Association of Dietary Fiber on Asthma, Respiratory Symptoms, and Inflammation in the Adult National Health and Nutrition Examination Survey Population

Association between diet-derived antioxidants and asthma: Insights from the NHANES survey 2003-2018 and Mendelian randomization analysis

BACKGROUND

Many studies have reported correlations between diet-derived antioxidants and asthma. Nevertheless, the probable association between diet-derived antioxidants and asthma remains a matter of discussion.

OBJECTIVES

We explored the association between Diet-Derived Antioxidants and Asthma.

METHODS

We used data from the 2003-2018 National Health and Nutrition Examination Survey (NHANES) to assess the relationship between diet-derived antioxidants and asthma and a two-sample Mendelian randomization (MR) study was employed to assess the causal associations between lifelong diet-derived circulating antioxidant levels and the risk of asthma.

RESULTS

Participants with asthma were more likely to be young-to-middle-aged females, smokers, have lower income, belong to non-Hispanic Black ethnicity, have a high school education, have a BMI over 30. The dietary intakes of vitamin C, zinc, selenium, and CDAI were negatively associated with asthma risk (Vitamin C: OR = 0.76, 95 % CI: 0.63-0.91, P = 0.032; Zinc: OR = 0.86, 95 % CI: 0.75-1.00, P = 0.046; Selenium: OR = 0.85, 95 % CI: 0.73-0.98, P = 0.004; CDAI: OR = 0.80, 95 % CI: 0.65-0.97, P = 0.027). There was a significant nonlinear relationship between the dietary intake of vitamin C, zinc, and selenium and the risk of asthma (Pnon-linear < 0.05). However, no causal link between circulating antioxidants and asthma risk was found in the MR analysis. Sensitivity analyses supported the robustness of the results.

CONCLUSION

In the observational study, we identified a negative correlation between the dietary intake of vitamin C, zinc, selenium, and CDAI and asthma risk, while our MR analyses did not find evidence to support a causal relationship between diet-derived antioxidants and the risk of asthma.

Respiratory diseases and gut microbiota: relevance, pathogenesis, and treatment

Preclinical evidence has firmly established a bidirectional interaction among the lung, gut, and gut microbiome. There are many complex communication pathways between the lung and intestine, which affect each other's balance. Some metabolites produced by intestinal microorganisms, intestinal immune cells, and immune factors enter lung tissue through blood circulation and participate in lung immune function. Altered gut-lung-microbiome interactions have been identified in rodent models and humans of several lung diseases such as pulmonary fibrosis, chronic obstructive pulmonary disease, lung cancer, asthma, etc. Emerging evidence suggests that microbial therapies can prevent and treat respiratory diseases, but it is unclear whether this association is a simple correlation with the pathological mechanisms of the disease or the result of causation. In this review, we summarize the complex and critical link between the gut microbiota and the lung, as well as the influence and mechanism of the gut microbiota on respiratory diseases, and discuss the role of interventions such as prebiotics and fecal bacteria transplantation on respiratory diseases. To provide a reference for the rational design of large-scale clinical studies, the direct application of microbial therapy to respiratory-related diseases can reduce the incidence and severity of diseases and accompanying complications.

Association between DASH diet and asthma symptoms among a large sample of adolescents: a cross-sectional study

BACKGROUND

The Dietary Approaches to Stop Hypertension (DASH) diet, which has a lot of emphasis on the consumption of fruits, vegetables, and whole grains, and on the other hand, the consumption of red meat and sodium is limited, due to its anti-inflammatory properties, which can be related to reducing the risk of asthma.

OBJECTIVES

The aim of this study was to determine the relationship between the DASH diet and asthma symptoms among children and adolescents.

METHODS

This cross-sectional study was conducted among7667 children (3414 boys and 4253 girls) aged 6-7 and 13-14 years living in central Iran. Dietary food consumption was assessed using a multiple-choice questionnaire. Logistic regression was used to obtain odds ratios for the association between the DASH-like diet with current asthma and asthma symptoms.

RESULTS

Our findings revealed that higher adherence to a DASH-like diet resulted in lower odds of asthma confirmed by a doctor among the whole population (OR = 0.53; 95%CI: 0.36-0.76) and also in females (OR = 0.47; 95%CI: 0.29-0.78). Moreover, the higher adherence to the DASH-like diet was inversely associated with the chance of wheezing in the past 12 months in all subjects (OR = 0.67; 95%CI: 0.51-0.86) and in boys (OR = 0.57; 95%CI: 0.38-0.85).

CONCLUSION

The findings of the present study showed that following the DASH diet can be associated with the improvement of asthma symptoms in children and adolescents. However, more research is needed to improve dietary recommendations for asthma prevention.

