The EAT Study: More food for thought on earlier introduction of solids to prevent food allergy

Would you offer your 3-month-old baby a taste of peanut butter? Hard-boiled egg? How about a little tilapia with tahini sauce? That’s exactly what parents did in a study published in May in The New England Journal of Medicine.¹ The study found that early introduction to these foods might protect children from development of food allergies, but many parents had a difficult time following the study instructions.

The study, called the Enquiring About Tolerance (EAT) study, was conducted in the U.K. and led by Dr. Gideon Lack. Lack was also the lead author on the LEAP study published in 2015, which found that earlier introduction of peanut to high risk infants prevented peanut allergy.² Previous observational studies have found a lower rate of peanut, egg, cow’s milk, and wheat allergy in children with earlier introduction to these foods.^3–6 However, LEAP and EAT are the first published randomized controlled trials of this question, giving us higher quality evidence than the earlier observational studies.

In the EAT study, 1303 exclusively breastfed 3-month-old babies were randomly divided into two groups. One was instructed to follow current U.K. recommendations to continue with exclusive breastfeeding until 6 months of age and then to introduce solid foods, leaving the types and amounts of foods up to the parents. The other group was instructed to begin introducing solids as early as 3 months, including six commonly allergenic foods: cow’s milk yogurt, peanut, cooked egg, sesame (in the form of tahini paste), whitefish, and wheat. Mothers in the early solids group were also asked to continue breastfeeding through at least 6 months.

Here is what parents in the early introduction group were asked to do (from the study protocol):

-Begin with rice cereal mixed with breast milk or water. Average age of enrollment was actually 3.4 months, so babies were starting foods sometime between 3 and 4 months.

-Next, offer cow’s milk yogurt with a goal of 4 grams of protein per week by 5 months of age. This comes out to a heaping one-third of a cup of whole milk yogurt, fed over the course of the week.

-Next, offer sesame, egg, fish, peanut, and wheat. Each family was given a randomly assigned order of introduction to these foods. The target amount was 4 grams of protein from each food per week. I show how that translates to amounts of actual foods in the photo below. Parents were asked to not introduce wheat before 4 months of age, because previous research has found an association between celiac disease and earlier introduction of wheat.

An earlier paper on the EAT study provides an example of a weekly calendar [PDF] for food introduction given to parents.7 (Please, please, please… don’t get caught up in following this protocol without reading to the end of this post!)

I happened to have all of these foods on hand, so I dished them up so you can see what a baby in the early introduction group of the EAT study should have been eating by 5 months. (Again, this is a week’s worth of food.) If you think it sound challenging to incorporate all of these foods into a young infant’s diet, then you are not alone. One of the big limitations of the study was that many babies (and/or their parents) didn’t actually follow these dietary instructions.

So, did timing of introduction of these foods make a difference to the development of food allergy?

The researchers looked at differences in food allergy between the two groups in a couple of different ways. The first was an intention-to-treat analysis, comparing the incidence of food allergies regardless of whether or not subjects had actually followed the study instructions. Looked at this way, 5.6% of the early introduction group and 7.1% of the standard introduction group developed an allergy to at least one food. This difference was not significant.

Next, the researchers looked more closely at how well the families actually followed the dietary advice they were given. They defined “adequate adherence” in the early introduction group as consuming at least 3 grams of protein per week of at least 5 of the 6 assigned foods for at least 5 weeks sometime between 3 and 6 months of age. Just 43% of babies met these criteria.

But those babies, it turned out, did enjoy significant protection from food allergies. Only 2.5% of them developed a food allergy, compared to 7.3% of the standard group that stuck to their instructions. For peanut, there were no cases of allergy in the early introduction group compared with 2.5% in the standard group. For egg, 1.4% of the early introduction group was allergic compared with 5.5% of the standard group. These differences were all statistically significant.

Babies in the early introduction who ate less than the prescribed amounts also seemed to benefit, particularly for peanut. Those who ate just 1.5 teaspoons of peanut butter per week for 4 weeks (prior to 6 months of age) had a 10-fold reduction in the risk of developing peanut allergy compared to the standard group.

