Prevention of exercise-induced asthma by a natural isomer mixture of beta-carotene

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.

Asthma in pregnancy

Background: Asthma is a frequent and potentially life-threatening disease that complicates many pregnancies. There are extensive data with regard to the diagnosis and treatment of asthma during pregnancy. Medical providers require an up-to-date summary of the critical aspects of asthma management during pregnancy. Objective: This review aimed to summarize the available data from clinical trials, cohort studies, expert opinions, and guideline recommendations with regard to asthma in pregnancy. Methods: A search through PubMed was conducted by using keywords previously mentioned and MeSH (Medical Subject Headings) terminology. Clinical trials, observational studies, expert opinions, guidelines, and other reviews were included. The quality of the studies was assessed, and data were extracted and summarized. Results: Asthma worsens in ∼40% of pregnant women, which can be associated with maternal and fetal complications. Physiologic changes in the respiratory, cardiovascular, and immune systems during pregnancy play a critical role in the manifestations of asthma. The diagnosis and the treatment of asthma are similar to that of patients who are not pregnant. Nonetheless, concern for fetal malformations, preterm birth, and low birth weight must be considered when managing pregnant patients with asthma. Importantly, cornerstones of the pharmacotherapy of asthma seem to be safe during pregnancy. Conclusion: Asthma in pregnancy is associated with adverse outcomes. Roadblocks to management include associated comorbidities, medication nonadherence, atopy, lack of education, and smoking habits. These need to be acknowledged and addressed for successful asthma management during pregnancy.

Nonpharmacologic Strategies to Manage Exercise-Induced Bronchoconstriction

Pharmacologic management of exercise-induced bronchoconstriction (EIB) is the mainstay of preventative therapy. There are some nonpharmacologic interventions, however, that may assist the management of EIB. This review discusses these nonpharmacologic interventions and how they may be applied to patients and athletes with EIB.

Stability of lutein encapsulated whey protein nano-emulsion during storage

Lutein is a hydrophobic carotenoid that has multiple health functions. However, the application of lutein is limited due to its poor solubility in water and instability under certain conditions during storage. Hereby we generated lutein loaded nano-emulsions using whey protein isolate (WPI) or polymerized whey protein isolate (PWP) with assistance of high intensity ultrasound and evaluate their stability during storage at different conditions. We measured the particle size, zeta-potential, physical stability and lutein content change. Results showed that the PWP based nano-emulsion system was not stable in the tested Oil/Water/Ethanol system indicated by the appearance of stratification within only one week. The WPI based nano-emulsion system showed stable physiochemical stability during the storage at 4°C. The lutein content of the system was reduced by only 4% after four weeks storage at 4°C. In conclusion, our whey protein based nano-emulsion system provides a promising strategy for encapsulation of lutein or other hydrophobic bioactive molecules to expand their applications.

Microalgae as healthy ingredients for functional food: a review

Microalgae are very interesting and valuable natural sources of highly valuable bioactive compounds, such as vitamins, essential amino acids, polyunsaturated fatty acids, minerals, carotenoids, enzymes and fibre.

Vitamin A-retinoid signaling in pulmonary development and disease

Retinoic acid (RA), the active form of vitamin A, regulates key developmental processes in multiple organs. In the developing lung, RA is crucial for normal growth and differentiation of airways. Disruption in RA signaling or vitamin A deficiency (VAD) has been linked to aberrant development of the lung including alterations in the airway smooth muscle (SM) differentiation, development, and function. These alterations have been linked to disease states including asthma in both human and animal models.

Improved lung function following dietary antioxidant supplementation in exercise-induced asthmatics

INTRODUCTION

Oxidative stress is a characteristic of exercise-induced asthma (EIA), however antioxidant supplementation may attenuate EIA. The purpose of this study was to determine if ascorbic (AsA) and α-tocopherol supplementation would improve airway function in subjects with EIA.

METHODS

A single-blind randomized crossover design with eight clinically diagnosed EIA subjects (22.0 ± 0.7 year) and five healthy control subjects (28.2 ± 1.4 year) was used. Subjects consumed vitamins (V) (AsA 500 mg; α-tocopherol 300 IU) or placebo (PLA) daily for three weeks, followed by a three week washout period and then three weeks of the alternative treatment. Ten-minute treadmill tests (90% VO2peak) were performed with pulmonary function testing (forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and between 25 and 75% (FEF25-75%), and peak expiratory flow rates (PEFR)) measured pre-exercise and 1, 5, 15, and 30 min post-exercise.

RESULTS

Supplementation led to significant improvements at minute 5 and minute 15 in FVC; FEV1; PERF; FEF25-75% and minute 30 in FEV1 and FEF25-75% post-exercise.

