Peanut Allergy: Big News About Little Peanuts

Peanut allergies have quadrupled in the last 15 years.  In the US, where 1 out of 13 children has food allergies (that's 6 million children), peanut allergies are the second most common, affecting 20% of allergic children--which is approximately 2% of all children (and just behind cow's milk which affects 25% of allergic children). How common are food allergies?

The second problem is that peanut allergies can be severe and are rarely outgrown.  They don't have to be eaten to cause the allergy. Someone who is sensitive can merely breathe in steam from roasting peanuts or peanut dust, or get residual peanut from surfaces on their hands, which are inevitably put in the mouth and have an anaphylactic reaction (those extreme reactions where the throat closes and breathing becomes difficult).  That is why peanuts are often excluded from school lunch rooms and why peanuts may not be served on airlines if someone on board indicates they have a peanut allergy.

The Teaching

Clinical practice guidelines in both the United States and the United Kingdom have long recommended that we avoid potentially allergenic foods in infants at high risk for allergy (those that have an allergic parent or sibling) and from the diets of their mothers during pregnancy and lactation.  However, studies in which these foods have been eliminated repeatedly failed to show that the e strategy prevented the development of classic (IgE-mediated) food allergy, and in 2008, the recommendations were rescinded.

In fact, peanut allergies are lower in China and Israel.  One study showed that the risk of peanut allergy was 10 times as high among Jewish children in the United Kingdom as it was in Israeli children of similar ancestry.  The difference seems in line with the time when peanuts are introduced in the diet in those countries: in the United Kingdom, peanut-based foods aren't eaten in the first year of life, while peanut-based foods are usually introduced in the diet when Israeli infants are approximately 7 months of age.

Newly Released Study

The group that did the comparison study suspected that the early introduction of peanuts may actually offer protection from developing peanut allergy.  So they designed and have now reported their new results (New England J Med 2015; 372:803-813 February 26, 2015)

They enrolled infants between 4 and 11 months of age who had egg allergy, severe eczema or both.  They then skin tested them for peanut allergy and gave infants with negative skin tests or those with small positive skin tests (1 – 4 mm in diameter) a small amount of peanut protein to try.  Infants who had large positive skin tests or those who had a reaction to the fed peanuts were eliminated from the trial and told to avoid peanuts.  The families of the other infants were then put in one of two groups, those that were given a small amount of peanut or peanut butter products 3 times per week or those who were told to avoid it.  And the goal was to determine which group had less of a reaction when fed peanuts at 5 years of age.  What do think happened?

Among the 530 infants who did not have a reaction on the skin-prick test in the beginning, 13.7% of those avoiding peanuts and 1.9% of those consuming them were allergic to peanuts at 5 years of age, an 86.1% relative reduction in peanut allergy development.  

Of the 98 children with small positive results on the initial skin-prick test, 35.3% of the avoidance group and 10.6% of the consumption group were allergic to peanuts; a 70.0% relative reduction in peanut allergy.

Among the 57 children (9 randomly assigned to consumption and 48 to avoidance) who had a positive response to the oral food challenge at 5 years of age, 14 had respiratory or cardiovascular reactions and 9 received intramuscular epinephrine owing to concerns about the severity of the allergic reaction.

What The Study Suggests

  • Peanut allergy remains a serious food allergy.
  • Earlier and frequent exposure to peanut-based products may prevent food allergies from developing at 5 years of age in infants with a high risk of allergies in their family.


  • They used 6 g of peanut protein weekly to 2 years of age in a peanut-butter and corn puff. This is a commercially available product. The amount is equal to about 1 1/2 tablespoons of peanut butter.  However, peanuts themselves are not safe for infants or even toddlers.  They can choke on peanuts, with peanuts getting lodged in the airway.  And peanut butter can be difficult for many infants to eat because of its texture.
  • If your family has food allergies and your child already has eczema or some food allergies, this is a particularly important study that you might want to discuss with your doctor.  It is essential that you first determine whether he or she has a reaction to peanut products and this should be done under medical supervision.
  • It is unclear whether the findings in this study will apply to other allergies and whether the children who did not react with a peanut allergy will develop one later.  These questions are still being studied.

Dr. Stan Cohen 01 March 2017

Dr. Stan Cohen is one of our founders and our CEO as well as the Chairman of our Medical Advisory Board. Dr. Stan is an internationally recognized expert in pediatric gastroenterology and nutrition. He is a Read More

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