Why was there a spike in peanut allergies in the early 2000s?

In the U.S., the rate of childhood peanut allergies more than tripled between 1997 and 2008. Today, we'll cover why now-outdated recommendations to delay peanut introduction contributed to this spike, and how recent landmark clinical studies show that introducing peanut to babies early and often is key to preventing peanut allergies.

In the United States, peanut allergies spiked in the 1990s and early 2000s, and the percentage of people with peanut allergies continues to rise. 

Between 1997 and 2008, the rate of childhood peanut allergy more than tripled.

But why did this happen? 

Today, we will cover:

• Why outdated recommendations (from 1990s to early 2000s) of waiting to feed babies peanut were a major reason that peanut allergies increased in prevalence 

• How recent landmark studies changed the way we think about introducing peanut to babies

• What current guidelines say about introducing peanut to prevent food allergies in babies. 

Delaying Peanut Introduction Led To Peanut Allergy Spike

When many of us were babies, our parents and grandparents fed us solid foods whenever we were ready to eat them---even foods that were common causes of allergies. 

According to Dr. Jonathan Spergel (Head of Allergy at Children's Hospital of Philadelphia), around the 1960s, infants would begin eating foods like peanut products starting at just a few months of age. At that time, food allergy prevalence was very low.

Until the 1990s, doctors also recommended introducing allergy-causing foods like peanut early, in baby's first year of life.

But in the late 1990s and early 2000s, doctors changed their approach. They mistakenly thought that delaying the feeding of peanut for several years was the best approach to preventing peanut allergies. 

In fact, the American Academy of Pediatrics issued a (now-outdated) recommendation in 2000, which directed parents to avoid feeding baby peanuts until they reached the age of three, especially if a baby was at high risk for a peanut allergy.

But when these recommendations to delay feeding peanut were introduced, there was no study to support these recommendations. Rather, they were just based on physicians' guesses.

As Dr. Spergel explains, "Back then, we gave people really bad advice. We told people to avoid food allergens... But there was never any evidence for this. It was just based on a few physicians’ best guess. There's never been any study that ever proved that food avoidance worked. "

Today, we know that this approach to delay peanut introduction actually increases food allergy risk, and that delayed introduction was a major factor that led to the sharp increase in peanut allergies.

Thanks to landmark clinical studies, we now know that the opposite approach---feeding baby peanut early and often, before they turn one---is the best way to prevent peanut allergies.

Learn more about the rise in food allergies from Dr. Spergel:

YouTube video: Introducing food allergens at Advocate Aurora (full webinar), with Ready, Set, Food!

New Research: Introduce Peanut Early for Peanut Allergy Prevention 

In 2008, Dr. Gideon Lack and others observed that Israeli babies developed peanut allergies much less frequently than babies in the UK. In fact, the rate of peanut allergy prevalence in the UK was ten times greater than the peanut allergy prevalence in Israel. He noticed that Israeli babies started eating peanut in their first year of life, but the babies in the UK (like the US) didn't eat peanut for several years. This prompted Dr. Lack to conduct further research on peanut introduction and peanut allergy prevention.

The landmark Learning Early About Peanut (LEAP) study, which Dr. Lack spearheaded, investigated whether consuming peanut early and often helped prevent children from  developing a peanut allergy. 

In the LEAP study (published 2015), babies were divided into two groups. One group started to consume peanut three times per week starting at 4-11 months of age, and continued this regular peanut consumption until they reached 5 years of age. The other group avoided peanut completely until they reached 5 years of age. 

The LEAP study found that introducing peanut to babies early and often reduced their peanut allergy risk by more than 80%.

• Early: Starting between 4 and 11 months of age---the earlier the better

• Often: 2-7 times a week for at least 6 months (The LEAP study sustained exposure over 4 years)

In the LEAP study, only 3% of the children who ate peanut regularly developed a peanut allergy by age 5. But 17% of the children who avoided peanut developed a peanut allergy by the age of 5. That's an 82.35% difference between the two groups. 

The LEAP study shows that you shouldn’t delay the introduction of peanut to your baby. It shows that the advice given in the 1990s and early 2000s, to delay peanut introduction, was harmful.

Delaying peanut introduction actually increases babies’ food allergy risk. Instead, to help prevent your baby from developing peanut allergies, it’s vital to feed your baby peanut early and often, starting between 4 and 11 months of age.

New Guidelines on Food Allergy Prevention 

The LEAP study prompted several leading American medical organizations, including the NIH, AAP and NIAID, to publish new guidelines promoting early and consistent peanut introduction. For some of these organizations, this represented a reversal of their previous advice to delay feeding peanut.

Notably, the AAP completely reversed the recommendation that they gave in 2000. Now,  in their 2019 guidelines, the AAP recommends introducing your baby to peanut as early as 4-6 months of age, especially if they are at high risk for peanut allergies. 

Most recently, the USDA published their first set of dietary guidelines for children under two years of age. Also prompted by LEAP, these guidelines recommend introducing babies to peanut early and often, starting as early as 4 months of age and regardless of their food allergy risk. As the guidelines report, "strong evidence suggests that introducing peanut in the first year of life may reduce risk of food allergy to peanuts."

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