CONCLUSION

AsA and α-tocopherol may aid the recovery of pulmonary function in subjects with EIA.

Marine yeast isolation and industrial application

Over the last century, terrestrial yeasts have been widely used in various industries, such as baking, brewing, wine, bioethanol and pharmaceutical protein production. However, only little attention has been given to marine yeasts. Recent research showed that marine yeasts have several unique and promising features over the terrestrial yeasts, for example higher osmosis tolerance, higher special chemical productivity and production of industrial enzymes. These indicate that marine yeasts have great potential to be applied in various industries. This review gathers the most recent techniques used for marine yeast isolation as well as the latest applications of marine yeast in bioethanol, pharmaceutical and enzyme production fields.

Vitamins C and E for asthma and exercise-induced bronchoconstriction

BACKGROUND

The association between dietary antioxidants and asthma or exercise-induced bronchoconstriction (EIB) is not fully understood. Vitamin C and vitamin E are natural antioxidants that are predominantly present in fruits and vegetables; inadequate vitamin E intake is associated with airway inflammation. It has been postulated that the combination may be more beneficial than either single antioxidant for people with asthma and exercise-induced bronchoconstriction.

OBJECTIVES

To assess the effects of supplementation of vitamins C and E versus placebo (or no vitamin C and E supplementation) on exacerbations and health-related quality of life (HRQL) in adults and children with chronic asthma. To also examine the potential effects of vitamins C and E on exercise-induced bronchoconstriction in people with asthma and in people without a diagnosis of asthma who experience symptoms only on exercise.

SEARCH METHODS

Trials were identified from the Cochrane Airways Review Group Specialised Register and from trial registry websites. Searches were conducted in September 2013.

SELECTION CRITERIA

We included randomised controlled trials of adults and children with a diagnosis of asthma. We separately considered trials in which participants had received a diagnosis of exercise-induced bronchoconstriction (or exercise-induced asthma). Trials comparing vitamin C and E supplementation versus placebo were included. We included trials in which asthma management for treatment and control groups included similar background therapy. Short-term use of vitamins C and E at the time of exacerbation or for cold symptoms in people with asthma is outside the scope of this review.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts of potential studies and subsequently screened full-text study reports for inclusion. We used standard methods as expected by The Cochrane Collaboration.

MAIN RESULTS

It was not possible to aggregate the five included studies (214 participants). Four studies (206 participants) addressed the question of whether differences in outcomes were seen when vitamin C and E supplementation versus placebo was provided for participants with asthma, and only one of those studies (160 children) included a paediatric population; the remaining three studies included a combined total of just 46 adults. An additional study considered the question of whether differences in outcomes were noted when vitamin C and E supplementation was compared with placebo for exercise-induced asthma; this trial included only eight participants. The randomisation process of the trials were unclear leading us to downgrade the quality of the evidence. Four of the studies were double blind while the other study was single blind.None of these studies provided data on our two prespecified primary outcome measures: exacerbations and HRQL. Lung function data obtained from the studies were inconclusive. The only studies that provided any suggestion of an effect, and only with some outcomes, were the paediatric study, especially for children with moderate to severe asthma, and the small study on exercise-induced asthma. Even so, this evidence was judged to be at moderate/low quality. Only one study contributed data on asthma symptoms and adverse events, reporting no evidence of an effect of the intervention for symptoms and that one participant in the treatment group dropped out due to cystitis.

AUTHORS' CONCLUSIONS

It is not possible to draw firm conclusions from this review with respect to the comparison of vitamin C and E supplementation versus placebo in the management of asthma or exercise-induced bronchoconstriction. We found only one study relevant to exercise-induced bronchoconstriction; most included participants came from studies designed to assess the effect of vitamin supplementation on the impact of atmospheric pollutants (such as ozone). Evidence is lacking on the comparison of vitamin C and E supplementation versus placebo for asthma with respect to outcomes such as HRQL and exacerbations, which were not addressed by any of the included studies.When compared with lung function tests alone, HRQL scores and exacerbation frequency are better indicators of the severity of asthma, its impact on daily activities and its response to treatment in a patient population. These end points are well recognised in good quality studies of asthma management. However, clinical studies of vitamins C and E in the management of asthma using these important end points of exacerbations and effects on quality of life are not available, and evidence is insufficient to support robust conclusions on the role of vitamin C and E supplementation in asthma and exercise-induced breathlessness.

