Early in 2015 the peanut allergy world was stunned by the results of the LEAP study conducted by Professor Gideon Lack and his team at King’s College in London.
Over 600 four to 11 month old babies at high risk of peanut allergy (coming from families with a high incidence of allergy) been randomised either to avoid peanuts or to consume them for five years, up to the age of five. And while 17% of the children who avoided peanuts had developed a peanut allergy by the age of five, only 3% of the children who had been eating peanuts had developed an allergy. In other words, regular consumption of peanuts from the time of weaning till the age of five led to an 81% reduction in the risk of peanut allergy amongst high risk children.
Results from the continuation LEAP-ON study which came out in March 2016 suggested that this tolerance would be sustained. Amongst 556 of the original cohort who then avoided peanut from the age five for one year, only 4.8% of the peanuts consumers were found to be allergic at the end of the year in which they had not eaten them, while 18.6% of the peanut avoiders were allergic.
(For those interested in the genesis of such studies, it arose from a visit made by Professor Lack some years ago to Israel where he addressed a group of paediatricians on the subject of peanut allergy. His talk was greeted by a sea of blank faces as peanut allergy is all but unheard of in paediatric populations in Israel. Further investigation revealed that mashed peanut was widely used as a weaning food for Israeli babies between the ages of 8 and 14 months; the parents of similar aged children in the UK were specifically warned never to feed their children peanuts. Professor Lack and his team decided to test the peanut-as-a-weaning-food theory out on British children.)
As always, it takes a while for the results of such research to work its way through into medical practice and while Public Health England and the NHS are no longer telling parents not to feed their children peanuts, neither are they yet telling them to do so. However, across the pond in the US the National Institute of Allergy and Infectious Diseases have been a touch speedier and have just issued new guidelines suggesting that:
- Children with other allergies or severe eczema should start on peanut-containing foods at between four and six months old, with medical supervision
- Babies with mild eczema should have peanut-containing food at about six months old
- Those with no eczema or allergies can have peanut-containing food freely introduced
Hopefully, the UK will catch up soon. While waiting for them to do so, UK parents who fear that their children may be at risk of peanut allergy and would like to follow the new advice, should talk to their GPs and point them in the direction of the American guidelines and the results of the LEAP study.
Meanwhile, or course, there has been concern that in their enthusiasm to feed their infants peanuts, parents should not feed them whole peanuts because of the risk of choking. There has also been concern that the new guidelines will be misunderstood. A piece in the Huffington Post last week described how the father of a pre-teen with a peanut allergy had read the study and, as a result had been feeding his son tiny bits of peanut and had been seeing ‘mini responses, which had been escalating’ – whatever that may have meant.
Of course feeding a peanut-allergic pre-teen bits of peanut is not at all what the guidelines are advising and certainly is not what any doctor would advise – quite the opposite. But dangerous though this practice could be, the concept is not that far out.
Oral immunotherapy does involve exactly that, feeding an allergic person very tiny, but slowly escalating, amounts of the food to which they are allergic in the hope of gradually educating their immune system to recognise it as friend rather than foe. The difference is that the amounts of the allergen used are tiny (micrograms, not ‘tiny bits’) and that it is only done under tightly controlled medical supervision lest a reaction should occur. However, it does appear to work, both for peanuts and for other allergens. And even if allergy sufferer never reaches the point where they could comfortably consume a peanut butter sandwich, as long as their sensitivity is reduced to a level at which they will not react to traces of the allergen, their quality of life will be enormously improved.
(If anyone wishes to follow up on immunotherapy research there have been a number of studies over the last few years that suggest that it can be successful: see this study and this study from 2014, and another one from 2014 although improvement may not always be sustained; this study on OIT combined with probiotics from 2015 and two more, one from 2015 assessing the efficacy of the treatment and this one from 2016 on who may or may not react well to immunotherapy.)
For much, much more on peanut allergy and for hundreds of research reports see this section of the Foodsmatter site.
