion to the vital signaling molecule nitric oxide. Such effects include improvement in cardiovascular, renal and metabolic function, which is partly mediated via reduction of oxidative stress. A recent study even indicates that low dose of dietary nitrite extends life span in fruit flies.

METHODS

In this study, 200 middle-aged Wistar rats of both sexes were supplemented with nitrate or placebo in the drinking water throughout their remaining life and we studied longevity, biochemical markers of disease, vascular reactivity along with careful determination of the cause of death.

RESULTS

Dietary nitrate did not affect life span or the age-dependent changes in markers of oxidative stress, kidney and liver function, or lipid profile. Ex vivo examination of vascular function, however, showed improvements in endothelial function in rats treated with nitrate. Neoplasms were not more common in the nitrate group.

CONCLUSION

We conclude that chronic treatment with dietary nitrate does not affect life span in rats nor does it increase the incidence of cancer. In contrast, vascular function was improved by nitrate, possibly suggesting an increase in health span.

Nitric oxide for the prevention and treatment of viral, bacterial, protozoal and fungal infections

Although the antimicrobial potential of nitric oxide (NO) is widely published, it is little used clinically. NO is a key signalling molecule modulating vascular, neuronal, inflammatory and immune responses. Endogenous antimicrobial activity is largely mediated by high local NO concentrations produced by cellular inducible nitric oxide synthase, and by derivative reactive nitrogen oxide species including peroxynitrite and S-nitrosothiols. NO may be taken as dietary substrate (inorganic nitrate, L-arginine), and therapeutically as gaseous NO, and transdermal, sublingual, oral, intranasal and intravenous nitrite or nitrate. Numerous preclinical studies have demonstrated that NO has generic static and cidal activities against viruses (including β-coronaviruses such as SARS-CoV-2), bacteria, protozoa and fungi/yeasts  in vitro. Therapeutic effects have been seen in animal models  in vivo, and phase II trials have demonstrated that NO donors can reduce microbial infection. Nevertheless, excess NO, as occurs in septic shock, is associated with increased morbidity and mortality. In view of the dose-dependent positive and negative effects of NO, safety and efficacy trials of NO and its donors are needed for assessing their role in the prevention and treatment of infections. Trials should test dietary inorganic nitrate for pre- or post-exposure prophylaxis and gaseous NO or oral, topical or intravenous nitrite and nitrate for treatment of mild-to-severe infections, including due to SARS-CoV-2 (COVID-19). This review summarises the evidence base from  in vitro, in vivo and early phase clinical studies of NO activity in viral, bacterial, protozoal and fungal infections.

Effects of chlorhexidine mouthwash on the oral microbiome

INTRODUCTION/OBJECTIVES

Chlorhexidine (CHX) is a commonly used mouthwash with potent anti-microbial effects useful for the management of oral disease. However, we are moving away from the view of simply 'killing' bacteria, towards managing oral microbial ecosystems (oral microbiome), as an integrated system, to promote oral and systemic health. Here, we aimed to review the effects of CHX mouthwash on the balance of microbial communities in the mouth in vivo in oral health and disease.

SOURCES AND STUDY SECTION

The hierarchy of evidence was applied, with systematic reviews and randomised controlled trials consulted where available and case controlled studies being described thereafter. Search terms for each subject category were entered into MEDLINE, PubMed, Google Scholar and the Cochrane database. Focussing on metagenomics studies provides unique overview of the oral microbiome as an integrated system.

DATA

Evidence was limited, but several next generation sequencing case-controlled studies suggested that in an integrated system, CHX may cause a shift towards lower bacterial diversity and abundance, in particular nitrate-reducing bacteria in vivo. CHX also appeared to alter salivary pH, lactate, nitrate and nitrite concentrations in saliva. Evidence regarding the effects of CHX on the oral microbiome during oral disease is still emerging.

CONCLUSIONS

CHX alters the composition the oral microbiome. However, as CHX use remains widespread in dentistry to manage oral disease, urgent research using metagenomics studies of microbial communities in vivo are still needed to determine CHX mouthwash is 'good', 'bad' or otherwise for bacteria, in the context of oral and systemic health.

