Introducing Allergens: The New Dutch Guidelines

The Allergen Revolution: Everything Has Changed

Until a few years ago, the standard advice was to avoid allergenic foods such as peanut, egg, and nuts for as long as possible with babies. Parents were told to wait until the child was at least one year, sometimes even three years old. This advice has now been completely overturned. Groundbreaking scientific research has shown that early introduction of allergens actually significantly reduces the risk of developing an allergy. The LEAP study from 2015 showed that early peanut introduction reduced the risk of peanut allergy by a remarkable 81 percent in high-risk children. The Dutch Nutrition Centre (Voedingscentrum) and the NVK (Dutch Association for Paediatrics) have since updated their guidelines to reflect these new insights. For parents, this reversal can be confusing, especially when receiving advice from an older generation that no longer applies. In this article, we explain step by step how to introduce allergens safely and effectively.

What Does the Science Say?

The scientific basis for early allergen introduction is now very solid. In addition to the LEAP study, multiple large studies show the same thing. The EAT study (Enquiring About Tolerance) examined 1,300 babies and found that early introduction of six allergens (peanut, egg, milk, sesame, fish, and wheat) reduced the risk of allergy, with the strongest results for peanut and egg. The Australian HealthNuts study confirmed that delaying egg introduction until after 12 months quadrupled the risk of egg allergy. The theory behind these findings is the dual allergen exposure model: the immune system learns to tolerate a food when it is introduced through the gut, but can actually become allergic when first exposed through damaged skin (for example with eczema). By introducing early through the gut, you essentially familiarize the immune system with the allergen before it can enter through the skin.

When to Start Complementary Feeding?

The Dutch guideline advises starting complementary feeding around 4 to 6 months of age. The exact timing depends on your baby's development. Signs that your baby is ready for complementary feeding include: being able to sit upright with some support, showing interest in food (reaching for your plate, making chewing movements), the disappearance of the tongue-thrust reflex (which automatically pushes food out), and being able to coordinate chewing and swallowing. Do not start before 4 months, as the digestive system is not yet mature enough. Also do not wait much longer than 6 months, as the protective effect of early introduction diminishes after that age. Begin with single, smooth purees of vegetables or fruit and introduce the first allergens after a week or two. The Nutrition Centre advises introducing allergens early, but in small amounts and one at a time, so you can easily link any reaction to a specific food.

The Big 8 Allergens Explained

There are eight foods responsible for more than 90 percent of all food allergies in children. Peanut is the most well-known and feared, but also one of the best-studied for early introduction. Introduce peanut as diluted peanut butter (not as whole nuts due to choking risk). Chicken egg is the second most common allergen and can be introduced as well-cooked or baked egg (not raw). Cow milk is the third relevant allergen, involving cow milk protein allergy, not lactose intolerance. Wheat (and gluten-containing grains), soy, tree nuts (walnut, cashew, hazelnut), fish, and shellfish complete the top eight. Each of these allergens has its own characteristics regarding introduction and risk. The most important principle is to introduce them one at a time, with at least three days between each new allergen, so you can trace any reaction to the right food.

A Practical Introduction Plan

Here is a concrete plan you can follow for introducing allergens. Start in week 1 with a small amount of smooth peanut butter, diluted with breast milk or water, on the tip of a teaspoon. Give this three days in a row and observe your baby for signs of an allergic reaction. If there is no reaction, move on in week 2 to well-cooked egg (start with a small piece of yolk). In week 3, introduce a smooth yogurt or cheese (cow milk). In week 4, a porridge with wheat or another gluten-containing grain. In week 5, you can try tofu or edamame (soy), and in week 6, a smooth fish puree or piece of soft fish. Then continue with tree nuts (as smooth nut paste, never as whole nuts) and optionally shellfish. After the first successful introduction, give each allergen regularly, at least once a week, to maintain tolerance. A one-time introduction without repetition is not sufficient.

Introduction Step by Step

• •Start with a tiny amount: a quarter teaspoon of the allergen, mixed with a known and accepted food.
• •Give the allergen preferably in the morning or afternoon, so you can observe any reactions while your baby is awake.
• •Wait at least three days before introducing the next allergen. During those three days, give the new allergen daily.
• •After each introduction, observe for: skin rash, swelling of lips or tongue, vomiting, diarrhea, or unusual irritability.
• •After successful introduction: keep giving the allergen at least once a week to maintain tolerance.
• •If you suspect an allergy: stop the food immediately and contact your GP or well-baby clinic.

Recognizing an Allergic Reaction

It is understandable that parents are nervous when introducing allergens, but it is important to know that severe allergic reactions at first introduction are rare. The most common mild reactions are: red spots or rash around the mouth or on the body, slightly swollen lips, and mild stomach pain or spitting up. These mild reactions usually resolve on their own and do not necessarily mean your baby is allergic; it could also be a contact irritation. Call your GP if the reaction persists or worsens. Severe allergic reactions (anaphylaxis) are rare but require immediate action. Symptoms include: severe swelling of face, lips, or tongue, breathing difficulties or wheezing, paleness or going limp, and vomiting combined with skin rash. With these symptoms, call 112 immediately and place the baby on their side. The risk of anaphylaxis at first introduction is very small (less than 1 percent), but it is good to be prepared.

Special Situations: Higher Risk

Some babies have a higher risk of food allergies and deserve extra attention during introduction. Babies with moderate to severe eczema have a two to four times higher risk of food allergies, especially peanut and egg. For these babies, it is actually extra important to start early with allergen introduction, but it is wise to do this in consultation with the GP or pediatrician. Some doctors recommend doing a blood test or skin prick test for peanut in babies with severe eczema before introducing it orally. Babies with a first-degree relative (parent, brother, or sister) with a confirmed food allergy also have a higher risk. Premature babies follow the same introduction advice, but based on their corrected age. Babies who already have a confirmed allergy to one food should of course avoid that food, but can have other allergens introduced according to the standard schedule.

Baby-Led Weaning and Allergens

Baby Led Weaning (BLW), where your baby picks up and eats pieces of food from the start instead of being spoon-fed, is increasingly popular in the Netherlands. BLW and allergen introduction work well together, but there are a few considerations. With BLW, your baby eats independently and determines the quantity, which means you have less control over how much of an allergen is actually consumed. For the first introduction of an allergen, it may therefore be wise to use a spoon so you know for certain your baby has actually swallowed the allergen. Peanut butter can be spread on a rice cake or piece of bread as finger food, but make sure it is not spread too thickly due to choking risk. Whole nuts, popcorn, and hard pieces are absolutely forbidden with BLW due to choking, regardless of age. Always use nut paste or finely ground nuts mixed into food. The most important thing is that the allergen is actually swallowed and not just played with or spat out.

Conclusion: Early Introduction Protects

The science is clear: starting early with allergens, between 4 and 6 months, protects your baby against developing food allergies. The old advice to avoid allergens was well-intentioned but incorrect, and likely contributed to the sharp rise in food allergies in recent decades. With the step-by-step plan in this article, you can safely and systematically introduce the major allergens. Remember the three basic rules: one at a time, at least three days between each new allergen, and after introduction keep offering regularly. When in doubt or with babies at higher risk, always consult your GP or well-baby clinic. The BabyProof app helps you track which allergens you have already introduced and when it is time for the next one.