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Understanding Food Intolerances (February 2024)

Food Allergies vs. Food Intolerances

Food intolerances differ greatly to food allergies. 33 million Americans have a food allergy, and every 10 seconds, a person is sent to the emergency room after being exposed to a food allergen. Having a food tolerance is much less severe, and people often suffer from them on a daily basis without life-threatening consequences. From stomachaches, changes in bowel movements and gurgling sounds, to skin rashes, brain fog and heart palpitations, let’s discuss the differences between a food intolerance and a food allergy.

Food Allergies

A food allergy appears systemically and can be life threatening when anaphylaxis occurs. Anaphylaxis affects the respiratory and nervous system when exposed to a food allergen. The throat can close, which cuts off oxygen supply, and rashes can form on the skin. It also dramatically decreases blood pressure and increases heart rate. These are severe symptoms that typically go into effect immediately, but can sometimes take up to 30 minutes to experience. For more information, check out the Food Allergy and Anaphylaxis Emergency Care Plan. The top nine food allergens are wheat, egg, milk, peanuts, tree nuts, soy, sesame, shellfish and fish.

The gut is the first line of defense when someone is exposed to an offending food, because immunity is stored in the gut. If the gut is not strong, a person is likely to experience discomfort from eating certain foods. When the gut barrier isn’t strong enough, proteins from food (on a microscopic level) will enter into the bloodstream, which can cause food allergy symptoms and anaphylaxis.

Food Intolerances

A food intolerance occurs on the gut level, meaning the person has trouble digesting the food to be absorbed and assimilated by the body. This can occur due to hypochlorhydria (being stressed at mealtime), drinking too much liquid at mealtime, eating too large of a meal, being constipated, etc.

Sufferers often experience symptoms like gas, bloating, constipation, diarrhea, stomach discomfort, or the general feeling of being ‘off’. These symptoms are not life threatening, and usually are a matter of discomfort rather than a severe condition. Sometimes, the sufferer can experience weight gain, weight loss retention, fluid retention, sinus problems and more.

Common Symptoms of Food Intolerances

  • Fatigue
  • Bloating
  • Throat Mucus
  • Constipation
  • Acne
  • Headache and Migraine
  • Psoriasis and Eczema
  • Diarrhea
  • Impaired Weight Loss
  • Joint Pain
  • Brain Fog
  • Nausea

Food intolerances can occur at any time, with any food, outside of the top nine allergens. This can include (but is not limited to) pineapple, black pepper, tomatoes, chicken breast, cumin powder, mint leaves, etc. Intolerances can occur due to a number of different reasons, like chronic stress, illness, a weakened digestive system or overconsumption of a particular food for a period of time.

Types of Food That Commonly Cause Food Intolerances

  • Dairy
  • Gluten
  • Grains
  • Nuts/Seeds
  • Yeast
  • Soy
  • Caffeine
  • Sugar
  • Citrus Fruits
  • Eggs (yolks and whites may cause differing sensitivities, so re-introduce separately)
  • Nightshades (including tomatoes, potatoes, eggplant and peppers)
  • Processed Foods (containing artificial colors, additives and preservatives such as MSG, soy and benzoates)

How To Determine if You Have a Food Intolerance

  1. Assess what foods may be contributing to uncomfortable symptoms. Many people start with gluten or dairy, as these are major culprits of digestive issues.
  2. Remove the potential offending food from your diet for one to two weeks and take notes of how you feel over this period of time. Remove only one food at a time.
  3. After the removal period ends, reintroduce that food back into your diet and eat a small portion consecutively for three days. It can take the digestive system this long to see any reaction.
  4. If you notice returning symptoms, you are likely intolerant to that food. Remove entirely for a few months and reintroduce later. Reassess in the same manner above for changes.
  5. If you want to try again with another food, allow yourself to become symptom-free before doing this process again with the next food.
  6. Following a low FODMAP diet may also be helpful. Please contact the dietitian for more information on this diet.

What Not To Do if You Are Intolerant to a Food

  1. Don't assume you’ll never be able to eat this food again. Intolerance to foods is not the same thing as being allergic to food. In fact, the stricter and more limited our diet, the more likely we’ll become intolerant to foods. Intolerance means that a certain food isn’t digesting well in your body at present. But because there are so many reasons for this, it’s best to periodically reintroduce the intolerant food to see if it becomes tolerable.
  2. Don’t declare to others that avoiding a particular food is the healthiest. We are all different and require so many different nutrients for our own unique physiology. What works for you may not work for someone else, and vice versa.
  3. Don’t ignore symptoms. Our bodies are talking to us all day, every day. We tend to ignore most of them, and this is when we have issues. If we experience skin rashes, acne, stomach pain, gas, bloating, etc., it’s our body’s way of alerting us that something is not right.
  4. Don’t rule out underlying causes of a food intolerance. I often see stress as a major factor when a person is unable to digest some foods. If you’re experiencing stress or have had a viral infection recently, focus on managing your stress and overall health first.

If you’d like to discuss your symptoms, please request dietitian services.