Nitric oxide for the prevention and treatment of viral, bacterial, protozoal and fungal infections

Although the antimicrobial potential of nitric oxide (NO) is widely published, it is little used clinically. NO is a key signalling molecule modulating vascular, neuronal, inflammatory and immune responses. Endogenous antimicrobial activity is largely mediated by high local NO concentrations produced by cellular inducible nitric oxide synthase, and by derivative reactive nitrogen oxide species including peroxynitrite and S-nitrosothiols. NO may be taken as dietary substrate (inorganic nitrate, L-arginine), and therapeutically as gaseous NO, and transdermal, sublingual, oral, intranasal and intravenous nitrite or nitrate. Numerous preclinical studies have demonstrated that NO has generic static and cidal activities against viruses (including β-coronaviruses such as SARS-CoV-2), bacteria, protozoa and fungi/yeasts  in vitro. Therapeutic effects have been seen in animal models  in vivo, and phase II trials have demonstrated that NO donors can reduce microbial infection. Nevertheless, excess NO, as occurs in septic shock, is associated with increased morbidity and mortality. In view of the dose-dependent positive and negative effects of NO, safety and efficacy trials of NO and its donors are needed for assessing their role in the prevention and treatment of infections. Trials should test dietary inorganic nitrate for pre- or post-exposure prophylaxis and gaseous NO or oral, topical or intravenous nitrite and nitrate for treatment of mild-to-severe infections, including due to SARS-CoV-2 (COVID-19). This review summarises the evidence base from  in vitro, in vivo and early phase clinical studies of NO activity in viral, bacterial, protozoal and fungal infections.

The Effect of Nitrate-Rich Beetroot Juice on Markers of Exercise-Induced Muscle Damage: A Systematic Review and Meta-Analysis of Human Intervention Trials

This systematic review and meta-analysis of randomized controlled trials examined whether dietary nitrate supplementation attenuates exercise-induced muscle damage (EIMD) and is reported according to the PRISMA guidelines. Medline and SPORTDiscus databases were searched from inception to June 2020. Inclusion criteria were studies in adult humans consuming inorganic nitrate before and after exercise and that measured markers implicated in the etiology of EIMD (muscle function, muscle soreness, inflammation, myocellular protein efflux, oxidative stress, range of motion) <168 h post. The Cochrane Collaboration risk of bias two tool was used to critically appraise the studies; forest plots were generated with random-effects models and standardized mean differences (SMD). Nine studies were included in the systematic review and six in the meta-analysis. All studies were rated to have some concerns for risk of bias. All trials in the meta-analysis provided nitrate as beetroot juice, which accelerated isometric strength recovery 72 h post-exercise (SMD: 0.54, p = 0.01) and countermovement jump performance 24-72 h post-exercise (SMD range: 0.75-1.32, p < 0.03). Pressure pain threshold was greater with beetroot juice 48 (SMD: 0.58, p = 0.03) and 72 h post-exercise (SMD: 0.61, p = 0.02). Beetroot juice had no effect on markers of oxidative stress and creatine kinase (p > 0.05), but c-reactive protein was higher vs. placebo at 48 h post-exercise (SMD: 0.55, p = 0.03). These findings suggest that nitrate-rich beetroot juice may attenuate some markers of EIMD, but more large-scale controlled trials in elite athletes are needed.

