Eating more fruits and vegetables may not protect children from developing allergies, according to a large Swedish study that questions earlier hints of benefit. Fruits and vegetables are rich in antioxidants, which are thought to reduce airway inflammation. So recent studies reporting less asthma, wheezing and hay fever among children who consumed more produce appeared to make sense.
But not all research has found that link, and the studies that did may have had a surprising flaw, said Helen Rosenlund of Karolinska Institutet in Stockholm, who led the new study. She said some proteins in fruits like apples and pears resemble the pollen parts that trigger hay fever, meaning that kids might react to both. In other words, existing allergies may have caused them to eat around the produce, rather than the other way around. “This could confuse research findings,” explained Rosenlund, “falsely suggesting that diets with fewer fruits and vegetables result in more allergic disease.”
To find out if this was the case, Rosenlund and her colleagues looked at data on nearly 2,500 eight-year-olds who had participated since birth in a larger Swedish study. Based on blood tests and questionnaires filled out by parents, the researchers found that seven percent of the children had asthma. The rates of hay fever and skin rashes were more than twice as high. The average child ate between one and two servings of fruit, and between two and three servings of vegetables each day.
At first glance, some produce did seem helpful: Kids with the biggest appetite for fruit had less than two-thirds the odds of developing hay fever than those who ate the least amount. Apples, pears and carrots appeared to be particularly helpful, the researchers report in the Journal of Allergy and Clinical Immunology, but there was no such link for vegetables overall. However, it turned out that half the children with hay fever were sensitive to birch tree pollen, one of the pollens known to resemble the proteins in apples and carrots. And sure enough, after the team repeated their analysis excluding the 122 kids with food-related allergy symptoms, the hay fever link disappeared as well. “Fruits do not seem to offer protection against allergic if diet modifications are considered,” say Rosenlund.
The researchers say more studies are needed, particularly in other parts of the world that may have a different variety of allergy triggers, or allergens. And they advise those studies should not forget to look at how allergies might influence what participants eat. “Studying diet it is not so easy when it comes to the relation with allergic disease,” Rosenlund said, “because it is such a complex disease pattern.”
SOURCE: bit.ly/g3DpI7 The Journal of Allergy and Clinical Immunology, online January 10, 2011.
Consumption of Vitamin B during pregnancy does not increase the risk of allergy in the infants, says a new study from Japan that challenges previous findings. Maternal consumption of folate and vitamins B2, B6, and B12 during pregnancy was not associated with the risk of the infant developing asthma or eczema, according to findings from 763 infants published in Pediatric Allergy and Immunology.
The link between folate and folic acid, the synthetic form of the vitamin, and respiratory health is not clear cut, with contradictory results reported in the literature. A study from Johns Hopkins Children’s Center found that higher levels of folate were associated with a 16 per cent reduction of asthma in (Journal of Allergy & Clinical Immunology, June 2009, Vol. 123, pp. 1253-1259.e2). However, a Norwegian study reported that folic acid supplements during the first trimester were associated with a 6 per cent increase in wheezing, a 9 per cent increase in infections of the lower respiratory tract, and a 24 per cent increase in hospitalisations for such infections, (Archives of Diseases in Childhood, doi:10.1136/adc.2008.142448). In addition, researchers from the University of Adelaide in Australia reported that folic acid supplements in late pregnancy may increase the risk of asthma by about 25 per cent in children aged between 3 and 5 years (American Journal of Epidemiology, 2010, doi:10.1093/aje/kwp315).
Illumination from the Land of the Rising Sun?
The new study, performed by researchers from Fukuoka University, the University of Tokyo, and Osaka City University, goes beyond folate and folic acid, and reports no link between Vitamin B intake and the risk of asthma or eczema in children. “To the best of our knowledge, there has been no birth cohort study on the relationship between maternal consumption of Vitamin B during pregnancy and the risk of allergic disorders in the offspring,” wrote the researchers. The findings were based on data from 763 pairs of Japanese mother and child. A diet history questionnaire was used to assess maternal intakes of the various B vitamins during pregnancy, and the infants were followed until the age of 16 to 24 months. Japan has no mandatory fortification of flour with folic acid.
