Peanut Allergies, Genetics, and When to Introduce Peanuts in Your Infant/Child’s Diet

peanuttyI love it when what we have told patients and thought to be true ends up being exactly the opposite of what actually is going on. Not happy that we had it wrong. Just happy we are now getting it right!

Bottom line: Introduce peanut protein (peanut butter or cooked into a teething biscuit) as soon as you can introduce solid foods to your infant (OK to start at 4-6 months)!

That’s crazy you say. My doctor told me no peanuts until age 3 due to peanut allergies in our family. Finally there is a well done study to clarify what to do. In the study, “Randomized Trial of Peanut Consumption in Infants at Risk for Peanut Allergy,” (which you can read here… ) researchers  divided 640 atopic infants (with severe eczema, egg allergy, or both) aged from 4 months to 11 months into 2 groups—those who had a positive skin-prick test for peanut allergy in 1 group and those who did not in another. Children in each of these 2 groups were then assigned to a group that would consume peanuts or to one that would not. Infants in the peanut-eating group received at least 6 grams of peanut protein (about 24 peanuts) a week, either in a peanut butter/puffed maize snack food or peanut butter itself, until they were aged 60 months. Infants in the avoidance group had no peanut protein until they were aged 60 months.

They found that of 530 infants who initially had negative results on the skin-prick test, 13.7% in the avoidance group had peanut allergy compared with 1.9% in the group that ate peanuts. Among the 98 infants with positive skin-prick results, only 10.6% of those fed food containing peanuts had developed peanut allergy compared with 35.3% of those whose parents had avoided feeding them peanuts.

This is a powerful study. If you don’t have obvious allergies and don’t eat peanuts, you have a 1 in 7 chance of becoming allergic to peanuts but if you do eat peanuts your chances are 1 in 53! If you are already skin prick reacting to peanuts you have a 1 in 9 chance of becoming allergic if you eat peanuts early or a 1 in 3 chance of being allergic if you avoid peanuts.

My guess is that if you eat organic peanuts, and start your babies on that early (by 6-9 months of age) allergies will be rare indeed, even when there is a family history or risk of developing allergies.

In another study, “Genome-wide association study identifies peanut allergy-specific loci and evidence of epigenetic mediation in US children,” (read the study here… ) found that the HLA-DR and -DQ gene region probably poses significant genetic risk for peanut allergy. “Not everyone with these mutations, however, develops peanut allergy, and researchers wondered why. One possible reason, they determined, was that epigenetic changes may also play a role. Epigenetic changes, in which a methyl group attaches itself to the DNA, alter the expression of a gene without altering its underlying code. The levels of DNA methylation regulate whether people with genetic susceptibility to the peanut allergy actually developed it.

So there you have it. Methylation, that key step in so many body reactions and functions, may be affected by the environment, in this case, eat your peanut butter and start young!

Obviously this will be controversial, so check with your doctor. Chances are, they may not be aware of this key study, so best you take it to them and then ask them. Before I read this, I would have given you the standard, old, tired, and WRONG line, “wait until your child is 2 or 3 years old, and perhaps never give peanuts if you have a strong family history.”


Dr. Paul





Reply To This Post