By FoodMarble     March 28, 2019 | Health

At FoodMarble, we’re often asked about the difference between a food allergy and intolerance. Allergies and intolerances can both be food related and are easy to confuse.  They can sometimes have similar symptoms, but there are distinct differences between the two.

What’s an allergy?

Your immune system acts quickly when you’re exposed to things like bacteria, viruses and toxins. This helps neutralize the threat and protect your health. However, when you have an allergy, your immune system can get a little confused and go into overdrive when it detects something harmless, like peanuts. This exaggerated immune response is an allergic reaction.

When you’re allergic to a certain food, even small amounts of it can cause a reaction. Symptoms can include:

  • abdominal pain
  • diarrhea
  • rash
  • itching
  • difficulty breathing
  • swelling and more.

While some allergies are mild, they can also be a serious medical emergency. In fact, many people with serious food allergies carry an adrenaline injection. It can slow the reaction to allow time for them to receive emergency medical attention.

What’s a food intolerance?

Food intolerances don’t involve an immune reaction. Instead, intolerances are when you have difficulty digesting certain foods, leading to digestive symptoms. One family of carbohydrates that can lead to symptoms are called FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols). For example, many people are intolerant to lactose, a common FODMAP carbohydrate found in many dairy products.

When foods aren’t fully digested, they’re consumed by bacteria in the large intestine. This process is called fermentation, and it causes the production of gases like hydrogen in your gut. In some people, this can contribute to digestive issues.

Symptoms of a food intolerance can include:

  • abdominal pain
  • diarrhea
  • bloating
  • flatulence
  • headache and more.

What’s the difference between the two?

When you have an allergy, even trace amounts of the allergen can cause a reaction. But with food intolerances, you may be able to eat small amounts of your trigger food without having symptoms.

Everyone’s tolerance level to specific foods is a little different. This adds to the complexity of identifying food intolerances. For instance, you may have a small portion of blueberries without experiencing any symptoms. This leads you to believe that blueberries aren’t an issue. Another day, you have a full cup of blueberries and start to feel bloated and unwell several hours later. This creates confusion, because you’ve previously had them without any problems! In this case, the serving size is the key.

Another difference between allergies and food intolerances is the speed of symptom onset. When you’re allergic to a certain food, you’ll start to have a reaction almost immediately after exposure. Food intolerance symptoms have a much slower onset, often appearing many hours after you ate your problem food.

However, the slower onset of symptoms can make it more difficult to pinpoint the cause. For instance, you may eat a trigger food for lunch, but not start to feel symptoms until the evening. If you’ve eaten dinner in the meantime, this delayed onset may give you the false impression that something in your dinner was the trigger food. As a result, many people find it difficult to pinpoint their food intolerances.

While food intolerances can have a major impact on a person’s quality of life, they aren’t a critical medical emergency.

If you believe you may have a food allergy or intolerance, talk to your doctor about your symptoms.

FoodMarble is a pocket-sized breath analysis device. It helps people with chronic digestive issues determine the foods that work best with their digestive system. To learn more about FoodMarble, visit

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