An overview: biomolecules from microalgae for animal feed and aquaculture

Despite being more popular for biofuel, microalgae have gained a lot of attention as a source of biomolecules and biomass for feed purposes. Algae farming can be established using land as well as sea and strategies can be designed in order to gain the products of specific interest in the optimal way. A general overview of the contributions of Algae to meet the requirements of nutrients in animal/aquaculture feed is presented in this study. In addition to its applications in animal/aquaculture feed, algae can produce a number of biomolecules including astaxanthin, lutein, beta-carotene, chlorophyll, phycobiliprotein, Polyunsaturated Fatty Acids (PUFAs), beta-1,3-glucan, and pharmaceutical and nutraceutical compounds which have been reviewed with respect to their commercial importance and current status. The review is further extended to highlight the adequate utilization of value added products in the feeds for livestock, poultry and aquaculture (with emphasis in shrimp farming).

Vitamin C for asthma and exercise-induced bronchoconstriction

BACKGROUND

Dietary antioxidants, such as vitamin C, in the epithelial lining and lining fluids of the lung may be beneficial in the reduction of oxidative damage (Arab 2002). They may therefore be of benefit in reducing symptoms of inflammatory airway conditions such as asthma, and may also be beneficial in reducing exercise-induced bronchoconstriction, which is a well-recognised feature of asthma and is considered a marker of airways inflammation. However, the association between dietary antioxidants and asthma severity or exercise-induced bronchoconstriction is not fully understood.

OBJECTIVES

To examine the effects of vitamin C supplementation on exacerbations and health-related quality of life (HRQL) in adults and children with asthma or exercise-induced bronchoconstriction compared to placebo or no vitamin C.

SEARCH METHODS

We identified trials from the Cochrane Airways Group's Specialised Register (CAGR). The Register contains trial reports identified through systematic searches of a number of bibliographic databases, and handsearching of journals and meeting abstracts. We also searched trial registry websites. The searches were conducted in December 2012.

SELECTION CRITERIA

We included randomised controlled trials (RCTs). We included both adults and children with a diagnosis of asthma. In separate analyses we considered trials with a diagnosis of exercise-induced bronchoconstriction (or exercise-induced asthma). We included trials comparing vitamin C supplementation with placebo, or vitamin C supplementation with no supplementation. We included trials where the asthma management of both treatment and control groups provided similar background therapy. The primary focus of the review is on daily vitamin C supplementation to prevent exacerbations and improve HRQL. The short-term use of vitamin C at the time of exacerbations or for cold symptoms in people with asthma are outside the scope of this review.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts of potential studies, and subsequently screened full text study reports for inclusion. We used standard methods expected by The Cochrane Collaboration.

MAIN RESULTS

A total of 11 trials with 419 participants met our inclusion criteria. In 10 studies the participants were adults and only one was in children. Reporting of study design was inadequate to determine risk of bias for most of the studies and poor availability of data for our key outcomes may indicate some selective outcome reporting. Four studies were parallel-group and the remainder were cross-over studies. Eight studies included people with asthma and three studies included 40 participants with exercise-induced asthma. Five studies reported results using single-dose regimes prior to bronchial challenges or exercise tests. There was marked heterogeneity in vitamin C dosage regimes used in the selected studies, compounding the difficulties in carrying out meaningful analyses.One study on 201 adults with asthma reported no significant difference in our primary outcome, health-related quality of life (HRQL), and overall the quality of this evidence was low. There were no data available to evaluate the effects of vitamin C supplementation on our other primary outcome, exacerbations in adults. One small study reported data on asthma exacerbations in children and there were no exacerbations in either the vitamin C or placebo groups (very low quality evidence). In another study conducted in 41 adults, exacerbations were not defined according to our criteria and the data were not available in a format suitable for evaluation by our methods. Lung function and symptoms data were contributed by single studies. We rated the quality of this evidence as moderate, but further research is required to assess any clinical implications that may be related to the changes in these parameters. In each of these outcomes there was no significant difference between vitamin C and placebo. No adverse events at all were reported; again this is very low quality evidence.Studies in exercise-induced bronchoconstriction suggested some improvement in lung function measures with vitamin C supplementation, but theses studies were few and very small, with limited data and we judged the quality of the evidence to be low.

AUTHORS' CONCLUSIONS

Currently, evidence is not available to provide a robust assessment on the use of vitamin C in the management of asthma or exercise-induced bronchoconstriction. Further research is very likely to have an important impact on our confidence in the estimates of effect and is likely to change the estimates. There is no indication currently that vitamin C can be recommended as a therapeutic agent in asthma. There was some indication that vitamin C was helpful in exercise-induced breathlessness in terms of lung function and symptoms; however, as these findings were provided only by small studies they are inconclusive. Most published studies to date are too small and inconsistent to provide guidance. Well-designed trials with good quality clinical endpoints, such as exacerbation rates and health-related quality of life scores, are required.

