Soy, isoflavones, and prevalence of allergic rhinitis in Japanese women: the Osaka Maternal and Child Health Study

Unlocking daidzein's healing power: Present applications and future possibilities in phytomedicine

BACKGROUND

Cancer is one of the leading causes of death and a great threat to people around the world. Cancer treatment modalities include surgery, radiotherapy, chemotherapy, radiochemotherapy, hormone therapy, and immunotherapy. The best approach is to use a combination of several types. Among the treatment methods mentioned above, chemotherapy is frequently used, but its activity is hampered by the development of drug resistance and many side effects. In this regard, the use of medicinal plants has been discussed, and in recent decades, the use of isolated phytochemicals came into the focus of interest. By critically evaluating the available evidence and emphasizing the unique perspective offered by this review, we provide insights into the potential of daidzein as a promising therapeutic agent, as well as outline future research directions to optimize its efficacy in clinical settings.

PURPOSE

To summarized the therapeutic potential of daidzein, an isoflavone phytoestrogen in the management of several human diseases with the focuses on the current status and future prospects as a therapeutic agent.

METHODS

Several search engines, including PubMed, GoogleScholar, and ScienceDirect, were used, with the search terms "daidzein", "daidzein therapeutic potential", or individual effects. The study included all peer-reviewed articles. However, the most recent publications were given priority.

RESULTS

Daidzein showed protective effects against malignant diseases such as breast cancer, prostate cancer but also non-malignant diseases such as diabetes, osteoporosis, and cardiovascular diseases. Daidzein activates multiple signaling pathways leading to cell cycle arrest and apoptosis as well as antioxidant and anti-metastatic effects in malignant cells. Moreover, the anticancer effects against different cancer cells were more prominent and discussed in detail.

CONCLUSIONS

In short, daidzein represents a promising compound for drug development. The comprehensive potential anticancer activities of daidzein through various molecular mechanisms and its therapeutic/clinical status required further detail studies.

Association of Dietary Polyunsaturated Fatty Acid Intake with Allergic Rhinitis in Adults: A Cross-Sectional Study of NHANES 2005-2006

INTRODUCTION

The incidence of allergic rhinitis (AR) is increasing year by year, and the pathogenesis is complex, in which diet may play an important role. The role of polyunsaturated fatty acids (PUFAs) in AR is still controversial. Previous studies have looked at the effects of PUFA during pregnancy, childhood, and adolescence. In this study, we aimed to determine the association between dietary intake of PUFA and AR in adults.

METHODS

We used the NHANES database from 2005 to 2006 to include a total of 4,211 adult subjects. We collected dietary PUFA intake data and information on AR. Logistic regression and restricted cubic spline models were constructed to examine the association between PUFA intake and AR in adults. The t test was used to compare daily PUFA intakes in patients with and without AR.

RESULTS

In the fully adjusted model (OR: 1.016; 95% CI: 1.003; 1.028), PUFA intake was positively correlated with allergic symptoms, hay fever, and AR in adults (p < 0.05). In addition, daily PUFA intake was significantly higher in people with allergic symptoms, hay fever, and AR than in people without the disease (p < 0.01).

CONCLUSIONS

Our results suggest a positive association between dietary PUFA intake and AR in adults to a certain extent. Future studies on dietary PUFA dose will provide new strategies for the prevention and treatment of allergic diseases such as AR related to non-pharmaceutical interventions.

Protective Effect of Daidzein against Diethylnitrosamine/Carbon Tetrachloride-Induced Hepatocellular Carcinoma in Male Rats

Hepatocellular carcinoma (HCC) is the second-largest cause of death among all cancer types. Many drugs have been used to treat the disease for a long time but have been mostly discontinued because of their side effects or the development of resistance in the patients with HCC. The administration of DZ orally is a great focus to address the clinical crisis. Daidzein (DZ) is a prominent isoflavone polyphenolic chemical found in soybeans and other leguminous plants. It has various pharmacological effects, including anti-inflammatory, antihemolytic, and antioxidant. This present study investigates the protective effect of DZ on chemically induced HCC in rat models. The DZ was administered orally four weeks before HCC induction and continued during treatment. Our study included four treatment groups: control (group 1, without any treatment), HCC-induced rats (group II), an HCC group treated with DZ at 20 mg/kg (group III), and an HCC group treated with DZ at 40 mg/kg (group IV). HCC rats showed elevation in all the HCC markers (AFP, GPC3, and VEGF), liver function markers (ALP, ALT, and AST), inflammatory markers (IL-6, TNF-α, and CRP), and lipid markers concomitant with a decrease in antioxidant enzymes and protein. However, groups III and IV demonstrated dose-dependent alleviation in the previous parameters resulting from HCC. In addition, the high dose of DZ reduces many hepatological changes in HCC rats. All study parameters improved with DZ administration. Due to its antioxidant and anti-inflammatory characteristics, DZ is a promising HCC treatment option for clinical use.

Associations between maternal urinary isoflavone concentrations and anogenital distance of offspring throughout infancy: a prospective cohort study

STUDY QUESTION

Are maternal urinary isoflavone (ISO) concentrations during pregnancy associated with anogenital distance (AGD) in infants at birth, and at 6 and 12 months of age?

SUMMARY ANSWER

Higher maternal urinary ISO concentrations during pregnancy were associated with longer AGD in infants of both sexes, and equol (EQU) and daidzein (DAD) were identified as the important ISO mixture components in the observed associations.

WHAT IS KNOWN ALREADY

Evidence of the association of prenatal exposure to ISO with offspring's AGD is mainly derived from animal studies, which used different study designs and had inconsistent results. Only one human study has been reported and it found null associations between maternal ISO exposure during pregnancy and AGD among boys at birth, with a small sample size and a wide range of exposure windows. No human study on girls was found.

STUDY DESIGN, SIZE, DURATION

Prospective cohort study (Shanghai-Minhang Birth Cohort Study), with pregnant women recruited at 12-16 weeks of gestation in Shanghai, China between April and December 2012. One thousand two hundred and twenty-five live singletons were left in the cohort at delivery of which 480 mother-infant pairs had data on both maternal urinary ISO concentrations and at least one AGD measurement and were included in the present study. Anopenile distance (AGDAP) and anoscrotal distance (AGDAS) of boys and anoclitoral distance (AGDAC) and anofourchette distance (AGDAF) of girls were measured at birth and at 6 and 12 months of age.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Multiple linear regression models were used to examine the associations between maternal ISO concentrations and AGD. Bayesian kernel machine regression (BKMR) was implemented to examine both the overall effects of ISO mixture and the single effect of each ISO and identify important components of ISO mixture.

MAIN RESULTS AND THE ROLE OF CHANCE

A general profile of higher concentrations of maternal ISO associated with longer AGD in infants of both sexes was observed, when maternal education, parity, BMI before pregnancy (BMI, categorical variable), passive smoking during early pregnancy, age at delivery, gestational weeks and infant body size were adjusted for. Among boys, EQU was associated with increased AGDAS at birth and at 6 and 12 months, and DAD was associated with increased AGDAP at birth. Among girls, the associations of EQU and DAD with increased AGDAC and AGDAF at birth were found. When gestational weight gain and feeding patterns of infants in the first 6 months were additionally adjusted for, and maternal BMI was adjusted for as a continuous variable, more pronounced associations were observed, especially for associations of genistein (GEN), DAD and glycitein (GLY) with increased AGDAP and AGDAS at 6 months in boys. However, these associations were not always observed in the highest tertile group, and no consistent dose-response relationships were found. Similar results were observed in BKMR models, showing positive correlations of concentration of ISO mixture with increased AGDAS at both 6 and 12 months among boys, and increased AGDAC and AGDAF at birth among girls. Statistically significant increments of 4.96 mm (95% credible interval (CrI): 1.40, 8.52) and 1.07 mm (95% CrI: 0.02, 2.13) in AGDAS at 6 months among boys and AGDAC at birth among girls, respectively, were observed at the 75th percentile of ISO mixture, compared with 25th percentile. EQU and DAD were identified as the important components among ISO-AGD associations.

LIMITATIONS, REASONS FOR CAUTION

First, due to the short half-lives of ISO, the accuracy of a single spot urine sample reflecting ISO exposure during pregnancy may be limited, and thus may cause non-differential misclassification. Second, despite the adjustments for several important covariates in the study, unmeasured and residual confounding factors may remain a concern. Third, false discovery due to multiple testing may remain. Finally, the reduced sample sizes attributed to the loss of follow-up and missing data of confounders may limit our ability to detect an association, if any existed.

