Could Allergic Reactions Start in Your Gut?

There have been many books and articles recently, which make the claim allergic reactions start in your gut or digestive system. Even pollen and dust reactions are said to come from the gut. So how can that be? To the average person that does not make sense, but if one knows the physiology of the gut and some basic immunology it makes perfect sense. Let’s see if I can explain this is a way that makes sense to you.
Our immune system consists of white blood cells. These white blood cells can circulate freely in the body and blood, they can also be specialized and reside in organs such as the lungs, or they can be concentrated in special tissue called lymphoid tissue or peyers patches. More than 50% of our white blood cells reside in the gut in these peyers patches and for good reason. The gut is where most of the contact with the outside environment occurs inside our body so it is where the bulk of our defenses need to be. The skin protects us as a barrier and the lungs are protected by special white blood cells called Kupfer cells. The food we eat is the bulk of foreign objects that enter our body and the peyers patches are our main defense. You may or may not know that in the gut are 2-3 pounds of bacterial flora, which reside there to help us digest our food.
Problems arise when we make poor dietary choices, which can cause a shift in the bacterial flora and damage to our intestinal wall. Poor food choices can increase populations of pathogenic bacteria, viruses and yeasts in our gut, which can also cause our gut to be compromised. When this happens our intestinal wall becomes permeable to larger proteins than our digestive system was designed to let through and these larger proteins can cause our white blood cells to react to them as if they were a foreign enemy. This then causes all white blood cells body-wide to be on the alert for undesirable invaders. When that happens we can become more reactive to dust, pollen and any other top inhaled allergen and it all started in the gut. So the lesson here is that it is important to eat healthy if you want your immune system to behave properly and if you have any digestive problems you might want to pay more attention to your eating habits. Things like less flour based products and more vegetables, eating more leafy green vegetables and make dinner one of your lightest, not your heaviest meals.