These affect at least 5% of the adult population. The true prevalence is probably much higher.
Repeated exposure to a food can lead to the development of either a food intolerance or a food allergy.
The definitions and descriptions of these different conditions are often confusing, particularly in non-scientific media. Strictly speaking, an allergy involves the immune system’s antibodies IgE (immunoglobulin E), which lead to the rapid onset of the classic symptoms of allergy (‘immediate hypersensitivity’): allergic rhinitis, asthma, angioedema (swelling of the lips and tongue) or anaphylaxis. In adults peanuts, tree nuts and seafood are the most common causes. If a true allergy is supected or found, I will often involve an allergist in the management process.
Food intolerance on the other hand is often used as an umbrella term which includes the inability to digest certain sugars (such as fructose or lactose intolerance, and other FODMAPs – see FODMAPs), a reaction to certain toxins in food (such as propionates used as preservatives in wheat), or an immune reaction involving the antibodies IgM and IgA against a whole range of foods including gluten. These latter food intolerances are sometimes referred to as food sensitivity.
Compared to food allergies, food intolerances typically have a delayed onset of hours to days after consuming the causative food, making it more difficult to pinpoint the culprits. And these are the conditions where my approach to gut health can alleviate symptoms.
What are the Food Intolerance Symptoms ?
They are very diverse, ranging from IBS symptoms (see section on IBS for more information) to headaches and worsening of inflammatory conditions such as arthritis.
What are the Causes of Food Intolerance?
In many cases the starting point for developing intolerances or allergies to certain foods is an increased permeability of the gut lining (sometimes referred to as ‘leaky gut’). This lining is normally selectively permeable. In simple terms this means that the gut lets the desirable nutrients through and keeps toxins and bacteria out.
The loss of this selective permeability is the result of imbalances in the complex interactions between the trillions of gut bacteria, the epithelium (the cells that line the inside of the gut) and the immune cells present in the gut (70% of the immune system is found in the gut).
What is my Approach to Managing Food Intolerance?
We first identify (usually by using a specialised food intolerance test) and then remove from the diet for a limited period the causative foods. This alone can lead to very significant improvements in symptoms and well-being.
The focus of management is then to restore the selective permeability of the gut lining (see above).