Our bodies have an automatic defense mechanism that is supposed to be dormant until it is activated. With an injury, or exposure to infection or poisons, the body immediately begins its response. The first phase is inflammation. Injured cells release chemicals that cause local blood vessels to become more porous, allowing more fluids and white blood cells to the area. (One of these chemicals is called histamine; I’m sure that name is familiar to many allergy sufferers.) This is where the swelling, redness and heat come from. Later on, the healing can begin in earnest, and the inflammation should resolve.

Allergies are basically an overreaction to a relatively mild trigger, known as an allergen. The body’s defenses react as if the small irritation was a life-threatening injury or invasion of the body. Even minimal exposure to the problem substance can trigger a reaction in people with severe allergies.

There is a genetic component to allergies; my mother was allergic to cats, and so am I. (Besides the fact that I am a dog person.) But the genetic link is not a total one. Identical twins have been known to be allergic to different allergens.

And there is certainly a link with lifestyle, especially American lifestyle; allergies are much more common in American children, and foreign children who move to America “catch up” with our higher levels of allergies after 10 years of living here.

A recent study from the Centers for Disease Control suggests that most allergies are on the increase in children; from 1998 to 2010, food allergies increased from 3.4 percent to 5.1 percent and skin allergies from 7.4 percent to 12.5 percent in children aged 0 to 17 years old.

From a wellness perspective, allergies are almost always a secondary problem, meaning they are caused or aggravated by some underlying stress in the body. A common condition called the “pro-inflammatory state” is a major behind the scenes cause of allergies. This means that there is a chronic, low-level irritation somewhere in the body that is causing the immune system to be on constant alert. After a time, the system begins to get out of balance; the body overreacts to even small exposures, and inflammation is very easily triggered — pretty much the definition of allergies. This state is often caused by a diet high in processed foods, such as white flour products and sugar; another cause is a diet with excessive Omega 6 fatty acids. These are found in grains and grain-fed livestock, as well as vegetable oils.

Another cause of the pro-inflammatory state is a stressed digestive tract, especially the bowel. The digestive tract is the largest source of exposure to bacteria and potential toxins; in fact, one of the biggest concentrations of immune tissues in the body is along the bowels. They have the job of letting only healthy, digested substances in, and keeping anything else out, and an unstressed bowel does this balancing act well. But if the lining is inflamed, it becomes more porous, and allows larger, less digested materials into the system. This is called the “leaky gut” syndrome. To the body, this is seen as an invasion, and of course it is the immune system that deals with invasions. If the amount of material that gets through is not too excessive, there will be no obvious symptoms, but the immune system will be on a chronic state of low-level alert, setting the person up for allergies anywhere in the body.

There are several substances that cause this weakening of the lining of the bowel. One of the most potent is gluten, the protein found in wheat and a few other grains. (This reactivity is worse in some people if the gluten has been chemically altered, a relatively common procedure. The final product is often used in foods that do not contain wheat, such as sausage, and may be labeled as “wheat products”.) Many of my patients notice big improvements in their allergies when they stop eating wheat; this was true for me as well. Another major source of leaky gut is anti-inflammatory drugs such as aspirin, ibuprofen, Celebrex and Toradol. Even the relatively newer anti-inflammatory drugs, called Cox-2, which are supposed to have fewer digestive side effects, still cause this condition.

Our immune systems can also be put on chronic alert by changes in the normal bacterial species that live in the gut. There are an estimated 100 trillion bacteria in the bowel — 10 times more cells than in our bodies. Our digestive tract, and the immune tissues that line it, are dependent on these bugs being there. If the usual species are replaced with other invasive ones, the immune system reacts to the change, and goes into a defensive mode. These changes in the bugs are usually due to antibiotics use, eating food low in fiber (fiber that we can’t digest is the main food for these bacteria) and eating overly sanitized foods. Our bodies are used to a steady stream of replacement bacteria from our foods; everything is so pasteurized now that very few bacteria get through.

There are many natural, drug-free treatments available for allergies, which we’ll talk about next week. In the meantime, stay gluten free and try to be nice to the bugs in your gut — remember, they outnumber you 10 to 1.

Dr. Michael Noonan practices chiropractic, acupuncture and other wellness therapies in Old Town. He can be reached at noonanchiropractic@gmail.com.