Exercise-induced asthma: nutritional management

Exercise-induced asthma (EIA) refers to the transient narrowing of the airways following strenuous exercise in asthmatic and otherwise healthy individuals. Despite the heterogeneous treatment options for patients with EIA, there remains a substantial burden of unaddressed disease, even with optimal treatment. Epidemiological studies indicate that patients frequently resort to complementary and alternative therapies while being treated for asthma and other chronic health conditions. There is now convincing evidence that many dietary factors such as increased omega-3 polyunsaturated fatty acids, antioxidant intake and caffeine, and a sodium-restricted diet can reduce the severity of EIA. It is important that these dietary therapies be safe, effective, and likely to be used by individuals with EIA. This review will critically examine whether dietary modification represents a beneficial intervention for asthmatic individuals with EIA.

Improving asthma during pregnancy with dietary antioxidants: the current evidence

The complication of asthma during pregnancy is associated with a number of poor outcomes for the mother and fetus. This may be partially driven by increased oxidative stress induced by the combination of asthma and pregnancy. Asthma is a chronic inflammatory disease of the airways associated with systemic inflammation and oxidative stress, which contributes to worsening asthma symptoms. Pregnancy alone also intensifies oxidative stress through the systemic generation of excess reactive oxidative species (ROS). Antioxidants combat the damaging effects of ROS; yet antioxidant defenses are reduced in asthma. Diet and nutrition have been postulated as potential factors to combat the damaging effects of asthma. In particular, dietary antioxidants may play a role in alleviating the heightened oxidative stress in asthma. Although there are some observational and interventional studies that have shown protective effects of antioxidants in asthma, assessment of antioxidants in pregnancy are limited and there are no antioxidant intervention studies in asthmatic pregnancies on asthma outcomes. The aims of this paper are to (i) review the relationships between oxidative stress and dietary antioxidants in adults with asthma and asthma during pregnancy, and (ii) provide the rationale for which dietary management strategies, specifically increased dietary antioxidants, might positively impact maternal asthma outcomes. Improving asthma control through a holistic antioxidant dietary approach might be valuable in reducing asthma exacerbations and improving asthma management during pregnancy, subsequently impacting perinatal health.

Oxidant--antioxidant imbalance in asthma: scientific evidence, epidemiological data and possible therapeutic options

Prevalence of asthma has increased considerably in recent decades throughout the world especially in developed countries. Airway inflammation is thought to be prime cause for repeated episodes of airway obstruction in asthmatics. Several studies have shown that reactive oxygen species (ROS) play a key role in initiation as well as amplification of inflammation in asthmatic airways. Excessive ROS production in asthma leads to alteration in key enzymatic as well as nonenzymatic antioxidants such as glutathione, vitamins C and E, beta-carotene, uric acid, thioredoxin, superoxide dismutases, catalase, and glutathione peroxidases leading to oxidant-antioxidant imbalance in airways. Oxidant-antioxidant imbalance leads to pathophysiological effects associated with asthma such as vascular permeability, mucus hypersecretion, smooth muscle contraction, and epithelial shedding. Epidemiological data also support the scientific evidence of oxidant-antioxidant imbalance in asthmatics. Therefore, the supplementation of antioxidants to boost the endogenous antioxidants or scavenge excessive ROS production could be utilized to dampen/prevent the inflammatory response in asthma by restoring oxidant-antioxidant balance. This review summarizes the scientific and epidemiological evidence linking asthma with oxidant-antioxidant imbalance and possible antioxidant strategies that can be used therapeutically for better management of asthma.

Retinoic acids are potent inhibitors of spontaneous human eosinophil apoptosis

Retinoic acids (RAs), which are active metabolites of vitamin A, are known to enhance Th2-type immune responses in vitro, but the role of RAs in allergic inflammatory cells remains unclear. In this study, we demonstrated that purified peripheral blood eosinophils expressed nuclear receptors for RAs at the mRNA and protein levels. Eosinophils cultured with all-trans RA (ATRA) and 9-cis-RA showed dramatically induced cell survival and nuclear hypersegmentation, and the efficacy of RAs (10(-6)M) was similar to that of IL-5 (1 ng/ml), the most critical cytokine for eosinophil activation. Pharmacological manipulation with receptor-specific agonists and antagonists indicated that the antiapoptotic effect of RAs was mediated through ligand-dependent activation of both retinoid acid receptors and retinoid X receptors (mainly retinoid acid receptors). Furthermore, using a gene microarray and a cytokine Ab array, we discovered that RAs induced vascular endothelial growth factor, M-CSF, and MCP-1 secretion, although they were not involved in eosinophil survival. RA-induced eosinophil survival appears to be associated with down-regulation of caspase 3 and inhibition of its enzymatic activity. These findings indicate an important role of RAs in homeostasis of granulocytes and provide further insight into the cellular and molecular pathogenesis of allergic reactions.