WIDER IMPLICATIONS OF THE FINDINGS

Prenatal ISO exposure may affect the reproductive development of offspring. As ISO can be widely detected in pregnant women, especially in Eastern countries, more studies are warranted to provide evidence of the effects of prenatal ISO exposure on long-term reproductive outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by grants from the National Key Research and Development Program of China (2021YFC2701003), the National Natural Science Foundation of China (22076123), the Science and Technology Commission of Shanghai Municipality (21ZR1454700 and 20ZR1448000), the Shanghai Municipal Health Commission (20194Y0160) and Innovation-oriented Science and Technology Grant from NHC Key Laboratory of Reproduction Regulation (CX2022-04). The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

The health effects of soy: A reference guide for health professionals

Soy is a hotly debated and widely discussed topic in the field of nutrition. However, health practitioners may be ill-equipped to counsel clients and patients about the use of soyfoods because of the enormous, and often contradictory, amount of research that has been published over the past 30 years. As interest in plant-based diets increases, there will be increased pressure for practitioners to gain a working knowledge of this area. The purpose of this review is to provide concise literature summaries (400-500 words) along with a short perspective on the current state of knowledge of a wide range of topics related to soy, from the cholesterol-lowering effects of soy protein to the impact of isoflavones on breast cancer risk. In addition to the literature summaries, general background information on soyfoods, soy protein, and isoflavones is provided. This analysis can serve as a tool for health professionals to be used when discussing soyfoods with their clients and patients.

The Fermented Soy Product ImmuBalanceTM Suppresses Airway Inflammation in a Murine Model of Asthma

The fermented soy product ImmuBalance contains many active ingredients and its beneficial effects on some allergic diseases have been reported. We hypothesized that ImmuBalance could have potential effects on airway inflammation in a murine model of asthma. Mice sensitized and challenged with ovalbumin developed airway inflammation. Bronchoalveolar lavage fluid was assessed for inflammatory cell counts and levels of cytokines. Lung tissues were examined for cell infiltration and mucus hypersecretion. Oral administration of ImmuBalance significantly inhibited ovalbumin-induced eosinophilic inflammation and decreased Th2 cytokine levels in bronchoalveolar lavage fluid (p < 0.05). In addition, lung histological analysis showed that ImmuBalance inhibited inflammatory cell infiltration and airway mucus production. Our findings suggest that supplementation with ImmuBalance may provide a novel strategy for the prevention or treatment of allergic airway inflammation.

Therapeutic Potential of Isoflavones with an Emphasis on Daidzein

Daidzein is a phytoestrogen isoflavone found in soybeans and other legumes. The chemical composition of daidzein is analogous to mammalian estrogens, and it could be useful with a dual-directional purpose by substituting/hindering with estrogen and estrogen receptor (ER) complex. Hence, daidzein puts forth shielding effects against a great number of diseases, especially those associated with the control of estrogen, such as breast cancer, diabetes, osteoporosis, and cardiovascular disease. However, daidzein also has other ER-independent biological activities, such as oxidative damage reduction acting as an antioxidant, immune regulator as an anti-inflammatory agent, and apoptosis regulation, directly linked to its potential anticancer effects. In this sense, the present review is aimed at providing a deepen analysis of daidzein pharmacodynamics and its implications in human health, from its best-known effects alleviating postmenopausal symptoms to its potential anticancer and antiaging properties.

Current Perspectives on the Beneficial Effects of Soybean Isoflavones and Their Metabolites for Humans

Soybeans are rich in proteins and lipids and have become a staple part of the human diet. Besides their nutritional excellence, they have also been shown to contain various functional components, including isoflavones, and have consequently received increasing attention as a functional food item. Isoflavones are structurally similar to 17-β-estradiol and bind to estrogen receptors (ERα and ERβ). The estrogenic activity of isoflavones ranges from a hundredth to a thousandth of that of estrogen itself. Isoflavones play a role in regulating the effects of estrogen in the human body, depending on the situation. Thus, when estrogen is insufficient, isoflavones perform the functions of estrogen, and when estrogen is excessive, isoflavones block the estrogen receptors to which estrogen binds, thus acting as an estrogen antagonist. In particular, estrogen antagonistic activity is important in the breast, endometrium, and prostate, and such antagonistic activity suppresses cancer occurrence. Genistein, an isoflavone, has cancer-suppressing effects on estrogen receptor-positive (ER+) cancers, including breast cancer. It suppresses the function of enzymes such as tyrosine protein kinase, mitogen-activated kinase, and DNA polymerase II, thus inhibiting cell proliferation and inducing apoptosis. Genistein is the most biologically active and potent isoflavone candidate for cancer prevention. Furthermore, among the various physiological functions of isoflavones, they are best known for their antioxidant activities. S-Equol, a metabolite of genistein and daidzein, has strong antioxidative effects; however, the ability to metabolize daidzein into S-equol varies based on racial and individual differences. The antioxidant activity of isoflavones may be effective in preventing dementia by inhibiting the phosphorylation of Alzheimer's-related tau proteins. Genistein also reduces allergic responses by limiting the expression of mast cell IgE receptors, which are involved in allergic responses. In addition, they have been known to prevent and treat various diseases, including cardiovascular diseases, metabolic syndromes, osteoporosis, diabetes, brain-related diseases, high blood pressure, hyperlipidemia, obesity, and inflammation. Further, it also has positive effects on menstrual irregularity in non-menopausal women and relieving menopausal symptoms in middle-aged women. Recently, soybean consumption has shown steep increasing trend in Western countries where the intake was previously only 1/20-1/50 of that in Asian countries. In this review, I have dealt with the latest research trends that have shown substantial interest in the biological efficacy of isoflavones in humans and plants, and their related mechanisms.

Maternal Dietary Protein Patterns During Pregnancy and the Risk of Infant Eczema: A Cohort Study

Background: Previous studies have suggested that maternal dietary protein was associated with allergic diseases in offspring, but few studies have evaluated the influence of dietary protein patterns. This study aimed to explore the prospective association between maternal dietary protein patterns during pregnancy and the risk of infant eczema.

Methods: A total of 713 mother-child pairs from a prospective cohort in Guangzhou, China were recruited. Maternal dietary protein was estimated using a validated face-to-face food frequency questionnaire at 20–28 weeks' gestation from 2017 to 2018. Dietary protein patterns were calculated based on the sources of protein. The data of infant eczema was assessed at 6 months of age using the symptom questionnaire of eczema. Logistic regression was carried out to examine the associations between maternal dietary protein patterns and infant eczema.

Results: The cumulative incidence of infant eczema at 6 months of age was 51.19%. Mothers of infants with eczema consumed more protein from poultry source during pregnancy than mothers of infants without eczema, while no statistical differences were observed in maternal intakes of protein from cereals and tubers, vegetables, fruits, red meat, fish and seafood, eggs, dairy, soybean, and nuts and seeds. Four dietary protein patterns were identified and termed poultry, plant, dairy and eggs, and red meat and fish. The cumulative incidence of eczema was 61.2, 45.8, 48.0, 51.4% for these four patterns, respectively. Compared to the poultry dietary pattern, the plant pattern and the dairy and eggs pattern were associated with a reduced risk of infant eczema, and the adjusted odds ratios (95% confidence interval) were 0.572 (0.330–0.992), 0.478 (0.274–0.837), respectively. No such association was observed for the red meat and fish dietary protein pattern.

Conclusion: This is the first study that focused on the association between maternal dietary protein during pregnancy from a whole-diet perspective and infant eczema. Compared with the poultry dietary protein pattern, the maternal plant pattern and the dairy and eggs pattern during pregnancy were associated with a reduced risk of infant eczema.

Neither soyfoods nor isoflavones warrant classification as endocrine disruptors: a technical review of the observational and clinical data

Soybeans are a rich source of isoflavones, which are classified as phytoestrogens. Despite numerous proposed benefits, isoflavones are often classified as endocrine disruptors, based primarily on animal studies. However, there are ample human data regarding the health effects of isoflavones. We conducted a technical review, systematically searching Medline, EMBASE, and the Cochrane Library (from inception through January 2021). We included clinical studies, observational studies, and systematic reviews and meta-analyses (SRMA) that examined the relationship between soy and/or isoflavone intake and endocrine-related endpoints. 417 reports (229 observational studies, 157 clinical studies and 32 SRMAs) met our eligibility criteria. The available evidence indicates that isoflavone intake does not adversely affect thyroid function. Adverse effects are also not seen on breast or endometrial tissue or estrogen levels in women, or testosterone or estrogen levels, or sperm or semen parameters in men. Although menstrual cycle length may be slightly increased, ovulation is not prevented. Limited insight could be gained about possible impacts of in utero isoflavone exposure, but the existing data are reassuring. Adverse effects of isoflavone intake were not identified in children, but limited research has been conducted. After extensive review, the evidence does not support classifying isoflavones as endocrine disruptors.

