GUIDE
Introduce the top 9 allergens early and often — starting around 6 months. Delaying them doesn't prevent allergies. Early exposure may actually reduce the risk.
The old 'wait until 12 months' advice is out. Here's the new playbook, allergen by allergen.
If you were born before 2000, your parents were probably told to keep you away from peanuts, eggs, fish, and other allergenic foods until you were at least 12 months old — sometimes until age 2 or 3. This was standard medical advice for decades.
It was wrong.
Starting with the LEAP study in 2015 and confirmed by the EAT study in 2016 and others, the evidence now overwhelmingly shows that early introduction of allergenic foods — not avoidance — is the better strategy for allergy prevention. The 2020-2025 USDA Dietary Guidelines now explicitly recommend introducing allergenic foods alongside other complementary foods starting around 6 months.
The shift was dramatic enough that many parents (and some pediatricians) are still operating on the old advice. If you've been told to wait, the science says otherwise. Early and often is the current approach.
| Allergen | When to Introduce | How to Serve Safely | Important Notes |
|---|---|---|---|
| Peanut | 6 months (4-6 months for high-risk) | Thinned smooth PB mixed with liquid, PB mixed into purees, very thin spread on toast, peanut puffs (Bamba) | LEAP study showed ~80% allergy risk reduction with early introduction. Must be smooth and thinned — never whole peanuts or thick PB. |
| Egg | 6 months (can be among first foods) | Well-cooked scrambled egg, mashed hard-boiled egg, thin omelet strips. Must be fully cooked. | Both white and yolk should be introduced. Some studies show baked egg (in muffins, pancakes) may be tolerated by babies who react to plain egg. |
| Cow's milk (dairy) | 6 months as an ingredient; not as a drink until 12 months | Plain whole-milk yogurt, soft cheese (ricotta, cottage cheese), butter in cooking, cheese melted on toast | Dairy as an ingredient or food is fine from 6 months. Cow's milk as a primary DRINK replaces breast milk/formula only after 12 months. |
| Wheat | 6 months | Soft bread strips, well-cooked pasta (small shapes or cut), infant oat/wheat cereal, pancakes | Wheat allergy is different from celiac disease and different from gluten sensitivity. Most babies tolerate wheat well. |
| Soy | 6 months | Silken or firm tofu (cut into strips), edamame (shelled and lightly mashed), soy yogurt | Soy is in many processed foods, so baby may already be exposed through other products. Whole soy foods (tofu, edamame) are the best introduction. |
| Tree nuts | 6 months | Thinned tree nut butters (almond, cashew) mixed into purees or spread very thin on toast. Finely ground nuts mixed into oatmeal. | Never whole nuts — choking hazard until age 4-5. Introduce different tree nuts individually since allergy to one doesn't mean allergy to all. |
| Fish | 6 months | Well-cooked, flaked salmon or cod (check meticulously for bones), fish mixed into purees | Start with low-mercury fish: salmon, cod, tilapia, trout. Avoid high-mercury options: swordfish, king mackerel, shark, tilefish. |
| Shellfish | 6 months | Well-cooked shrimp (finely minced or pureed for younger babies, small pieces for older), crab | Shellfish allergy is separate from fish allergy. You can be allergic to one and not the other. Cook thoroughly. |
| Sesame | 6 months | Tahini thinned with water and mixed into purees, thin spread of tahini on toast, sesame seeds ground and sprinkled on food | Added as the 9th major allergen in the US in 2023. Sesame allergy is increasing. Tahini is the easiest way to introduce it. |
You don't need to introduce all 9 allergens in the first week. Spreading them out over 6-8 weeks gives you time to observe for reactions while still getting through the list at a reasonable pace.
| Week | Focus Allergen | Plan |
|---|---|---|
| Week 1 | Peanut | Day 1: First peanut exposure (thinned PB). Day 3-4: Second peanut exposure. Day 5-6: Third exposure. Goal: confirm tolerance. |
| Week 2 | Egg | Day 1: First egg exposure (scrambled). Day 3-4: Second egg exposure. Continue peanut 2-3x this week. |
| Week 3 | Dairy | Day 1: First dairy exposure (yogurt). Day 3-4: Second dairy exposure. Continue peanut and egg in rotation. |
| Week 4 | Wheat + Soy | Day 1: Wheat (toast strip). Day 3-4: Soy (tofu). Continue rotating previously introduced allergens. |
| Week 5-6 | Tree nuts + Sesame | Introduce almond butter (thinned) and tahini on separate days. Add to rotation. |
| Week 7-8 | Fish + Shellfish | Introduce well-cooked salmon and shrimp on separate days. All 9 allergens now in rotation. |
During allergen introduction, knowing exactly which food was new and when you offered it is critical. If a reaction happens at 3 PM, you need to know what was new at lunch. Write it down or log it in an app. Your memory at 6 months postpartum is not as reliable as you think it is.
Mixing a new allergen into a familiar food (peanut butter into banana puree, egg into oatmeal) increases the chance baby will actually eat it. And if they spit out the new food, they've still had oral contact, which counts as immune exposure.
If baby has a cold, stomach bug, or is teething badly, hold off on new allergens. You want to be able to distinguish between allergy symptoms and illness symptoms. Wait until baby is their baseline healthy self.
Introducing an allergen once and then not offering it again for months defeats the purpose. The protection comes from regular, repeated exposure. Keep all introduced allergens in your weekly food rotation — aim for each allergen 2-3 times per week.
Logging which food you introduced and when — along with any symptoms — creates a record that's genuinely useful. tinylog's feed tracking makes this easy, so if a reaction does happen, you know exactly what was new.
"Allergen introduction" products are mostly unnecessary. There's now a growing market of products specifically designed for allergen introduction — pre-portioned peanut powders, multi-allergen sachets, subscription boxes. These are fine if they make the process easier for you, but they're not necessary. Thinned peanut butter, scrambled egg, plain yogurt, and soft toast provide the same allergen exposure at a fraction of the cost.
Not all reactions are allergies. Babies frequently get redness around their mouth from acidic or irritating foods (tomatoes, citrus, strawberries). This is contact irritation, not an allergic reaction. True allergic reactions typically involve hives, swelling, vomiting, or breathing difficulty — not just redness where food touched the skin. If you're unsure, take a photo and call your pediatrician.
This guide is for informational purposes only and is not a substitute for professional medical advice. Consult your pediatrician before starting solids, especially regarding allergen introduction for high-risk infants. All caregivers should be trained in infant CPR before offering solid foods.
