Food intolerance is a condition where you experience difficulty digesting certain foods, leading to unpleasant physical reactions.

Food Intolerance

Understanding Food Intolerance


The primary cause of food intolerance is the digestive system’s inability to handle certain components of foods. This can be due to:

  1. Enzyme Deficiencies: The most common example of this deficiency is lactose intolerance, where the body lacks lactase, the enzyme needed to digest lactose found in dairy products.
  2. Chemical Sensitivities: Sensitivity to chemicals in foods such as caffeine or artificial additives can provoke symptoms.
  3. Irritable Bowel Syndrome (IBS): People suffering from IBS may have trigger foods that exacerbate their symptoms, even though these foods are not harmful to most people.
  4. Histamine Intolerance: Some people have trouble breaking down histamine, a chemical that occurs naturally in certain foods.

General Symptoms of Food Intolerance

Symptoms of an intolerance to any specific food can vary widely, but generally affect the digestive system. Common symptoms include:

  • Stomach pain
  • Gas, bloating, or indigestion
  • Diarrhea
  • Headaches
  • Nausea
  • Fatigue

Symptoms can appear hours or even days after consuming the offending food, which can make the diagnosis of food intolerance challenging.

It is important to differentiate food intolerance from food allergies, which involve the immune system and can be more severe.

Food Intolerance Explained

1. Enzyme Deficiencies

Enzyme deficiencies play a significant role in various types of food intolerances, impacting how the body processes and digests certain foods.

While lactase deficiency is one of the most commonly recognized forms, there are other enzyme deficiencies that can affect digestion and overall health. Below, we are some of these less commonly discussed enzyme deficiencies:

→ Sucrase-Isomaltase Deficiency

Enzymes Involved: Sucrase and isomaltase Primary Function: These enzymes are crucial for the digestion of sucrose (table sugar) and some starches into simpler sugars that the body can absorb. Symptoms of Deficiency:

  • Diarrhea
  • Bloating
  • Stomach cramps
  • Gas

Management: People with sucrase-isomaltase deficiency often benefit from a diet low in sucrose and certain starches. They may also use enzyme replacement therapies to aid digestion.

→  Alpha-galactosidase Deficiency

Enzyme Involved: Alpha-galactosidase Primary Function: This enzyme helps break down complex sugars found in legumes (like beans and lentils) and certain vegetables into simpler sugars. Symptoms of Deficiency:

  • Gas
  • Bloating
  • Discomfort after eating foods rich in galactooligosaccharides

Management: Over-the-counter products containing the alpha-galactosidase enzyme can help manage symptoms, and dietary adjustments may be necessary.

→ Pancreatic Enzyme Deficiency

Enzymes Involved: A group of enzymes including amylase, lipase, and proteases Primary Function: These enzymes, produced in the pancreas, are essential for the digestion of fats, proteins, and carbohydrates. Symptoms of Deficiency:

  • Weight loss
  • Diarrhea
  • Fatty stools (steatorrhea)
  • Nutritional deficiencies

Management: Pancreatic enzyme replacement therapy (PERT) is commonly used to treat this deficiency. It involves taking these enzymes in pill form with meals.

→ Maltase Deficiency

Enzyme Involved: Maltase Primary Function: Maltase breaks down maltose, a sugar found in grains, into glucose molecules. Symptoms of Deficiency:

  • Diarrhea
  • Abdominal pain
  • Bloating after consuming grains

Management: Avoiding foods high in maltose or supplementing with digestive enzymes can help manage symptoms.

→ Congenital Lactase Deficiency

Enzyme Involved: Lactase (different from lactose intolerance) Primary Function: Lactase breaks down lactose in milk. Congenital lactase deficiency is a rare condition where newborns lack lactase from birth. Symptoms of Deficiency:

  • Diarrhea
  • Failure to thrive
  • Dehydration

Management: Infants with this condition require lactose-free infant formulas.

→ Conclusion

Enzyme deficiencies can vary widely in terms of their effects on the body and the specific foods that trigger symptoms. Understanding these different conditions can help individuals tailor their diets to avoid discomfort and promote better digestive health.

If you suspect that you might have an enzyme deficiency, it is important to consult with a healthcare provider who can offer diagnosis and management strategies specific to your needs.

2. Chemical sensitivities

Chemical sensitivities related to food involve adverse reactions to certain chemicals found in foods and drinks that are not caused by the immune system (unlike food allergies). These sensitivities can affect various systems in the body, leading to a range of symptoms that often impact digestion, mood, and overall well-being.

Here are some common chemical sensitivities, including but not limited to caffeine:

→ Caffeine Sensitivity

Chemical Involved: Caffeine Overview: Caffeine sensitivity varies greatly among individuals due to differences in how quickly the body metabolizes caffeine. Symptoms:

  • Jitters
  • Insomnia
  • Heart palpitations
  • Anxiety
  • Gastrointestinal disturbances

Management: Those who are sensitive to caffeine may need to limit or avoid caffeine-containing beverages and foods, such as coffee, tea, chocolate, and some sodas.