Metabolomic pathways in food allergy

Food allergy (FA) is a widespread issue, affecting as many as 10% of the population. Over the past two to three decades, the prevalence of FA has been on the rise, particularly in industrialized and westernized countries. FA is a complex, multifactorial disease mediated by type 2 immune responses and involving environmental and genetic factors. However, the precise mechanisms remain inadequately understood. Metabolomics has the potential to identify disease endotypes, which could beneficially promote personalized prevention and treatment. A metabolome approach would facilitate the identification of surrogate metabolite markers reflecting the disease activity and prognosis. Here, we present a literature overview of recent metabolomic studies conducted on children with FA.

Dietary carbohydrate types, genetic predisposition, and risk of adult-onset asthma: A longitudinal cohort study

We aimed to investigate the longitudinal associations among carbohydrate intake types, genetic predisposition, and risk adult onset asthma (AOA). A dataset of 96,487 participants from UK Biobank was included with 1830 cases of incident AOA during an average follow-up of 9.68 years. Participants with the highest intake of total sugar, free sugar, and fiber intake, as compared to those with the lowest intake of total sugar, free sugar, and fiber intake, showed a 17 % and 22 % increased risk of incident AOA, and a 16 % decreased risk of AOA, respectively. Substitution of 5 % energy from free sugars with 5 % energy from non-free sugars was associated with a significantly lower risk of AOA (Hazard Ratio [HR] = 0.93, 95 % Confidence Interval [CI]: 0.88, 0.99). Participants with high genetic risk and the highest intake of free sugar showed a 112 % (HR = 2.12, 95%CI: 1.68, 2.68) increased risk of incident AOA. Participants with low genetic risk and highest intake of fiber showed a 50 % (HR = 0.50, 95%CI: 0.39, 0.64) reduced risk of AOA. This study highlights the critical role of carbohydrate types in AOA prevention, with an emphasis on reduced free sugar, moderate non-free sugar, and increased fiber intake.

Application of Microbiome-Based Therapies in Chronic Respiratory Diseases

The application of microbiome-based therapies in various areas of human disease has recently increased. In chronic respiratory disease, microbiome-based clinical applications are considered compelling options due to the limitations of current treatments. The lung microbiome is ecologically dynamic and affected by various conditions, and dysbiosis is associated with disease severity, exacerbation, and phenotype as well as with chronic respiratory disease endotype. However, it is not easy to directly modulate the lung microbiome. Additionally, studies have shown that chronic respiratory diseases can be improved by modulating gut microbiome and administrating metabolites. Although the composition, diversity, and abundance of the microbiome between the gut and lung are considerably different, modulation of the gut microbiome could improve lung dysbiosis. The gut microbiome influences that of the lung via bacterial-derived components and metabolic degradation products, including short-chain fatty acids. This phenomenon might be associated with the cross-talk between the gut microbiome and lung, called gut-lung axis. There are multiple alternatives to modulate the gut microbiome, such as prebiotics, probiotics, and postbiotics ingestion and fecal material transplantation. Several studies have shown that high-fiber diets, for example, present beneficial effects through the production of short-chain fatty acids. Additionally, genetically modified probiotics to secrete some beneficial molecules might also be utilized to treat chronic respiratory diseases. Further studies on microbial modulation to regulate immunity and potentiate conventional pharmacotherapy will improve microbiome modulation techniques, which will develop as a new therapeutic area in chronic respiratory diseases.

Life's Essential 8, genetic predisposition, and risk of incident adult-onset asthma: a prospective cohort study

BACKGROUND

Adult-onset asthma (AOA) and cardiovascular diseases shared common risk factors and similar pathophysiologic resemblances. The American Heart Association (AHA) unveiled the life's essential 8 (LE8) to promote cardiovascular health (CVH). This study aimed to assess the overall impact of LE8 implementation on AOA prevention.

METHODS

According to the guideline of AHA's Construct of CVH in 2022, LE8 score was calculated from 8 health status concerning diet, physical activity, nicotine exposure, sleep health, body mass index, blood lipids, blood glucose, and blood pressure. Cox proportional-hazards models were used to estimate effect sizes of associations between CVH, asthma genetic risk, and risk of incident AOA in participants selected from the UK Biobank study.

