This blog has always been focused on eczema, rather than allergy. However, I came across a very good book by Dr Wayne Shreffler and Dr Qian Yuan on ‘Understanding your food allergies and intolerances‘ and found that it clarified many food allergy concepts. Thus, this 4-part series is to share that knowledge with you!
Each week is a different concept de-mystified, so let’s get started!
Kids Food Sensitivities – What is Sensitivity?
What does it mean to be sensitive to a food? In layman’s term, it could mean a range of symptoms from headaches to tummy upset, but medically, it covers two main terms:
Food Allergy and Food Intolerance – both have similar symptoms but the cause and treatment is different, which is why it is important to differentiate the two.
|Food Allergy||Food Intolerance|
|Direct immune system’s response to food protein||Not a direct immune response but different causes (not all known), e.g. lack of specific enzymes to digest the food (not necessarily a protein)|
|Cause is the reaction to food protein, can be tested with fair accuracy with allergy tests||Cause is not always known and not easy to test a food intolerance|
|Symptoms can be immediate (few hours) or delayed, and include
Itch, hives, breathing difficulty (including anaphylaxis), eczema, runny nose, coughing, vomiting, diarrhea, abdominal pain, swallowing difficulty, chronic chest pain, heart burn, constipation, weight loss, swelling of facial features
Symptoms can affect the skin, intestines, respiratory tract and cause behavior change
|Symptoms may take place gradually – nausea, stomach pain, gas (bloating)/cramps/bleeding, vomiting, diarrhea, heartburn, headache or migraine
Symptoms typically affect intestines.
|Happens every time||May not happen for the tolerated amount or in certain forms; the more you take, the more severe the symptoms and symptoms may differ in each incident|
|Small amount triggers||Certain amounts may be tolerated (trial and error process to figure out)|
|Common food allergens: Milk, soy, egg, wheat, peanuts, tree nuts, fish and shellfish||Common food intolerances: Frutose, Sucrose, Lactose, MSG (monosodium glutamate), sulfite, tyramine, histamine|
|Except for peanuts, tree nuts, fish/shellfish that are harder to outgrow, other food allergens tend to be outgrown at older age||May actually onset at older age|
|Genetics play a role||Genetics play a role|
As seen above, there are distinct differences between food allergy and food intolerance although the symptoms of both are similar. However, to be concerned that there is indeed a food sensitivity issue, there has to be a reproducible reaction with the food – i.e. not referring to a one-time stomach upset after eating prawns in the past year (that might be food poisoning!).
The diagnosis of food intolerance is generally difficult, except for lack of digestive enzymes lactase, frutase and sucrase. The lack of the digestive enzymes result in lactose, fructose and sucrose not being broken down and result in pain, bloating, spasm and diarrhea. Even stress or anxiety associated with a certain food can cause an intolerance.On the other hand, symptoms such as swelling are closely associated with allergic reaction.
The diagnosis of immediate food allergy is more straight forward than delayed food allergy, with allergy testing and blood test to detect elevated levels if immunoglobulin E (IgE). The common food allergens differ in different country (taken from allergyuk.org)
- Worldwide – milk, egg
- USA, UK, Australia – peanut and tree nuts
- France – mustard seed
- Italy, Spain – peach, apple, shellfish
- Israel – sesame
- Spain, Japan – fish
- Japan – buckwheat
- Singapore – birds’ nest, shellfish
For those in Singapore, it is interesting that fish isn’t on our list of common food allergens possibly due to it being so much part of our diet. Birds’ nest on the other hand is given as ‘tonic’ to children early and may actually trigger an allergy!
Treatment wise – for both food allergy and food intolerance, avoidance is key. For food allergy, children can undergo another allergy test to see if they have ‘outgrown’ it. For food intolerance which usually does not result in fatal reaction, small amounts of food can be re-introduced in different forms to see which form/amount can be tolerated. There is no cure for allergy or intolerance; however, for certain food intolerance, enzyme supplements can be taken beforehand to digest the food to be ingested e.g. lactose.
Here’s a graphic for recap!