Evidence-based guidance for parents on protecting your child from food allergies

Everything Has Changed (And That’s Good News!)

If you’re a parent or expecting, you might remember being told to avoid giving babies peanuts, eggs, and other common allergens until they were older—sometimes as late as age 3. Well, here’s the surprising news: we got it backward.

New research has completely flipped the script on food allergy prevention. It turns out that introducing these foods early and regularly is actually one of the best ways to prevent food allergies from developing in the first place.

Let me explain what we now know and, more importantly, give you a practical roadmap for protecting your baby.

Why the Change?

Scientists discovered something fascinating about how food allergies develop. Your baby’s immune system learns about foods in two ways:

1. Through the skin (the “allergy pathway”) – When food proteins enter through dry or broken skin, the body can mistakenly flag them as dangerous invaders
2. Through the gut (the “tolerance pathway”) – When foods are eaten, the digestive system teaches the immune system that these foods are safe

Think of it this way: the gut is designed to help your baby’s body accept foods, while the skin can accidentally trigger it to reject them.

This is why babies with eczema (dry, irritated skin) are at higher risk for food allergies—food proteins can sneak in through those tiny cracks in the skin barrier.

The Groundbreaking Research

A landmark study called the LEAP trial showed that infants who ate peanut products regularly starting around 4-6 months of age had an 81% lower risk of developing peanut allergy compared to babies who avoided peanuts.

Even better? Recent real-world data from 2024 shows that after early introduction guidelines were published in 2017, we’ve seen:

• 27-43% reduction in peanut allergies
• 28-37% reduction in overall food allergies

This isn’t just theory—it’s working in the real world!

When to Start: The 4-6 Month Window

The golden window is 4-6 months of age, when your baby:

• Can hold their head up steadily
• Shows interest in food
• Has started or is ready to start solid foods

Don’t wait beyond 11 months—the window for optimal allergy prevention may close.

You can continue breastfeeding while introducing these foods. In fact, breastfeeding while introducing allergens may provide extra benefits!

The “Big 8” Allergens to Introduce

Here are the major food allergens to introduce early:

• Peanuts
• Eggs
• Cow’s milk (dairy products like yogurt, not whole milk as a drink)
• Tree nuts (almonds, cashews, walnuts, etc.)
• Soy
• Wheat
• Fish
• Shellfish

Plus sesame, which is increasingly recognized as a common allergen.

How Much and How Often?

This is where parents often get confused. Here’s the practical breakdown:

Peanuts

Amount:

• Start with about ¼ teaspoon of smooth peanut butter
• Gradually work up to 2 teaspoons of peanut butter (or 2 teaspoons of peanut powder)
• This equals about 2 grams of peanut protein

Frequency:

• At least 3 times per week (daily is even better!)

How to serve:

• Mix smooth peanut butter with breast milk, formula, or applesauce to thin it out
• Stir peanut powder into infant cereal or purees
• Never whole peanuts or chunky peanut butter (choking hazard until age 4-5)

Example: Mix ½ teaspoon of smooth peanut butter into your baby’s oatmeal on Monday, Wednesday, and Friday. As they get used to it, increase to 1-2 teaspoons.

Eggs

Amount: Start with a small taste of well-cooked scrambled egg; work up to age-appropriate portions

Frequency: Several times per week

How to serve:

• Scrambled eggs (well-cooked, not runny)
• Hard-boiled egg, mashed
• Mixed into other foods
• Never raw or undercooked eggs

Cow’s Milk Products

Amount: Small amounts of dairy products

Frequency: Several times per week

How to serve:

• Plain, whole-milk yogurt (no added sugar)
• Small amounts of cheese
• Dairy mixed into foods
• Note: Don’t give whole cow’s milk as a drink until 12 months, but dairy products in food are fine!

The Game Plan: Your Step-by-Step Introduction Strategy

Week 1: Introduce your first allergen (many parents start with peanut)

• Give a small taste
• Watch for 2 hours for any reaction
• If all goes well, continue offering 2-3 times that week

Week 2: If the first allergen is going well, introduce a second (like egg)

• Space new allergens 3-5 days apart
• This helps you identify which food caused a reaction if one occurs

Weeks 3-8: Continue introducing new allergens one at a time

• Keep offering previously introduced allergens regularly
• Don’t stop giving foods once you’ve started—regular exposure is key!