RESULTS

A total of 6180 incident AOA cases occurred in 249,713 participants during an average of 11.60 y' follow-up. A higher LE8 score was associated with a lower risk of incident AOA with a significant linear trend (P < 0.0001). Every standard deviation increment of LE8 was associated with a 17% (HR: 0.83; 95% CI: 0.81, 0.85) lower risk of incident AOA. Compared with participants with low-CVH score, participants with moderate (HR: 0.72; 95% CI: 0.67, 0.78) and high CVH scores (HR: 0.52; 95% CI: 0.47, 0.58) were associated with a lower risk of incident AOA (P-trend < 0.0001). No significant multiplicative or additive interaction was found between LE8 score and genetic risks. Stratified analysis showed a consistent association between CVH and risk of incident AOA across different asthma polygenic risk score (PRS) levels. Compared with participants with high PRS and low CVH, participants with low PRS and high CVH experienced the lowest risk (HR: 0.28; 95% CI: 0.23, 0.34) of incident AOA.

CONCLUSIONS

Our findings suggest that maintaining optimal CVH should be recommended as a preventive strategy for AOA, regardless of their asthma genetic risks.

Alveolar macrophage modulation via the gut-lung axis in lung diseases

Several studies have demonstrated great potential implications for the gut-lung axis in lung disease etiology and treatment. The gut environment can be influenced by diet, metabolites, microbiotal composition, primary diseases, and medical interventions. These changes modulate the functions of alveolar macrophages (AMs) to shape the pulmonary immune response, which greatly impacts lung health. The immune modulation of AMs is implicated in the pathogenesis of various lung diseases. However, the mechanism of the gut-lung axis in lung diseases has not yet been determined. This mini-review aimed to shed light on the critical nature of communication between the gut and AMs during the development of pulmonary infection, injury, allergy, and malignancy. A better understanding of their crosstalk may provide new insights into future therapeutic strategies targeting the gut-AM interaction.

The associations between dietary fibers intake and systemic immune and inflammatory biomarkers, a multi-cycle study of NHANES 2015-2020

Background

In recent years, there has been considerable growth in abnormal inflammatory reactions and immune system dysfunction, which are implicated in chronic inflammatory illnesses and a variety of other conditions. Dietary fibers have emerged as potential regulators of the human immune and inflammatory response. Therefore, this study aims to investigate the associations between dietary fibers intake and systemic immune and inflammatory biomarkers.

Methods

This cross-sectional study used data from the National Health and Nutrition Examination Survey (2015-2020). Dietary fibers intake was defined as the mean of two 24-h dietary recall interviews. The systemic immune-inflammation index (SII), systemic inflammation response index (SIRI), neutrophil-to-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), red blood cell distribution width-to-albumin ratio (RA), ferritin, high-sensitivity C-reactive protein (hs-CRP), and white blood cell (WBC) count were measured to evaluate systemic immune and inflammatory states of the body. The statistical software packages R and EmpowerStats were used to examine the associations between dietary fibers intake and systemic immune and inflammatory biomarkers.

Results

Overall, 14,392 participants were included in this study. After adjusting for age, gender, race, family monthly poverty level index, alcohol consumption, smoking status, vigorous recreational activity, body mass index, hyperlipidemia, hypertension, diabetes, and dietary inflammatory index, dietary fibers intake was inversely associated with SII (β = -2.19885, 95% CI: -3.21476 to -1.18294, p = 0.000248), SIRI (β = -0.00642, 95% CI: -0.01021 to -0.00263, p = 0.001738), NLR (β = -0.00803, 95% CI: -0.01179 to -0.00427, p = 0.000284), RA (β = -0.00266, 95% CI: -0.00401 to -0.00131, p = 0.000644), ferritin (β = -0.73086, 95% CI: -1.31385 to -0.14787, p = 0.020716), hs-CRP (β = -0.04629, 95% CI: -0.0743 to -0.01829, p = 0.002119), WBC (β = -0.01624, 95% CI: -0.02685 to -0.00563, p = 0.004066), neutrophils (β = -0.01346, 95% CI: -0.01929 to -0.00764, p = 0.000064). An inverse association between dietary fibers and PLR was observed in the middle (β = -3.11979, 95% CI: -5.74119 to -0.4984, p = 0.028014) and the highest tertile (β = -4.48801, 95% CI: -7.92369 to -1.05234, p = 0.016881) and the trend test (βtrend = -2.2626, 95% CI: -3.9648 to -0.5604, Ptrend = 0.0150). The observed associations between dietary fibers intake and SII, SIRI, NLR, RA, ferritin, hs-CRP, WBC, and neutrophils remained robust and consistent in the sensitivity analysis. No significant interaction by race was found.

Conclusion

Dietary fibers intake is associated with the improvement of the parameters of the immune response and inflammatory biomarkers, supporting recommendations to increase dietary fibers intake for enhanced immune health.

Associations of dietary fiber intake with chronic inflammatory airway diseases and mortality in adults: a population-based study

Objective

The objective of this study was to investigate the potential association between dietary fiber intakes and the prevalence of chronic inflammatory airway diseases (CIAD), as well as mortality in participants with CIAD.