→ Monosodium Glutamate (MSG) Sensitivity

Chemical Involved: Monosodium Glutamate Overview: MSG is a flavor enhancer commonly added to food products like soups, processed meats, and fast foods. Symptoms:

  • Headache
  • Flushing
  • Sweating
  • Facial pressure or tightness
  • Numbness, tingling or burning in the face, neck and other areas

Management: Avoiding MSG in foods by reading labels and asking about ingredients at restaurants can help manage symptoms.

→ Salicylate Sensitivity

Chemical Involved: Salicylates (a group of plant chemicals found naturally in many fruits, vegetables, and spices) Overview: Some people are sensitive to salicylates and may react even to the small amounts found in food. Symptoms:

  • Hives
  • Itchy skin or rashes
  • Asthma symptoms
  • Gastrointestinal symptoms
  • Nasal congestion

Management: Following a low-salicylate diet can help reduce symptoms, which involves avoiding high-salicylate foods like berries, tomatoes, and almonds.

→ Sulfite Sensitivity

Chemical Involved: Sulfites Overview: Sulfites are preservatives used in dried fruits, bottled wine, and some condiments. Symptoms:

  • Wheezing
  • Chest tightness
  • Hives
  • Diarrhea
  • Stomach cramps

Management: People sensitive to sulfites should avoid foods and drinks containing these additives. Reading labels and asking about food preparation when dining out are key strategies.

→ Histamine Intolerance

Chemical Involved: Histamine Overview: Histamine is naturally present in certain aged and fermented foods. Some people lack enough of the enzyme (diamine oxidase) needed to break down histamine. Symptoms:

  • Headache
  • Nasal congestion
  • Hives
  • Digestive issues
  • Irritability or anxiety

Management: A low-histamine diet, which includes avoiding foods like aged cheeses, smoked meats, and alcoholic beverages, can be beneficial.

→ Conclusion

Managing chemical sensitivities involves a combination of recognizing the offending chemicals, avoiding foods and drinks containing them, and, in some cases, taking medications to alleviate symptoms.

Since the degree and type of sensitivity can vary greatly from person to person, it is often helpful to work with a healthcare professional or a dietitian to develop a personalized management plan. This approach can help reduce symptoms and improve quality of life for those affected by food-related chemical sensitivities.

3. Irritable Bowel Syndrome (IBS)

Irritable Bowel Syndrome (IBS) is a common gastrointestinal disorder that affects the large intestine.  Symptoms can be exacerbated by certain foods or beverages, commonly referred to as “trigger foods.” Identifying and avoiding these triggers can be a crucial step in managing IBS symptoms.

→ Understanding IBS and Trigger Foods

Common IBS Symptoms

    • Abdominal pain or cramping
    • Bloating and gas
    • Diarrhea, constipation, or alternating between the two
    • Mucus in the stool

Factors That Exacerbate IBS

While the exact cause of IBS is not fully understood, a combination of physical and mental health issues may contribute to condition flare-ups. These can include:

    • Muscle contractions in the intestine
    • Abnormalities in the nervous system
    • Inflammation in the intestines
    • Severe infection or a surplus of bacteria in the intestines
    • Changes in gut microbes (like bacteria, fungi, and viruses)

→ Common IBS Trigger Foods

Managing IBS often involves avoiding foods and drinks that trigger symptoms. Here’s a breakdown of common IBS trigger foods:

1. High FODMAP Foods

FODMAPs (Fermentable Oligo-, Di-, Monosaccharides And Polyols) are short-chain carbohydrates that are poorly absorbed in the intestines and can cause excessive water and gas production, leading to pain, gas, and diarrhea.

High FODMAP foods include:

    • Certain fruits such as apples, pears, and cherries
    • Certain vegetables such as onions, garlic, and cauliflower
    • Dairy products that contain lactose
    • Wheat and rye products
    • Legumes and pulses

2. Gluten

Gluten can be a trigger for some individuals with IBS, even without celiac disease.

Gluten-containing foods:

    • Wheat-based products like bread and pasta
    • Rye, barley, and triticale

3. Dairy Products

Dairy can be problematic for individuals with IBS due to lactose intolerance.

Common problematic dairy products include:

    • Milk
    • Cheese
    • Ice cream

4. Fried and Fatty Foods

High-fat meals can cause contractions of the colon, which might lead to or worsen diarrhea in some IBS sufferers.

5. Caffeine

Caffeine can stimulate the intestines and exacerbate diarrhea, a common IBS symptom.

6. Artificial Sweeteners

Sweeteners like sorbitol and mannitol can cause diarrhea and worsen IBS symptoms.

7. Alcohol

Alcohol can irritate the gut and can cause IBS symptoms to flare.

8. Beans and Legumes

These are high in fiber and can produce significant amounts of gas, leading to discomfort and bloating in IBS patients.

