We often hear people talk about having a food intolerance but what do they mean?
And what is the difference between food intolerance, food sensitivity, and a food allergy?
I think most of us know or have heard about people with allergies to certain foods such as peanuts, shellfish, or sesame seeds. On exposure to the offending food they instantly react with some or all of the following symptoms: swelling of the lips, face, tongue, and throat; itching, hives, welts, or eczema; tummy pain, nausea, vomiting, or diarrhea; feeling lightheaded or dizzy. In some cases, the inflammatory symptoms can develop very quickly and be quite severe leading to very low blood pressure and worst-case scenario death.
In contrast, food intolerance is a term that is now used quite loosely and sometimes interchangeably with allergy. Generally, people can mean anything from the allergic symptoms described above to a desire not to eat a certain food group. Food sensitivity can include coeliac disease, or vague unrelated systemic symptoms such as headaches, joint pains, and skin rashes. So, what really is the difference? And more significantly how important are food allergies, food sensitivities, and food intolerances to our long-term health?
The difference really starts in the way our individual immune systems recognise and respond to different food proteins. Some people are born with a genetic predisposition to develop allergic-type responses. In their case, the immune cells lining the gut will recognise some food proteins as the enemy (foreign to the body) and attack them by making a type of antibody called IgE. IgE binds to the food protein and stimulates white blood cells known as mast cells to instantly release histamine and other inflammatory proteins into the circulation. This results in symptoms of heat, redness, swelling, pain. IgE can remain attached to mast cells for years and so they are primed to activate the mast cells whenever the person is next exposed to the food allergen.
In regard to food sensitivity, the immune system uses a different approach to ‘attack’ the ‘enemy’ food protein. The outcome of this response is much slower and can be varied but the predominant antibody produced is IgG. IgG molecules can form large lattice-like structures. These structures circulate through the body where they get caught in our joints, skin, and other tissues, even the brain! They then activate white blood cells, resulting in tissue damage and inflammatory response in the local area. In the long term, chronic low-level inflammation like this reduces our quality of life and leads to the development of autoimmune diseases such as celiac disease, arthritis, even possibly Alzheimer’s.
Food intolerance is different again. Food intolerances do not normally involve the immune system. Instead, they are a result of an enzymatic malfunction or inability to metabolise certain foods. For example, intolerance to lactose in milk is due to deficiency in the enzyme lactase. Other food components that some people can be intolerant to include caffeine, monosodium glutamate (MSG), and some naturally occurring food chemicals (salicylates and amines). Adverse reactions can also occur with artificial preservatives such as sulphites (often used in dried fruits) and benzoates (often used in soft drinks).
If we have already developed an allergy, sensitivity, or intolerance to a specific food we need to be very vigilant in eliminating this food from our diet. Our immune system is very clever and remembers all ‘enemies’, instantly jumping into attack mode with every subsequent exposure. The good news is there are now several treatment options that aim to skew the immune response and reduce reactivity. This is achieved by treating the person with very low concentrations of the allergen over many months. However, the best way to dodge developing food allergies or sensitivities is to start by making sure we have a healthy gut with a strong intact cell wall and mucosal layer lined with healthy gut microbiota.
Functional Medicine will help you as an individual find the right way to eat—using specific foods to maximize your health potential, reverse inflammation, and reduce the symptoms of allergy and food intolerance. Functional Nutrition offers effective strategies and tools including weekly food and shopping lists, healthful recipes, and recommendations about cooking and food storage methods.
If you need some help understanding your food reactivity, book in for a FREE, 20-minute consultation with Shelley Cavezza, Ph.D.
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