Food Intolerances

Overview of Food Intolerances

A person can suffer from food intolerance when he/she has difficulty digesting particular foods. It is, however, often confused with food allergy.

As compared to food allergies, food intolerances are more common and they affect 15-20% of the overall population. People suffering from irritable bowel syndrome or IBS are mostly affected by food intolerances.

Food allergy on the other hand is due to the reaction of the immune system, in response to any particular food. While, in food intolerance, the digestive system is involved. That is why food intolerances are less serious as compared to food allergies.

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Signs and Symptoms of Food Intolerances

When you have food intolerances, you would normally experience unwell or discomfort right after eating certain foods.

Some of the common food intolerances symptoms include:

In case of food intolerances, the amount of food taken can really affect the severity of the symptoms in an individual. The onset of symptoms can occur a few hours after eating food. The symptoms can stay from several hours to days.

It should be noted that symptoms of food allergies and food intolerances also overlap, so it can be difficult to diagnose properly.

Can My Symptoms Points Towards Something Else?

If you are someone who regularly suffers from skin rashes, tummy pain, bloating or diarrhea, you need to consult a medical health practitioner. Your doctor would help you diagnose the real cause of your symptoms. Your doctor may also recommend blood tests for proper diagnosis.

Following are some of the health conditions that have similar symptoms like that of food tolerance such as:

  • Lactose intolerance
  • Stress and anxiety disorder
  • Coeliac disease
  • Irritable bowel syndrome
  • Food allergy
  • Inflammatory bowel disease

Types of Food Intolerances

There are several types of food intolerances, each with its own set of symptoms and underlying mechanisms. Here are some of the most common types:

  • Lactose intolerance: This occurs when the body is unable to digest lactose, a sugar found in milk and dairy products. Symptoms may include bloating, gas, diarrhea, and abdominal pain.
  • Gluten intolerance: Gluten is a protein found in wheat, barley, and rye. People with gluten intolerance, also known as non-celiac gluten sensitivity, may experience symptoms such as bloating, gas, diarrhea, and fatigue.
  • Histamine intolerance: This occurs when the body is unable to break down histamine, a compound found in certain foods such as aged cheese, fermented foods, and alcohol. Symptoms may include headaches, flushing, hives, and digestive problems.
  • Fructose intolerance: Fructose is a sugar found in many fruits and vegetables, as well as sweeteners such as high-fructose corn syrup. People with fructose intolerance may experience symptoms such as bloating, gas, diarrhea, and abdominal pain.
  • Food additive intolerance: Some people may be intolerant to certain food additives, such as monosodium glutamate (MSG), artificial sweeteners, and food dyes. Symptoms may vary depending on the specific additive.

It's important to note that food intolerances are different from food allergies. While food intolerances may cause uncomfortable symptoms, food allergies can be life-threatening and require immediate medical attention. If you suspect you have a food allergy or intolerance, it's important to speak with a dietician/nutritionist for proper diagnosis and treatment.

Causes of Food Intolerances

Food intolerances occur when our body is unable to digest certain food items. This is due to the sensitivity of certain chemicals or when our body lacks certain digestive enzymes. Foods that normally trigger or cause food intolerances are:

  • Sulfites
  • Gluten
  • Milk
  • Fructose and caffeine
  • Preservatives and food coloring

Now, let’s have a look at the various types and causes of food intolerances.

Food Poisoning

Some foods can naturally produce toxins in the human body and cause nausea, diarrhea, vomiting, and rashes.

Normally undercooked foods are the major cause as it allows bacteria to produce toxins. Therefore, people may confuse it with the food when it’s the cooking time that causes the production of toxins.

In the same way, food poisoning from canned food is again due to toxin production as a result of the improper way of storing and processing food. It can cause a severe allergic reaction, which can mimic food allergies.

Salicylate Intolerance

These compounds are mainly present in the plant foods such as fruits, vegetables, spices, and herbs. Salicylates are the common compounds in preservatives and artificial food flavoring. Normally, people can tolerate salicylate while some may have reduced tolerance.

Some of the common symptoms of salicylate intolerance include:

  • Diarrhea
  • Stomach pain
  • Hives
  • Rashes

Lactose Intolerance

Our digestive system has different enzymes to digest and break down food. If someone lacks a certain enzyme then, they are unable to digest those certain food items.

