Q. What is the difference between food allergy, food sensitivity, and food intolerance?
Food allergies, food sensitivities, and food intolerance are often used interchangeably and inappropriately. In fact, there is active debate in scientific and medical circles as to how to define and use these three terms. The general consensus is that food allergy can be defined as any adverse reaction to food that involves our immune system. This breaks down into two kinds of reactions: food allergy and food sensitivity. Food intolerance does not involve the immune system.
Perhaps the best known example of a food allergy is also its least common but most dangerous. Anaphylactic shock is a severe hyper-reaction of the immune system caused by a massive release of histamine and other chemical mediators from certain types of white blood cells called mast cells and basophils. Not everyone with food allergies experiences anaphylaxis though. The immunological triggering mechanism that causes the mast cells (and basophils) to release their chemicals is called IgE (immunoglobulin E) and is very well understood phenomenon. This underlying mechanism is considerably different from the triggering mechanisms found in food sensitivities. The most common foods implicated in IgE food allergies are peanuts, tree nuts, shellfish, milk, egg whites, certain white fish, and sulfite containing foods. People with anaphylaxis can die within minutes if they ingest even one molecule of their allergic food.
Food allergy affects about 1-2% of the population and accounts for only a small percentage of all adverse food reactions. Most immediate reactions are not life threatening but do produce uncomfortable symptoms. I do not treat these conditions as people suffering from food allergy can often identify what foods they are allergic to without the help of a doctor or testing.
Food sensitivity (also known as delayed food allergy and in research circles “loss of oral tolerance”) is quite another story. Delayed reactions manifest in many different ways as they can affect any organ system in the body and can take from 45 minutes to several days for symptoms to become apparent. The delayed onset of symptoms and complex physiological mechanisms involved in food sensitivities make them an especially difficult puzzle to try to solve on your own or with most laboratory serum tests. In fact food sensitivities often go undiagnosed or misdiagnosed. The treatments prescribed usually provide only temporary relief that mask the symptoms instead of addressing the root cause of the problem.
|Food Sensitivities||Food Allergies|
|Body organs involved||any organ system in the body can be affected||Usually limited to airways, skin, gastrointestinal tract|
|Symptom onset occurs||From 45 minutes to 72 hours after ingestion||From seconds to 1 hour after ingestion|
|Acute or Chronic??||Usually chronic, sometimes acute for example in histamine response||Acute, rarely chronic|
|Percentage of Population affected||20-30%+||1-2%|
|Immunologic Mechanism||White Blood Cells, IgG, IgM, C3,C4||IgE|
|Non-Immunologic Mechanism||Toxicity, Pharmacologic||None|
|How much food is needed to trigger reaction?||From small amount to large. Dose dependent.||1 molecule of food|
Food intolerance can produce some digestive symptoms that are similar to food sensitivity but it doesn’t involve the immune system. Instead, when the food in question is consumed, it is not properly digested and begins to ferment inside the gut. The best example of food intolerance is lactose intolerance. This condition is characterized by bloating, loose stools or diarrhea, and gas. Lactose intolerance is caused by an inability of the body to produce enough of the enzyme lactase which breaks down lactose, the primary sugar found in milk.
Q. Why do I have food sensitivities; how did I get them?
Researchers do not have all the answers to this question and there is still much to be learned about how food sensitivities develop. The following are the most widely accepted factors that can cause food sensitivities:
- Poor digestion – In Ayurvedic medicine it is said that all disease begins in the gut
- Unbalanced gut flora – for example overgrowth of candida
- Chronic stress/severe acute trauma – A shock to the system can cause the immune system to respond unfavorably to food antigens
- Immune system overload – A chronic immune system stress can cause the immune system to target benign molecules food in food
- Genetics –
- Toxic induced loss of oral tolerance – for example repeated exposure to chemicals such as pesticides, food colorings and preservatives
- Gut permeability – (leaky gut) causing larger food molecules to pass into the blood stream
Q. How do food sensitivities cause symptoms?
The symptoms that result when we have food sensitivities are caused by the release of toxic chemicals such as histamine from from immune cells. The table below describes the sequence of events involved in developing symptoms from food sensitivities.
|Step 1 Identification||Step 2 Mobilize the ‘troops’||Step 3 Chemical Release||Step 4 Symptoms|
|Immune system identifies foods and food substances as foreign.||Immune mechanisms (IgG, IgM, IgA, Complement) and non-Immune mechanisms trigger immune cells to attack||Chemicals such as histamine are released from immune cells to destroy invaders.||Tissue inflammation and damage occurs leading to symptoms. Migraines, Fibromyalgia, IBS, Arthritis etc.|