Methods

Data was collected from the National Health and Nutrition Examination Survey (NHANES) 2013-2018, with dietary fiber intakes being calculated as the average of two 24-h dietary reviews and divided into four groups. CIAD included self-reported asthma, chronic bronchitis, and chronic obstructive pulmonary disease (COPD). Through December 31, 2019, mortality was identified from the National Death Index. In cross-sectional studies, multiple logistic regressions were used to assess dietary fiber intakes associated with the prevalence of total and specific CIAD. Dose-response relationships were tested using restricted cubic spline regression. In prospective cohort studies, cumulative survival rates were calculated using the Kaplan-Meier method and compared using log-rank tests. Multiple COX regressions were used to assess dietary fiber intakes associated with mortality in participants with CIAD.

Results

A total of 12,276 adults were included in this analysis. The participants had a mean age of 50.70 ± 17.4 years and was 47.2% male. The prevalence of CIAD, asthma, chronic bronchitis, and COPD were 20.1, 15.2, 6.3, and 4.2%, respectively. The median daily consumption of dietary fiber was 15.1 [IQR 10.5, 21.1] g. After adjusting for all confounding factors, linear and negative associations were observed between dietary fiber intakes and the prevalence of total CIAD (OR = 0.68 [0.58-0.80]), asthma (OR = 0.71 [0.60-0.85]), chronic bronchitis (OR = 0.57 [0.43-0.74]) and COPD (OR = 0.51 [0.34-0.74]). In addition, the fourth quartile of dietary fiber intake levels remained significantly associated with a decreased risk of all-cause mortality (HR = 0.47 [0.26-0.83]) compared to the first quartile.

Conclusion

Dietary fiber intakes were found to be correlated with the prevalence of CIAD, and higher dietary fiber intakes were associated with a reduced mortality in participants with CIAD.

Environmental influences on childhood asthma-The effect of diet and microbiome on asthma

Early life dietary patterns and timely maturation of mucosa-associated microbial communities are important factors influencing immune development and for establishing robust immune tolerance networks. Microbial fermentation of dietary components in vivo generates a vast array of molecules, some of which are integral components of the molecular circuitry that regulates immune and metabolic functions. These in turn protect against aberrant inflammatory processes and promote effector immune responses that quickly eliminate pathogens. Multiple studies suggest that changes in dietary habits, altered microbiome composition, and microbial metabolism are associated with asthma risk and disease severity. While it remains unclear whether these microbiome alterations are a cause or consequence of dysregulated immune responses, there is significant potential for using diet in targeted manipulations of the gut microbiome and its metabolic functions in promoting immune health. In this article, we will summarize our knowledge to date on the role of dietary patterns and microbiome activities on immune responses within the airways. Given the malleability of the human microbiome, its integration into the immune system, and its responsiveness to diet, this makes it a highly attractive target for therapeutic and nutritional intervention in children with asthma.

Role of dietary fiber in promoting immune health-An EAACI position paper

Microbial metabolism of specific dietary components, such as fiber, contributes to the sophisticated inter-kingdom dialogue in the gut that maintains a stable environment with important beneficial physiological, metabolic, and immunological effects on the host. Historical changes in fiber intake may be contributing to the increase of allergic and hypersensitivity disorders as fiber-derived metabolites are evolutionarily hardwired into the molecular circuitry governing immune cell decision-making processes. In this review, we highlight the importance of fiber as a dietary ingredient, its effects on the microbiome, its effects on immune regulation, the importance of appropriate timing of intervention to target any potential window of opportunity, and potential mechanisms for dietary fibers in the prevention and management of allergic diseases. In addition, we review the human studies examining fiber or prebiotic interventions on asthma and respiratory outcomes, allergic rhinitis, atopic dermatitis, and overall risk of atopic disorders. While exposures, interventions, and outcomes were too heterogeneous for meta-analysis, there is significant potential for using fiber in targeted manipulations of the gut microbiome and its metabolic functions in promoting immune health.

Dietary patterns in patients with asthma and their relationship with asthma-related emergency room visits: NHANES 2005-2016

RATIONALE

Extensive interdependencies exist between dietary intake, metabolic dysregulation, and asthma; however, the dietary pattern in adults with asthma remains unknown.

OBJECTIVES

To evaluate the association between dietary patterns and asthma ER visits and explore the effect of the interaction between race and diet on asthma.

METHODS

Using NHANES data, we compared dietary patterns between adults with asthma with and without asthma-related emergency room (ER) visits in the previous year, and between subjects of different races. The 2015 Healthy Eating Index (HEI-2015) was used to assess alignment between dietary patterns and the 2015-2020 Dietary Guideline for Americans.

