Asthma study may reignite pregnancy-peanut debate

Over 4,000 women took part in the study, and data was obtained for 2,832 children. The results are published in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine​. "We were pretty surprised to see the adverse associations between daily versus rare nut product consumption during pregnancy and symptoms of asthma in children, because we haven't seen this in similar previous studies,"​ said lead author Saskia Willers. Despite the worrying associations, the researchers noted that it is "too early to make recommendations of avoidance".​ 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 is the most common long-term condition in the UK. Study details​​ Expectant mothers taking part in the Prevention and Incidence of Asthma and Mite Allergy study were asked to complete food frequency questionnaires (FFQ) to quantify their consumption of fruit, vegetables, fish, egg, milk, milk products, nuts, and nut products. Their children were then followed from birth to age eight, and the prevalence of asthma recorded. While no affects were found for vegetable, fish, egg, milk or milk products during pregnancy on asthma in the offspring, the researchers did calculate that the daily consumption of nut products was associated with a 42 per cent increase in the risk of wheeze, a 58 per cent increase in shortness of breath, and a 47 per cent increase in asthma symptoms, compared to rare consumption. "The only consistent association between the maternal intake of the investigated food groups during pregnancy and childhood asthma symptoms until eight years of age that we found was with nut products,"​ said Willers. Commenting on the research, John Heffner, MD, past president of the American Thoracic Society, said: "These findings emphasise the critical important of additional investigations into the environmental exposures for both mother and child that underlie the pathogenesis of asthma. ​ ​"It is important, however, to emphasise that such associations do not confirm a causative linkage,"​ he added. The wider issue ​ The study is particularly timely after the UK's House of Lords called for a review in September 2007 of the advice on peanut consumption by pregnant women and children to reduce allergy risk. The UK's Department of Health currently advises pregnant women with a family history of allergies to avoid eating peanuts, and not feed them to their children until they are at least three years old. This advice dates from 1998, when the Food Standards Agency's Committee on Toxicology (COT) last reviewed the evidence. A report from the Lords' Select Committee on Science and Technology on allergy noted that the most dramatic increase in food allergy prevalence in recent years has been seen for peanut allergy. The Isle of Wight Birth Cohort Study reported in 2002 that peanut sensitisation had "increased three-fold in children born between 1994 and 1996, compared to those born in 1989".​ However the committee drew on evidence from a number of experts, who cited studies indicating that exposing a child's immune system to peanut allergen at an early age could actually result in tolerance. In particular, they said that in Israel, where the incidence of peanut allergy is lower than in the UK, peanuts are commonly used in infants' weaning foods. While the new study from The Netherlands deals with asthma and not peanut allergy, it does suggest caution when reviewing or reversing current advice. Source: American Journal of Respiratory and Critical Care Medicine ​Volume 178, Pages 124-131 "Maternal Food Consumption during Pregnancy and the Longitudinal Development of Childhood Asthma" ​Authors: S.M. Willers, A.H. Wijga, B. Brunekreef, M. Kerkhof, J. Gerritsen, M.O. Hoekstra, J.C. de Jongste, H.A. Smit