Results showed that, according to criteria from the International Study of Asthma and Allergies in Childhood, 22 and 19 percent of the children had symptoms of wheeze and eczema, respectively, but there was no association between these children and the dietary intakes of the various B vitamins by their mothers. “Our results suggest that maternal intake of folate, vitamin B12, vitamin B6, and vitamin B2 during pregnancy was not measurably associated with the risk of wheeze or eczema in the offspring,” said the researchers. “Further investigation is warranted to draw conclusions as to the question of whether maternal Vitamin B intake during pregnancy is related to the risk of childhood allergic,” they concluded.
According to the European Federation of Allergy and Airway Diseases Patients Association (EFA), over 30m Europeans suffer from asthma, costing Europe €17.7bn every year. The cost due to lost productivity is estimated to be around €9.8bn. The condition is on the rise in the Western world and the most common long-term condition in the UK today. According to the American Lung Association, almost 20m Americans suffer from asthma. The condition is reported to be responsible for over 14m lost school days in children, while the annual economic cost of asthma is said to be over $16.1bn.
Source: Pediatric Allergy and Immunology. Volume 22, Issue 1-Part-I, February 2011, Pages: 69–74 DOI: 10.1111/j.1399-3038.2010.01081.x
“Maternal B vitamin intake during pregnancy and wheeze and eczema in Japanese infants aged 16–24 months: The Osaka Maternal and Child Health Study”. Authors: Y. Miyake, S. Sasaki, K. Tanaka, Y. Hirota
The vitamin D levels of newborn babies appear to predict their risk of respiratory infections during infancy and the occurrence of wheezing during early childhood, but not the risk of developing asthma. Results of a study in the January 2011 issue of Pediatrics support the theory that widespread vitamin D deficiency contributes to risk of infections.
“Our data suggest that the association between vitamin D and wheezing, which can be a symptom of many respiratory diseases and not just asthma, is largely due to respiratory infections,” says Carlos Camargo, MD, DrPH, of the Massachusetts General Hospital (MGH), who led the study. “Acute respiratory infections are a major health problem in children. For example, bronchiolitis – a viral illness that affects small airway passages in the lungs – is the leading cause of hospitalization in U.S. infants.”
Although vitamin D is commonly associated with its role in developing and maintaining strong bones, recent evidence suggests that it is also critical to the immune system. Vitamin D is produced by the body in response to sunlight, and achieving adequate levels in winter can be challenging, especially in regions with significant seasonal variation in sunlight. Previous studies by Camargo's team found that children of women who took vitamin D supplements during pregnancy were less likely to develop wheezing during childhood. The current study was designed to examine the relationship between the actual blood levels of vitamin D of newborns and the risk of respiratory infection, wheezing and asthma.
The researchers analyzed data from the New Zealand Asthma and Allergy Cohort Study, which followed more than 1,000 children in the cities of Wellington and Christchurch. Midwives or study nurses gathered a range of measures, including samples of umbilical cord blood, from newborns whose mothers enrolled them in the study. The mothers subsequently answered questionnaires – which among other items asked about respiratory and other infectious diseases, the incidence of wheezing, and any diagnosis of asthma – 3 and 15 months later and then annually until the children were 5 years old. The cord blood samples were analyzed for levels of 25-hydroxyvitamin D (25OHD) – considered to be the best measure of vitamin D status.
Cord blood samples were available from 922 newborns in the study cohort, and more than 20 percent of them had 25OHD levels less than 25 nmol/L, which is considered very low. The average level of 44 nmol/L would still be considered deficient – some believe that the target level for most individuals should be as high as 100 nmol/L – and lower levels were more common among children born in winter, of lower socioeconomic status and with familial histories of asthma and smoking. By the age of 3 month, infants with 25OHD levels below 25 nmol/L were twice as like to have developed respiratory infections as those with levels of 75 nmol/L or higher.
Survey results covering the first five years of the participants' lives showed that, the lower the neonatal 25OHD level, the higher the cumulative risk of wheezing during that period. But no significant association was seen between 25OHD levels and a physician diagnosis of asthma at age 5 years. Some previous studies had suggested that particularly high levels of vitamin D might increase the risk for allergies, but no such association was seen among study participants with the highest 25OHD levels. Camargo notes that very few children in this study took supplements; their vitamin D status was determined primarily by exposure to sunlight.
