Posted 1/26/2014 6:25 PM (GMT 0)
A lot of us have certain food intolerances or trigger foods. This has always puzzled me - and made me wonder what the heck is the deal with this. Especially when it comes to say breads… I really, really miss bread..
At the same time there is some diets that people swear by (myself included) such as SCD/GAPS/FODMAPS/Paleo etc etc. I personally have always responded well to SCD – others not so much though. But even within these diets many people still have issues with certain foods etc. So this always puzzled me. So I have spent the last little while studying and learning about immune reactions trying to figure out what the commonality is or why we (people with IBD) tend to experience a lessoning (or sometimes worsening) of symptoms when we follow/alter our diets.
What I have learnt over the last while is that there is a reason behind this and more so some pretty strong evidence that in us (people with IBD) there is probably either a barrier function issue (mucus barrier issue) where larger molecules are getting through or a bacterial issue, where say some type of bacteria is missing and we can no longer break down certain types of food particles into a simpler form or a combination of both. And this generates an immune reaction within us.
Regardless of what the “actual” cause may be, in many of us it frustrates us to no end trying to understand what food to eat, or not to eat... it sure is one hot topic on here! haha. And one with many theories and hypothesis behind them. But at the root is some pretty simple science. And it starts with what causes an immune reaction:
Substances that cause our immune systems to react are called Immunogens.
There's a couple of properties that enable them (immunogens) to induce an adaptive immune response. And these apply to a lot of our problems we all experience with various foods and such:
1) Molecular size - Low molecular weight compounds (called haptens) are an example. They can bind to antibodies and therefore are called antigens but they cannot induce an immune response. Examples of these are simple sugars, amino acids and other low weight molecular compounds. BUT when they are bound or coupled to a larger protein carrier they all of a sudden become very effective immunogens and therefor cause an adaptive immune response.
2) Molecular Complexity - Non repeating polymers such as large complex proteins are very effective immunogens (they induce an immune response). The same applies to complex carbohydrates - whereas things like simple polysaccharides (simple starches) with repeating subnits, and certain lipids (fats) are not and do not induce an immune response because they are composed of identical or nearly identical monomers. (a monomer is a molecule that can bind to another molecule, so think glucose, as it is a simple sugar molecule). Because of this, sufficient molecular complexity is a property of an immunogen or a "cause" of an immune reaction when they get through into our bodies..
3) Physical Form - Large complex molecules in insoluble or aggregated form (like say a protein that has been heated) are usually excellent immunogens so they can generate quite an immune reaction in some cases. The insoluble material is taken up by a phagocyte "or eaten" by a phagocyte and this in turn leads to an adaptive immune response. On the other hand, a soluble form of the very same molecule is often a very poor immunogen as it's not ingested efficiently by phagocytes and therefore does not trigger or cause an adaptive immune response.
Though many speak of SCD as a diet that is supposed to alter the gut flora and eliminate the food source for the “bad guys” - in reality SCD is really a diet based primarily on simple carbs and proteins – so low molecular weight, non-complex, somewhat soluble food molecules. These all tend to produce minimal immune reaction in us. GAPS falls into this as well. As we get further along in healing (be it through meds or through diet) we tend to shift and try other diets like paleo etc – and these diets tend to fall under the same category foods based or that have minimal properties of causing immune reactions. Likewise when we are in a flare certain foods trigger strong reactions and make inflammation etc worse.
Anyway the point to this whole thing was that we have a lot of inflammation going on in our bodies – and certain foods can just make this worse, leading to greater symptoms. But altering our diet to low-inflammatory foods or more correctly low Immunogen type foods is a good option for us.
Obviously the whole diet thing get's a lot more complicated when it comes to byproducts produced by bacteria fermentation and the effects of these on us and available nutrients and so on and so on - but at the root of diet as a treatment option, this is the commonality between the proposed diets that is often overlooked in research or studies. And more so its a pretty simple explanation as to why some of us benefit from these diets.