Food Allergy Versus Food Intolerance: What’s The Difference?

November 29, 2022
Food Allergy Versus Food Intolerance: What's The Difference?

Food intolerance, unlike food allergies, are typically not life-threatening. However, they cause uncomfortable symptoms for individuals affected. Food intolerance is more common than you think, affecting up to 2 out of 10 individuals in the world.

In this article, we will explain the difference between food intolerance and food allergy and review some of the more commonly known food intolerances.

What is the difference between food intolerance and food allergies?

Food intolerance and food allergy are not the same. People sometimes confuse the two. Food allergies are an immune mediated response to a specific allergen whereas food intolerances are not.

Food allergies are an Immunoglobulin IgE-mediated immune response to a specific allergen e.g. nuts or shellfish. However, any food can in theory cause an allergic reaction. An allergic reaction typically develops rapidly within a few minutes after ingestion of the food (allergen). Allergies can lead to life-threatening consequences such as anaphylactic shock. Patients with allergies must avoid these foods.

Food intolerances in contrast can arise through different mechanisms. Food intolerance includes sugar malabsorption including lactose and fructose and may lead to bloating, nausea and diarrhoea. Other foods such as caffeine or amines may cause side-effects due their effects on vasodilation of blood vessels. The symptoms may mimic an allergic reaction, but to a lesser degree. Examples include flushing and palpitations. Food intolerances are not life-threatening. Here are some of the more commonly known food intolerances.

1. Lactose intolerance

Lactose is a sugar found in dairy products, such as milk and cheese. An enzyme known as lactase helps to break down the lactose we consume. Lactose intolerance happens when the individual’s body is not able to produce lactase anymore. This occurs in most Asians after childhood because the gene encoding the lactase enzyme switches off. The gene may stay switched on in other racial groups later into life but may eventually switch off at some point leading to lactose malabsorption and intolerance as the individual gets older.

Symptoms associated with lactose malabsorption and intolerance:

If you suspect you are lactose intolerant, then avoid dairy products, such as ice cream, milk, and cheese.

2. Caffeine intolerance

You find caffeine in several key beverages, such as soda, energy drinks, tea, and coffee. When consumed, it increases alertness and reduces fatigue by blocking receptors for adenosine which is a neurotransmitter that helps to regulate one’s sleep-wake cycle.

Most individuals can consume up to four cups of coffee without any major side effects. However, there are some that are more intolerable and sensitive to caffeine, resulting in hypersensitivity to the ingredient. It is vital to note that caffeine intolerance or sensitivity is not the same as caffeine allergy. Individuals with caffeine intolerance may experience the following symptoms:

  • Anxiety
  • Insomnia
  • Restlessness
  • Rapid heartbeat

3. Alcohol intolerance

Deficiency of aldehyde dehydrogenase presents as flushing after alcohol and is more prevalent in people of Asian descent.

4. Biogenic Amine and Sulphite sensitivity

Amines can cause vasodilation of small blood vessels or capillaries. Amines can be associated with flushing, migraines and nasal congestion in some people. Sulfites are also thought to affect patients with severe asthma who can develop wheezing when they consume dietary sulfites.


As you can see, food intolerance and allergies may share similar symptoms. While food intolerances are not life threatening, they can still negatively affect your health and quality of life. Hence, it is always recommended to visit a doctor should you suspect yourself of having sensitivity or intolerance. At GUTCARE, we take care of your gastroenterology needs. Talk to us about your gut health today.

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