Nowadays we really are spoilt for choice, with a wide variety of delicious low allergenic options. “Allergies’ are becoming more and more common. In fact, if I had 10 friends round for dinner I’d estimate that at least 7 of them would be avoiding some food item or another. So how do you know if you are eating a food that is affecting your health? Well it might come down to symptoms, or to some testing. But before we explore these areas, we need to understand what exactly food ‘allergies’ are.
Food Allergies - IgE Mediated Reactions
The easiest way to think of a true food allergy is to think of someone who is allergic to peanuts or seafood. If they eat or come in contact with the food they get an immediate and severe reaction.
Technically it is called an IgE-mediated reaction. IgE is a class of antibody that makes up the immune system in mammals. IgE plays an essential role in type 1 hypersensitivity reactions which present as various allergic diseases including allergic asthma, sinusitis, allergic rhinitis and some types of chronic dermatitis. IgE also plays a pivotal role in anaphylactic reactions to certain drugs, foods and bee stings.
The reaction occurs immediately after contact, and is easy to detect with symptoms such as abdominal cramping, diarrhoea, hives, rashes, swelling wheezing and anaphylaxis.
What I am getting at here, is that this type of allergy isn’t something you spend a long time guessing about. You might eat a peanut, have your lips swell and tingle and then vomit. This happens again the next time you eat a peanut, and the next. By now you know you don’t want to be eating peanuts. You don’t usually need a test to tell you, you are allergic to peanuts. More than likely, you will always be allergic to peanuts, and you’ll never be able to eat them. The allergy is static.
This is the type of ‘allergy’ that most naturopaths deal with. It is in fact, not an allergy. It is an intolerance. In IgE allergies, we saw that the allergy is fixed, you’d most likely always have it. In an IgG intolerance, it is possible to heal the body of these intolerances and return the food to the diet. Not in 100% of intolerances, but in the weaker reactions, this is entirely possible.
Again, IgG is a different class of antibody, making up the immune system. It is involved in type 2 and 3 hypersensitivity reactions which can occur hours or days after the exposure to the offending food. This is what makes these intolerances difficult to detect. Testing is often the best way to identify IgG intolerances, as often the foods patients are reactive to comes as a surprise. It may be something the patient really enjoys, or even craves.
Unlike IgE antibodies, the IgG antibodies can affect any organ or tissue in the body. This allows for a wide variety of symptoms, with the most common being bloating, fluid retention, inflammatory bowl disease (IBD), inflammatory bowl syndrome (IBS), irritable bowel syndrome, migraines, depression, mood swings, asthma, skin conditions and behavioural problems in children (possibly what my naturopath was going on!).
As you can see, it is easy to think your migraines don’t have anything to do with the food you eat. But perhaps, 2 days prior to the onset, you ate the offending food. It is highly unlikely that you remember or make this correlation as 2 days ago was a long time when it comes to thinking about what you ate.
The good thing about these intolerances, is that once you have identified the offending food/foods, you can go ahead and avoid those foods. After a minimum of 6-8 weeks of total avoidance, the immune complexes have left the body and your symptoms should be much better. With slight intolerances, these foods may be reintroduced into the diet on an occasional or rotational basis. For stronger intolerances, once every few months may be all you can consume without symptoms.
After testing, I know myself to have a strong intolerance to dairy (that darn naturopath was right!!!). If I avoid dairy in my daily life, and consume it only on rare and special occasions, I can usually get away with waking the next day feeling pretty good. But if I over indulge (like at Christmas time), I will start waking with blocked sinuses, puffy eyes and a fuzzy head. That is the signal that my body has had enough. So, let’s look now at testing!
How to Test?
I regularly have people coming in to clinic with what I recognise to be food intolerances. When I suggest testing, quite a few will say they have already had a skin prick allergy test, and they weren’t allergic to any of the foods I believe to be causing the problem (usually wheat and dairy, my old nemesis’s). This is where they are often mistaken. They may have been IgE allergy tested for wheat and dairy, and no, they have no true allergy to either of these foods, but it does not mean they are not intolerant! So making things difficult, you may be intolerant to wheat but not allergic to it. Please remember this, the allergy test done by your doctor is an IgE test- it has nothing to do with IgG. And it is IgG intolerances that are rapidly becoming common place (another story).
I hope that clears up the difference between allergies and intolerances. It is not the easiest subject to understand, and many people are surprised to know these differences exist. Please feel free to ask any questions you may have in the comment box.
Thanks to Rhiana for this comprehensive coverage.