An associate professor of Medicine at Harvard Medical School, Camargo notes that the study results do not mean that vitamin D levels are unimportant for people with asthma. “There's a likely difference here between what causes asthma and what causes existing asthma to get worse. Since respiratory infections are the most common cause of asthma exacerbations, vitamin D supplements may help to prevent those events, particularly during the fall and winter when vitamin D levels decline and exacerbations are more common. That idea needs to be tested in a randomized clinical trial, which we hope to do next year.”
Co-authors of the Pediatrics paper are Ravi Thadhani, MD, and Janice Espinola, MPH, from MGH; Tristram Ingham, MBChB, Kristin Wickens, PhD, and Julian Crane, FRACP, from University of Otaga, Wellington, New Zealand; Karen Silvers, PhD, Michael Epton, PhD, FRACP, and Philip Pattemore, MD, FRACP, from University of Otago, Christchurch, NZ; and Ian Town, DM, from University of Canterbury, Christchurch, NZ. The study was supported by grants from the Health Research Council of New Zealand, the David and Cassie Anderson Bequest and the MGH Center for D-receptor Activation Research.
Asthma and chronic obstructive pulmonary disease (COPD) patients who are treated with inhaled corticosteroids may face a significantly higher relative risk for both the development and progression of diabetes, new Canadian research suggests. The warning stems from an analysis of data involving more than 380,000 respiratory patients in Quebec. Inhaler use was associated with a 34 percent increase in the rate of new diabetes diagnoses and diabetes progression, the researchers found. What's more, asthma and COPD patients treated with the highest dose inhalers appear to face even higher diabetes-related risks: a 64 percent jump in the onset of diabetes and a 54 percent rise in diabetes progression. “High doses of inhaled corticosteroids commonly used in patients with COPD are associated with an increase in the risk of requiring treatment for diabetes and of having to intensify therapy to include insulin,” the study team noted in a news release.
Based on their results, researchers from McGill University and the Lady Davis Research Institute at Jewish General Hospital in Montreal suggest “patients instituting therapy with high doses of inhaled corticosteroids should be assessed for possible hyperglycemia and treatment with high doses of inhaled corticosteroids limited to situations where the benefit is clear.”
Lead investigator Samy Suissa colleagues report their findings in the most recent issue of the American Journal of Preventive Medicine.
The research team wrote that despite the fact that inhalers are recommended for use solely by the most severely ill COPD patients, they are typically prescribed for a much broader pool that amounts to about 70 percent of all COPD patients. The authors found that more than 30,000 of the COPD/asthma patients in their study developed a new diagnosis diabetes over the course of five and a half years of treatment. This amounted to a diabetes onset rate of a little more than 14.2 out of every 1,000 inhaler patients per year.
“These are not insubstantial numbers,” Suissa said. “Over a large population,m the absolute numbers of affected people are significant.” In addition, in the same timeframe nearly 2,100 patients already diagnosed with diabetes before using inhalers experienced a worsening of their disease that ultimately required upgrading their diabetes care from pills to insulin shots.
Dr. Stuart Weiss, an endocrinologist with the New York University Medical Center, suggested that concern should be directed more at the underlying causes of both diabetes and asthma/COPD rather than at inhalers themselves. “I would say that a lot more attention should first be paid to the lifestyle choices, dietary-wise, that lead to the pro-inflammatory conditions that raise the risk for both type 2 diabetes as well as COPD and asthma,” said Weiss, who is also a clinical assistant professor at the NYU School of Medicine in New York City. “We don't look at asthma as being a dietary condition, but it absolutely is. Which means that in terms of diabetes and asthma risk, the body is reacting to similar stresses brought about by the over-consumption of overprocessed foods and the lack of consumption of green vegetables.”