Dietary Sodium Nitrate Activates Antioxidant and Mitochondrial Dynamics Genes after Moderate Intensity Acute Exercise in Metabolic Syndrome Patients

Exercise can induce a pro-inflammatory response in aged subjects with metabolic disorders and nitrate supplementation has shown anti-inflammatory effects. We evaluated the influence of dietary nitrate on the response of the antioxidant and mitochondrial dynamics genes to acute exercise in peripheral blood mononuclear cells (PBMCs), as well as the antioxidant and the inflammatory response of PBMCs against immune stimulation. Metabolic syndrome patients participated in a crossover study in which they consumed a beverage containing 16 mM sodium nitrate or a placebo with the same composition without nitrate before performing a submaximal test at 60–70% of their maximal heart rate for 30 min. The intake of nitrate increased the nitrate plus nitrite plasma levels about 8-fold and induced the upregulation of catalase, superoxide dismutase, glutathione peroxidase, mitofusin 2 and PGC1α in PBMCs after exercise. The gene expression of catalase and TNFα was enhanced by phorbol myristate acetate (PMA) only in the placebo group, while the glutathione peroxidase expression was enhanced by PMA only after nitrate intake. The intake of nitrate by metabolic syndrome patients induces an antioxidant and mitochondrial response to exercise at the same time that it attenuates the pro-inflammatory response to immune stimulation.

Association of habitual intake of fruits and vegetables with depressive symptoms: the AusDiab study

PURPOSE

To investigate the relationship of habitual FV intake, different types of FV, and vegetable diversity with depressive symptoms.

METHODS

Australian men and women (n = 4105) aged > 25 years from the Australian Diabetes, Obesity and Lifestyle Study were included. Dietary intake was assessed using a Food Frequency Questionnaire at baseline, 5 and 12 years. Depressive symptoms were assessed using the validated 10-item Centre for Epidemiology Studies Short Depression Scale at 12 years. Multiple logistic regression models were used to investigate the association between the exposures of interest and depressive symptoms using odds ratios (OR) and 95% confidence intervals (CI) across quartiles of FV intake and vegetable diversity. Analyses were multivariable-adjusted for confounding factors.

RESULTS

At 12 years, 425 (10.4%) participants had "any depressive symptoms". Habitual FV intake was inversely associated with depressive symptoms at 12 years. After adjustment, participants in quartile 2 of FV intake (Q2; median 317 g/day) had a 20% lower odds of having any depressive symptoms (OR [95% CI] 0.80 [0.69, 0.95]) in comparison to those in the lowest quartile of FV intake (Q1; median 223 g/day). Yellow/orange/red and leafy green vegetables were the key vegetable types driving this association. Higher vegetable diversity (4-6 different vegetables/day) was associated with a 24-42% lower odds of having depressive symptoms when compared to < 3 different vegetables/day. The associations remained similar after further adjusting for diet quality.

CONCLUSION

A FV-rich diet, consisting of a diverse range of vegetables, particularly yellow/orange/red and leafy green vegetables may help to lower depressive symptoms. Promoting such a diet, particularly in men and women with a low FV intake, may have a significant public health impact.

Nitrate-rich diet alters the composition of the oral microbiota in periodontal recall patients

BACKGROUND

This follow-up study evaluated microbiome changes in periodontal recall patients after consuming a nitrate-rich diet that led to a marked decrease of gingival inflammation.

METHODS

Subgingival microbial samples of 37 patients suffering from gingival inflammation with reduced periodontium were taken before professional mechanical plaque removal (baseline) and subsequently after 2 weeks of regularly consuming a lettuce juice beverage (day 14) containing a daily dosage of 200 mg of nitrate (test group, n = 18) or being void of nitrate (placebo group, n = 19). Three hundred base pairs paired-end sequencing of the V3-V4 hypervariable region of the 16S rDNA was performed.

RESULTS

At baseline, there were no significant differences about the bacterial diversity parameters between the groups (Mann-Whitney U test). After intervention in the test group, Rothia and Neisseria, including species reducing nitrate, increased significantly (negative binomial regression model). Alpha diversity decreased significantly from 115.69 ± 24.30 to 96.42 ± 24.82 aRSVs/sample (P = 0.04, Wilcoxon signed-rank test), accompanied by a significant change in beta diversity (P < 0.001, PERMANOVA). In the control group, however, no genus changed significantly, and alpha-, as well as beta-diversity did not change significantly.

CONCLUSIONS

The decrease of gingival inflammation in periodontal recall patients induced by a nitrate-rich diet is accompanied by significant compositional changes within the subgingival microbiome.