PRODUCTION OF NATURAL BUTYLATED HYDROXYTOLUENE AS AN ANTIOXIDANT BY FRESHWATER PHYTOPLANKTON(1)

Butylated hydroxytoluene (BHT) is one of the synthetic antioxidant agents commonly used for food additives. In the present study, we determined that four freshwater phytoplankton, including a green alga (Botryococcus braunii Kütz.) and three cyanobacteria [Cylindrospermopsis raciborskii (Wolłosz.) Seenaya et Sabba Raju, Microcystis aeruginosa (Kütz.) and Oscillatoria sp.] were capable of producing this compound. Hexane extracts from all the studied species exhibited various degrees of antioxidative properties when they were tested with the β-carotene-linoleate (β-CL) assay and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical-scavenging assay. The highest antioxidant activity was observed in the crude extracts of M. aeruginosa and B. braunii, which displayed a similar activity to synthetic BHT. Gas chromatography/mass spectroscopy (GC-MS) analysis of the purified fractions revealed that the active compound was identical to synthetic BHT. Culturing under various irradiances gave rise to different magnitudes of BHT production in cyanobacterial cells, showing that more BHT was produced in the cells irradiated with a higher light intensity, and its production was irradiance dependent. Moreover, the quantity of cellular BHT displayed a positive correlation with the antioxidative activity of the tested species. The present study confirms the production of BHT in all four of the studied freshwater phytoplankton and suggests that these species constitute a potential source for producing natural BHT.

A nutritional approach to managing exercise-induced asthma

Exercise-induced asthma (EIA) is traditionally treated with the use of pharmacotherapy. However, there is now convincing evidence that a variety of dietary factors such as elevated omega-3 polyunsaturated fatty acids and antioxidant intake, and a sodium-restricted diet can reduce this condition. New therapies that are safe, effective, and likely to be used by individuals with EIA are needed.

Dietary factors and the development of asthma

Asthma and allergies continue to be major public health problems in affluent westernized countries. Changes in dietary habits dating from before the increase in asthma prevalence may have a role in the development of asthma and allergies. Many studies have investigated the role of specific nutrients in asthma and allergies, and intervention studies with supplementation of particular nutrients have been conducted, but results have been mixed. It is likely that nutrients may exert their strongest effect early in life, when both the immune system and the lungs are not yet fully developed.

Ascorbic acid supplementation attenuates exercise-induced bronchoconstriction in patients with asthma

BACKGROUND

Previous research has shown that diet can modify the bronchoconstrictor response to exercise in asthmatic subjects.

OBJECTIVE

Determine the effect of ascorbic acid supplementation on pulmonary function and several urinary markers of airway inflammation in asthmatic subjects with exercise-induced bronchoconstriction (EIB).

METHODS

Eight asthmatic subjects with documented EIB participated in a randomized, placebo controlled double-blind crossover trial. Subjects entered the study on their usual diet and were placed on either 2 weeks of ascorbic acid supplementation (1500 mg/day) or placebo, followed by a 1-week washout period, before crossing over to the alternative diet. Pre- and post-exercise pulmonary function, asthma symptom scores, fraction of exhaled nitric oxide (FENO), and urinary leukotriene (LT) C4-E4 and 9alpha, 11beta-prostagladin (PG) F2] were assessed at the beginning of the trial (usual diet) and at the end of each treatment period.

RESULTS

The ascorbic acid diet significantly reduced (p < 0.05) the maximum fall in post-exercise FEV1 (-6.4 +/- 2.4%) compared to usual (-14.3 +/- 1.6%) and placebo diet (-12.9 +/- 2.4%). Asthma symptoms scores significantly improved (p<0.05) on the ascorbic acid diet compared to the placebo and usual diet. Post-exercise FENO, LTC4-E4 and 9alpha, 11beta-PGF2 concentration was significantly lower (p<0.05) on the ascorbic acid diet compared to the placebo and usual diet.

CONCLUSION

Ascorbic acid supplementation provides a protective effect against exercise-induced airway narrowing in asthmatic subjects.