RESULTS

Among 1681 individuals included in the study, 193 reported asthma-related ER visit. Patients with asthma had low fruit and vegetable intake, and a low mean (SE) HEI-2015 score [52.6 (0.53)]. Individuals with asthma-related ER visits had lower vegetable consumption compared to those without (median 0.61 vs. 0.85 cup equivalents). Furthermore, non-Hispanic Blacks (NHB) reported lower amount of vegetable (median cup equivalent 0.58 vs. 0.89) and fruit intake (0.17 vs. 0.39) and had a lower HEI-2015 score (49.9 vs. 52.9) comparing to non-Hispanic Whites. No association was discovered between dietary patterns and ER visits in multivariable analysis, or significant interactions between diet and race in predicting the need for ER visits.

CONCLUSIONS

Dietary patterns in adult with current asthma are frequently misaligned with current dietary guidelines. Patients with asthma-related ER visits and of NHB race had lower vegetable consumption; however, the associations disappeared in multivariable analysis. The impact of diet on asthma is not straightforward and deserves further investigation.

Supplemental data for this article is available online at at www.tandfonline.com/ijas.

Dietary fibre in relation to asthma, allergic rhinitis and sensitization from childhood up to adulthood

Background

Dietary fibre may reduce the risk of allergy. Our aim was to investigate the association between fibre intake in childhood, asthma, allergic rhinitis and IgE sensitization up to adulthood.

Methods

The individual fibre intake of 2285 participants from the Swedish population-based birth cohort BAMSE was estimated between 98- and 107-item food frequency questionnaires at ages 8 and 16 years, respectively. At 8, 16 and 24 years, asthma and allergic rhinitis symptoms were assessed by questionnaires, and sensitization to common allergens by serum IgE. Longitudinal associations were analysed by generalized estimating equations, adjusting for potential confounders.

Results

An inverse overall association was indicated between fibre intake at 8 years and allergic rhinitis symptoms up to 24 years (OR per 5 g/d 0.86; 95% CI 0.77-0.96), particularly in combination with airborne (0.74; 0.62-0.89) and food (0.69; 0.54-0.88) allergen sensitization. Higher fibre intake was also associated with specific allergen sensitization, for example, birch (0.77; 0.67-0.88) and soy (0.68; 0.53-0.87). No association was observed with asthma. Regarding sources, fruit (0.79; 0.67-0.94) and other (potatoes, chips/popcorn, legumes, and nuts, 0.71; 0.50-0.99), but not cereal or vegetable fibre were associated with allergic rhinitis. In additional analyses, including long-term fibre intake at 8 and 16 years, excluding participants with food-related allergic symptoms to examine reverse causation, as well as adjusting for antioxidant intake, associations were attenuated and became non-significant.

Conclusion

Higher fibre intake in mid-childhood may be inversely associated with allergic rhinitis and sensitization to specific allergens up to adulthood. However, avoidance of food triggers of allergic symptoms in allergic rhinitis patients may contribute to the protective associations.

Association between dietary carotenoid intakes and the risk of asthma in adults: a cross-sectional study of NHANES, 2007-2012

OBJECTIVE

To investigate the association between dietary carotenoid intake and asthma using data from a nationally representative sample of US adults.

DESIGN

Cross-section study.

SETTING

The National Health and Nutrition Examination Survey 2007-2012.

PARTICIPANTS

A total of 13 039 participants aged 20-80 years (current asthma n=1784, non-current asthma n=11 255) were included in this study.

PRIMARY AND SECONDARY OUTCOME MEASURES

Asthma was defined by self-report questionnaires. Weighted logistic regression analyses and the smooth curve fittings were performed to explore the association between total carotenoid intake, dietary carotenoid subgenera, including (α-carotene, β-carotene, β-cryptoxanthin, lutein with zeaxanthin and lycopene) and the risk of asthma.

RESULTS

The ORs with 95% CIs of dietary α-carotene, dietary β-carotene, dietary β-cryptoxanthin, total lutein with zeaxanthin, total lycopene, dietary carotenoid and total carotenoid intake for individuals with current asthma after adjusting the confounders in model 3 were 0.80 (0.67 to 0.95), 0.67 (0.57 to 0.79), 0.68 (0.55 to 0.85), 0.77 (0.61 to 0.98), 0.71 (0.57 to 0.87), 0.75 (0.59 to 0.96) and 0.61 (0.48 to 0.76) in the highest versus lowest quartile, respectively. The smooth curve fittings suggested a non-linear relationship between total carotenoid intake and the risk of current asthma.

CONCLUSIONS

Higher intake of a-carotene, β-carotene, β-cryptoxanthin, lycopene, lutein with zeaxanthin and total carotenoid were associated with lower odds of having current asthma in the US adults. This is a cross-sectional study and no causal relationship can be drawn, so caution is needed to interpret the results.