High intake of vegetables is linked to lower white blood cell profile and the effect is mediated by the gut microbiome

BACKGROUND

Chronic inflammation, which can be modulated by diet, is linked to high white blood cell counts and correlates with higher cardiometabolic risk and risk of more severe infections, as in the case of COVID-19.

METHODS

Here, we assessed the association between white blood cell profile (lymphocytes, basophils, eosinophils, neutrophils, monocytes and total white blood cells) as markers of chronic inflammation, habitual diet and gut microbiome composition (determined by sequencing of the 16S RNA) in 986 healthy individuals from the PREDICT-1 nutritional intervention study. We then investigated whether the gut microbiome mediates part of the benefits of vegetable intake on lymphocyte counts.

RESULTS

Higher levels of white blood cells, lymphocytes and basophils were all significantly correlated with lower habitual intake of vegetables, with vegetable intake explaining between 3.59 and 6.58% of variation in white blood cells after adjusting for covariates and multiple testing using false discovery rate (q < 0.1). No such association was seen with fruit intake. A mediation analysis found that 20.00% of the effect of vegetable intake on lymphocyte counts was mediated by one bacterial genus, Collinsella, known to increase with the intake of processed foods and previously associated with fatty liver disease. We further correlated white blood cells to other inflammatory markers including IL6 and GlycA, fasting and post-prandial glucose levels and found a significant relationship between inflammation and diet.

CONCLUSION

A habitual diet high in vegetables, but not fruits, is linked to a lower inflammatory profile for white blood cells, and a fifth of the effect is mediated by the genus Collinsella.

TRIAL REGISTRATION

The ClinicalTrials.gov registration identifier is NCT03479866 .

Strategies to Improve Meat Products' Quality

Meat products represent an important component of the human diet, their consumption registering a global increase over the last few years. These foodstuffs constitute a good source of energy and some nutrients, such as essential amino acids, high biological value proteins, minerals like iron, zinc, selenium, manganese and B-complex vitamins, especially vitamin B12. On the other hand, nutritionists have associated high consumption of processed meat with an increased risk of several diseases. Researchers and processed meat producers are involved in finding methods to eliminate nutritional deficiencies and potentially toxic compounds, to obtain healthier products and at the same time with no affecting the sensorial quality and safety of the meat products. The present review aims to summarize the newest trends regarding the most important methods that can be applied to obtain high-quality products. Nutritional enrichment with natural bioactive plant compounds (antioxidants, dietary fibers) or probiotics, reduction of harmful components (salt, nitrate/nitrite, N-nitrosamines) and the use of alternative technologies (high-pressure processing, cold plasma, ultrasounds) are the most used current strategies to accomplish this aim.

Dietary nitrite extends lifespan and prevents age-related locomotor decline in the fruit fly

Aging is associated with decreased nitric oxide (NO) bioavailability and signalling. Boosting of a dietary nitrate-nitrite-NO pathway e.g. by ingestion of leafy green vegetables, improves cardiometabolic function, mitochondrial efficiency and reduces oxidative stress in humans and rodents, making dietary nitrate and nitrite an appealing intervention to address age-related disorders. On the other hand, these anions have long been implicated in detrimental health effects of our diet, particularly in formation of carcinogenic nitrosamines. The aim of this study was to assess whether inorganic nitrite affects lifespan in Drosophila melanogaster and investigate possible mechanisms underlying any such effect. In a survival assay, female flies fed a nitrite supplemented diet showed lifespan extension by 9 and 15% with 0.1 and 1 μM nitrite respectively, with no impact of nitrite on reproductive output. Interestingly, nitrite could also protect female flies from age-dependent locomotor decline, indicating a protective effect on healthspan. NO generation from nitrite involved Drosophila commensal bacteria and was indicated by a fluorescent probe as well as direct measurements of NO gas formation with chemiluminescence. Nutrient sensing pathways such as TOR and sirtuins, have been strongly implicated in lifespan extension. In aged flies, nitrite supplementation significantly downregulated dTOR and upregulated dSir2 gene expression. Total triglycerides and glucose were decreased, a described downstream effect of both TOR and sirtuin pathways. In conclusion, we demonstrate that very low doses of dietary nitrite extend lifespan and favour healthspan in female flies. We propose modulation of nutrient sensing pathways as driving mechanisms for such effects.