Milk has lactose in it. People who suffer from lactose intolerance, do not have lactase enzymes in their bodies. Hence, the body is unable to break down the lactose into smaller molecules. So, when lactose stays in the digestive system, it can cause diarrhea, gas, bloating, and stomach ache.

Fructose Intolerance

Fructose is a sugar that is present in honey, fruits, and vegetables. Fructose intolerance is also due to the lack of an enzyme that breakdown the fructose. This is rare food intolerance. People who suffer from fructose intolerance show symptoms of diarrhea, cramps, bloating, fullness, and gas, after eating foods having fructose in them.

Gluten Intolerance

Gluten is a protein and it is majorly present in some cereals such as barley, wheat, and rye. A person who suffers from gluten intolerance suffers from bloating, pain, and nausea after eating certain food items.

Some non-digestive symptoms can be associated with a gluten intolerance such as:

  • Headaches
  • Joint Pain
  • Depression
  • Brain fog
  • Fatigue
  • Anxiety
  • Lack of general well-being

Gluten intolerance is also called “nonceliac gluten sensitivity”. The symptoms of gluten intolerance and celiac disease normally improve after removing gluten from the diet. However, when reintroduce, the symptoms return.


Risk Factors of Food Intolerances

Food intolerances can result in a variety of risk factors and complications, including:

  • Nutritional deficiencies: If you are intolerant to certain foods, you may avoid them, which can lead to nutritional deficiencies if you don't get the necessary nutrients from other sources.
  • Gastrointestinal problems: Food intolerances can cause a range of gastrointestinal problems, including bloating, gas, diarrhea, and constipation.
  • Inflammation: In some cases, food intolerances can lead to inflammation in the gut, which can cause damage to the intestinal lining and lead to chronic conditions such as inflammatory bowel disease.
  • Allergic reactions: Some people with food intolerances may also be at risk of developing allergic reactions to certain foods, which can cause symptoms such as hives, swelling, and difficulty breathing.
  • Anaphylaxis: Although rare, severe food intolerances can lead to anaphylaxis, a life-threatening allergic reaction that requires immediate medical attention.
  • Mood disorders: Certain food intolerances have been linked to mood disorders such as depression and anxiety.
  • Skin problems: Food intolerances can sometimes cause skin problems such as rashes, itching, and eczema.

It's important to note that the severity of the symptoms can vary widely depending on the individual and the specific food intolerance. If you suspect that you may have a food intolerance, it's important to consult with a healthcare provider to determine the best course of action.



Yes, you can opt for the following simple steps to prevent and relieve the symptoms of food intolerances.

  • Firstly, you need to track the food you eat.
  • After this, you need to know the amount of food that is triggering food intolerance. You need to limit the intake of amount of food, which you can handle.
  • Make sure to ask the server about your food when you are dining out. Because your meal may contain such food items that you cannot tolerate. This is a necessary step as all the ingredients may not be mentioned on the menu.
  • You should also carefully read the food labels. Properly check the ingredients in order to avoid the problem of food. Make sure to not skip the seasonings and condiments as they contain any additive or MSG that can lead to food intolerance.


Food allergies and food intolerances can have similar symptoms. Therefore, it is not easy to differentiate and diagnose these two conditions. It becomes more difficult when a person suffers from various food intolerances.

Interestingly, the symptoms of food intolerance also overlap with some chronic health conditions such as chronic digestive conditions- IBS. But, still, the doctor can confirm the diagnosis by the certain pattern in the symptoms.

People can also keep a track of the food they are eating, symptoms that are appearing, and their timings. This health record can help the medical practitioner in preventing severe allergic reactions to foods.

Celiac disease and lactose intolerance are the only reliable, accurate, and even validated tests to identify food intolerance. The best diagnostic tool, in this case, is only the “exclusion diet” or “elimination/diagnostic diet”.

Medical healthcare providers may also recommend blood tests (such as CBC) or skin prick tests to eliminate the chances of food allergy. Skin reactions can indicate the allergy while blood tests would help measure the IgE antibodies levels. A high level of IgE antibodies indicates that it is an allergy.

Treatment of Food Intolerances | When to Consult a Doctor

The treatment of food intolerance is based on simply reducing and avoiding the intake of foods causing or triggering food intolerances. You can also treat the side effects of food intolerance by treating the symptoms of the food-causing problems. Your doctor will recommend taking medication for the symptoms of stomach ache or heartburn.