When what you eat eats you from the inside. Part 2 Food Intolerance


What Are Food Intolerances?

Well, it’s first important to understand that a food intolerance is NOT the same as a food allergy. To read about food allergies see part 1 of this series. 

Food allergies are reactions to food that trigger the immune system. On the other hand, food intolerances are reactions to food that do not initiate an immune response.

Causes of Food Intolerances

Enzyme deficiencies and digestive dysfunction are the most common causes of food intolerances. Let’s take a closer look…

Enzyme Deficiencies

Different types of enzymes are necessary to successfully digest some substances in food. And if your body lacks a specific enzyme, then you may react to a certain substance.

For example, lactase is an enzyme that breaks down lactose (a sugar) found in dairy products. Thus, those suffering from lactose intolerance simply lack the enzyme lactase. Symptoms then arise from the inability to properly digest lactose.

In addition, some people may lack an enzyme known as diamine oxidase, which is responsible for breaking down histamines naturally found in food. Thus, they may experience unpleasant symptoms when they consume foods high in histamine (i.e., fish, cheese, and fermented foods).

Digestive Dysfunction and Disorders

Two of the main responsibilities of the digestive tract are to neutralize potential threats and digest food into their basic components. But if you’re digestive system is not functioning properly, you’re more likely to experience reactions from the food you ingest. Thus, the health of your gut highly influences how your body reacts to food.

Gut infections, bacterial imbalances, and intestinal permeability (leaky gut) are just some of the digestive related conditions that may trigger food intolerances.

One specific example of an intolerance due to digestive dysfunction is known as fructose intolerance (or malabsorption). Fructose is a type of sugar naturally found in fruit as well as highly refined sugars, such as agave nectar and high fructose corn syrup.

For one reason or another, some people are unable to fully absorb fructose. Thus, it remains in the digestive tract and eventually begins to ferment. And the fermentation process typically causes uncomfortable gas and bloating.

Signs & Symptoms of Food Intolerances

Food intolerances typically cause delayed reactions as opposed to allergic reactions that usually occur within two to four hours. Thus, food intolerances are often more difficult to diagnose.

The most common signs and symptoms of food intolerances include:

  • Gas
  • Bloating
  • Fatigue
  • Diarrhea
  • Constipation
  • Abdominal pain

In addition, the frequency and severity of symptoms may fluctuate. As previously mentioned, gut health is a big factor. And sometimes the dose matters. Maybe you can tolerate a small dose of an offending food, but you react when that food is consumed in larger quantities.

It’s also worth noting that while these symptoms are not life threatening, they can severely (and often do) impact your sense of well-being and quality of life. Thus, diagnosis and treatment is critical to achieving optimal health.

Food Intolerances and Irritable Bowel Syndrome

Food intolerances share many of the same symptoms of irritable bowel syndrome (IBS), which include gas, bloating, constipation, diarrhea, and abdominal pain.

And IBS is typically diagnosed when all other intestinal disorders are ruled out. Thus, it’s extremely possible that food intolerances are an underlying factor. Especially since most medical doctors only test for food allergies.

So…if you’ve been diagnosed with IBS (as 15% of the U.S. population has), set up a free 15 minute chat with me to see if I can help you get your life back by identifying offending foods. 

Common Food Offenders

You can be intolerant to any food for a variety of reasons. And some of the most common food allergens are also known to cause non-immune related reactions, which include:

  • Dairy
  • Fructose

What are FODMAPs?  

FODMAPs stand for fermentable oligo-, di-, and monosaccharides and polyols. In laymen terms, this means fermentable carbohydrates.


For some, FODMAPs are poorly absorbed by the small intestine. Thus, similar to fructose, they remain in the digestive tract where they are fermented by gut bacteria.

Examples of FODMAPs include specific carbohydrates found in:

  • Wheat
  • Garlic
  • Onions
  • Legumes
  • Seeds
  • Dairy
  • Fruit
  • Sweeteners (natural and artificial)

How to Identify Problematic Foods

One of the best ways to identify problematic foods is by keeping a food journal. Essentially, you’ll need to start tracking the foods you’re eating and how they make you feel.

Maybe you’ll notice that you feel bloated when you drink milk. Or, that fruit gives you gas.

Another option is to consider implementing a low FODMAP diet. Essentially this means limited your consumption of foods with high concentrations of fermentable carbohydrates. If your symptoms improve, it may be a sign that FODMAPs are problematic for you.

Finally, if you suspect dairy is a source of your digestive distress, there is a lactose intolerance test known as the hydrogen breath test. After consuming a solution containing lactose, the test measures the amount of hydrogen in your breath over the course of several hours.

If you’re successfully able to digest lactose, your hydrogen breath levels will be low. On the other hand, if lactose remains in your digestive tract, the fermentation process releases gas as well as hydrogen. Thus, if your hydrogen levels are high, it may be a sign of lactose intolerance.


Generally, it is recommended to avoid problematic foods. However, gut-healing protocols are often put into place as well. And once the gut heals, you may be able to tolerant small doses of certain foods again.

In Conclusion

Food intolerances are:

  • reactions to food that do not involve the immune system;
  • most often related to enzyme deficiencies and digestive dysfunction
  • difficult to diagnose because symptoms are delayed and not always consistent;
  • best identified by journaling your food intake and symptoms; and
  • treatment often involves the elimination of offending foods as well as gut healing protocols.

[clickToTweet tweet=”Could food intolerances be at the root of your health concerns? ” quote=”Could food intolerances be at the root of your health concerns? “]Come join the discussion on my private Facebook group (The Eat.Nourish.Thrive Collective) to learn more and get all your questions answered.

References[social_warfare buttons=”Facebook, Twitter, Pinterest “]

Hayes, P. A., et al. (2014). Irritable Bowel Syndrome: The Role of Food in Pathogenesis and Management. Gastroenterology & Hepatology10(3), 164–174.

Manzotti, G., et al. (2016). Serum diamine oxidase activity in patients with histamine intolerance. International Journal of Immunopathology and Pharmacology,29(1), 105-111. doi:10.1177/0394632015617170

Pasqui, F., et al. (2015). Adverse food reaction and functional gastrointestinal disorders: role of the dietetic approach. Journal of Gastrointestinal and Liver Diseases,24(3). doi:10.15403/jgld.2014.1121.243.paq

Ross, E., et al. (2016). The Low FODMAPS Diet and IBS: A Winning Strategy. Journal of Clinical Nutrition & Dietetics,02(01). doi:10.4172/2472-1921.100013

Turnbull, J. L., et al. (2014). Review article: the diagnosis and management of food allergy and food intolerances. Alimentary Pharmacology & Therapeutics,41(1), 3-25. doi:10.1111/apt.12984

Zopf, Y., et al. (2009). The Differential Diagnosis of Food Intolerance. Deutsches Ärzteblatt International106(21), 359–370. http://doi.org/10.3238/arztebl.2009.0359



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