Beyond 2 months:

• Maintain variety—offer all these foods regularly as part of your baby’s normal diet
• Aim for 2-3 times per week minimum for each allergen
• Daily exposure is ideal

The Critical “Keep Eating” Rule

Here’s what many parents don’t realize: One-time exposure isn’t enough.

Think of it like learning a language. Your baby’s immune system needs regular “practice” with these foods to stay comfortable with them. If you introduce peanut butter once and then stop for weeks or months, you lose the protective benefit.

The magic formula: Early + Regular + Sustained

Safety First: What to Watch For

Normal reactions (not allergic):

• Rash around the mouth from contact (common with acidic foods)
• Not liking the taste
• Spitting out food

Possible allergic reactions—call your doctor:

• Hives or widespread rash
• Swelling of lips, face, or tongue
• Vomiting or diarrhea within 2 hours
• Difficulty breathing or wheezing
• Extreme fussiness or lethargy

If you see signs of a serious reaction (difficulty breathing, severe swelling, multiple symptoms), call 911.

Common Questions Parents Ask

“What if I’m allergic to peanuts? Should I still give them to my baby?”

Yes! Even if you have food allergies, your baby has only a 20-30% chance of developing them too. The other 70-80% is environmental, and early introduction can help protect them.

“I’m breastfeeding. Do I need to eat these foods too?”

You don’t need to restrict your own diet—in fact, eating a diverse diet while breastfeeding may be helpful. However, your baby still needs direct exposure to these foods.

“My baby has a little eczema. Should I wait?”

No! Actually, babies with eczema benefit most from early introduction. Just work on getting their eczema under control with good moisturizers and any treatments your family physician recommends.

“Can I just give these foods once a week?”

For best protection, aim for at least 2-3 times per week, and daily is even better. Think of it as teaching your baby’s immune system—regular practice works better than occasional exposure.

The Bottom Line

The science is clear: Early introduction of allergenic foods (starting at 4-6 months) and regular consumption throughout infancy significantly reduces the risk of food allergies.

We now have real-world evidence showing this works—food allergies have dropped by 27-43% in communities that have adopted these guidelines.

As a parent, you have more power to prevent food allergies than we ever thought possible. It’s as simple as:

• Start at 4-6 months
• Introduce all major allergens
• Keep giving them regularly (2-3+ times per week)
• Make them part of your baby’s normal, varied diet

Your Action Steps This Week

1. Talk to your family physician at your baby’s next visit about starting allergen introduction
2. Stock up on smooth peanut butter, eggs, and plain whole-milk yogurt
3. Plan your introduction schedule—which allergen will you start with?
4. Start early—don’t wait! The 4-6 month window is ideal
5. Keep a simple food diary for the first few weeks to track what you’ve introduced and how your baby responded

A Final Word of Encouragement

Introducing allergens to your baby might feel intimidating at first, especially if you’ve heard the old “avoid and delay” advice. But remember: you’re giving your child a gift that lasts a lifetime—the freedom to eat a wide variety of foods without fear.

Thousands of families have successfully done this. The research supports it. Your family physician can guide you. And most importantly, you’re doing something proactive to protect your baby’s health.

Take it one food at a time, stay consistent, and know that with each spoonful of peanut butter oatmeal or bite of scrambled egg, you’re helping your baby’s immune system learn that these foods are friends, not foes.

You’ve got this!

References and Resources

Primary Guideline:

Fleischer DM, Chan ES, Venter C, et al. A consensus approach to the primary prevention of food allergy through nutrition. J Allergy Clin Immunol Pract. 2021;9(1):22–43.

Full article: https://doi.org/10.1016/j.jaip.2020.11.002

Helpful Organizations:

• FARE (Food Allergy Research & Education): www.foodallergy.org – Excellent parent resources, introduction guides, and recipes
• American Academy of Allergy, Asthma & Immunology: www.aaaai.org – Patient education materials
• Canadian Paediatric Society: www.cps.ca – Evidence-based guidance for parents

Need More Help?

If you have concerns about your baby’s specific situation, don’t hesitate to reach out to your family physician or ask for a referral to a pediatric allergist. They can provide personalized guidance based on your baby’s health history.

Note: This information is based on current guidelines from the American Academy of Allergy, Asthma, and Immunology; American College of Allergy, Asthma, and Immunology; and the Canadian Society for Allergy and Clinical Immunology (2021). Always consult with your family physician before starting solid foods or if you have specific concerns about your baby. © 2026 – Evidence-Based Family Medicine | Caring for Families in Toronto for Over 30 Years