Associations between healthy Japanese dietary patterns and depression in Japanese women

OBJECTIVE

Higher quality dietary patterns such as healthy/prudent and Mediterranean dietary patterns have been protectively associated with depression. This study examined whether healthy Japanese dietary patterns, which differ from dietary patterns derived from Western areas, are associated with depressive symptoms among Japanese women.

DESIGN

A cross-sectional study (the Nagano Nutrition and Health Study). Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale. Dietary patterns were derived with a principal component analysis of the consumption of fifty-six food and beverage items, which were assessed by a validated brief diet history questionnaire.

SETTING

Nagano, Japan.

PARTICIPANTS

Japanese women (n 1337) aged 20-72 years.

RESULTS

We identified three dietary patterns: 'healthy Japanese', 'sweets-fat' and 'seafood-alcohol'. The highest quality dietary pattern was 'healthy Japanese'. It is characterised by a high intake of vegetables, mushrooms, seaweed, soyabean products, potatoes, fish/shellfish and fruit. The age- and multivariate-adjusted OR (95 % CI) of depressive symptoms for the highest quartiles of the 'healthy Japanese' pattern score were 0·58 (95 % CI 0·41, 0·82) and 0·69 (95 % CI 0·45, 1·06), respectively. Meanwhile, no associations were observed for 'sweets-fat' and 'seafood-alcohol' patterns.

CONCLUSIONS

The 'healthy Japanese' pattern may be inversely associated with depressive symptoms with an exposure-response association. The specific Japanese food groups in the 'healthy Japanese' pattern included mushrooms, seaweed, soyabean products and potatoes, as well as vegetables, fish/shellfish and fruit. These seem to create an anti-inflammation-prone dietary pattern, and this factor might be associated with better mental health.

The Hekinan Children's Study: Design and Profile of Participants at Baseline

BACKGROUND

The early life environment is now recognized as a key factor contributing to susceptibility to certain diseases in later life.

METHODS

We initiated a cohort study among school children in 2011 to primarily investigate the associations between lifestyle and environmental factors and some surrogate markers of chronic diseases, such as cardiometabolic risk factors (ie, obesity, high blood pressure, high blood glucose, insulin, or lipids) and cancer risk factors (ie, height and age at menarche). A baseline questionnaire asked for information, including demographic variables, medical history and use of medication, dietary habits, physical activity, sleep habits, and behavioral and emotional problems of children. Follow-up surveys are planned for the fourth grade of elementary school and the first grade of junior high school. At these follow-up surveys, fasting blood samples will be obtained to measure cardiometabolic markers. We also checked the validity of a food frequency questionnaire, which was originally created for 6-year-olds but was modified for use in older children.

RESULTS

A total of 3,141 first-year students at elementary schools in Hekinan City, Aichi Prefecture, participated in the study. The response rate was 87.4%. The means of age and body mass index were 6.99 (standard deviation, 0.28) years and 15.3 (standard deviation, 1.7) kg/m2, respectively, in the 3,067 Japanese children (1,639 boys and 1,428 girls).

CONCLUSIONS

This cohort will reveal determinants of cardiometabolic risk factors and cancer risk factors during childhood.

Anti-inflammatory effects of flavonoids

Inflammation plays a key role in diseases such as diabetes, asthma, cardiovascular diseases and cancer. Diet can influence different stages of inflammation and can have an important impact on several inflammatory diseases. Increasing scientific evidence has shown that polyphenolic compounds, such as flavonoids, which are found in fruits, vegetables, legumes, or cocoa, can have anti-inflammatory properties. Recent studies have demonstrated that flavonoids can inhibit regulatory enzymes or transcription factors important for controlling mediators involved in inflammation. Flavonoids are also known as potent antioxidants with the potential to attenuate tissue damage or fibrosis. Consequently, numerous studies in vitro and in animal models have found that flavonoids have the potential to inhibit the onset and development of inflammatory diseases. In the present review, we focused in flavonoids, the most abundant polyphenols in the diet, to give an overview of the most recent scientific knowledge about their impact on different inflammatory diseases.

The inhibitory effect of soybean and soybean isoflavone diets on 2,4-dinitrofluorobenzene-induced contact hypersensitivity in mice

Murine contact hypersensitivity (CHS) is one of the most frequently used animal models of human allergic contact dermatitis. We investigated the inhibitory effects of soybean and soy isoflavone (SI) diets on 2,4-dinitrofluorobenzene- (DNFB) induced CHS in mice. The DNFB-induced ear swelling was inhibited in the soy- and SI-treated groups. Histopathological investigations revealed that oral feeding of soybean and SI attenuated ear tissue edema and reduced the number of Gr-1(+) cell infiltrations into ear tissues. DNA microarray analysis showed that the expression of Ccl24, Xcl1, Ifng, and Ccl17 in the ear tissues was lower in the soy-treated mice than in the positive controls. In addition, CCL24 mRNA and protein expression in the ear tissues were more highly suppressed in the soy- and SI-treated groups. These results suggest that soybean and SI consumption downregulated the gene and protein expression of CCL24, thereby affording protection against CHS in mice.

Effect of a soy isoflavone supplement on lung function and clinical outcomes in patients with poorly controlled asthma: a randomized clinical trial

IMPORTANCE

Soy isoflavone supplements are used to treat several chronic diseases, although the data supporting their use are limited. Some data suggest that supplementation with soy isoflavone may be an effective treatment for patients with poor asthma control.

OBJECTIVE

To determine whether a soy isoflavone supplement improves asthma control in adolescent and adult patients with poorly controlled disease.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter, randomized, double-blind, placebo-controlled trial conducted between May 2010 and August 2012 at 19 adult and pediatric pulmonary and allergy centers in the American Lung Association Asthma Clinical Research Centers network. Three hundred eighty-six adults and children aged 12 years or older with symptomatic asthma while taking a controller medicine and low dietary soy intake were randomized, and 345 (89%) completed spirometry at week 24.

INTERVENTIONS

Participants were randomly assigned to receive soy isoflavone supplement containing 100 mg of total isoflavones (n=193) or matching placebo (n=193) in 2 divided doses administered daily for 24 weeks.

MAIN OUTCOMES AND MEASURES

The primary outcome measure was change in forced expiratory volume in the first second (FEV1) at 24 weeks. Secondary outcome measures were symptoms, episodes of poor asthma control, Asthma Control Test score (range, 5-25; higher scores indicate better control), and systemic and airway biomarkers of inflammation.

RESULTS

Mean changes in prebronchodilator FEV1 over 24 weeks were 0.03 L (95% CI, -0.01 to 0.08 L) in the placebo group and 0.01 L (95% CI, -0.07 to 0.07 L) in the soy isoflavone group, which were not significantly different (P = .36). Mean changes in symptom scores on the Asthma Control Test (placebo, 1.98 [95% CI, 1.42-2.54] vs soy isoflavones, 2.20 [95% CI, 1.53-2.87]; positive values indicate a reduction in symptoms), number of episodes of poor asthma control (placebo, 3.3 [95% CI, 2.7-4.1] vs soy isoflavones, 3.0 [95% CI, 2.4-3.7]), and changes in exhaled nitric oxide (placebo, -3.48 ppb [95% CI, -5.99 to -0.97 ppb] vs soy isoflavones, 1.39 ppb [95% CI, -1.73 to 4.51 ppb]) did not significantly improve more with the soy isoflavone supplement than with placebo. Mean plasma genistein level increased from 4.87 ng/mL to 37.67 ng/mL (P < .001) in participants receiving the supplement.

CONCLUSIONS AND RELEVANCE

Among adults and children aged 12 years or older with poorly controlled asthma while taking a controller medication, use of a soy isoflavone supplement, compared with placebo, did not result in improved lung function or clinical outcomes. These findings suggest that this supplement should not be used for patients with poorly controlled asthma.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01052116.

Pre-illness isoflavone consumption and disease risk of ulcerative colitis: a multicenter case-control study in Japan

Introduction

Previous studies have suggested that estrogens play a role in the development of ulcerative colitis (UC). Because isoflavones have a similar structure to 17β-estradiol, dietary consumption of isoflavones may have similar influences on the development of UC. We examined the association between pre-illness isoflavone consumption and the risk of UC.

Materials and Methods

We conducted a hospital-based case control study, and compared the dietary habits of 126 newly diagnosed UC cases with those of 170 age- and gender-matched hospital controls. Information on dietary factors was collected using a self-administered diet history questionnaire. To consider potential changes in dietary habits due to disease symptoms, the habits were assessed separately during the previous 1 month and at 1 year before the recruitment.

