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What is an Intolerance? (Or, Why Am I Doing This?)

What is a Dietary Intolerance?

Since you are on this website, then you probably already know what an intolerance is. Likely, your Naturopathic Doctor has evaluated your diet and determined what yours are.

But, if you aren’t sure what it means to have an intolerance, or why it’s important to follow it, here are the basics.

First, an intolerance isn’t an allergy.

An allergy is an immune system response, whereas an intolerance involves the digestive system.

The immune system creates antibodies to fight invading viruses, pathogens, etc. Antibodies are also called “immunoglobulins” (which is abbreviated as “Igs”). When the immune system encounters particles of food, it can create Igs to attack them by mistake. The most common Igs that are associated with food allergies are IgE and IgG. When you have an allergy test done, that is what they’re looking for.

An intolerance is different.

Dr. Zeff states that, “Standard medicine recognizes lactose intolerance and gluten intolerance as true food intolerances. This means that one does not have the genetic basis to generate specific enzymes to digest milk, or wheat. These foods and the ensuing mal-digestion produce symptoms in the intestine and toxins which enter the blood stream, which are eliminated by their removal from the diet.”

Many Traditional Naturopaths use the Carroll Intolerance Evaluation Method to determine what foods a person can’t digest correctly. This is part of the basis of their treatment protocols. Through it, many other food categories have been identified to be intolerances and cause mal-digestion.

Why are they a problem?

Dr. Zeff goes on to explain that, “Foods that do not digest well ferment and putrefy in the intestines. These processes are driven usually by less-than-optimal bacteria, and result in the generation of many toxic metabolites. (Drasar and Hill, Human Intestinal Flora, 1974) These toxins are absorbed into the blood…This becomes the basis of chronic inflammatory reactions throughout the body, depending upon where there are stressed tissues, genetic weakness, other pathology or trauma, etc.”

So, intolerances are a genetically determined inability to digest certain foods. In order to heal from an illness or to remain healthy, we should avoid the foods that cause inflammation and lead to chronic illness.

Unlike an allergy, you may not realize that you have an intolerance at all.

Sometimes we get questions from people who have had mild recurring illnesses but are otherwise healthy, and are told that they have an intolerance to certain foods, but don’t see how the two are connected.

Most recently, a young man expressed this confusion to me while I was helping him navigate his new intolerance. He was otherwise healthy, but tended to get pneumonia several times a year. It didn’t correlate to times he ate foods he was intolerant to (since that was all the time), so he didn’t see how there could be a connection.

The explanation is that the intolerance is the groundwork for the other treatments your doctor is prescribing for you to be effective. Removing foods from your diet that impede good digestion sets the stage for the other medicine and treatments to work.

Traditional Naturopathic philosophy includes the idea that the body knows how to be healthy. It can heal, if the right environment and support is given to it to do so.

In the case of the young man who gets pneumonia sometimes, the idea is that following his intolerance will reduce inflammation all over the body including his lungs, where he may have an existing weakness. Whatever other treatments his doctors will want to do to help support his body will be aided by improving his digestion in this way.

What kinds of intolerances are there?

Dr. Otis Carroll, who developed the intolerance evaluation method, determined main categories of intolerances. The most common of these are:








Typically, one of these is found to be something that the person can’t metabolize. Once determined, that should be avoided completely.

Sometimes a second food is found to be a problem too, but that is less common. Those tend to be things like fish, soy, wheat, gluten, honey - very specific things.

Along with a food category that should be completely avoided will be a combination of foods that should be avoided within a period of 4-8 hours. The most common of these are:

Fruit with Sugar

Potato with Grain

Egg with Grain

Dairy with Grain

Sugar with Grain

Fruit with Grain

The combination foods are ok if eaten alone. For example, if your combination to avoid is Fruit with Sugar, you could eat as much fruit as you’d like, as long as that meal doesn’t include sugar too - and that no sugar is eaten before or after the fruit within a certain period of time. The idea is that they will ferment faster than they will digest, so they should not interact in your system.

Sometimes it is easiest to just not eat one of the food categories in your combination. Like, just don’t eat sugar so there is no risk of eating your intolerance combination.

Naturally, some of these food categories are harder to avoid than others. The fruit category, for example, is extremely difficult because fruits and fruit extracts/derivatives are used in so many things. Doing that one right often means having to eat very simply or making most of your food from scratch.

But, once you know what your intolerance is and how to follow it correctly, you will make progress on your health journey with the guidance of your doctor.

I hope that this has helped to explain what a dietary intolerance is, and why following it is beneficial to your health.


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