Dietary antioxidants for the athlete

Physical exercise induces oxidative stress and tissue damage. Although a basal level of reactive oxygen species (ROS) is required to drive redox signaling and numerous physiologic processes, excess ROS during exercise may have adverse implications on health and performance. Antioxidant nutrients may be helpful in that regard. Caution should be exercised against excess antioxidant supplements, however. This article presents a digest for sports practitioners. The following three recommendations are made: 1) it is important to determine the individual antioxidant need of each athlete performing a specific sport; 2) multinutrient preparations, as opposed to megadoses of any single form of nutrient, seem to be a more prudent path to choose; and 3) for outcomes of antioxidant supplementation, performance should not be the only criteria. Overall well being of the athlete, faster recovery, and minimization of injury time could all be affected by antioxidant therapy.

Carotenoid actions and their relation to health and disease

Based on extensive epidemiological observation, fruits and vegetables that are a rich source of carotenoids are thought to provide health benefits by decreasing the risk of various diseases, particularly certain cancers and eye diseases. The carotenoids that have been most studied in this regard are beta-carotene, lycopene, lutein and zeaxanthin. In part, the beneficial effects of carotenoids are thought to be due to their role as antioxidants. beta-Carotene may have added benefits due its ability to be converted to vitamin A. Additionally, lutein and zeaxanthin may be protective in eye disease because they absorb damaging blue light that enters the eye. Food sources of these compounds include a variety of fruits and vegetables, although the primary sources of lycopene are tomato and tomato products. Additionally, egg yolk is a highly bioavailable source of lutein and zeaxanthin. These carotenoids are available in supplement form. However, intervention trials with large doses of beta-carotene found an adverse effect on the incidence of lung cancer in smokers and workers exposed to asbestos. Until the efficacy and safety of taking supplements containing these nutrients can be determined, current dietary recommendations of diets high in fruits and vegetables are advised.

Airway and Circulating Levels of Carotenoids in Asthma and Healthy Controls

BACKGROUND

Elevated oxidative stress and impaired antioxidant defences are increasingly recognised features of asthma. Carotenoids are potent dietary antioxidants that may protect against asthma by reducing oxidative damage.

OBJECTIVES

This study aimed firstly, to characterise circulating and airway levels of carotenoids in asthma compared to healthy controls, in relation to dietary intake. Secondly, the study aimed to test whether airway lycopene defences can be improved using oral supplements.

METHODS

Induced sputum and peripheral blood samples were collected from subjects with asthma (n = 15) and healthy controls (n = 16). Dietary carotenoid intakes were estimated using the 24-hour recall method and analysed using a modified version of the Foodworks 210 Nutrient Calculation Software. Another group of healthy controls (n = 9) were supplemented with 20 mg/day lycopene for 4 weeks. Carotenoids (beta-carotene, lycopene, alpha-carotene, beta-cryptoxanthin, lutein/zeaxanthin) were measured by HPLC.

RESULTS

Despite similar dietary intake, whole blood levels of total carotenoids, lycopene, lutein, beta-cryptoxanthin, alpha-carotene and beta-carotene were significantly lower in asthma than controls. However, there were no differences in plasma or sputum carotenoid levels. Induced sputum carotenoid levels were significantly lower than plasma and whole blood levels, but correlated strongly with plasma levels (r = 0.798, p < 0.001). Although there were no overall increases in either plasma or sputum lycopene levels following supplementation, changes in airway lycopene levels correlated with changes in plasma levels (r = 0.908, p < 0.002).

CONCLUSIONS

Whole blood, but not plasma or sputum, carotenoid levels are deficient in asthma. Plasma carotenoid levels reflect airway carotenoid levels and when plasma levels are improved using oral supplements this is reflected in the airways.

Effect of lycopene supplementation on lung function after exercise in young athletes who complain of exercise-induced bronchoconstriction symptoms

BACKGROUND

It has been suggested that exercise-induced bronchoconstriction may involve oxidative stress. Strenuous exercise promotes free radical production, which can lead to many of the pathophysiologic changes associated with asthma, including bronchoconstriction, mucus secretion, and microvascular leakage. Lycopene has been shown to have high antioxidative activity.

OBJECTIVE

To evaluate the effect of lycopene supplementation on airway hyperreactivity and inflammation in young athletes who complain of difficulty in breathing related to physical exertion.

METHODS

Nineteen young athletes with exercise-related difficulty in breathing visited the exercise laboratory 3 times. During the first visit, participants underwent a baseline evaluation of exercise-induced bronchoconstriction. Daily for 1 week before each of the 2 subsequent visits, participants ingested 30 mg of lycopene (a natural antioxidant) or placebo (in randomized order, double-blind). A 2-week washout period was given between each visit. During each visit, lung functions were evaluated before and after an 8-minute run on the treadmill (85% of the predicted maximal heart rate).