Results

In the assessment of dietary habits during the previous 1 month, the highest tertile of isoflavone consumption revealed an increased odds ratio (OR) for UC (OR = 2.79; 95% confidence interval (CI), 1.39–5.59; Trend P = 0.004). A significant association was also observed for the dietary assessment at 1 year before, when most UC cases had not yet experienced their first disease symptoms (OR = 2.06; 95% CI, 1.05–4.04; Trend P = 0.04). Associations were more pronounced in females (OR in highest tertile of isoflavone consumption at 1 year before = 4.76; 95% CI, 1.30–17.5; Trend P = 0.02) but were obscured in males (corresponding OR = 1.21; 95% CI, 0.49–3.01; Trend P = 0.63).

Conclusions

Dietary isoflavone consumption may be associated with an increased risk of UC, particularly in females. Prospective cohort studies are warranted to confirm these findings.

A legume product fermented by Saccharomyces cerevisiae modulates cutaneous atopic dermatitis-like inflammation in mice

Background

Isoflavone-containing soy products modulate allergic inflammation in mice. In our previously study, IFN-γ and IL-10 production increased in mice fed with Saccharomyces cerevisiae legume fermented product (SCLFP), demonstrating that SCLFP had immunomodulatory activity. In this study, we tested the anti-inflammatory effects of SCLFP in a mouse model of cutaneous atopic dermatitis inflammation induced by epicutaneous sensitization.

Methods

Epicutaneous exposure to protein allergens plus Staphylococcal enterotoxin B induced a T helper (Th)-2–dominant immune response as well as cutaneous atopic dermatitis-like inflammation in BALB/c mice. The thickness of the skin epithelium, eosinophil migration, and T helper responses were determined in patched skin and draining lymph nodes of mice fed with and without SCLFP.

Results

Epicutaneous exposure to protein allergens plus Staphylococcal enterotoxin B induced a T helper (Th)-2–dominant immune response as well as cutaneous atopic dermatitis-like inflammation in BALB/c mice. SCLFP feeding attenuated this cutaneous Th2 response, as evidenced by decreased thickening of the epidermis, less eosinophil infiltration, and lower levels of IL-5, IL-13, and CXCL11 expression compared to controls. Oral administration of SCLFP also modulated Th1 responses in draining lymph nodes, with lower levels of IFN-γ, IL-4, and IL-17 expression.

Conclusion

Oral intake of SCLFP modulated the induced Th2 inflammatory responses in skin and might have potential applications for the prevention and treatment of atopic dermatitis.

7,3',4'-Trihydroxyisoflavone Ameliorates the Development of Dermatophagoides farinae-Induced Atopic Dermatitis in NC/Nga Mice

Atopic dermatitis is an inflammatory and chronically relapsing skin disorder that commonly occurs in children; the number of atopic dermatitis patients is increasing. The cause and mechanism of atopic dermatitis have not been defined clearly, although many studies are ongoing. Epidemiological studies suggest that soybean and its isoflavones have immunoregulatory activities. Here, we report that 7,3′,4′-trihydroxyisoflavone (7,3′,4′-THIF), a major metabolite of daidzin, effectively inhibited lipopolysaccharide (LPS)-induced nitric oxide (NO), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 production in RAW 264.7 cells, and also reduced β-hexosaminidase secretion in RBL-2H3 cells. Moreover, 7,3′,4′-THIF significantly reduced scratching time, transepidermal water loss, and mast cell infiltration. It also decreased protease-activated receptor (PAR)-2 and IL-4 expression and increased filaggrin expression in skin lesions of NC/Nga mice. These results suggest that 7,3′,4′-THIF improves Dermatophagoides farina body extract-induced atopic dermatitis in NC/Nga mice.

Oxidative stress and antioxidant deficiencies in asthma: potential modification by diet

The lungs of asthmatic patients are exposed to oxidative stress due to the generation of reactive oxygen and nitrogen species as a consequence of chronic airway inflammation. Increased concentrations of NO*, H2O2 and 8-isoprostane have been measured in exhaled breath and induced sputum of asthmatic patients. O2*-, NO*, and halides interact to form highly reactive species such as peroxynitrite and HOBr, which in turn cause nitration and bromination of protein tyrosine residues. Oxidative stress may also reduce glutathione levels and cause inactivation of antioxidant enzymes such as superoxide dismutase, with a consequent increase in apoptosis, shedding of airway epithelial cells and airway remodelling. The oxidant/antioxidant equilibrium in asthmatic patients may be further perturbed by low dietary intakes of the antioxidant vitamins C and E, selenium and flavonoids, with a consequent lowering of the concentrations of these and other non-dietary antioxidants such as bilirubin and albumin in plasma and airway epithelial lining fluid. Although supplementation with vitamins C and E appears to offer protection against the adverse effects of ozone, recent randomised, placebo-controlled trials of vitamin C or E supplements for patients with mild asthma have not shown significant benefits over standard therapy. However, genetic variation in glutathione S-transferase may influence the susceptibility of asthmatic individuals to oxidative stress and the extent to which they are likely to benefit from antioxidant supplementation. Long-term prospective trials are required to determine whether modification of dietary intake will benefit asthma patients and reduce the socio-economic burden of asthma in the community.

Therapeutic effects of fermented soycrud on phenotypes of atopic dermatitis induced by phthalic anhydride

Atopic dermatitis (AD), which is known as the most common pruritic skin disease, is caused by epidermal barrier dysfunction, allergies, microwave radiation, histamine intolerance, and genetic defects. To investigate the therapeutic effects of fermented soycrud (FSC) on AD pathology, alteration of AD phenotypes induced by phthalic anhydride (PA) treatment was assessed by ear thickness analysis, measurement of immune-related organ weights, ELISA, and histological and pathological analyses of ICR mice after FSC treatment for 2 weeks. Except for water content, the concentrations of most major components were lower in FSC compared to common tofu (CMT). Thymus and lymph node weights were significantly reduced in ICR mice treated with PA+CMT or PA+FSC, whereas spleen and body weights were maintained. Elevation of ear thickness induced by PA treatment was rapidly diminished in the CMT- and FSC-treated groups, although there was no significant difference between the two groups. Furthermore, significant reduction of epidermal thickness was detected in both the PA+CMT- and PA+FSC-treated groups. However, IgE concentration and dermal thickness were reduced only by PA+FSC treatment, whereas PA+CMT treatment maintained levels comparable to PA+vehicle treatment. The number of infiltrated mast cells was higher in the PA+vehicle-treated group compared to the untreated control. Following CMT or FSC treatment, mast cell infiltration was slightly reduced, although the CMT-treated group showed greater cell numbers. These results indicate that FSC may significantly relieve the phenotypes of AD induced by PA treatment and should be considered as a potential candidate for AD therapy.

Regulation of the immune response by soybean isoflavones

Soybeans are rich in immuno-modulatory isoflavones such as genistein, daidzein, and glycitein. These isoflavones are well-known antioxidants, chemopreventive and anti-inflammatory agents. Several epidemiological studies suggest that consumption of traditional soy food containing isoflavones is associated with reduced prevalence of chronic health disorders. Isoflavones are considered to be phytoestrogens because of their ability to bind to estrogen receptors. The literature is extensive on the chemistry, bio-availability, and bio-activity of isoflavones. However, their effects on immune response are yet to be fully understood, but are beginning to be appreciated. We review the role of isoflavones in regulation of the immune response and their potential clinical applications in immune-dysfunction. Special emphasis will be made regarding in vivo studies including humans and animal model systems.

Isoflavones, genistein and daidzein, regulate mucosal immune response by suppressing dendritic cell function

Lipopolysaccharide (LPS), a component of gram-negative bacterial cell walls, has been shown to have a strong adjuvant effect towards inhaled antigens contributing to airway inflammation. Isoflavones are anti-inflammatory molecules present in abundant quantities in soybeans. We investigated the effect of isoflavones on human dendritic cell (DC) activation via LPS stimulation and subsequent DC-mediated effector cell function both in vitro and in a mouse model of upper airway inflammation. Human monocyte-derived DCs (MDDC) were matured with LPS (or TNF-α) +/− isoflavones (genistein or daidzein). The surface expression levels of DC activation markers were analyzed by flow cytometry. Mature DCs +/− isoflavones were washed and cultured with freshly-isolated allogenic naïve CD4⁺ T cells for 5 days or with autologous natural killer (NK) cells for 2 hours. The percentages of proliferating IFN-γ⁺ CD4⁺ T cells and cytokine levels in culture supernatants were assessed. NK cell degranulation and DC cytotoxicity were measured by flow cytometry. Isoflavones significantly suppressed the activation-induced expression of DC maturation markers (CD83, CD80, CD86) and MHC class I but not MHC class II molecules in vitro. Isoflavone treatment inhibited the ability of LPS-DCs to induce IFN-γ in CD4⁺ T cells. NK cell degranulation and the percentage of dead DCs were significantly increased in isoflavone-treated DC-NK co-culture experiments. Dietary isoflavones suppressed the mucosal immune response to intra-nasal sensitization of mice to ovalbumin. Similar results were obtained when isoflavones were co-administered during sensitization. These results demonstrate that soybean isoflavones suppress immune sensitization by suppressing DC-maturation and its subsequent DC-mediated effector cell functions.