Noting that the underlying risk for both conditions is similar, Weiss said he suspected the steroids themselves should not bear all the blame. “What may be more at the root of this problem,” he said, “is the fact that those who are most at risk for diabetes are the same people who have the worst asthma and COPD that requires steroid treatment in the first place.” “Yes, we do know that steroids increase insulin resistance and that people treated with steroids require more aggressive diabetes management,” he conceded. “But if we don't generally take an approach that deals with the poor quality of food that people are routinely consuming, the incidence of both these diseases will continue to go up at a dramatic rate.”
Metabolic syndrome is a cluster of risk factors which can result in heart disease and diabetes. Researchers have now found that poor diet and lack of exercise that lead to an imbalance in metabolism may also increase a child's risk of developing asthma.
Dr. Giovanni Piedimonte and researchers from West Virginia University School of Medicine analyzed data from nearly 18,000 children aged 4 to 12 years who were taking part in the Coronary Artery Risk Detection in Appalachian Communities (CARDIAC) project. Factors considered included triglyceride levels and evidence of acanthosis nigricans, which are raised patches of brown skin that are often biomarkers for insulin resistance.
The team also considered body mass index or BMI, and almost 21% of the children were considered obese. Fourteen percent of the children had asthma.
The researchers found that asthma prevalence among the children was strongly associated with certain symptoms of metabolic syndrome including dyslipidemia and abnormal glucose metabolism, but not weight status. Although those who were obese were more likely to have asthma, even children of a healthy weight who had imbalanced metabolism were at increased risk.
Certain metabolic factors participate in the asthma disease process by contributing to inflammation of the airways in the lungs and hyperreactivity (contraction of smooth muscle in the bronchial walls), says Dr. Piedimonte. He says that strict monitoring and control of triglyceride and glucose levels early in life may play a role in the management of chronic asthma in children.
Dr. Piedimonte would like to see the findings used as further support for universal lipid screening in children. “The rationale is that by using selective screening, we would have missed over a third of children with significant genetic dyslipidemia,” he said.
Both poor diet – one lacking in antioxidants but high in fat – and inadequate exercise play a role in the metabolic syndrome, a group of risk factors that increase the risk for coronary artery disease, stroke, and type 2 diabetes. The goal of treatment is often weight loss (if overweight), a minimum of 30 minutes of daily moderate intensity exercise, and a lowering of cholesterol, blood pressure and blood sugar through diet or medication.
Cottrell L, et al “Metabolic abnormalities in children with asthma” Am J Respir Crit Care Med 2010; DOI: 10.1164/rccm.201004-0603OC.
A new study shows that adolescents who take acetaminophen, better known as Tylenol, have a higher risk of asthma, allergic nasal conditions and the skin disorder eczema.
Acetaminophen is widely viewed as a very safe drug—one reason why hospitals use it routinely as a painkiller instead of aspirin or ibuprofen. The major problem associated with it is liver damage caused by overdoses. Recently, however, there has been a growing drumbeat about possible dangers from the drug. One study, for example, found that acetaminophen increased the risk of hearing loss in men. And some others have hinted that the drug is linked to asthma in newborns whose mothers used the drug during pregnancy and in young children exposed to it.
The new findings were reported in the American Journal of Respiratory and Critical Care Medicine by researchers in the International Study of Asthma and Allergies in Childhood. The team, headed by epidemiologist Richard Beasley of the Medical Research Institute in Wellington, New Zealand, gave written questionnaires to 322,959 13- and 14-year-olds in 50 countries exploring their use of acetaminophen, other drugs, and asthma symptoms. They were also shown a video containing five scenes of clinical asthma and asked whether they had experienced any symptoms similar to those shown. About 73% of the teens said they had used acetaminophen at least once in the previous year and 30% said they had used it monthly.
Taking into account maternal education, smoking, diet and siblings, the team found that those subjects who had used the drug at least once per year were 43% more likely to have asthma, while those who used it at least monthly were 2.5 times as likely to suffer from the condition. The risk of rhinoconjunctivitis (a severe nasal congestion) was 38% higher for those who used it once per year and 2.39 times as high for those who used it at least monthly. The comparable increases in risk for eczema were 31% and 99%, respectively.
Overall, the increased risk of asthma associated with acetaminophen was 41%, the authors found. That could, at least in part, explain why there has been an increase in the prevalence of asthma in the 50 years since the drug was introduced. Given the widespread use of the drug, it could also represent a large public health problem.