Perspectives: on Precision Nutrition Research in Heart, Lung, and Blood Diseases and Sleep Disorders

The release of the 2020-2030 Strategic Plan for NIH Nutrition Research (SPNR) and its emphasis on precision nutrition has provided an opportunity to identify future nutrition research that addresses individual variability in response to diet and nutrition across the life span-including those relevant to the Strategic Vision of the National Heart, Lung, and Blood Institute (NHLBI). The SPNR and the NHLBI's Strategic Vision were developed with extensive input from the extramural research community, and both have 4 overarching strategic goals within which are embedded several objectives for research. For the SPNR, these include 1) spur discovery science and normal biological functions (e.g., role of the microbiome in health and disease), 2) population science to understand individual differences (e.g., biomarkers including 'omics that predict disease status), 3) emerging scientific areas of investigation and their application (e.g., data science, artificial intelligence), and 4) cross-cutting themes (e.g., training the scientific workforce and minority health and health disparities). These strategic goals and objectives serve as blueprints for research and training. Nutrition remains important in the prevention and treatment of heart, lung, blood, and sleep (HLBS) disorders and diseases, and the NHLBI has played a pivotal role in supporting nutrition research. In this paper, we report important gaps in the scientific literature related to precision nutrition in HLBS diseases. Research opportunities that could stimulate precision nutrition and their alignment with the SPNR and the NHLBI Strategic Vision Objectives are provided. These opportunities include 1) exploring individual differences in response to varying dietary patterns and nutrients; 2) investigating genetic/epigenetic, biological (e.g., microbiome, biomarkers), social, psychosocial, and environmental underpinnings of individual variability in diet; 3) elucidating the role of circadian rhythm and chrononutrition; and 4) applying implementation science research methods in precision nutrition interventions relevant to HLBS diseases.

Relationship Between Dietary Fiber and Vitamin C Intake and Oral Cancer

Background

Dietary fiber and vitamin C has been reported to play a possible role in tumorigenesis. However, few studies have estimated their association with oral cancer risk. In this project, we investigated the relationship between dietary fiber and vitamin C and oral cancer risk in adults in Southern China.

Methods

382 patients newly diagnosed with oral cancer were matched to 382 hospital derived controls by frequency matching in age and sex. Pre-diagnostic consumption of dietary fiber and vitamin C intake were measured through food frequency questionnaire. Association between nutrients intake and oral cancer risk were evaluated by logistic regression. OR value and 95% confidence interval was calculated.

Results

Intake of dietary fiber and vitamin C was significantly lower in oral cancer patients (8.15 g/day) than in control participants (8.88 g/day). Increased dietary fiber or vitamin C intake was linked to a decreased incidence of OC after adjustment of age, marital status, residence, BMI, occupation, education, tobacco smoking, alcohol consumption and family history of cancer P_trend< 0.001). Compared with the lowest tertile, the adjusted OR of the top tertile of dietary fiber was 0.47 (95 % CI 0.32, 0.68). While the adjusted OR of the highest tertile was 0.60 (95 % CI 0.42, 0.87) compared with the lowest tertile of vitamin C.

Conclusions

Dietary intake of fiber and vitamin C were lower in oral cancer patients than in control participants. Dietary fiber and vitamin C were inversely related to risk of oral cancer risk.

Clinical Characteristics and Management Strategies for Adult Obese Asthma Patients

The rates of asthma and obesity are increasing concurrently in the United States. Epidemiologic studies demonstrate that the incidence of asthma increases with obesity. Furthermore, obese individuals have asthma that is more severe, harder to control, and resistant to standard medications. In fact, specific asthma-obesity phenotypes have been identified. Various pathophysiologic mechanisms, including mechanical, inflammatory, metabolic and microbiome-associated, are at play in promulgating the obese-asthma phenotypes. While standard asthma medications, such as inhaled corticosteroids and biologics, are currently used to treat obese asthmatics, they may have limited effectiveness. Targeting the underlying aberrant processes, such as addressing steroid resistance, microbiome, metabolic and weight loss approaches, may be helpful.

