Immune System Response to Food

The last several posts have been focused on symptoms that can be created by the immune system’s responses to food – responses like sensitivity to a food, allergic to a food, and autoimmune conditions. These words are just labels intended to describe a condition at a high level. While the descriptions are accurate, they don’t answer the question “so what?’ So we need to make a few things clearer.

Symptomatic reactions to food are generally due to either the absence of enzymes to digest the food OR an allergic reaction to another protein which is a major part of the food. Note: I said a part, not the whole food.

Enzymes vs Proteins

Technically enzymes are also proteins, just those with a specific digestive purpose. The name of an enzyme always ends in –ase. Enzymes in the body are made primarily in the pancreas. So anyone with chronic pancreatic issues will have a shortfall of enzymes, creating massive digestive issues.

There are approximately 1300 known enzymes so you can imagine it would be tough if not impossible to even find the exact right enzyme supplement for what you are eating. I have a friend with chronic pancreatitis who suffers with this problem.

Just for the record, protein is the basic structure of animal and plant cells. There may be 400,000 different proteins in the body. Only ten of those are considered essential to be included in diet; the body makes the rest of them all by itself. As a group protein names don’t all end in anything.

Milk as an Example

A simple comparative example of enzymes versus other proteins is milk.

Many Americans lose or have a diminished amount of the enzyme lactase when they become adults. Lactase breaks down the sugar lactose in milk. On the other hand a milk “allergy” generally results from the immune system’s response to the milk protein casein.

US dairy cows are mostly Holstein, the winner in the milk production contest. Both A1ß and A2ß casein are in their milk. European dairy cows are usually Guernsey, producing milk with A2ß casein. If you look hard in some grocery stores you may find A2 milk, identified by big letters on the label.

Goat’s milk is also A2ß. I have a friend who absolutely loves ice cream but standard ice cream gives him a digestive fit. Fortunately he raises goats and goats have A2ß casein. So when he makes ice cream with goat’s milk he has no problem. It’s a celebration!

Food Allergens

The milk situation described above is only one example.

The top eight food or food groups account for 90% of all food allergy reactions. They are milk, peanuts, wheat, crustacean shellfish (e.g., crab, lobster, shrimp), soybeans, eggs, finned fish (e.g., bass, flounder, cod), and tree nuts (e.g., almonds, walnuts, pecans). The most common are in bold print.

There are certainly many proteins in other foods that any one individual might be sensitive or allergic to.


I’ve listed symptoms before time and again. The problem is that the symptoms for many things can be similar. This explains why you usually can’t just Google a symptom or a disease and make a good diagnosis on your own.

However, severe allergic reactions to milk, peanuts, wheat, and crustaceans/shellfish(along with bee stings) cause easily identifiable symptoms. Your body goes into shock, blood pressure drops, throat closes blocking breathing. If this has ever happened to you I’m betting you are carrying around an epinephrine (epi) pen.

Conversely, not all allergic reactions are immediately severe for everyone. For example, many years ago my husband and I decided to celebrate New Year’s Eve with lobster, crab, and shrimp. That is all we ate. The next day I awoke with hives all over my body. I am now much more thoughtful about the frequency and volume of shellfish I eat.

When the Damage Starts

Damage from food always has symptoms. Symptoms should not be ignored because they carry a message – something I ate did not agree with me. Why is this a big deal? Because the immune reaction damage can evolve from sensitivity to allergy.

The symptoms of a food sensitivity are gastrointestinal, in the stomach and the gut. Damage to the gut is determined by the volume and frequency of the reaction.

When the damage is persistent, poorly digested food particles escape the gut into the blood stream. The body knows that those particles don’t belong and begins an immune response – the same kind of response you get with a virus or bacteria. Only in this case it’s called an allergic reaction.

Anyone with an allergy knows they aren’t desirable. Some allergens are environmental, entering your body through your lungs or skin. However, 80% of your immune system is in your gut, doing its best to keep problematic food stuff from escaping into your blood.

A cut on your finger engages your immune system which, in turn, damages the cells as a part of preventing infection. Your body creates new cells to replace the damage. This is called healing. Likewise, occasional damage to the gut heals because the intestinal cells turn over every couple of days.

Perpetual damage (volume and frequency), however, thwarts healing and can allow allergens to escape into your blood stream, requiring the other 20% of your immune system to deal with additional damage to internal cells.

Symptoms tell you that all this is going on. Take a look at The Tricky Part.

Pat Smith is the author of “It’s All about the Food,” a book that guides nutritious food choices as the way to avoid illness and maintain a healthy weight. Proceeds from her book benefit the Montgomery County Food Pantry. Her website is She can be contacted at, 870-490-1836. Her Facebook page is