Supplementation of the fermented soy product ImmuBalance™ effectively reduces itching behavior of atopic NC/Tnd mice

BACKGROUND

Effects of probiotics on the prevention of atopic diseases have been proposed recently. Although we have already reported the suppressive effects of the probiotic, ImmuBalance™, on a mouse model for peanuts allergy, its influence on atopic diseases remains unclear.

OBJECTIVE

Potential efficacy of ImmuBalance™, which is the fermented soy product, on treatment of atopic dermatitis (AD) was investigated using a mouse model for human AD, NC/Tnd mice.

METHODS

For in vivo study, ImmuBalance containing chow or a control diet were fed to NC/Tnd mice with moderate dermatitis for 2 weeks. Topical application of FK506 ointment was used as a positive control. Clinical skin severity scores, scratching behaviors, trans-epidermal water loss (TEWL), and histological features were analyzed. For in vitro study, suppressive effect of ImmuBalance™ on nerve growth factor (NGF)-activated neurite outgrowth of PC12 cells was examined.

RESULTS

Clinical skin severity scores of the mice fed with ImmuBalance containing chow were gradually reduced as well as the mice treated with FK506. Feeding with ImmuBalance completely inhibited the increase in scratching behavior of NC/Tnd mice. The value of TEWL of NC/Tnd mice fed with ImmuBalance was significantly decreased. In addition, histological examination revealed that application of ImmuBalance decreased the number of PGP9.5-positive neuronal fibers in the lesional skin. When ImmuBalance extract was added to the culture, NGF-activated neurite outgrowth of PC12 cells was diminished through the inhibition of the phosphatidylinositol 3-kinase phosphorylation.

CONCLUSION

ImmuBalance could exhibit favorable alterations on AD symptoms, particularly through down regulation of the itch sensation.

Dairy products and calcium intake during pregnancy and dental caries in children

Background

Maternal nutrition status during pregnancy may affect fetal tooth development, formation, and mineralization, and may affect dental caries susceptibility in children. We investigated the association between maternal intake of dairy products and calcium during pregnancy and the risk of childhood dental caries.

Methods

Subjects were 315 Japanese mother-child pairs. Data on maternal intake during pregnancy were assessed through a diet history questionnaire. Outcome data was collected at 41–50 months of age. Children were classified as having dental caries if one or more primary teeth had decayed or been filled.

Results

Higher maternal cheese intake during pregnancy was significantly inversely associated with the risk of dental caries in children, showing a clear inverse dose–response relationship; the adjusted odds ratio (OR) in comparison of the highest tertile with the lowest was 0.37 (95 % confidence interval [CI]: 0.17-0.76, P for trend = 0.01). The inverse associations between maternal intake of total dairy products, yogurt, and calcium during pregnancy and the risk of childhood dental caries were of borderline significance: the adjusted ORs for the highest tertile of total dairy products, yogurt, and calcium were 0.51 (95 % CI: 0.23-1.09, P for trend = 0.07), 0.51 (95 % CI: 0.23-1.10, P for trend = 0.07), and 0.50 (95 % CI: 0.23-1.07, P for trend = 0.08), respectively. There was no evident relationship between maternal milk intake and the risk of childhood dental caries.

Conclusion

These data suggested that high intake of maternal cheese during pregnancy may reduce the risk of childhood dental caries.

Genistein attenuated allergic airway inflammation by modulating the transcription factors T-bet, GATA-3 and STAT-6 in a murine model of asthma

BACKGROUND

Genistein, a flavonoid in legumes and some herbal medicines, has various biological actions. Previous studies have shown that genistein decreased airway inflammation in allergic asthma. However, studies on how genistein affects immunoreactions in asthma are very limited.

OBJECTIVE

It was the aim of this study to investigate the effect of genistein on T helper 1 (Th1)/Th2 cytokines in a murine asthma model and to explore its underlying mechanisms.

METHODS

The asthma model was set up both in vivo and in vitro: the mice were divided into four groups in vivo, i.e. control group, ovalbumin-sensitized (OVA) group, Gen20 group (20 mg/kg genistein) and Gen40 group (40 mg/kg genistein), and into three groups in vitro, i.e. control group, OVA group, genistein group. Changes in lung histology were observed and concentrations of interleukin-4, interleukin-5 and interferon-γ in bronchoalveolar lavage fluid and serum were measured by enzyme-linked immunosorbent assay. The mRNA expression of GATA binding protein 3 (GATA-3), signal transducer and activator of transcription 6 (STAT-6) and T-box transcription factor (T-bet) in the lungs and CD4+ T cells of each group were detected by real-time PCR and the corresponding proteins were detected by Western blot.

RESULTS

The results showed that genistein attenuated OVA-induced airway inflammation, decreased Th2-type cytokines and increased Th1-type cytokines. Additionally, our data suggested that genistein may modulate the Th1/Th2 reaction by inhibiting GATA-3 and STAT-6 production while increasing T-bet production.

CONCLUSION

Genistein may modulate the immunomodulatory actions caused by Th1/Th2 cytokines in asthma, at least partially, by the down-regulation of GATA-3 and STAT-6 and the up-regulation of T-bet.

Soybean isoflavones regulate dendritic cell function and suppress allergic sensitization to peanut

BACKGROUND

Although peanut and soybean proteins share extensive amino acid sequence homology, the incidence and severity of allergic reactions to soy are much less than those to peanut. Soybeans are rich in anti-inflammatory isoflavones and are the most common source of isoflavones in the human food supply.

OBJECTIVE

We hypothesized that the active isoflavones in the gut milieu are capable of modulating immune responses to dietary antigens by regulating dendritic cell (DC) function.

METHODS

We tested this hypothesis in a murine model of peanut allergy and in human monocyte-derived dendritic cells (MDDCs). C3H/HeJ mice were fed a diet containing genistein and daidzein. The mice were sensitized and challenged with peanut, and the anaphylactic symptoms were compared with those of mice fed a soy-free diet. Human MDDCs were activated with cholera toxin in the presence of isoflavones. The surface expression of DC activation markers and DC-mediated effector functions were analyzed by means of flow cytometry.

RESULTS

Dietary isoflavones significantly reduced the anaphylactic symptoms and mast cell degranulation in vivo after peanut challenge. Serum peanut-specific antibodies were markedly reduced in mice fed the isoflavone diet. Isoflavones inhibited cholera toxin-induced DC maturation in the mesenteric lymph nodes and human MDDCs and subsequent DC-mediated CD4(+) T-cell function in vitro.

CONCLUSIONS

These data suggest that dietary isoflavones suppress allergic sensitization and protect against peanut allergy in vivo. Dietary supplementation of soybean isoflavones could be a novel strategy to prevent the development of allergic reactions to food.

Effect of soybean supplementation on the memory of alprazolam-induced amnesic mice

Soybean, Glycine max (L.) Merr. (Leguminoseae), is known as golden bean. It contains vegetable protein, oligosaccharide, dietary fiber, vitamins, isoflavones and minerals. Earlier studies have demonstrated a cholesterol lowering, skin protective, antitumour, antidiabetic and antioxidative potential of soybean. Soy isoflavones are also utilized as estrogen replacement therapy in postmenopausal women. The present study was undertaken to investigate the effect of soybean on memory of mice when consumed along with diet. Soybean was administered chronically for 60 consecutive days as three soybean diets viz. Soy2, Soy5, Soy10. These diet contains soybean in normal diet at concentration of 2%, 5%, 10% w/w respectively. Passive avoidance paradigm and elevated plus maze served as exteroceptive behavioral models for testing memory. Alprazolam (0.5 mg/kg; i.p.) induced amnesia served as interoceptive behavioral model. The administration of soybean significantly reversed alprazolam-induced amnesia in a dose-dependent manner as indicated by the increased step down latency of mice using passive avoidance paradigm and increased transfer latency using elevated plus maze. Theses results suggest that consumption of soybean in diet may not only improve memory but also reverse the memory deficits, owing to its multifarious activities. It would be worthwhile to explore the potential of this nutrient in the management of Alzheimer's disease.