RESULTS

There was no difference in the mean+/-SD decrease in forced expiratory volume in 1 second after exercise during lycopene treatment compared with placebo treatment (11.8%+/-12.5% and 11.0%+/-11.6%). In addition, there was no apparent division into responders and nonresponders.

CONCLUSION

A daily dose of lycopene for 1 week does not affect lung function after exercise and may not provide any protective effect against clinical difficulty in breathing in young athletes.

Serum antioxidant concentrations among U.S. adults with self-reported asthma

Antioxidants may protect the lungs of people with asthma against oxidative stress. Among participants aged > or = 20 years from the Third National Health and Nutrition Examination Survey (1988-1994), we examined serum antioxidant concentrations of 771 persons with current asthma, 352 persons with former asthma, and 15,418 persons without asthma. After adjustment for age, participants with current asthma had similar mean concentrations of vitamin A, retinyl esters, vitamin C, vitamin E, vitamin E/cholesterol ratio, vitamin E/triglyceride ratio, alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein/zeaxanthin, lycopene, and selenium as participants without asthma. We repeated these analyses among participants who did not use vitamin or mineral supplements. After age adjustment, participants with current asthma had lower vitamin C and beta-cryptoxanthin concentrations and a lower mean vitamin E/triglyceride ratio than participants without asthma. In multiple linear regression models that included age, sex, race or ethnicity, education, smoking status, nonhigh-density lipoprotein cholesterol concentration, high-density lipoprotein cholesterol concentration, body mass index, physical activity, and alcohol use, asthma status was not significantly associated with any of the antioxidant concentrations. However, lower vitamin C concentrations were observed among people with current or former asthma than among people who never had asthma (p = 0.014). In the United States, people with asthma do not have manifest antioxidant deficiencies.

Dietary components with demonstrated effectiveness in decreasing the severity of exercise-induced asthma

Exercise-induced asthma (EIA) occurs in up to 90% of individuals with asthma and approximately 10% of the general population without asthma. EIA describes a condition in which vigorous physical activity triggers acute airway narrowing with heightened airway reactivity resulting in reductions in forced expiratory volume in 1 second of greater than 10% compared with pre-exercise values. Treatment of EIA almost exclusively involves the use of pharmacological medications. However, there is accumulating evidence that a dietary excess of salt and omega-6 fatty acids, and a dietary deficiency of antioxidant vitamins and omega-3 fatty acids, can modify the severity of EIA. The modification of these dietary factors has the potential to reduce the incidence and prevalence of this disease. The dietary component most studied to date is dietary salt. Recent studies have supported a role for dietary salt as a modifier of the severity of EIA, suggesting that salt-restrictive diets can reduce the severity of EIA. Since EIA is part of the asthmatic diathesis, it is possible that EIA may serve as a useful model for investigation of potential dietary interventions for reducing airway hyperresponsiveness.

Fish oil supplementation reduces severity of exercise-induced bronchoconstriction in elite athletes

In elite athletes, exercise-induced bronchoconstriction (EIB) may respond to dietary modification, thereby reducing the need for pharmacologic treatment. Ten elite athletes with EIB and 10 elite athletes without EIB (control subjects) participated in a randomized, double-blind crossover study. Subjects entered the study on their normal diet, and then received either fish oil capsules containing 3.2 g eicosapentaenoic acid and 2.2 g docohexaenoic acid (n-3 polyunsaturated fatty acid [PUFA] diet; n = 5) or placebo capsules containing olive oil (placebo diet; n = 5) taken daily for 3 weeks. Diet had no effect on preexercise pulmonary function in either group or on postexercise pulmonary function in control subjects. However, in subjects with EIB, the n-3 PUFA diet improved postexercise pulmonary function compared with the normal and placebo diets. FEV1 decreased by 3 +/- 2% on n-3 PUFA diet, 14.5 +/- 5% on placebo diet, and 17.3 +/- 6% on normal diet at 15 minutes postexercise. Leukotriene (LT)E4, 9alpha, 11beta-prostaglandin F2, LTB4, tumor necrosis factor-alpha, and interleukin-1beta, all significantly decreased on the n-3 PUFA diet compared with normal and placebo diets and after the exercise challenge. These data suggest that dietary fish oil supplementation has a markedly protective effect in suppressing EIB in elite athletes, and this may be attributed to their antiinflammatory properties.