Chemistry, safety, and regulatory considerations in the use of nitrite and nitrate from natural origin in meat products - Invited review

Nitrite and nitrate have been traditionally used for the preservation of meat products because of the effective antimicrobial action of nitrite against Clostridium botulinum, the outgrowth of its spores as well as other bacteria. However, the use of nitrite and nitrate has been questioned in last half century due to the possible generation of N-nitrosamines through reaction of nitrite with secondary amines. Nitrite replacement strategies began in the 70s addressing these issues and instigated searches for natural alternatives to nitrate and nitrite, or for natural sources of nitrite and nitrate such as vegetable extracts. These alternatives have been considered by producers and consumers as an attractive practice even though they may also have some risks. This manuscript reviews and discusses the chemistry, safety, and regulatory considerations in the use of nitrite and nitrate from natural origin for the preservation of meat products.

Ion-exchange polymers modified bacterial cellulose electrodes for the selective removal of nitrite ions from tail water of dyeing wastewater

Ion-exchange polymer and modified carbonization bacterial cellulose (CBC) electrodes were fabricated using varying amounts of cation-exchange polymers (glutaric acid (GA) and sulfosuccinic acid (SSA)) and assembled within an asymmetric capacitive deionization unit (p-CDI). The performance of selective NO₂^- electro-adsorption was studied. The AC/CBC-SSA group showed a better salt adsorption capacity (14.56 mg/g) and nitrite removal efficiency (71.01%) than the AC/CBC-GA (10.72 mg/g, 47.83%) and AC/AC (4.81 mg/g, 12.74%) groups. It was confirmed that the CBC-SSA/GA electrodes enhanced nitrite selectivity and increased the adsorption capacity, and the total amounts of adsorbed anions increased when the applied voltage was increased from 0.8 to 1.2 V, while the molar fraction of nitrate decreased. The competitive and preferential adsorption of anions was further investigated using different binary solutions of anions and occurred in the following sequence: NO₂^- >SO₄^2- >NO₃^- >F^-≈ Cl^-. Furthermore, the p-CDI units were applied to remove nitrite in real wastewater samples, and the results showed that they had excellent reusability and application for use in dyeing wastewater treatment.

"Removal of nitrate and nitrite by hemodialysis in end-stage renal disease and by sustained low-efficiency dialysis in acute kidney injury"

BACKGROUND & PURPOSE

It is well established that end-stage renal disease (ESRD) is associated with increased cardiovascular morbidity and mortality both in the adult and pediatric population. Although the underlying molecular mechanisms are poorly understood, compromised nitric oxide (NO) bioactivity has been suggested as a contributing factor. With this in mind, we investigated the effects of hemodialysis on NO homeostasis and bioactivity in blood.

METHODS & RESULTS

Plasma and dialysate samples were obtained before and after hemodialysis sessions from adults (n = 33) and pediatric patients (n = 10) with ESRD on chronic renal replacement therapy, and from critically ill adults with acute kidney injury (n = 12) at their first sustained low-efficiency dialysis session. Levels of nitrate, nitrite, cyclic guanosine monophosphate (cGMP) and amino acids relevant for NO homeostasis were analyzed. We consistently found that nitrate and cGMP levels in plasma were significantly reduced after hemodialysis, whereas post-dialysis nitrite and amino acids coupled to NO synthase activity (i.e., arginine and citrulline) were only significantly reduced in adults with ESRD. The amount of excreted nitrate and nitrite during dialysis were similar to daily endogenous levels that would be expected from endothelial NO synthase activity.

CONCLUSIONS

Our results show that hemodialysis significantly reduces circulating levels of nitrate and cGMP, indicating that this medical procedure may impair NO synthesis and potentially NO signaling pathways.