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The Top 5 Food Sensitivities and Intolerances You Will See in Your Practice

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The Top 5 Food Sensitivities and Intolerances You Will See in Your Practice

Food sensitivities and intolerances are common conditions that can significantly impact quality of life and overall health. While many food sensitivities and intolerances can exist, some of the most common include lactose, gluten, histamine, fructose, and FODMAPs.

While enzyme replacement can be helpful in some intolerances, dietary management including eliminating the offending agent is required in virtually all cases. Adhering to the necessary long-term dietary modifications requires targeted patient education and collaboration between the patient and healthcare providers to ensure successful treatment.


Understanding Food Sensitivities and Intolerances

Food sensitivities and intolerances occur when patients react adversely to certain foods or ingredients. They differ from food allergies, which involve an exaggerated immune response leading to severe symptoms such as hives or anaphylaxis. 

Sensitivities and intolerances occur from a direct response within the gastrointestinal tract, like abnormal digestive factors, enzyme deficiencies, or other conditions. Sensitivities may involve a delayed response, making them more challenging to diagnose. 

While food allergies necessitate complete avoidance of the offending agents, patients with intolerances and sensitivities may be able to tolerate them in small amounts.

Symptoms and Effects 

Common symptoms of food sensitivities and intolerances may include the following:

  • Bloating
  • Abdominal pain
  • Diarrhea
  • Constipation
  • Headaches
  • Skin rash

The Top 5 Common Food Sensitivities and Intolerances

While individuals can have a sensitivity or intolerance to any food, here are the top 5 most common ones that you will see in practice:

Lactose Intolerance 

Lactose intolerance results from deficient lactase levels, an enzyme that breaks down lactose, a sugar in milk and dairy products. It affects at least 65% of the global population, although the prevalence does vary, with some ethnicities at a higher risk. 

The diagnosis of lactose intolerance is made by clinical evaluation or may entail lactose tolerance tests or breath tests. Treatment of lactose intolerance hinges upon dietary modifications, including avoiding lactose or using supplemental lactase to assist digestion.

Gluten Sensitivity 

Non-celiac gluten sensitivity occurs when patients without celiac disease or gluten allergy experience adverse reactions to gluten. Common symptoms include diarrhea, abdominal pain, bloating, fatigue, headaches, and joint pain. Unlike gluten allergy, non-celiac gluten sensitivity does not involve autoimmune reactions or severe damage to the gut mucosa.

Making the diagnosis can be challenging. While positive results of some tests may increase the likelihood that gluten sensitivity is present, there are no definitive diagnostic laboratory tests. Making the diagnosis requires noting symptom resolution with a gluten-free diet. 

Treatment of gluten sensitivity requires avoidance of gluten-containing foods, such as wheat, barley, rye, malt, farro, and others. Gluten is often hidden in processed foods, so reading labels on food products and notifying restaurant staff of food intolerances is necessary when dining out.

Histamine Intolerance 

Histamine intolerance occurs when histamine levels are higher than the body's ability to break it down, often due to lower activity of the diamine oxidase (DAO) enzyme. Common symptoms of histamine intolerance are headaches, nasal congestion, itching, and gastrointestinal upset. 

Managing histamine intolerance hinges on dietary modifications. High-histamine foods like aged cheeses, processed meats, and fermented foods (like kombucha and sauerkraut), plus foods that release histamine (like citrus and acidic foods), are likely to worsen symptoms.

Fructose Malabsorption 

Fructose malabsorption is the inability to properly absorb fructose, a type of sugar, caused by an insufficient concentration of the fructose transporter enzyme in the small intestine. Common symptoms include bloating, abdominal pain, diarrhea, and flatulence, usually after consuming fructose-rich foods like fruits, honey, sweeteners, and high-fructose corn syrup. 

Managing fructose malabsorption involves limiting or avoiding foods high in fructose, like certain fruits, vegetables, and sweeteners, depending on each patient's tolerance level.

FODMAPs Sensitivity 

FODMAPs, an acronym for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, are carbohydrates that are poorly absorbed in the small intestine. As a result, they can ferment in the colon, leading to gas production and digestive discomfort. 

FODMAPs are known to exacerbate symptoms in patients with irritable bowel syndrome (IBS). The low-FODMAP diet aims to improve symptoms by eliminating the broad category of high-FODMAP foods, followed by gradual, individual reintroduction of each to identify individual triggers.

Examples of common high-FODMAP foods include:

  • Bread
  • Cereals
  • Legumes
  • Cherries
  • Pears
  • Garlic
  • Onion

Diagnosing Food Sensitivities and Intolerances

The first step towards diagnosing food sensitivities and intolerances requires a detailed history and clinical evaluation. Along with the signs and symptoms experienced, a food diary is necessary to identify possible connections.

Diagnostic Tests 

Diagnostic tests for lactose intolerance, fructose malabsorption, and FODMAP intolerances include hydrogen breath tests. These tests quantify hydrogen in breath samples after ingesting a food or ingredient. Elevated hydrogen levels are suggestive of malabsorption. 

Top Food Sensitivities and Intolerance Tests Ordered by Practitioners:

Elimination diets involve completely eliminating potentially aggravating foods or ingredients from the diet, often for at least 4 weeks. The food is then gradually reintroduced to evaluate for symptom recurrence. To ensure clear results, elimination diets should only be done with one food at a time.

Management and Treatment Strategies

The following management and treatment strategies can be helpful for your patients with food sensitivities:

Dietary Modifications 

Dietary modifications are the primary treatment for food sensitivities and intolerances. Eliminating the offending agent followed by slow reintroduction helps assess potential tolerance in small amounts. However, if symptoms recur after reintroducing the ingredient, the best management is to eliminate it entirely from the diet. 

Supplementation and Enzymes 

Supplements can help manage digestive disorders. Lactase enzyme supplements may help patients with lactose intolerance to digest lactose.

Diamine oxidase enzyme supplements can help reduce symptoms of histamine intolerance by enhancing histamine breakdown. 

Inulinase is an enzyme that is under development to help with fructose intolerance and other FODMAP sensitivities.

Patient Education 

Adhering to an appropriate diet for food sensitivities and intolerances involves reading food labels and recognizing hidden ingredients. For example, "high-fructose corn syrup" and "corn syrup" are the same ingredient, each containing fructose, which can be problematic in patients with fructose malabsorption. 

In addition, dining out can present a challenge, as you may be unaware of all the ingredients in various dishes. Be sure to discuss your dietary restrictions with the restaurant staff.

Long-Term Care and Monitoring

Adhering to a dietary management plan for food intolerances and sensitivities requires long-term commitment. However, intolerances and sensitivities may change over time, potentially allowing the reintroduction of certain foods and necessitating additional elimination diets to find other triggers. Utilizing a personalized care plan helps ensure the best control of symptoms and optimal well-being.


Key Takeaways

  • Common food sensitivities and intolerances are encountered regularly in clinical practice.
  • While they are often not associated with severe illnesses, they can significantly impact patients' quality of life. 
  • Using a comprehensive history, including symptoms, food intake, a thorough clinical evaluation, indicated diagnostic testing, and elimination diets, healthcare providers can gather the necessary information to diagnose food sensitivities and intolerances and create personalized care plans for effective treatment.
The information provided is not intended to be a substitute for professional medical advice. Always consult with your doctor or other qualified healthcare provider before taking any dietary supplement or making any changes to your diet or exercise routine.
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