But—and it is a very big but—the study shows only an association, not causality. That could only be determined by a randomized clinical trial, which the authors recommend. Furthermore, the study relies on the recall of teenagers. Recall is notoriously inaccurate in adults, and it is probably worse in adolescents, clouding the results. For the time being then, you can probably continue to feel comfortable giving the drug to your children.
In a statement, McNeil Consumer Healthcare, which manufactures Tylenol, said that the drug “has over 50 years of clinical history to support its safety and effectiveness” and that no clinical trial has demonstrated that the drug causes asthma.
A study of UK schoolchildren has revealed that Black Africans, Indians and Bangladeshis have a similar or lower prevalence of asthma than White children, while Black Caribbean and Mixed Black Caribbean/White boys are more likely to have asthma. Researchers writing in the open access journal BMC Pediatrics studied the occurrence of asthma, investigating ethnic differences in risk factors.
Melissa Whitrow and Seeromanie Harding from the Social and Public Health Sciences Unit of the Medical Research Council, UK, used data taken from 51 London schools to investigate a random selection of 11-13 year old pupils. The final sample for analysis included 1219 children who identified themselves as 'White UK', 933 'Black Caribbean', 1095 'Black African', 459 'Indian', 215 'Pakistani', 392 'Bangladeshi' and 299 'Mixed White UK and Black Caribbean'.
According to Whitrow and Harding, “Social and environmental factors may influence risk of asthma through early life exposures regulating the allergic inflammatory response and/or later life exposures to allergens. A positive association between body mass index (BMI) and asthma has also been reported. We aimed to investigate the influence of these factors on ethnic differences in asthma prevalence”.
The researchers found that a family history of asthma and psychological well-being were consistent correlates for asthma regardless of ethnicity. Less than six years of residence in the UK had an independent protective effect for Black Caribbeans and Black Africans, possibly reflecting continuing protection from early life exposures in their home countries. A gender difference was observed for Indians and Bangladeshis, with less asthma in girls than boys. Speaking about these results, the authors said, “These findings point to early protective influences which are not properly understood. International comparisons could provide useful insights into prevention of asthma, for ethnic minority children and for all children”.
Avoid eating meals high in fat, especially if you suffer from asthma, urges Australian researchers after finding the fat leads to inflamed breathing passages and hinders drug interventions.
Lisa Wood, PhD, research fellow and lecturer in the biomedical sciences and pharmacy department of Hunter Medical Research Institute, at the University of Newcastle, led the study with a team of researchers and presented their findings at ATS 2010, the international meeting of the American Thoracic Society, in New Orleans.
The researchers challenged 14 non-obese asthmatics and 16 obese participants to a high-fat diet (1,000 calories with 52%/60g of fat) of burgers and fried potatoes and another group of 16 non-obese asthmatics to eat a low-fat yogurt diet (200 calories, 13%/3g fat). “Induced sputum samples were collected at baseline and at 4 hours” according to the study's abstract.
“Subjects who had consumed the high-fat meal had an increase in airway neutrophils and TLR4 mRNA gene expression from sputum cells, that didn't occur following the low fat meal, ” said Wood.
She continued, “The high fat meal impaired the asthmatic response to albuterol. In subjects who had consumed a high fat meal, the post-albuterol improvement in lung function at three and four hours was suppressed.”
The researchers were surprised to find that the fatty diet also impacted the effectiveness of asthma medications, like albuterol. Wood added, “This is the first study to show that a high fat meal increases airway inflammation, so this is a very important finding. The observation that a high fat meal changes the asthmatic response to albuterol was unexpected as we hadn't considered the possibility that this would occur.”
It's unclear how and why fat not only inflames the airways but also prevents known asthma therapies from working. The researchers intend to design “more studies to investigate this effect. We are also investigating whether drugs that modify fat metabolism could suppress the negative effects of a high fat meal in the airways. If these results can be confirmed by further research, this suggests that strategies aimed at reducing dietary fat intake may be useful in managing asthma.”
Whether you have asthma or not is becoming increasingly more important for heart and now lung health to avoid the fat.