Education, but not occupation or household income, is positively related to favorable dietary intake patterns in pregnant Japanese women: the Osaka Maternal and Child Health Study

Although a large body of epidemiologic data accumulated in Western countries show that individuals with a higher socioeconomic position consume higher quality diets, information on such socioeconomic differences in the diets of non-Western populations, including Japanese, is absolutely lacking. This cross-sectional study examined the association of socioeconomic position with dietary intake in a group of pregnant Japanese women. Subjects were 1002 Japanese women during pregnancy. Socioeconomic position was assessed by education, occupation, and household income. Dietary intake was estimated using a validated, self-administered, comprehensive diet history questionnaire. Education was associated positively with intake of protein; total n-3 and marine-origin n-3 polyunsaturated fatty acids; dietary fiber; cholesterol; potassium; calcium; magnesium; iron; vitamins A, D, E, and C; and folate 9 and inversely with that of carbohydrate. No associations were seen between education and intake of total fat; saturated, monounsaturated, and total and n-6 polyunsaturated fatty acids; alcohol; or sodium. Regarding food, higher education was associated with a higher intake of vegetables, fish and shellfish, and potatoes and lower intake of rice. Education was not associated with intake of bread, noodles, confectioneries and sugars, fats and oils, pulses and nuts, meat, eggs, dairy products, or fruit. For occupation, housewives had a higher intake of dietary fiber, magnesium, iron, vitamin A, folate, and pulses and nuts than working women. Household income was not associated with any nutrient or food examined. In conclusion, education, but not occupation or household income, was positively associated with favorable dietary intake patterns in a group of pregnant Japanese women.

Monetary Diet Cost is Associated with not only Favorable but also Unfavorable Aspects of Diet in Pregnant Japanese Women: The Osaka Maternal and Child Health Study

While several observational studies in European countries have shown that higher monetary diet cost is associated with healthier diets, information on the relationship of cost to diet quality in other countries is sparse, including Japan. This cross-sectional study examined the association between monetary diet cost and dietary intake in a group of pregnant Japanese women. Subjects were 596 pregnant Japanese housewives. Dietary intake was estimated using a validated, self-administered, comprehensive diet history questionnaire. Monetary diet cost was calculated using retail food prices. Values of monetary diet cost and nutrient and food intake were energy-adjusted using the density method. Monetary diet cost was associated positively with the intake of protein, total fat, saturated fatty acids, dietary fiber, cholesterol, sodium, potassium, calcium, magnesium, iron, vitamins A, D, E, C, and folate, and inversely with that of carbohydrate. For foods, cost was associated positively with the intake of potatoes, pulses and nuts, fish and shellfish, meat, dairy products, vegetables, and fruits, and inversely with that of rice and bread. No association was seen for noodles, confectioneries and sugars, fats and oils, or eggs. Cost was also associated inversely with dietary energy density. In conclusion, monetary diet cost was associated with not only favorable aspects of diet, including a higher intake of dietary fiber, key vitamins and minerals, fruits, and vegetables and lower dietary energy density, but also unfavorable aspects, including a higher intake of fat and sodium and lower intake of carbohydrate and rice, in a group of pregnant Japanese women.

Therapeutic effects of a fermented soy product on peanut hypersensitivity is associated with modulation of T-helper type 1 and T-helper type 2 responses

BACKGROUND

ImmuBalance is a koji fungus (Aspergillus oryzae) and lactic acid fermented soybean product. This unique production process is believed to create a food supplement that helps to induce or maintain normal immune response.

OBJECTIVE

To assess possible therapeutic effects of ImmuBalance on peanut (PN) hypersensitivity using a murine model of peanut allergy (PNA).

METHODS

PN allergic C3H/HeJ mice were fed standard mouse chow containing 0.5% or 1.0% ImmuBalance (ImmuBalance 2X), radiation-inactivated 1.0% ImmuBalance (I-ImmuBalance 2X), or regular diet chow (sham) for 4 weeks, beginning 10 weeks after the initial PN sensitization, and then challenged with PN. Anaphylactic symptom scores, plasma histamine, serum PN specific-IgE levels and splenocyte cytokine profiles were determined.

RESULTS

While 100% of sham-treated PNA mice developed anaphylactic reactions with a median score of 3.3 following PN challenge, only 50% of ImmuBalance, 30% of ImmuBalance 2X and 40% of I-ImmuBalance 2X-treated mice developed allergic reactions with median scores of 1.0, 0.4 and 0.5 respectively, which were significantly less than that in the sham-treated mice (P<0.05). Plasma histamine and PN specific-IgE levels were also significantly less in all treated mice than in sham-treated mice (P<0.05). Furthermore, IL-4, IL-5 and IL-13 production by PN-stimulated splenocytes in vitro from ImmuBalance fed mice were markedly reduced compared with sham-treated mice, whereas IFN-gamma production was moderately increased. TGF-beta and TNF-alpha production were similar.

CONCLUSIONS

ImmuBalance protects against PN-induced anaphylaxis when administered as a food supplement in this model. Protection was associated with down-regulation of Th2 responses. This supplement may provide a potential novel therapy for PNA.

(Xeno)estrogen regulation of food allergy

Food allergy and other types of allergies are becoming epidemic in both the developed and developing countries. A large amount of information is available in literature that (xeno)estrogens can regulate the immune response in general, and the development of allergy in particular; however, the effect of (xeno)estrogens on food allergy is basically unknown. With increasing use of xenobiotics worldwide, chemicals with estrogenic activity have been accumulating in our environment. This review has summarized the current literature relating to the topic (xeno)estrogen regulation of food allergy. The effect of (xeno)estrogens on enterocytes, proteases for protein hydrolysis, dendritic cells and T-regulatory cells in the gastrointestinal tract has been discussed. Finally, considering the current confusion in literature regarding the effect of phytoestrogen genistein on the immune system, a brief discussion has been included for its effect on T(H)1-T(H)2 polarization, and possibly food allergy in its relation to windows of exposure. Sufficient evidences exist to support the notion that (xeno)estrogens can regulate food allergy, with the developmental periods more sensitive. Further clinical and animal studies are needed to determine the causal relationship between the exposure of (xeno)estrogens and incidence of food allergy, and the underlying mechanisms.

Soy isoflavones and immunity

The amount of soy products consumed in Japan is much greater than that in Western countries. Recent evidence indicates that soy isoflavones play a beneficial role in obesity, cancer, osteoporosis, and cardiovascular disease. The soybean isoflavone genistein is present at high levels in soy products. Genistein is structurally similar to 17beta-estradiol (E2), and genistein has been suggested to be act as E2 or an antagonist against E2. Genistein suppresses antigen-specific immune response in vivo and lymphocyte proliferation response in vitro. However, genistein enhances the cytotoxic response mediated by NK and cytotoxic T cells and the cytokine production from T cells. Thus, the effect of genistein on immunity is immune cell-dependent. Due to its unique effect on immune function, genistein has been used for the treatment of the diseases in animal models and it has been found that genistein inhibits allergic inflammatory responses. In this review, we summarize current studies related to the effect of isoflavone genistein on the immune system.

Investigating the Optimal Soy Protein and Isoflavone Intakes for Women: A Perspective

Traditional soyfoods have been consumed for centuries throughout much of East Asia and, recently, these foods have also become popular in the West. Soyfoods and specific soybean components, such as the protein and isoflavones, have attracted attention for their possible health benefits. Isoflavones are classified as phytoestrogens and have been postulated to be natural alternatives to hormone therapy for menopausal women. To provide guidance on optimal soy intake, this article evaluates Asian soy consumption and both clinical and Asian epidemiologic studies that examined the relationship between soy intake and a variety of health outcomes. On the basis of these data and the standard principles of dietary practice the author suggests that optimal soy protein and isoflavone intakes are 15–20 g/day and 50–90 mg/day, respectively. In addition, an intake of 25 g/day soy protein can be specifically used as the recommendation for cholesterol reduction.

Soy isoflavone intake is not associated with the development of cedar pollinosis in adults

Although soy isoflavone has been suggested to have both immune-enhancing and immune-suppressive effects, the effects of soy isoflavone intake on allergic disorders are unclear. A cross-sectional study indicated that a high intake of soy isoflavone is associated with a decreased risk of allergic rhinitis. We aimed to prospectively examine the relationship between soy isoflavone intake and risk of cedar pollinosis, the most common seasonal allergic rhinitis in Japan. The study was conducted in a population-based cohort of Japanese men and women. Each subject's usual diet, including soy isoflavone intake, was determined with the use of a validated FFQ in 1992. In 2002, a total of 11,229 persons who were 35-69 y old and had no history of cancer or allergic diseases at the baseline responded to a follow-up questionnaire asking about 4 symptoms related to cedar pollinosis. Cox hazard regression model was used to determine the association between soy isoflavone intake and the risk of cedar pollinosis. During the 10-y follow-up, 931 of these subjects reported that they had cedar pollinosis. There was no significant association between soy isoflavone intake and risk of cedar pollinosis in men and women after controlling for covariates. For the highest compared with the lowest quartile of soy isoflavone intake, hazard ratios were 1.07 (95% CI: 0.81-1.42) in men and 0.89 (95% CI: 0.68-1.15) in women. These data did not support an association between soy isoflavone intake and risk of cedar pollinosis.

