Keeping allergens in your baby's diet

Why the first taste isn’t enough

Introducing an allergen is step one. Keeping it in your baby’s diet is what protects them.

• In the LEAP trial, babies at high risk of peanut allergy ate peanut regularly, at least three times a week, until age 5. That’s the pattern behind the US peanut guidelines, and the AAP describes the protection as coming from early peanut with continued, regular servings.
• In the EAT trial in UK babies, eating about 2 g a week of peanut or egg-white protein was linked to less peanut and egg allergy than eating less.
• The 2021 US and Canadian allergy consensus says regular exposure over several years matters more than any fixed dose or schedule.
• The NHS says that once allergens are introduced and tolerated, they should become part of your baby’s usual diet to lower the risk of allergy. ASCIA, the Australian allergy society, says keeping them in the diet can reduce the chance of food allergy.

How often

No one has proven an exact amount, so the guidance gives a reasonable minimum:

• Most babies: at least once a week for each allergen your baby has had, in a normal portion for their age (ASCIA). The 2021 consensus gives 1 to 2 teaspoons of peanut butter or egg at least once a week, and says there are no data on how much or how often for the other allergens, only that they should be eaten regularly. More is fine if your baby enjoys it.
• Babies at high risk of peanut allergy (severe eczema or egg allergy) whose doctor has cleared peanut: about 6 to 7 g of peanut protein a week over three or more feedings (NIAID). That’s roughly 2 teaspoons of peanut butter three times a week. Follow your doctor’s plan if it’s different.

How much is a portion

The AAP and the 2021 consensus give these examples of a regular serving once a food is tolerated:

• Peanut: 1 to 2 teaspoons of smooth peanut butter, thinned or stirred into food, or spread very thinly on soft toast. Never spoonfuls or chunks of peanut butter (CDC). See peanut butter.
• Egg: about a third of a well-cooked egg, such as hard-boiled and mashed, or a fully cooked omelet in strips (AAP). See egg.
• Tree nuts and sesame: about 2 teaspoons of a smooth nut butter, such as cashew or almond butter, or tahini, thinned or stirred in (AAP). Never whole or chopped nuts or seeds (CDC).
• Milk, wheat, soy, fish and shellfish: offer them in normal baby portions as part of meals: yogurt, pasta or toast strips, tofu, well-cooked flaked salmon checked for bones, fully cooked shrimp finely minced into soft food (small pieces from around 9 months).

A sample week

This is our example, not a rule. It assumes your baby has already had each food on its own without a reaction. Swap days and foods to suit your family’s meals.

• Monday: thinned peanut butter stirred into oatmeal
• Tuesday: omelet strips, and yogurt with fruit
• Wednesday: soft pasta with flaked salmon
• Thursday: thinned tahini stirred into mashed vegetables, or smooth homemade hummus
• Friday: mashed hard-boiled egg, and peanut butter spread very thinly on soft toast strips
• Saturday: soft tofu strips, and almond butter stirred into porridge
• Sunday: finely minced cooked shrimp stirred into a family dish, and thinned peanut butter in yogurt

That covers peanut three times, egg twice, and the other allergens at least once. If your baby isn’t at high risk, once a week for peanut is enough (ASCIA, 2021 consensus).

Making it easier

• Use family food. ASCIA suggests starting with allergens your family already eats, and offering babies the same foods as everyone else.
• Mix it in. Stir nut butter or tahini into foods your baby already likes. The consensus says to focus on forms your child likes and tolerates, rather than a fixed dose.
• Use a checklist. A simple list on the fridge of what your baby had each week makes gaps easy to spot.
• If someone in the family is allergic, ASCIA says it’s still important to give that food to your baby. Feed it in a high chair, wash hands, faces and dishes afterward, and consider offering it when the allergic family member isn’t home.
• Don’t rub food on your baby’s skin to test it. ASCIA says it won’t show an allergy, and may make one more likely.

If a food gets dropped

Life happens: illness, travel, a picky phase.

• Don’t stop on purpose. The 2021 consensus says that once peanut is in your baby’s diet, it shouldn’t be stopped unless there are signs of an allergic reaction.
• If your baby refuses it, wait a few days and try again (ASCIA), or offer it in a different form your baby has already had: tahini in hummus, well-cooked egg in a pancake, peanut butter stirred into yogurt.
• If you’ve had a gap, go back to your regular servings as soon as you can. None of the guidance we cite sets special steps for restarting after a short break. If your baby is at high risk, had a long gap, or you feel unsure, ask your pediatrician before offering it again.
• If your baby reacted, even mildly, don’t offer that food again until you’ve seen your doctor. ASCIA says to get specialist advice before trying it again, and to keep offering the other allergens your baby hasn’t reacted to.

In LEAP-On, children who had eaten peanut regularly from infancy to age 5 stayed protected after a full year without it. That was in 5-year-olds after years of regular eating, so it doesn’t mean a gap in infancy is safe: keep going with regular servings.

Signs of a reaction

Reactions usually start within minutes of eating, but can take up to 2 hours (NHS).

Mild to moderate: hives or a red, itchy rash, especially around the mouth; mild puffiness of the face or around the eyes; vomiting once, tummy pain or diarrhea; sneezing or a runny nose. If it’s only one of these, stop offering the food, stay with your baby and watch them closely for the next couple of hours, and call your pediatrician before you try it again. If signs show up in more than one part of the body at once, treat it as severe (below).

Severe (anaphylaxis): trouble breathing, wheezing, or a cough that won’t stop; swelling of the tongue or throat, lips or mouth that suddenly swell, a hoarse cry, drooling or trouble swallowing; turning pale or floppy, or very sleepy or unresponsive; or signs in more than one part of the body at once, such as hives with repeated vomiting.

If your baby has an epinephrine (adrenaline) auto-injector, use it right away, then call for an ambulance. Call 911.Call 999.Call your local emergency number (such as 112 in Europe or 000 in Australia). If you don’t have an auto-injector, call straight away. Keep your baby lying down, never standing or walking (on their side if they’re vomiting, head and shoulders a little raised if breathing is hard), and go to hospital even if they seem better. See signs of anaphylaxis.

Where US and UK advice differs

• How often. US and Canadian allergy societies suggest at least once a week for peanut and egg, and regular servings of the other allergens. NIAID suggests peanut about three times a week for high-risk babies. The NHS doesn’t give a number: it says to make tolerated allergens part of your baby’s usual diet.
• Nut butter. The AAP suggests thinning peanut butter into cereal, purée or yogurt. The NHS suggests spreading it onto a food such as toast (we suggest thinly). Both say never on its own.

For first introductions, see how to introduce allergens, peanut, egg allergy, sesame and wheat allergy.