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Food Intolerances, Sensitivities and Allergies: What’s the Difference?

Food Intolerances, Sensitivities and Allergies: What’s the Difference?

Jul 7, 2022

Symptoms of food intolerances, sensitivities and allergies can look similar, but they’re three distinct responses to food. Understanding these differences can equip you to handle how certain foods affect your body. 

Food intolerance

“Food intolerance is the inability to digest or process certain foods, resulting in unpleasant gastrointestinal reactions,” said Jill Darminio, Lead Registered Dietitian at Inspira Medical Center Vineland. “The most common of these is lactose intolerance.” Food intolerance symptoms are inconvenient and uncomfortable, but they’re not life-threatening. They usually show up within a few hours of consumption and may include the following: 

  • Bloating and gas
  • Diarrhea
  • Stomach pain
  • Heartburn
  • Nausea 

Food sensitivities

Food sensitivities appear to be an immune reaction due to exposure to a food or ingredient, such as gluten. The body doesn’t always respond to food sensitivities right away, and it may take up to three days for symptoms to appear. Symptoms of food sensitivities may include: 

  • Flushed skin
  • Stuffy or runny nose
  • Sneezing 
  • Itchiness
  • Muscle pain or fatigue 
  • Headaches, migraines or brain fog 
  • Stomach pain or bloating 

Food allergies

“A food allergy is when your immune system mistakes an ingredient or type of food for a harmful substance,” said Darminio. “When this happens, your body produces chemicals to fight the perceived threat.” This immune response causes symptoms such as a runny nose or itchy, watery eyes. The body’s response is immediate, and symptoms usually occur within 30 minutes to 2 hours.

The following foods account for about 90 percent of all allergic reactions: 

  • Fish
  • Shellfish
  • Eggs
  • Soy
  • Tree nuts
  • Peanuts
  • Milk
  • Wheat


In some people, allergic reactions are more severe and can even be fatal. In these cases, ingesting or touching a small amount of the allergen can lead to a rapid, acute reaction called anaphylaxis. Anaphylaxis usually starts with extreme itchiness on the face or in the eyes. Within a few minutes, the following symptoms may also occur: 

  • Difficulty swallowing 
  • Swelling of the tongue, lips or throat 
  • Shortness of breath or wheezing
  • A red rash or hives 
  • Abnormal stomach pain, cramps, diarrhea or vomiting 
  • Tightness in the chest 

Anaphylaxis symptoms typically occur within 5 to 30 minutes. “If you notice the warning signs of anaphylaxis, it’s vital to seek medical help immediately or take your prescribed allergy medication,” said Darminio. “Failure to do so can result in more severe symptoms, such as a drop in blood pressure, increased heart rate or unconsciousness.”

Seeking medical care

Your doctor can help you determine if you have an allergy, intolerance or sensitivity. Allergy skin testing can help pinpoint the body’s reaction to an allergic substance, but more information is often needed. Your doctor may recommend a food diary to help you link your symptoms to specific foods. Another option is an elimination diet, which can help narrow down which foods cause discomfort. 

At Inspira, our experienced providers work alongside you to develop a plan that works.

Inspira Health is a high reliability organization (HRO), which means safety is the top priority for patients and staff. To make an appointment, call 1-800-INSPIRA.

Topics: Nutrition, Gastroenterology