Mediterranean-Type Diets as a Protective Factor for Asthma and Atopy

We are currently riding the second wave of the allergy epidemic, which is ongoing in affluent societies, but now also affecting developing countries. This increase in the prevalence of atopy/asthma in the Western world has coincided with a rapid improvement in living conditions and radical changes in lifestyle, suggesting that this upward trend in allergic manifestations may be associated with cultural and environmental factors. Diet is a prominent environmental exposure that has undergone major changes, with a substantial increase in the consumption of processed foods, all across the globe. On this basis, the potential effects of dietary habits on atopy and asthma have been researched rigorously, but even with a considerable body of evidence, clear associations are far from established. Many factors converge to obscure the potential relationship, including methodological, pathophysiological and cultural differences. To date, the most commonly researched, and highly promising, candidate for exerting a protective effect is the so-called Mediterranean diet (MedDi). This dietary pattern has been the subject of investigation since the mid twentieth century, and the evidence regarding its beneficial health effects is overwhelming, although data on a correlation between MedDi and the incidence and severity of asthma and atopy are inconclusive. As the prevalence of asthma appears to be lower in some Mediterranean populations, it can be speculated that the MedDi dietary pattern could indeed have a place in a preventive strategy for asthma/atopy. This is a review of the current evidence of the associations between the constituents of the MedDi and asthma/atopy, with emphasis on the pathophysiological links between MedDi and disease outcomes and the research pitfalls and methodological caveats which may hinder identification of causality. MedDi, as a dietary pattern, rather than short-term supplementation or excessive focus on single nutrient effects, may be a rational option for preventive intervention against atopy and asthma.

Kisspeptins inhibit human airway smooth muscle proliferation

Sex/gender disparity in asthma is recognized, and suggests a modulatory role for sex-steroids, particularly estrogen. However, studies including our own show a dichotomous role for estrogen in airway remodeling, making it unclear whether sex hormones are protective or detrimental in asthma, and suggesting a need to explore mechanisms upstream or independent of estrogen. We hypothesize that Kisspeptin (Kp)/KISS1R signaling serves this role. Airway smooth muscle (ASM) is a key structural cell type that contributes to remodeling in asthma. We explored the role of Kp/KISS1R in regulating ASM proliferation. We report novel data that Kp and KISS1R are expressed in human airways, especially ASM, with lower expression in ASM from females compared to males, and asthmatics showing lowest expression compared to non-asthmatics. Proliferation studies showed that cleaved forms of Kp, particularly Kp-10 mitigates PDGF-induced ASM proliferation. Pharmacological inhibition and shRNA knockdown of KISS1R increased basal ASM proliferation, further amplified by PDGF. The anti-proliferative effect of Kp-10 in ASM was found to be mediated by inhibition of MAPK-ERK-Akt pathways, with altered expression of PCNA, C/EBP-alpha, Ki-67, Cyclin-D1, and Cyclin-E leading to cell-cycle arrest at G0/G1 phase. Overall, we demonstrate the importance of Kp/KISS1R signaling in regulating ASM proliferation and a potentially novel therapeutic avenue to blunt remodeling in asthma.

Dietary Fibers: Effects, Underlying Mechanisms and Possible Role in Allergic Asthma Management

The prevalence of asthma is increasing, but the cause remains under debate. Research currently focuses on environmental and dietary factors that may impact the gut-lung axis. Dietary fibers are considered to play a crucial role in supporting diversity and activity of the microbiome, as well as immune homeostasis in the gut and lung. This review discusses the current state of knowledge on how dietary fibers and their bacterial fermentation products may affect the pathophysiology of allergic asthma. Moreover, the impact of dietary fibers on early type 2 asthma management, as shown in both pre-clinical and clinical studies, is described. Short-chain fatty acids, fiber metabolites, modulate host immunity and might reduce the risk of allergic asthma development. Underlying mechanisms include G protein-coupled receptor activation and histone deacetylase inhibition. These results are supported by studies in mice, children and adults with allergic asthma. Fibers might also exert direct effects on the immune system via yet to be elucidated mechanisms. However, the effects of specific types of fiber, dosages, duration of treatment, and combination with probiotics, need to be explored. There is an urgent need to further valorize the potential of specific dietary fibers in prevention and treatment of allergic asthma by conducting more large-scale dietary intervention trials.

The Role of CD4+ T Cells and Microbiota in the Pathogenesis of Asthma

Asthma, a chronic respiratory disease involving variable airflow limitations, exhibits two phenotypes: eosinophilic and neutrophilic. The asthma phenotype must be considered because the prognosis and drug responsiveness of eosinophilic and neutrophilic asthma differ. CD4+ T cells are the main determinant of asthma phenotype. Th2, Th9 and Tfh cells mediate the development of eosinophilic asthma, whereas Th1 and Th17 cells mediate the development of neutrophilic asthma. Elucidating the biological roles of CD4+ T cells is thus essential for developing effective asthma treatments and predicting a patient's prognosis. Commensal bacteria also play a key role in the pathogenesis of asthma. Beneficial bacteria within the host act to suppress asthma, whereas harmful bacteria exacerbate asthma. Recent literature indicates that imbalances between beneficial and harmful bacteria affect the differentiation of CD4+ T cells, leading to the development of asthma. Correcting bacterial imbalances using probiotics reportedly improves asthma symptoms. In this review, we investigate the effects of crosstalk between the microbiota and CD4+ T cells on the development of asthma.

