Professor Gideon Lack, a paediatric allergy specialist at Kings College London, believes there is growing evidence to suggest that parents should feed their children peanuts from a young age to protect them from allergies. The same may apply to other potentially-allergenic foods including fish and eggs.
The professor's work, which proposes a new mechanism for what leads children to develop allergies, is contrary to advice from public health officials at the Department of Health and the World Health Organisation, who insist children should avoid eating peanuts until three years old.
The Food Standards Agency has now launched a full review of the evidence to determine if a shift in the advice is needed.
Professor Lack is conducting the first clinical trial into whether eating peanuts in the first year of life can protect children from allergy, but he insisted it was still too early to know if official health advice should be changed.
He said: "Peanut allergy in English-speaking countries has almost trebled in the last 15 years and occurs in almost one in 50 primary school children. In traditional societies in Africa and Asia, however, it doesn't occur in children to the same extent. In these societies babies are allowed to eat peanuts from a very early age.
"The hypothesis is that by eating peanuts in the first year of life, babies become tolerant of those foods.
"The gut is surrounded by a belt of immune tissue which help to recognise friendly proteins such as those from food. Without this you would reject everything you ate.
"The immune system learns early in life, through the repeated introduction of food, that proteins from food are harmless and innocuous substances. So regular exposure in a healthy baby in early life may actually help the immune system to distinguish between friend and foe."
Professor Lack will describe his work at the official opening of new research laboratories in the Medical Research Council's and Asthma UK's Centre in Allergic Mechanisms of Asthma at Kings College London on Monday October 27.
Peanut allergy is now the most common food allergy. Symptoms can vary from rashes and itching to breathing difficulties, narrowing of the airways and leaking of the blood vessels. In severe cases, known as anaphylactic shock, it can lead to death.
Allergies occur due to an over-reaction of the immune system to molecules that are normally harmless, triggering an attack that releases toxic biological chemicals into the blood stream.
These in turn damage the body's own tissues and causes inflammation.
Professor Lack believes that children who have not eaten peanuts may be more prone to suffer an allergic reaction when they come into contact with them through their skin, particularly if they suffer from skin conditions.
He said: "The problem is that food proteins can be found everywhere in a house, so what I believe is happening is that when babies suffer from eczema, the skin barrier is broken down and there is a lot of inflammation as molecules of peanut and other food get through the skin.
"The body sees the food molecules as a threat and responds to it as it would to a parasite, by mounting an antibody response."
Professor Lack is currently two years into a five-year clinical trial to examine whether it is possible to make children more tolerant of a food by feeding it to them earlier in life. Using 650 children who suffer from eczema, which is known increase the risk of developing an allergy, he has asked half the parents to feed their children peanuts while they are weaning between the ages of four and eleven months.
The other half have been asked not to feed their children any peanuts. As the youngsters grow up they are having regular blood samples taken to observe how their immune systems are developing. At the age of five they will be tested for food allergies.
Professor Lack is also planning a second trial to look at other food allergies in 2,500 children. Again, half the parents will be encouraged to feed their children a variety of solid foods from an earlier age than the other half.
A spokesman for the Food Standards Agency said a panel of independent experts on the Committee of Toxicity had been asked to review the current advice, issued in 1998, on early exposure to peanuts and other allergens. In the meantime, he said, parents should continue to follow existing advice.
He said: "The independent experts of the Committee on Toxicity are considering the findings of the review and other relevant evidence, and have been informed about ongoing research in this area, including the King's College study. They are considering whether their previous recommendations are still appropriate."