Diet among Japanese female university students and asthmatic symptoms, infections, pollen and furry pet allergy

OBJECTIVES

To study associations between diet, respiratory symptoms and allergy among female university students in Japan.

METHODS

A standardised questionnaire was distributed to students in Kobe and Kamakura (N=153). Multiple logistic/linear regression was applied, controlling for age, smoking, heredity and diet.

RESULTS

Totally 15.7% reported doctor-diagnosed asthma, 3.3% current asthma medication, 56.9% pollen allergy, 15.7% cat allergy, 11.1% dog allergy, 25.0% wheeze, 24.2% daytime and 9.3% nocturnal attacks of breathlessness. Meat consumption was related to wheeze (OR=2.00; 95% CI 1.12-3.60) and respiratory infections (OR=2.10; 95% CI 1.08-4.09). Fish consumption was related to less respiratory infections (OR=0.49; 95% CI 9.28-0.86), seafood to less pollen allergy (OR=0.66; 95% CI 0.44-0.99), and milk consumption to less daytime breathlessness (OR=0.72; 95% CI 0.55-0.95). Fast food consumption was related to wheeze (OR=1.89; 95% CI 1.23-2.91), daytime breathlessness (OR=1.50; 95% CI 1.00-2.28) and pollen allergy (OR=1.69; 95% CI 1.07-2.65). In total, 23.0% used butter, 21.7% margarine, 40.1% olive oil and 55.3% rapeseed oil. Those consuming butter (OR=2.65; 95% CI 1.11-6.32) and rapeseed oil (OR=2.35; 95% CI 1.03-5.38) had more wheeze. Those consuming margarine had more nocturnal breathlessness (OR=4.40; 95% CI 1.42-13.7). An asthma symptom score was related to fast food (p<0.05) and margarine consumption (p<0.01). Factor analysis identified five dietary patterns. A pattern including fast food, juice and soft drinks was related to wheeze and respiratory infections.

CONCLUSION

Fish, seafood and milk consumption seems to be beneficial, while butter, margarine, rapeseed oil, fast food and soft drinks could be risk factors for allergy and respiratory health.

Ambient formaldehyde levels and allergic disorders among Japanese pregnant women: baseline data from the Osaka maternal and child health study

PURPOSE

The effects of formaldehyde (FA) exposure on allergic disorders are not clearly understood. This cross-sectional study examined the relationship between FA exposure and the prevalence of allergic disorders in Japan.

METHODS

Subjects were 998 pregnant women. Participants were considered to have asthma, atopic eczema, or allergic rhinitis (including cedar pollinosis) if they had received any medical treatment for any of these allergic disorders during the previous 12 months. Passive air sampling tubes were worn for 24 hours and analyzed for FA.

RESULTS

When FA levels were categorized into four groups, there was a tendency for a positive exposure-response relationship between FA levels and the prevalence of atopic eczema, although the adjusted odds ratio for highest vs. lowest FA categories did not reach statistical significance. When FA levels were categorized into two groups to assess the effects of exposure to high levels of FA on allergic disorders, FA levels of 47 ppb or more were independently associated with an increased prevalence of atopic eczema (adjusted odds ratio = 2.25; 95% confidence interval, 1.01-5.01). The positive association was more pronounced in women with a negative familial allergic history than in those with a positive familial allergic history. No clear association was found between FA levels and the prevalence of asthma or allergic rhinitis.

CONCLUSIONS

FA exposure may be associated with an increased prevalence of atopic eczema in Japanese pregnant women.

Relationship between soy and isoflavone intake and periodontal disease: the Freshmen in Dietetic Courses Study II

Background

Much research has shown that soy products inhibited various diseases. However, no published studies have examined the effects of consumption of soy and isoflavones on periodontal disease. The aim of this study was to investigate whether soy and isoflavone intake is associated with the prevalence of periodontal disease.

Methods

The subjects were 3956 Japanese female students, aged 18 to 22 years, who were taking a dietetic course. Periodontal disease was defined as present when a subject reported diagnosis of the disorder by a dentist. Information on dietary factors was collected using a validated diet history questionnaire. Logistic regression analysis was used to estimate the odds ratios and their confidence intervals of periodontal disease. Adjustment was made for cigarette smoking, toothbrushing frequency, region of residence, and body mass index.

Results

The prevalence of periodontal disease was 8.0%. Intake of total soy product and tofu was independently associated with a decreased prevalence of periodontal disease; multivariate odds ratios in comparison of the highest with the lowest quintile were 0.68 and 0.68, respectively (95% confidence intervals = 0.47–0.97 and 0.47–0.98, P for trend = 0.01 and 0.004, respectively). A significant inverse dose-response relationship between the intake of isoflavones and the prevalence of periodontal disease was observed, although the difference in the adjusted odds ratio between the extreme quintiles was of borderline significance (P for trend = 0.04). There were no measurable dose-response relationships between consumption of tofu products, fermented soybeans, boiled soybeans, miso, or miso soup and the prevalence of periodontal disease.

Conclusion

Our findings suggest that soy and isoflavone intake may decrease the likelihood of periodontal disease. Further investigations with objective measures for periodontal disease are needed to confirm our findings.

A mechanism of benefit of soy genistein in asthma: inhibition of eosinophil p38-dependent leukotriene synthesis

BACKGROUND

Dietary intake of the soy isoflavone genistein is associated with reduced severity of asthma, but the mechanisms responsible for this effect are unknown.

OBJECTIVE

To determine whether genistein blocks eosinophil leukotriene C(4) (LTC(4)) synthesis and to evaluate the mechanism of this effect, and to assess the impact of a 4-week period of soy isoflavone dietary supplementation on indices of eosinophilic inflammation in asthma patients.

METHODS

Human peripheral blood eosinophils were stimulated in the absence and presence of genistein, and LTC(4) synthesis was measured. 5-lipoxygenase (5-LO) nuclear membrane translocation was assessed by confocal immunofluorescence microscopy. Mitogen-activated protein (MAP) kinase activation was determined by immunoblot. Human subjects with mild-to-moderate persistent asthma and minimal or no soy intake were given a soy isoflavone supplement (100 mg/day) for 4 weeks. The fraction of exhaled nitric oxide (FE(NO)) and ex vivo eosinophil LTC(4) production were assessed before and after the soy isoflavone treatment period.

RESULTS

Genistein inhibited eosinophil LTC(4) synthesis (IC(50) 80 nm), blocked phosphorylation of p38 MAP kinase and its downstream target MAPKAP-2, and reduced translocation of 5-LO to the nuclear membrane. In patients with asthma, following 4 weeks of dietary soy isoflavone supplementation, ex vivo eosinophil LTC(4) synthesis decreased by 33% (N=11, P=0.02) and FE(NO) decreased by 18% (N=13, P=0.03).

CONCLUSION

At physiologically relevant concentrations, genistein inhibits eosinophil LTC(4) synthesis in vitro, probably by blocking p38- and MAPKAP-2-dependent activation of 5-LO. In asthma patients, dietary soy isoflavone supplementation reduces eosinophil LTC(4) synthesis and eosinophilic airway inflammation. These results support a potential role for soy isoflavones in the treatment of asthma.

The association of diet with respiratory symptoms and asthma in schoolchildren in Taipei, Taiwan

This study aimed to evaluate the association of diet with respiratory symptoms and asthma in schoolchildren in Taipei, Taiwan. An in-class interview survey elicited experiences of asthma and respiratory symptoms and consumption frequencies of the major food categories in 2290 fifth graders. Respiratory symptoms surveyed included persistent cough, chest tightness, wheezing with cold, wheezing without cold, dyspnea-associated wheezing, and exercise-induced cough or wheezing. Results showed that the consumption of sweetened beverages had the strongest association with respiratory symptoms and was positively associated with six of the seven respiratory symptoms (all p < 0.05). The adjusted odds ratios (aOR) ranged from 1.05 (95% confidence interval (CI = 1.01-1.09) for exercise-induced cough to 1.09 (95% CI = 1.03-1.16) for wheezing without cold. Egg consumption was associated with 5 of the 7 respiratory symptoms. Consumptions of seafood, soy products, and fruits were each negatively associated with one of the seven respiratory symptoms (all p < 0.05). Consumption of seafood was negatively associated with physician-diagnosed asthma and consumptions of sweetened beverages and eggs were positively associated with suspected asthma (p < 0.05). In conclusion, the study suggests that diet is associated with the respiratory symptoms in schoolchildren in Taipei. Consumptions of sweetened beverages and eggs are associated with increased risk of respiratory symptoms and asthma whereas consumptions of soy products and fruits are associated with reduced risk of respiratory symptoms.

