What is Food Intolerance?

Food intolerance occurs when food chemicals produce side effects, similar to the manner in which drugs produce side effects. Some people are more sensitive than others to those effects.

Food intolerance aren't allergies. An allergy to food is an oversensitivity to a protein in a single food whereas food intolerance is a reaction to chemicals present in a wide range of foods.

Organic, fresh, or processed foods can all cause adverse reactions – not all trigger chemicals are man-made.

Symptoms, especially in children, can be physical or behavioral. Some people have more than one symptom, and over time, the symptoms will change.


Although some of the symptoms may be similar, a food intolerance is not the same as a food allergy.

Indeed, food allergies and food intolerances may be difficult to tell apart so it's important to talk with your doctor if you suspect that you might be intolerant.

When you have a food intolerance, symptoms usually begin within a few hours of eating the food that you are intolerant to.

However, the symptoms can be delayed by up to 48 hours or even days, making it particularly difficult to detect offending food.

Moreover, it can be difficult to correlate symptoms with a certain food if you frequently consume food to which you are intolerant.

Although food intolerance symptoms vary, they most often involve the digestive system, skin and respiratory system.

Common symptoms include:

  • Diarrhea

  • Bloating

  • Rashes

  • Headaches

  • Nausea

  • Fatigue

  • Abdominal pain

  • Runny nose

  • Reflux

  • Flushing of the skin


1) Absence of an enzyme

Enzymes are needed to fully digest foods. If some of these enzymes are missing or insufficient it may undermine proper digestion.

People who are intolerant of lactose do not have enough lactase, an enzyme that breaks down milk sugar (lactose) into smaller molecules which the body can further break down and absorb through the intestine. This can cause spasm, stomachache, bloating, diarrhea, and gas if lactose remains in the digestive tract.

2) Chemical causes of food intolerance

Some chemicals in foods and drinks can cause intolerance in some cheeses, including amines, and caffeine in coffee, tea, and chocolates. Some people are more susceptible than others to those chemicals.

3) Food poisoning – toxins

Some foods have naturally occurring chemicals that can cause diarrhea, nausea, and vomiting to cause toxic effects on humans.

Under cooked beans have aflatoxins that can cause digestive issues particularly unpleasant. Fully cooked beans have no toxin to them. Therefore, people may wonder why after one meal they react to beans, and not after another.

4) Natural occurrence of histamine in some foods

Some foods, such as fish that has not been properly processed, may have histamine accumulation as they "rot." A number of people are especially susceptible to this natural histamine and develop skin rashes, stomach cramps, diarrhea, vomiting and nausea.

5) Salicylates are present in many foods

Salicylate intolerance, also known as salicylate sensitivity, occurs when somebody reacts to normal amounts of ingested salicylate.

Salicylates are derivatives of salicylic acid, which occurs naturally in plants as a defense mechanism against harmful bacteria, fungi, insects, and diseases.


Some common types of food intolerance are:

  • lactose

  • wheat

  • gluten

  • caffeine

  • histamine, present in mushrooms, pickles, and cured food

  • additives such as artificial sweeteners, coloring, or other flavorings

After eating bread, some people experience a reaction but this does not necessarily indicate an intolerance to gluten. Anyone who suspects that they may have a gluten intolerance should see a doctor before giving up gluten, since cereals can be an important source of different nutrients.


Food intolerances and allergies differ. Most do not trigger the immune system and normally their symptoms are less severe.

They can, however, have an adverse effect on your health and should be taken seriously.

Many people are intolerant or hypersensitive to foods and additives, such as dairy, caffeine and gluten products.

If you suspect you may be intolerant to a particular food or food additive, talk to your doctor or dietitian about the options for testing and treatment.

Although food intolerances are usually less serious than food allergies, they can affect your quality of life in a negative way.

That's why it's important to take steps to identify food intolerances to avoid unwanted symptoms and health problems.

©2018 by Blue Zone Innergy. All Rights Reserved. Terms Of Use & Disclaimer.