Study links food allergies to hyperactive immune system at birth

The prevalence of food allergies has increased greatly over the last ten years.

An Australian study, published this week in Science Translational Medicine, establishes a link between food allergies and an overactive immune system at birth. The findings could help scientists understand the origin of food allergies and develop new preventative treatments. 

Food shopping can be a real headache for parents whose children who are allergic to milk, eggs, nuts or wheat. The causes of food allergies remain unknown and, for the time being, the medical profession has no means of preventing allergic reactions. The only option is to remove allergy-causing foods from a child's diet.

New research may now shine light onto why some people to develop food allergies while others don't. Research by Dr Yuxia Zhang and associates from the Walter + Eliza Hall Institute of Medical Research in Parkville, Australia, found that the root of the problem could be linked to hyperactive immune cells present from birth. The team saw that babies carrying these overactive cells, or "monocytes," at or prior to birth were at greater risk of developing food allergies.

Symptoms of food allergies can include rashes, nausea, swelling of the throat, and difficulty in swallowing or breathing when a certain food is consumed.

The study was based on 1,000 pregnant women and their babies, examining immunity, allergies, and respiratory, cardiovascular and neurological development.

Food allergies have increased greatly over the last ten years and are now relatively commonplace. Hospital consultations for food allergies have tripled in Australia, with one in ten children developing a food allergy before their fifth birthday. "We don't know why the increase in food allergy has occurred. The important thing about this study is that we've shown the immune systems of babies who develop food allergy are in a sense 'primed' for allergic disease by the time they are born," said Associate Professor Peter Vuillermin, who also worked on the research.

The next step for scientists is to examine why some babies have these hyperactive immune cells at birth whereas others don't, and to establish whether the phenomenon is genetic or occurs at or after birth.

More generally, the study's authors have underlined the importance of studying pregnancy and the first moments of life to understand why chronic immune and inflammatory disorders like allergies develop in childhood and later in life.

As many as 15 million people in the US have food allergies, including approximately 4-6% of children. In Europe, average rates are 3.2% for adults and 4.2% for children. The World Health Organization now classifies allergies -- including respiratory allergies, skin reactions or food allergies -- as the fourth most important chronic disease in the world.