Dietary Fibre Intake in Relation to Asthma, Rhinitis and Lung Function Impairment-A Systematic Review of Observational Studies

A high intake of dietary fibre has been associated with a reduced risk of several chronic diseases. This study aimed to review the current evidence on dietary fibre in relation to asthma, rhinitis and lung function impairment. Electronic databases were searched in June 2021 for studies on the association between dietary fibre and asthma, rhinitis, chronic obstructive pulmonary disease (COPD) and lung function. Observational studies with cross-sectional, case–control or prospective designs were included. Studies on animals, case studies and intervention studies were excluded. The quality of the evidence from individual studies was evaluated using the RoB-NObs tool. The World Cancer Research Fund criteria were used to grade the strength of the evidence. Twenty studies were included in this systematic review, of which ten were cohort studies, eight cross-sectional and two case–control studies. Fibre intake during pregnancy or childhood was examined in three studies, while seventeen studies examined the intake during adulthood. There was probable evidence for an inverse association between dietary fibre and COPD and suggestive evidence for a positive association with lung function. However, the evidence regarding asthma and rhinitis was limited and inconsistent. Further research is needed on dietary fibre intake and asthma, rhinitis and lung function among adults and children.

Nutritional status, diet and viral respiratory infections: perspectives for severe acute respiratory syndrome coronavirus 2

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was recognised by the WHO as a pandemic in 2020. Host preparation to combat the virus is an important strategy to avoid COVID-19 severity. Thus, the relationship between eating habits, nutritional status and their effects on the immune response and further implications in viral respiratory infections is an important topic discussed in this review. Malnutrition causes the most diverse alterations in the immune system, suppressing of the immune response and increasing the susceptibility to infections such as SARS-CoV-2. On the other hand, obesity induces low-grade chronic inflammation caused by excess adiposity, which increases angiotensin-converting enzyme 2. It decreases the immune response favouring SARS-CoV-2 virulence and promoting respiratory distress syndrome. The present review highlights the importance of food choices considering their inflammatory effects, consequently increasing the viral susceptibility observed in malnutrition and obesity. Healthy eating habits, micronutrients, bioactive compounds and probiotics are strategies for COVID-19 prevention. Therefore, a diversified and balanced diet can contribute to the improvement of the immune response to viral infections such as COVID-19.

[Diet and asthma: Better eating for better breathing?]

Inhaled therapies are the cornerstone of asthma treatment. However, according to national and international guidelines, non-pharmacological interventions should not be neglected in asthma. It has been demonstrated that a healthy diet is beneficial to general health. Recently, the effect of diet on asthma has been highlighted in many studies. Two diets have been particularly studied: the Mediterranean diet (high in fruits and vegetables and low in fat) and the Western diet (high in saturated fat and low in fruits and vegetables). A beneficial effect of the Mediterranean diet and deleterious effect of the Western diet on the development or control of asthma has been shown in some studies even after adjustment for overweight. Study findings have not been unanimous, probably related to the complexity of conducting studies on a diet that may change from day to day for any individual subject. In addition, the effect of physical exercise, which is known to be beneficial in asthma, is rarely taken into account in these studies. However, studies on diet are becoming more complex with the use of specific dietary indices, which should bring interesting data in the future.

Small Airway Disease in Pediatric Asthma: the Who, What, When, Where, Why, and How to Remediate. A Review and Commentary

Asthma affects all portions of the airways. Small airways, however, comprise a substantial component of the conducting lung air flow. In asthma, inflammatory processes can affect the whole respiratory tract, from central to peripheral/small airways. The emphasis in adult and pediatric respiratory disease clinics is to focus on large airway obstruction and reversibility. This information, although valuable, underemphasizes a large portion of the conduction airway of asthmatics. Standard descriptions of asthma management focus on a multiple medication approaches. We particularly focused on the management of asthma in the international guidelines for the Global Initiative for Asthma (GINA). Overall, however, minimal attention is placed on the small airway pool in asthma medical management. We took the opportunity to thoroughly review and present specific data from the adult asthma literature which supported the concept that small airway abnormalities may play a role in the pathogenesis and clinical expression of asthma. Based on the conclusions of the adult asthma literature, we here present a thorough review of the literature as it relates to small airway disease in children with asthma. We used, collectively, individual data sources of data to expand the information available from standard diagnostic techniques, especially spirometry, in the evaluation of small airway disease. As the pharmacological approaches to moderate to severe asthma are advancing rapidly into the realm of biologics, we sought to present potential pharmacological options for small airway dysfunction in pediatrics prior to biological modifier intervention.