Do we need to wait 3-5 days before we introduce another new food?

Have you heard:

  • The right baby food is very important.
  • You should feed your children at 4 months to prevent allergies. 
  • You should wait until 6 months to start solids.
  • You should breastfeed exclusively for 6 months. 
  • You should wait to introduce allergens. 
  • You should introduce one food at a time.
  • You can introduce multiple foods. 
  • You have to wait 5 days between foods to introduce another one. 

Yes! I am sure you have heard all of these things at different times or even on the same day from different sources. It is frustrating and very confusing. I get it. The most frustrating part is that mixed messages come from the fact that expert guidelines are conflicting and change over time! As parents we are left wondering- which one is the right thing to do?! As a pediatrician I also wonder what I should counsel on. So here we go…today I’m talking to those of you ready to introduce foods. What’s really behind this guideline: You have to wait 3 to 5 days between foods to introduce another one. 


What are the actual expert guidelines?

The American Academy of Asthma, Allergy, and Immunology (AAAAI) says between four to six months, single-ingredient infant foods may be introduced… Food can be introduced this way every 3 to 5 days as appropriate for the infant’s developmental readiness.

In its last guideline the American Academy of Pediatrics recommended introducing single-ingredient complementary foods one at a time for a several day trial.However, this guideline was last updated in 2000 and notably there is no recommendation to wait on the main AAP feeding site currently.


Why is this wait period recommended? 

Basically, it has been said that going slowly allows caregivers to figure out which was the offender if a child has an allergic reaction. It is used as a way to help parents know what foods to avoid. 


Is this recommendation backed by science?

Nope. No studies are cited in either the AAP or AAAAI guidelines and we couldn’t find any evidence looking in to this waiting rule at all. 


But it makes sense, doesn’t it?

It does and it doesn’t. It does in that the majority of food allergies do get diagnosed when a child is less than two, so worrying about a baby is reasonable. Also, if the only thing you fed your child for 4 days in a row was potatoes and they break out in hives, the most likely culprit is potatoes. However, allergies can still occur at any time. Babies can have a reaction the first time they have potatoes or the 58thtime. Also, if your baby has a reaction to those potatoes or anything else, you most likely will end up at a doctor’s office and need to get testing done anyways. 


Ok.. but doesn’t it take several days for some reactions to appear?

There are several kinds of food reactions. A food allergy happens when your immune system has a response to a food. Typically, this means that your body makes antibodies against the food, and your body goes into overdrive when you expose yourself to this allergen. These food allergies can cause anaphylaxis and most occur within minutes or hours of exposure. This can stop a child from breathing. If you see hives, coughing or trouble breathing, or vomiting you should call 911 or go to the ER immediately. (or administer an epi pen if you have one!)

Other food reactions that are not caused by antibodies may take longer to appear. However, there is no guarantee that they will happen within the three days of waiting and can happen later.


But is there harm in waiting and just do 1 food at a time?

Again, there is no evidence or even studies looking specifically on these waiting “rules”. However, we are learning more and more about how having a diverse diet in the beginning is good for helping kids eat a variety of foods later on AND in the prevention of food allergy itself ! If your child is not ready to start solids until they are 6 months old and the goal is to have a varied diet with several textures by age 1 you don’t have that much time. If you wait three days between each new food, that means at most the number of foods that you can introduce is around 61 foods. If you wait 5 days, you can only introduce about 37. This might be enough diversity, but we just don’t know. 

Furthermore, the LEAP trial completely changed what we tell parents about introducing allergens, especially in kids at high risk of peanut allergies. We now recommend introducing them early. If you want to read more about that check out my blog post taking on that here.


So, what is the bottom line?

The bottom line is that there is actually no evidence to suggest you should wait three to five days to introduce a new food. I feel that in this case parents can choose what feels right to then and not feel tied down to waiting in between foods. Keeping track can be tedious! In the end we want to prevent allergies and build healthy confident eaters, and that means introducing a large variety of foods at an early age! 

One last piece of advice- at your 4-month well child visit with your pediatrician, talk to them about introducing solids and ask them what to look out for as signs your child may be having a reaction. This way you can feel prepared to identify one. 


Happy feeding!


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