The prevalence of peanut allergy among children is high and has become the leading cause of anaphylaxis which is potentially life-threatening. A latest study conducted by Du Toit et al., which has been published in The New England Journal of Medicine, suggests that early introduction of allergic foods (a concept called LEAP, Learning Early about Peanut allergy) significantly reduces the frequency of development of allergy.
This study has been done in infants of 4 to 11 months of age who are at high risk of developing peanut allergy. A skin prick test was done in those infants with pre-existing sensitivity to peanut extract and was randomly assigned into two groups. One group consisting of participants with no measurable wheal (negative) after testing and the other group consisting of those with a wheal measuring 1 to 4mm in diameter (mild sensitivity). The group which had a wheal measuring more than 4mm was excluded from the study because of concerns that they would have severe concerns.
Infants, randomly assigned to consumption, underwent a food challenge in which those who had negative results on the skin-prick test were given 2 g of peanut protein in a single dose and those who had positive test results (mild sensitivity) were given incremental doses up to a total of 3.9 g. These feeding patterns continued until the children were 5 years old and they were monitored and tested regularly during regular visits.
Serum levels of peanut-specific IgE, IgG, and IgG4 antibodies were measured at each visit, since these are known biomarkers of allergic responses, antigen exposure, and potential immune modulation, respectively. The peanut-specific IgG4: IgE ratio was also calculated, since it has been reported that this ratio may additionally reflect immune modulation.
The preferred peanut source was Bamba, a snack food manufactured from peanut butter and puffed maize. Smooth peanut butter (the brands Sunpat or Duerr’s) was provided to infants who did not like Bamba.
The results were striking! Those who consumed the foods that had peanuts in them were far less likely to be allergic to peanuts when they turned 5. Only 1.9% of those who were fed peanuts (consumption group) were allergic compared with 13.7% of the children in the group that avoided peanuts (avoidance group).
The mean diameter of wheals and number of participants with elevated levels of peanut-specific IgE titers were higher in peanut-avoidance group than in the consumption group. Also, unless peanut-specific IgE levels were very high, elevated IgG4 levels were associated with the absence of an allergic reaction to peanuts. In contrast, the peanut-consumption group showed a significantly greater and earlier increase in levels of peanut-specific IgG and IgG4. Both observations indicate that IgG4 is associated with a protective role against the development of allergy.
So this study shows that early, sustained consumption of peanut products is associated with a substantial and significant decrease in the development of peanut allergy in high risk infants. It is really a boon for parents given that these results are prospective, but many questions arise and remain unanswered and any such trials has been advised to be done with doctor’s consent and supervision.
More about this can be read here.