(Originally posted on bcotoronto.com on Mar 22nd, 2012)
Before my generation came along, allergies were something people had to bees and pollen, then when I was a kid more food allergies, like peanuts, started to become more publically known. By the time I reached high school, more and more people were being diagnosed with food intolerances. Then when I became a doctor sensitivities were on the map too. A lot of people are confused about what all this means and the differences between them. I’ve covered this a little bit in the past but never at once to distinguish them from one another. I would like to take this week to clearly define these terms for everyone.
The main distinction revolves around the response of the immune system to food.
Having an intolerance means that the body is missing the ability to produce something necessary in the digestion of our food. For example the enzyme Lactase is not produced in people who are Lactose intolerant. There is no immune reaction in this case as the lactose does not enter our blood stream to trigger one. The symptoms that occur with intolerance are the result of the steps our body takes to get rid of what it perceives as an irritant. By pushing water into the gut to dilute the concentration bloating and loose stools are created. Contractions of the bowels occur to push the undigested food through faster to limit exposure. This results in cramping. The bacteria of the large intestine feed off of the extra sugar (remember, anything ending with –ose is a sugar) and produce extra gas which adds to the bloating and gaseousness.
Back in September we talked about Leak Gut and Sensitivities so I’m going to get a little bit more technical now and only gloss over the previous material. A sensitivity requires some breakdown of the intestinal lining (Leaky Gut) for food particles that have not been completely digested may be exposed to the immune system. This triggers a generic immune response creating antibodies and inflammation. This inflammation becomes widespread in the body and is the cause of the vague symptoms associated with a food sensitivity such as fatigue, malaise (a fancy term for feeling crappy), and bloating.
To make a proper distinction between sensitivities and allergies (beyond the symptoms) we need to delve into the specifics of immunology for a little bit. Most people know that antibodies are an important part of our immune systems but did you know that there are five difference types of antibodies. They are; IgA, IgD, IgE, IgG, and IgM (Ig stands for Immunoglobulin) and they all have different purposes. In food sensitivities the important antibodies are IgG and IgA. IgG is the generic antibody that is made for any threat perceived by the immune system and it has a long life in the blood to provide long-term protection. This is one of the reasons why a food sensitivity will last for a long time after avoiding the trigger. IgA is the antibody that is pushed through the mucus membranes of our bodies (eyes, mouth, nose, lungs, and gut) and targets triggers before they enter the blood stream to limit the body’s exposure. This little guy is responsible for most of the intestinal inflammation and symptoms of a food sensitivity. These two antibodies are the reason both a blood test and a saliva test can be used to find food sensitivities. Through strict avoidance of the sensitive food over a period of time a food sensitivity can be decreased and many times resolved once the cells producing the specific antibodies have dies off and the gut has been healed.
Allergies, on the other hand, involve the antibody IgE, which is the “Hypersensitivity” antibody. In this case, hypersensitivity means a large reaction of the immune system to a small stimulus. This over reaction is to substances that the body comes in contact with normally and does not require the intestinal lining to be compromised to develop. And allergic reaction can range from a mild irritation of mucus membranes (itchy eyes, nose, or throat) to a contraction of those membranes causing anaphylaxis (tightened throat and airways to a potentially life threatening point). Allergies cannot be eliminated the same way sensitivities can and are generally present throughout life.
I hope that clears up the issue for everyone. If you have any further questions or need clarification please comment below or e-mail my at firstname.lastname@example.org
Thanks for reading,