Environmental factors and allergic disorders

Despite numerous studies on possible associations between environmental exposure and allergic disorders, any conclusions made remain a matter of controversy. We conducted a review of evidence in relation to environmental and nutritional determinants and wheeze, asthma, atopic dermatitis, and allergic rhinitis. Identified were 263 articles for analysis after consideration of 1093 papers that were published since 2000 and selected by electronic search of the PubMed database using keywords relevant to epidemiological studies. Most were cross-sectional and case-control studies. Several prospective cohort studies revealed inconsistent associations between various environmental factors and the risk of any allergic disorder. Therefore, the evidence was inadequate to infer the presence or absence of a causal relationship between various environmental exposures and allergic diseases. However, evidence is suggestive of positive associations of allergies with heredity. Because almost all the studies were performed in Western countries, the application of these findings to people in other countries, including Japan, may not be appropriate. Further epidemiological information gained from population-based prospective cohort studies, in particular among Japanese together with other Asians, is needed to assess causal relationships between various environmental factors and allergic diseases.

Prevalence and risk factors for allergic rhinitis in primary school children

OBJECTIVE

Allergic rhinitis is a common chronic illness of childhood. The aim of the study was to evaluate the prevalence and risk factors of allergic rhinitis in 6-12-year-old schoolchildren in Istanbul.

METHODS

A total of 2500 children aged between 6 and 12 years in randomly selected six primary schools of Istanbul were surveyed by using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire between April and May 2004.

RESULTS

Of them 2387 (1185 M/1202 F) questionnaires were appropriately completed by the parents with an overall response of 95.4%. The prevalence of physician-diagnosed allergic rhinitis was 7.9% (n=189). A family history of atopy (aOR=1.30, 95% CI=1.00-1.68), frequent respiratory tract infection (aOR=1.36, 95% CI=1.08-1.70) and sinusitis (aOR=2.29, 95% CI=1.64-3.19), antibiotic use in the first year of life (aOR=1.26, 95% CI=1.01-1.57), cat at home in the first year of life (aOR=2.21, 95% CI=1.36-3.61), dampness at home (aOR=1.31, 95% CI=1.04-1.65) and perianal redness (aOR=1.26, 95% CI=1.01-1.57) were significant for increased risk for allergic rhinitis. Frequent consumption of fruits and vegetables were inversely, and frequent consumption of lollipops and candies were positively associated with allergic rhinitis symptoms.

CONCLUSION

Our study reconfirmed that family history of atopy, frequent respiratory tract infections, antibiotics given in the first year of life, cat at home in the first year of life, dampness at home, perianal redness and dietary habits are important independent risk factors for AR. Researchers worldwide should be focused to these factors and try to develop policies for early intervention, primary and secondary preventions for allergic diseases.

Treating allergic rhinitis in pregnancy

Numerous pregnant women suffer from allergic rhinitis, and particular attention is required when prescribing drugs to these patients. In addition, physiologic changes associated with pregnancy could affect the upper airways. Evidence-based guidelines on the management of allergic rhinitis have been published. Medication can be prescribed during pregnancy when the apparent benefit of the drug is greater than the apparent risk. Usually, there is at least one "safe" drug from each major class used to control symptoms. All glucocorticosteroids are teratogenic in animals but, when the indication is clear (for diseases possibly associated, such as severe asthma exacerbation), the benefit of the drug is far greater than the risk. Inhaled glucocorticosteroids (eg, beclomethasone or budesonide) have not been incriminated as teratogens in humans and are used by pregnant women who have asthma. A few H1-antihistamines can safely be used as well. Most oral decongestants (except pseudoephedrine) are teratogenic in animals. There are no such data available for intranasal decongestants. Finally, pregnancy is not considered to be a contraindication for the continuation of immunotherapy.

Dietary folate and vitamins B12, B6, and B2 intake and the risk of postpartum depression in Japan: the Osaka Maternal and Child Health Study

BACKGROUND

Previous studies showed an inverse association between folate intake and depression. However, epidemiological evidence for folate intake and postpartum depression is unavailable. This prospective study examined the relationship of dietary consumption of folate and B vitamins during pregnancy with the risk of postpartum depression.

METHODS

Study subjects were 865 Japanese women. Dietary data were obtained during pregnancy from a validated self-administered diet history questionnaire. Postpartum depression was defined as present when subjects had an Edinburgh Postnatal Depression Scale score of 9 or higher between 2 and 9 months postpartum. Adjustment was made for age, gestation, parity, cigarette smoking, alcohol intake, family structure, family income, education, changes in diet in the previous 1 month, season when data at baseline were collected, body mass index, time of delivery before the second survey, medical problems in pregnancy, baby's sex, and baby's birth weight.

RESULTS

Postpartum depression developed in 121 subjects (14.0%) 2 to 9 months postpartum. There was no measurable association between intake of folate, cobalamin, or pyridoxine and the risk of postpartum depression. Compared with riboflavin intake in the first quartile, only riboflavin consumption in the third quartile was independently related to a decreased risk of postpartum depression (multivariate odds ratio: 0.53, 95% CI: 0.29-0.95, P for trend=0.55).

LIMITATIONS

Personal and family psychiatric history, sociocultural factors, and personal and family relations were not controlled for. The possibility of misclassification of dietary information during pregnancy should be considered.

CONCLUSIONS

Our results suggest that moderate consumption of riboflavin may be protective against postpartum depression.

Endocrine disrupters--potential modulators of the immune system and allergic response

Endocrine disrupters (EDs) are environmental pollutants of industrial or agricultural origin (e.g. herbicides, fungicides, insecticides, industrial chemicals) that may influence health of wildlife and human. Endocrine-disrupting effect is obtained by mimicking the action of the steroid hormones and has been associated with several reproductive disorders as well as cancerogenesis both in animals and humans. EDs can also influence synthesis of cytokines, immunoglobulins, and cell mediators as well as immune cell activation and survival. Modulation by EDs of interleukin-4 production, Th1/Th2 balance and IgE production suggest their potential effect on allergic immune responses. The aim of this review was to summarize data indicating a potential effect of EDs exposure on the immune system and allergic responses.

Advances in upper airway diseases and allergen immunotherapy

The purpose of this review is to highlight important articles on upper airway disease and immunotherapy that appeared in the Journal of Allergy and Clinical Immunology and elsewhere during 2005. In recent studies of tissue from patients with chronic hypertrophic eosinophilic sinusitis, increased leukotriene C4 synthase and 5-lipoxygenase activity and increased levels of cysteinyl leukotriene production were demonstrated that correlated with disease severity but not with whether the patient was aspirin sensitive. However, the cysteinyl leukotriene 1 receptor was increased in leukocytes in the sinus tissue only in those patients with aspirin sensitivity. Major basic protein, released by eosinophils into the mucus in the paranasal sinus lumen, was found to reach concentrations capable of damaging the sinus epithelium, predisposing to bacterial infections. Testing the hypothesis that chronic hypertrophic eosinophilic sinusitis represents a reaction to common fungi, a double-blind trial of intranasal instillation of amphotericin B was conducted. There were marginal but significant differences in favor of amphotericin B treatment for sinus mucosal thickening on the basis of computed tomography and the evidence of eosinophilic inflammation in the sinus mucus. The effectiveness of topical nasal corticosteroids for treatment of nasal polyps was confirmed in 2 large studies. Improvement in sleep quality and daytime drowsiness in patients with allergic rhinitis treated with nasal corticosteroids was reported to correlate with reduction in nasal obstruction. The statistical analysis behind studies that reported a decrease in asthma exacerbations with nasal corticosteroids or oral antihistamines has been questioned. It appears that the results of at least one of these studies are indeed too good to be true. Although caution is still indicated in administering immunotherapy to patients receiving beta-adrenergic blocking agents, the prohibition might not be absolute. A study in patients with Hymenoptera sensitivity given venom immunotherapy revealed no increase in serious adverse reactions to venom injections and no greater incidence of reactions to insect stings in those taking beta-blocking agents. Sublingual immunotherapy for 8 to 12 weeks in patients with hazelnut sensitivity significantly increased their tolerance to hazelnut in double-blind, placebo-controlled challenges while inducing increased IgG4 and IL-10 levels, indicating induction of regulatory T cells. There were a number of articles in the Journal of Allergy and Clinical Immunology in 2005 that addressed the entity of chronic hypertrophic eosinophilic sinusitis. In addition, an update of the "Practice parameters on sinusitis" was published. The major focus in allergen immunotherapy continues to be sublingual administration.