Dietary Dunaliella bardawil, a beta-carotene-rich alga, protects against acetic acid-induced small bowel inflammation in rats

BACKGROUND

Reactive oxygen species mediate tissue injury in inflammatory bowel disease. Beta-carotene is known as a potent free radical quencher and antioxidant.

AIM

The authors evaluated the efficacy of prefeeding Dunaliella bardawil, rich in beta-carotene, to ameliorate acid-induced enteritis in a rat model.

METHODS

Enteritis was induced in female Sprague-Dawley rats by injection of 2 mL acetic acid (0.67 mol/L) to a ligated duodenal loop following 10 weeks of feeding diets containing beta-carotene and compared with various controls. The effects of beta-carotene were evaluated by changes in myeloperoxidase activity, histology, and histomorphometry.

RESULTS

Feeding beta-carotene resulted in suppressed mucosal myeloperoxidase activity, both basal and that induced by acetic acid injection. Acetic acid treatment induced major histopathologic changes in the duodenal mucosa, including small, irregular, and distorted villi; damage to the epithelium; edema of the lamina propria; accumulation of inflammatory cells; and hemorrhage. Beta-carotene treatment prevented these acid-induced histopathologic changes, and this was confirmed by histomorphometry of the villi.

CONCLUSIONS

These results demonstrate the effectiveness of beta-carotene in a rat model as a prophylactic dietary measure in reducing the effects of acid-induced enteritis and raise the possibility that patients with Crohn's disease may benefit from the consumption of natural beta-carotene.

Review of exercise-induced asthma

PURPOSE

The purpose of this manuscript is to review the recent literature on exercise-induced asthma (EIA) and summarize the pathogenesis, diagnosis, and treatment of this condition.

METHOD

A review of the English language medical literature was performed to obtain articles on EIA.

RESULTS

The pathophysiology of EIA is not fully understood, but there are two theories: 1) the hyperosmolar theory and 2) the airway rewarming theory. In addition, there have been data to show that airway inflammation is present in some elite athletes, especially in cold weather sports. The diagnosis of EIA is usually straightforward in most patients, but a number of patients may have atypical symptoms and may be more difficult to diagnose. They may well need exercise testing or eucapnic voluntary ventilation testing. Most people respond to treatment with an inhaled beta agonist and or cromolyn before exercise, but some patients will also need other medications, including daily medications such as inhaled steroids. When treatment does not control the problem, then further diagnostic evaluation should be done to rule out conditions other than EIA, such as vocal cord dysfunction or cardiac or pulmonary problems.

CONCLUSIONS

EIA is a condition that may occur in schoolchildren in gym class and also in Olympic athletes. The diagnosis and treatment is usually fairly straightforward, but at times it may be challenging. However, all patients should be followed to make sure that the correct diagnosis is made and to make sure that treatment is effective.

Reduction of exercise-induced asthma oxidative stress by lycopene, a natural antioxidant

BACKGROUND

Lycopene has previously been shown to have high antioxidative activity. In view of the controversy regarding the beneficial effect of antioxidants on asthma, the acute effects of lycopene (LYC-O-MATO) on airway hyperreactivity were assessed in patients with exercise-induced asthma (EIA).

METHODS

Twenty patients with EIA participated in our study to verify the antioxidative effects. The test was based on the following sequence: measurement of baseline pulmonary function, 7-min exercise session on a motorized treadmill, 8-min rest and again measurement of pulmonary function, 1-week, oral, randomly administered, double-blind supplementation of placebo or 30 mg/day of lycopene (LYC-O-MATO), measurement of pulmonary function at rest, 7-min exercise session, and 8-min rest and again measurement of pulmonary function. A 4-week washout interval was allowed between each protocol.

RESULTS

All patients given placebo showed significant postexercise reduction of more than 15% in their forced expiratory volume in 1 s (FEV1). After receiving a daily dose of 30 mg of lycopene for 1 week, 11 (55%) patients were significantly protected against EIA. Serum analyses of the patients by high-pressure liquid chromatography detected in the lycopene-supplemented patients an elevated level of lycopene compared to the placebo group, with no change in retinol, tocopherols, or in the other carotenoids.

CONCLUSIONS

Our results indicate that a daily dose of lycopene exerts a protective effect against EIA in some patients, most probably through an in vivo antioxidative effect.

Atopic diseases and upper respiratory infections

This article reviews information on the topics of asthma, atopic dermatitis, food allergy, and upper respiratory infections. The asthma section provides an in-depth look at sociodemographic factors contributing to asthma morbidity and the barriers to asthma control. New findings on the triggers and therapies of atopic dermatitis and new articles on formula allergy and peanut allergy are presented. Recent publications in the areas of sinusitis and upper respiratory infections are also reviewed.