Feeding babies peanuts at least three times a week could protect them from developing nut allergies in later life, a study has found.
Scientists at King's College London have been studying hundreds of children for more than 10 years to see if early exposure to nuts could prevent potentially lethal allergies.
They discovered that introducing nuts regularly in the first year of life was enough to build up a tolerance by the age of 6, even if the child stopped eating them for 12 months.
All the children tested had a family history of peanut allergies, placing them at high risk. The NHS recommends that children at risk should avoid nuts for the first three years of life. But the study suggests that could do more harm than good.
Around one in 50 children suffers from a peanut allergy, which in extreme cases can cause the throat to constrict and can prove fatal if adrenalin is not given in time.
The research suggests that allowing children to get used to nuts early prevents an allergic reaction.
The LEAP-On study followed on from the LEAP (Learning Early About Peanut Allergy) study, both led by Professor Gideon Lack, to find out if allergies could be prevented through exposure.
"The aim of our study was to find out whether infants who had consumed peanut in the LEAP study would remain protected against peanut allergy after they stopped eating peanut for 12 months," said Professor Lack.
"It demonstrates that the majority of infants did in fact remain protected and that the protection was long-lasting."
More than 250 children who had completed the original study, and were free of peanut allergies, were instructed to avoid peanuts for 12 months. A similar-size control group continued to eat peanuts regularly. They were then tested to see if they had developed an allergy.
The study found that at 6 years of age, there was no statistically significant increase in allergy after 12 months of avoidance.
There was a 74 per cent relative reduction in the prevalence of peanut allergy in those who ate peanuts compared to those who avoided them.
Peanut allergy develops early in life, is rarely outgrown and there is no cure. The occurrence of peanut allergy has more than doubled in 10 years in the UK.
Michael Walker, a consultant science manager and referee analyst for the Government Chemist programme, welcomed the findings, but added that parents should not attempt to replicate what the studies did by themselves but should follow general guidance. The research was published in the New England Journal of Medicine.