Experts ponder why so many children have food allergies

Oct 31 2007

Experts say the number of people, especially young children with food allergies in the United States is on the increase and specialists are seeing more and more children with multiple allergies.

It is now estimated that as many as 8% of children under the age of 3 have some sort of food allergy, and 11 million Americans are thought to be allergic to some sort of food related product.

The most commonly heard of food that people are allergic to is peanuts which can induce serious life threatening reactions in some people who eat them.

Peanut allergies amongst the under 5's doubled between 1997 and 2002 and experts suspect that in the future the numbers will further increase.

A food allergy is characterized by the body's immune system reacting due to it believing that whatever is ingested is harmful.

Food allergies can range from skin rashes, eczema, gastrointestinal and anaphylactic shock, a life-threatening, full-body reaction that can lead to breathing difficulties and collapse.

Allergists say they're now seeing more children with multiple allergies than ever before, and not just to foods such as milk and wheat but to global foods such as sesame and kiwi fruit.

They also say allergies do not appear to 'outgrow' but instead linger on for longer.

According to the National Institute of Allergy and Infectious Disease, every year in the States there are more than 30,000 episodes of anaphylaxis, resulting in 100 to 200 deaths.

Today many schools and childcare centres ensure that common foods that are known to be the source of serious allergic reactions, such as peanuts are not available and many states have implemented allergy guidelines, focusing on allergy education for both children and staff.

Experts who are looking at why allergies appear to be on the rise have come up with a number of theories - for example that we have all become too clean.

Clean water, antibiotics and vaccines have eliminated many of the most toxic challenges which the immune system is designed to fight such as parasites, viruses and infections, so the immune system finds something else to battle such as eggs, wheat or some other innocuous food.

It has also been suggested that children born by Caesarean section, which have risen 40 percent in the last decade, could be at higher risk for allergies, perhaps because their bodies are never exposed to the healthy bacteria in their mothers' birth canals.

But much of this is no more than speculation and while scientists may have a basic understanding of how allergies occur, the complex immune system remains in many respects a puzzle.

Novel approaches are being tried with some success where the offending ingredients are introduced in tiny amounts to see if they can treat, cure or even prevent food allergies from developing in the first place.

The hope is to ultimately come up with a peanut-allergy vaccine.

Experts who have studied allergy incidence worldwide have discovered a paradox whereby countries that have advised avoidance of peanuts in early childhood, such as the U.S., have had the greatest rise in peanut allergies, while in Asian and African countries, where children eat a variety of peanut products starting at a very young age, peanut allergies are far less common.

A new study by Professor Gideon Lack, of King's College London has enrolled more than 200 babies with eczema or egg allergies but no known peanut allergy.

The groundbreaking trial plans to give half the babies a snack containing peanut while the others will avoid peanuts.

He will then follow them all until age 5 to see if he has stopped a peanut allergy before it takes hold.

Professor Lack says the idea is to try to intervene during a narrow window of immunological opportunity in the first year of life and if it works it could apply to other foods as well.

Professor Lack says if the study is successful it could lead to a turnaround in medical advice.