It seems to be the question on every waiter’s lips when you ask them about the ingredients in a dish. To the person with a food intolerance, it’s a sensible question. But imagine the mother of an allergic child, carrying an epipen in her handbag, or a coeliac who knows that one hundredth of a slice of bread can damage their bowel. These three people could all become sick from eating the wrong foods, but the reasons for it are quite different.
Allergic reactions can happen frighteningly fast, and vary from mild eczema to severe reactions that can lead to breathing difficulties. An allergic reaction is an immune response to a protein in a particular food (e.g., egg, peanut or milk), which is normally diagnosed in early childhood. Allergies can be diagnosed using skin or blood tests. The treatment is completely avoiding the food. During a severe reaction an injection with adrenaline from an Epipen can save the life of someone with an allergy.
Unlike allergies, intolerances can take hours or days to cause symptoms. That’s because the reaction is dose dependent – the more of something you eat, the bigger the reaction. Sometimes it takes several meals for the levels of a particular chemical to reach the threshold for symptoms. The symptoms vary from hives to headaches to stomachaches to sinus. Intolerances are caused by food additives and natural food chemicals irritating nerve endings. An elimination diet can reveal which foods are causing the intolerance, and the treatment is to change the diet to reduce these foods to a level that can be tolerated.
Unlike allergies or intolerances, coeliac disease causes chronic symptoms. The symptoms occur all the time because the small bowel is damaged by the immune system. Coeliac is an autoimmune disease that also involves food – the gluten protein from wheat, barley, rye and oats. The symptoms include bloating, diarrhoea, anaemia and fatigue. After an initial blood test, the diagnosis requires the doctor to see the lining of the small bowel under a microscope (a small bowel biopsy). The treatment is a strict lifelong gluten-free diet.
So “How intolerant are you?” is only a good question for some people. Catering for special diets is tricky, but the more you know, the better you can look after people.
|Food Allergy||Food Intolerance||Coeliac Disease|
|Common symptoms||eczema as an infant, acute cases of hives, vomiting, breathing problems||episodic cases of hives, headaches, stomach irritation, sinus||chronic fatigue, bloating, diarrhoea, anaemia|
|Reaction||minutes to 2 hours||hours to days||chronic|
|Food triggers||specific proteins in certain foods (egg, milk, peanut…)||natural food chemicals (salicylates, amines, glutamate), or food additives||gluten (wheat, barley, rye, oats)|
|Amount involved||trace amount||dose dependent||trace amount|
|Diagnostic tests||skin/blood tests||elimination diet and food challenges||small bowel biopsy|
|Mechanism||IgE (immune)||Irritates nerve endings||T Cells (immune)|
|Treatment||complete avoidance, adrenaline in emergency||manage levels of food chemicals in the diet||strict lifelong gluten free diet|
|Further information||Anaphalaxis Australia||RPA Hospital Allergy Unit||Coeliac Australia|
For a visual idea of how much food causes each of these food reactions, take a look at this video in another post here at the Chameleon’s Tongue.
This post is the first in a series on the subject of allergies, food intolerances and coeliac disease. There’ll be more posts on this theme coming up over the next few weeks.