Food Allergy and Intolerance Testing
As a Clinical Nutritionist, I often ask clients to do a food allergy and/or intolerance test. I have a few different tests available depending on the client’s symptoms.
Food allergies are IgE antibody mediated reactions to proteins in our food. The IgE antibodies are released in response to the food being ingested and pinpointed by our immune system as an allergen. This response results in the release of T2 helper cells which triggers the release of mast cells and basophils. These cells trigger the release of histamine and histamine is responsible for the immediate symptoms of skin rashes, runny eyes and nose, swelling of body parts, heart palpitations etc. As there is an immediate response, the problem food may be easier to identify although allergy symptoms can range from very intense (the body goes into anaphylactic shock) to very mild (bit of runny nose and low-grade itch).
The most common food allergies include:
- Dairy products – milk, cheese, cream, ice cream etc.
- Tree nuts (walnuts, almonds, pine nuts, brazil nuts, pecan etc)
On the other hand, food intolerances are driven by an IgG antibody mediated response. There is no immediate histamine release and allergic reaction, and food intolerance symptoms can include but are not limited to:
- Abdominal pain
- Breathing difficulties
- Constipation and/or diarrhoea
- Fatigue & lethargy
- Fluid retention
- Gastric reflux and hyperacidity
- Chronic Fatigue Syndrome
- Crohn’s Disease
- Irritable Bowel Syndrome
These symptoms can occur shortly after the food is ingested or up to 2 days later so identifying food intolerances can be a challenge without testing.
The most common food intolerances are:
- Gluten or wheat
However, I have found in clinical practice that some clients can have quite random food intolerances like lettuce, walnuts or kiwi fruit.
The scientific consensus behind IgE mediated allergies is quite definitive, the mechanisms of action are well understood and they are recognised by the mainstream medical profession. That is not the case for food intolerances. The testing I do is testing for a definite reaction in the blood (IgG antibodies), but some practitioners in the medical profession claim that this measurement is not relevant. However, I have been doing food intolerance testing for my clients for a few years with very positive diagnostic results. Taking highly reactive foods out of the diet generally helps a wide range of conditions, especially irritable bowel syndrome, and multi system disorders such as chronic fatigue syndrome and fibromyalgia.
I decide which testing should be prescribed by looking at a client’s symptoms. If there is evidence of an allergy (permanently runny nose, itchy eyes, mucousy chest, skin rashes etc) I would definitely recommend allergy testing plus food intolerances (which can also be linked to all of these symptoms). However, if I have a client with IBS, IBD, headaches, gastric reflux etc I would be more likely to just test food intolerances. I can do food intolerance testing in the clinic via a blood spot test. The allergy and intolerance test requires a kit to be ordered and a blood draw to be taken. The results normally return in 4-5 weeks.
I have found both forms of testing to be excellent diagnostic tools and altering the diet to take into account a person’s individual food reactions can be the difference between feeling slightly unwell or chronic ill health and feeling amazing.