Food allergies are on the rise in the U.S., so the idea that we might be able to at least partially reverse this trend by giving babies earlier exposure to certain foods is intriguing. However, the fact that so many infants in the EAT study didn’t follow the early introduction protocol makes it hard to interpret the results with certainty. For example, there may have been factors that affected both the early acceptance of solids and the incidence of allergies. Although the researchers did not think this was the case, more studies with an easier-to-follow protocol (maybe just focusing on two to three foods instead of six, for example) would help clarify these relationships. One such study is currently underway in Norway.

There were no cases of anaphylaxis in the early introduction group, and hospitalization and growth rates were similar between the two groups. Parents of the early introduction babies were a bit more likely to report vomiting and constipation, but not diarrhea, at 4-6 months. These differences were small.

In a paper published separately earlier this year, the EAT researchers reported no difference in the rates of breastfeeding at 6 months in the control and early introduction groups (98% and 97%, respectively – much higher than typical rates in the U.K., but this was part of the EAT protocol).⁷ It’s important to note that since the EAT study specifically focused on breastfed babies, these findings may not translate to formula-fed infants.

The NEJM produced a short video summary of the study, available here.

My Take:

This was a careful, well-designed study of an important question facing every parent: when should we start offering solids to our babies? The results suggest that giving babies solids (particularly common allergens) as early as 3-4 months might cut the risk of food allergies. Previous studies suggest that breastfeeding at the time of solids introduction may be protective against allergies, and earlier solids introduction might mean that more babies experience that combo.

We’re seeing more and more studies that show benefits of earlier introduction of solids with little risk. This flies in the face of current recommendations from the WHO, the AAP’s Section on Breastfeeding, and the U.K.’s NHS that babies should be exclusively breastfed for six months. I hope that medical organizations are reevaluating that advice, at least in developed countries. (You can read more of my analysis of this question here.)

I find the EAT study really promising, but I also feel worried when I think of parents trying to follow this prescriptive food introduction protocol, especially as early as 3 months. It is an important finding that more than half of babies and their parents failed to follow it. You can’t rush a baby in starting solid foods – they need to have key motor and oral developmental skills in place. It is rare to see these before 4 months, and many babies won’t be ready until 6 months. For example, a baby needs to have lost the tongue thrust reflex, allowing her to move food to the back of her mouth and swallow it with ease. She also needs to be able to sit upright comfortably. And she needs to be interested in eating!

Trying to push a baby without the interest or the developmental skills to eat may backfire. The baby may reiterate her displeasure with this weird stuff called food by spitting it out and putting up a fuss, and further pressure to eat might just make that negative response even stronger. Meanwhile, parents may feel more stressed that they are somehow failing in the feeding department, and that’s the last thing any of us need.

What we can do is watch for signs of readiness and give our babies opportunities to try new foods, including these potentially allergenic ones, as they are ready. I started offering tastes of solids to my babies around 4.5-5 months, but neither ate more than a couple of bites per day until around 6 months. For my second baby, who benefited from my hours of reading on this topic, those bites did intentionally include all of the foods in the EAT study, except for tahini.

CORRECTION: An earlier version of this post incorrectly stated the food amounts shown in the photograph. The current amounts match what was recommended to parents participating in the EAT study.

References:

Perkin, M. R. et al. Randomized Trial of Introduction of Allergenic Foods in Breast-Fed Infants. N. Engl. J. Med. 374, 1733–1743 (2016).
Du Toit, G. et al. Randomized Trial of Peanut Consumption in Infants at Risk for Peanut Allergy. N. Engl. J. Med. 0, null (2015).
Poole, J. A. et al. Timing of Initial Exposure to Cereal Grains and the Risk of Wheat Allergy. Pediatrics 117, 2175–2182 (2006).
Koplin, J. J. et al. Can early introduction of egg prevent egg allergy in infants? A population-based study. J. Allergy Clin. Immunol. 126, 807–813 (2010).
Du Toit, G. et al. Early consumption of peanuts in infancy is associated with a low prevalence of peanut allergy. J. Allergy Clin. Immunol. 122, 984–991 (2008).
Katz, Y. et al. Early exposure to cow’s milk protein is protective against IgE-mediated cow’s milk protein allergy. J. Allergy Clin. Immunol. 126, 77–82.e1 (2010).
Perkin, M. R. et al. Enquiring About Tolerance (EAT) study: Feasibility of an early allergenic food introduction regimen. J. Allergy Clin. Immunol. 137, 1477–1486.e8 (2016).