Food ladder is a method for safe introduction of tolerated foods to individuals with food allergies. The term "ladder" refers to the varying allergenicity of foods based on their cooking and processing methods. Similar to ascending a ladder, allergic foods are introduced into one’s daily diet step-by-step. This approach is commonly used for people with milk or egg allergies and serves two main purposes. Firstly, starting with less allergenic milk or egg foods such as baked goods, bread, cakes, and biscuits can help to accelerate the self-healing process, enabling one to eat other food types containing eggs and milk more quickly. Secondly, the food ladder is sometimes used alongside desensitisation therapy as part of the treatment process.
Q2. Do different cooking methods affect the allergenicity of food?
Yes. Eggs and milk are very special foods. When they are cooked at higher temperatures, such as during baking, allergenicity will change when the temperature exceeds 180°C. During the baking process, the proteins in eggs and milk may break down. In cakes and bread which typically contain wheat, these broken-down protein molecules can form a complex with wheat proteins, scientifically known as "Egg Wheat Matrix" or "Milk Wheat Matrix." This matrix can be hardly recognised as eggs or milks by the human body, thereby eliciting no immune response and thus allergic reaction. In contrast, if eggs and milk are simply boiled, their allergencity will get higher than that of baked goods.
Raw or lightly cooked eggs, such as soft-boiled eggs or sunny-side-up eggs, have the highest allergenicity. As for milk, boxed milk is typically pasteurised, and has a higher allergenicity than cooked milk or baked products like milk bread or milk cakes.
Q3. How does the food ladder help children manage allergies?
We are often told that, as egg and milk allergies may diminish with age, children can outgrow these allergies. Studies show that most children with egg or milk allergy can actually eat baked goods, such as cakes, breads, biscuits. Consistent consumption of these foods can help them tolerate a wider variety of foods containing eggs and milk sooner.
For example, a child tested positive for or clinically diagnosed with egg allergy cannot eat boiled or scrambled eggs. Doctor usually arranges an Oral Food Challenge for them. During the test, the child is given a cake containing eggs. If the child can finish the entire cake and exhibit no adverse reactions, he or she may tolerate other baked goods as well. If he or she fails to keep eating a bit of baked goods every day, we will follow up after 3 to 6 months and perform further tests to see if allergic reactions have improved. And this time we may test with hard-boiled eggs, and the child needs to eat them regularly for 3 to 6 months as well. Then come another 3 to 6 months with lightly cooked eggs, such as those used in scrambled egg sandwiches. They can be more difficult to tolerate, and this is the next step. Once they can eat fully cooked eggs, they can move on to soft-cooked eggs, and then the raw or less cooked ones like soft-boiled eggs.
The same method applies to milk allergy. It starts with cakes, then cooked dairy products such as cheese, cooked cream soups, or boiled milk, and finally unheated dairy products, like boxed, pasteurised-only milk.
Q4. If my child cannot complete the entire challenge, what shall we do?
Sometimes, children may not be able to finish the entire cake during the Oral Food Challenge. They might feel full or simply do not want to eat. Some may show allergic reactions after consuming half a cake. Doctor will determine that they cannot eat half a portion at home. We will then suggest a specific dosage after discussion, perhaps a quarter of a cake, and teach the parents how to prepare it, so that the children can consume a lower dose at home over a period of time. The dosage will be increased at the next follow-up consultation until the children can eat the entire cake. Only then will we change the cooking method, such as introducing boiled eggs. When the children start eating boiled eggs, they may only be able to eat a quarter of an egg. Starting with a quarter, we will gradually increase the portion. Only when they can finish the full amount will we change the cooking method again.
Q5. What should be done if allergic symptoms arise during treatment?
When children can consume baked goods during the Food Challenge Test, we will ask them to eat the items daily. However, if a mild allergic reaction occurs at home on a particular day, it should be addressed according to the doctor’s guidelines. Generally, doctor will provide guidelines, such as Action Plan for Allergic Reactions, on how to respond to allergic reactions before the test. These guidelines can help manage the situation based on the nature of the allergic reaction. As the treatment process does carry risks, people should not conduct food ladder tests and keep those foods on their own without medical supervision.
Although baked goods are generally safe, the baking temperature can vary among different types. Baked goods should be made at 180°C for at least 20 minutes. However, some cakes, particularly those with a soft texture, such as paper-wrapped cakes or chiffon cakes, may be baked at only 150 to 160 °C and have different allergenicity. Therefore, dietitians will clearly communicate with patients about which types of baked goods to consume when dining out. If the patients wish to eat a specific type of cake, they must follow a particular recipe. Research has indicated that different baking methods and recipes can result in varying allergenic level, and we need to make sure that the patients are clear about this.
Q6. Is food ladder the same as oral desensitisation therapy?
They are actually different. The food ladder is basically about the differences in allergenicity of a specific food after processing or cooking, while oral desensitisation therapy usually starts with extremely low doses of the allergen, usually its “allergen protein” amount from 1mg to 5mg and beyond. In the early stages of oral desensitisation therapy, the doses are often barely noticeable.
While for food ladder, the foods consumed are visible, but with varying allergenic level due to different cooking methods. By focusing on these cooking methods, we can gradually enhance the patient's tolerance to the related foods. The two approaches are slightly different.
However, since some children cannot tolerate even the low doses used in oral desensitisation therapy, it is necessary to reduce allergenicity through cooking methods. Food ladder is also conducted before oral desensitisation therapy as part of the treatment process.
Q7. Is the food ladder only applicable to egg and milk allergies?
The traditional food ladder is primarily applied to milk and egg allergies. However, recent studies have tried this method with other foods, such as fish. Local research has also focused on fish-related allergies, emphasising the varying allergenicity of different fish types rather than cooking times or methods. It starts with low-allergen fish like tuna, then salmon and cod, and finally the more common types like grass carp and grouper.
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