Breastfeeding A to Z

Breastmilk & Allergies

The majority of babies have no problems with drinking breastmilk.  There is no need to avoid any particular food(s) when breastfeeding in general or to avoid allergies.  But sometimes, even if a baby who has never had formula or any other food besides breastmilk may have signs of a food allergy.  Which can be:  diarrhea, bloody stools, vomiting, colic, eczema, constipation and poor growth.  Babies can develop allergies to foods that you are eating while you are breastfeeding.  This is not typical unless their is a family history of either or both parents having food or environmental allergies.
Generally, if both parents do not have food or environmental allergies to anything, it is rare that baby would be bothered by anything that you are eating.  If it causes you gas, it can cause your baby gas, and sometimes they are uncomfortable, irritable and “toot” a lot!  If you aren’t fond of the behavior surrounding increased gas–you’ll need to slow down on the food that seems to cause it.
Sometimes it might be the amount of something you ate.  If that chocolate cake was really good, or the cold milk tasted awesome and you drank several glasses at once or you had more than 2 cups of coffee this a.m, or that fruit or vegetable came into season and was delicious–you get the idea.  Sometimes this can be resolved by just having less of the item, or not having it every day.
A good way to check if the fussiness or behavior your concerned about is caused by food.  Think back 3-6 hours prior to the baby having symptoms.  What did you have that was different than you normally eat, or more of something you might usually eat.  If you can pinpoint something, try it again–preferably in the daytime hours–so you won’t be up during the night with a cranky baby–and see if you have the same response 2 times in a row.  If the behavior seems to be all the time, it may be something you have at every meal, or multiple times per day.
We don’t want you to take something out of your diet that is good for you, or you enjoy, based on one episode of crankiness by your baby.  That can be caused by something besides food.   If the behavior is repeated, then try going without this item for 2-3 days and see if baby improves.  If fussiness or baby’s discomfort resolves than it may be something you choose to eliminate from your diet.  By all means check with your doctor/healthcare provider or request to see a Registered Dietitian for some assistance.
The most common allergies in breastfed infants are when you have cow’s milk and anything made with cow’s milk, eggs, nuts: including peanuts, soy and wheat.  The proteins in these items appear in your breastmilk within 3-6 hours after you’ve eaten them.  Usually you can see a difference in baby’s symptoms in 2-3 days, after eliminating the food item.  Sometimes it an take up to 1-2 weeks.
Sources of information are:
https://www.chop.edu/pages/breastfeeding-baby-food-allergies
https://www.foodallergy.org/