9. Spicy Foods

Spicy foods can irritate the intestines, leading to discomfort in some people with IBS.

10. Processed Foods

These often contain ingredients like xanthan gum or carrageenan that can trigger IBS symptoms.

→ Managing IBS with Diet

A key strategy for managing IBS is the implementation of a tailored diet plan to help reduce symptoms:

  • Low FODMAP Diet: Temporarily reducing the intake of high FODMAP foods to see if symptoms improve.
  • Gluten-Free Diet: Trying a gluten-free diet can help identify if gluten is a trigger.
  • Lactose-Free Options: Switching to lactose-free dairy or plant-based alternatives.
  • Eating Regularly: Eating smaller, regular meals can help reduce the incidence of cramps and diarrhea.

→ Conclusion

IBS is a complex condition that can be significantly influenced by diet. Identifying and avoiding personal trigger foods is an effective way to manage symptoms and improve quality of life for those suffering from IBS.

Again, it’s important to work with a healthcare professional or a dietitian to ensure nutritional needs are met while managing food triggers effectively.

4. Histamine intolerance

Histamine intolerance occurs when there’s a buildup of histamine in the body because the body can’t break it down sufficiently. This imbalance is often due to a deficiency in an enzyme called diamine oxidase (DAO), which is primarily responsible for breaking down histamine ingested through food.

→ Understanding Histamine and Histamine Intolerance

What is Histamine?

Histamine is a chemical involved in your immune system, proper digestion, and your central nervous system’s functioning. It is also a component of stomach acid, which helps break down food in the stomach. While histamine is necessary for health, too much histamine can cause a variety of symptoms.

Causes of Histamine Intolerance

  • Enzyme Deficiency: The primary cause is usually a deficiency in DAO, the enzyme that breaks down histamine.
  • Gastrointestinal Disorders: Conditions like Crohn’s disease or IBS can reduce DAO activity.
  • Medications: Some medications can inhibit DAO function or trigger histamine release.
  • High Histamine Foods: Consuming a lot of histamine-rich foods can exacerbate symptoms.

Symptoms of Histamine Intolerance

Symptoms can vary widely but may include:

  • Headaches or migraines
  • Nasal congestion or sinus issues
  • Fatigue
  • Hives
  • Digestive issues
  • Irregular menstrual cycle
  • Nausea
  • Vomiting

These symptoms often appear like an allergic reaction and can be mistaken for allergies.


Diagnosis typically involves:

  • Medical History: Assessing symptoms and dietary habits.
  • Elimination Diet: Removing high-histamine foods to see if symptoms improve.
  • Blood Tests: Checking levels of DAO in the blood or histamine levels can provide further clues.

→ Foods High in Histamine

Managing histamine intolerance often involves avoiding foods that are known to be high in histamine:

  • Aged cheeses
  • Smoked meats
  • Fermented foods (sauerkraut, kombucha, soy sauce)
  • Alcoholic beverages, especially wine and beer
  • Vinegar
  • Processed meats

→ Management of Histamine Intolerance

  • Diet Modification: Avoiding foods high in histamine and adopting a low-histamine diet are typically recommended.
  • DAO Supplements: These can help some people manage their symptoms by providing the enzyme needed to break down histamine.
  • Medications: Antihistamines can reduce symptoms, although they do not address the underlying issue of enzyme deficiency.
  • Lifestyle Changes: Reducing stress and avoiding medications that interfere with histamine metabolism may also help.

→ Conclusion

Histamine intolerance can significantly affect quality of life due to its wide range of symptoms and often being misdiagnosed as other allergic conditions.

Of course, if you suspect you have histamine intolerance, it’s important to consult with healthcare providers who can help diagnose and manage the condition through dietary changes, lifestyle adjustments, and possibly supplements or medications.

By carefully managing your diet and lifestyle, you can minimize the impact of histamine intolerance and improve your overall well-being.


Diagnosing food intolerance often starts with keeping a detailed food diary to track what you eat and any symptoms that follow. Other methods include:

  • Elimination Diet: This involves removing foods suspected of causing symptoms from the diet and then gradually reintroducing them to see if symptoms reappear.
  • Breath Tests: Used primarily to diagnose lactose intolerance and fructose intolerance.
  • Blood Tests: Although not as commonly used for food intolerances (more for allergies), they can help rule out other conditions.


Managing food intolerance primarily involves avoiding the trigger foods or reducing their intake to levels that the body can handle without symptoms. In some cases, supplements can help:

  • Enzyme Supplements: For instance, people with lactose intolerance might take lactase supplements. (Like these)
  • Probiotics: These can help enhance digestion and reduce symptoms of food intolerance. (Like these)


Food intolerance is a manageable condition with the right diet and lifestyle adjustments.

If you suspect you have a food intolerance, consider consulting a healthcare professional for testing and advice on managing your diet. This can greatly improve your quality of life by alleviating uncomfortable symptoms associated with eating certain foods.

Eat Well!