Pregnant mother’s diet may affect child’s risk of allergic asthma
Posted Nov 21 2008 4:29pm
Recent research strongly suggests a link between a pregnant woman’s diet and the child’s risk of developing allergic asthma.
The study, conducted by researchers at the National Jewish Health and Duke University Medical Centre used mice to investigate the effects of diets high in methyl-donor supplements such as folic acid. They found that this group of mice produced offspring with more severe allergic airway disease than the offspring from mice that consumed a low methyl-containing diet.
David Schwartz, MD, senior author on the paper and Professor of Medicine at National Jewish Health said: “Our findings suggest that a mother’s diet that alters DNA methylation can affect the development of the fetus’s immune system, predisposing it to allergic airway disease.” He added: “It also suggests the dramatic increase in asthma during the past two decades may be related in part to recent changes in dietary supplementation among women of childbearing age.”
According to the charity, The National Asthma Campaign (NAC), the number of people suffering from asthma has dramatically increased. Their figures show that approximately 1 in 13 adults and 1 in 8 children are treated for asthma – that’s 5.1 million people throughout the UK. Their previous figure from 1999 reported that 3.4 million people were asthmatic. The source of this increase is not certain and is thought to be a mixture of genetic and environmental factors, from pollution levels to a diet containing too many additives. However, it is generally agreed that a viral infection is a significant contributory factor in asthma.
This current study is important because it helps to examine the potential role of epigenetics (the study of gene regulation) in the role of allergic asthma. With asthma accounting for over 74,000 A&E admissions, understanding the root of condition is important in developing treatments and prevention advice.
The research team examined how different variables can alter methyl groups. Variables included environmental exposures, from diet to tobacco smoke, to medications. They found no changes occurred in the genetic code, however, epigenetic effects were seen to be passed on to offspring from the mother. The research suggested that epigenetic mechanisms may play a role in the development of the immune system, steering the child’s predisposition to allergies. The results from this study demonstrated more airway hyperactivity, greater allergic inflammation, and elevated levels of IgE (a class of antibody associated with hypersensitivity) in the mice’s blood.
Co-author of the study, John W. Hollingsworth said: “There seems to be a crucial stage, during development in utero, when a young mouse is susceptible to epigenetic changes that can alter its immune system.” He explained: “These epigenetic changes may partially explain why it has been so difficult to definitively identify genes that contribute to asthma risk; the effect of genetic variations can be masked or further complicated by epigenetic changes.”
Although folic acid is implicated as one of the triggers of allergic asthma, Drs. Schwartz and Hollingsworth emphasis that the importance of folic acid supplementation during pregnancy outweighs the any potential risks for asthma. On this point they say more research is needed.
The study is published in the Journal of Clinical Investigation.