Food Sensitivity vs. Food Allergy: Key Differences

Food sensitivity or food intolerance can cause significant stress on your day-to-day eating habits and your overall well-being. You may be unable to enjoy your favorite foods, severely limited in your grocery list, or even nervous about enjoying a meal at a restaurant. While most food sensitivity or food intolerance symptoms range from mild to moderate, food allergy symptoms can be severe — and in some cases, life-threatening. Determining whether you have a food allergy is crucial to ensuring your safety, health, and quality of life.

But how do you know if you are experiencing a food sensitivity or intolerance, or if you have a true food allergy? Symptoms can often overlap, and it’s important to know the difference between an allergy and an intolerance. In the sections below, we’ll outline the key traits of a food sensitivity/food intolerance to help highlight the differences from food allergies. 

What is a Food Sensitivity or Intolerance?

Often used interchangeably, a food sensitivity is synonymous to a food intolerance. An estimated 20 percent of the global population suffers from some form of food sensitivity/intolerance. Food intolerances primarily impact the digestive system, though they can also manifest in skin or respiratory issues such as rashes or breathing difficulty. 

A food intolerance may be caused by a variety of factors. Deficiencies in enzymes, sensitivities to certain food additives, environmental allergies, or even naturally occurring chemicals in foods can all contribute to the body’s inability to properly digest or safely come into contact with a certain food or ingredient. 

One of the most common forms of food sensitivity is lactose intolerance. Those who are lactose intolerant are unable to produce the enzyme lactase, which breaks down lactose (a sugar present in milk and diary). Lactose intolerance symptoms primarily involve the digestive system, resulting in gas, nausea, and abdominal pain.

Those who are gluten intolerant (non-celiac gluten sensitivity) are unable to properly digest wheat, barley, or rye, causing them to avoid foods such as cereals or breads. Symptoms of gluten intolerance can fall under a broad umbrella, ranging from bloating and constipation to joint pain and anemia. Depression and anxiety have even been linked to gluten intolerance. 

Irritable Bowel Syndrome (IBS) can be another common example of a food intolerance, although the role of food sensitivity and intolerance in IBS is not yet fully understood. Studies have shown that IBS flare-ups often worsen after consuming certain foods and beverages, such as wheat, dairy products, milk, and carbonated drinks. Interestingly, emerging evidence shows that IBS symptoms may in fact be triggered by an underlying intolerance. A thorough, expert diagnosis is crucial in understanding the causes, symptoms, and treatment.

Symptoms of Food Sensitivity/Intolerance

Symptoms of food sensitivity or intolerance can vary greatly from one patient to the next, depending on the type of sensitivity and the severity. The most common symptoms include: 

    • Gastrointestinal discomfort
    • Bloating
    • Stomach pain
    • Excess gas
    • Diarrhea
    • Vomiting
    • Nausea
    • Acid reflux/heartburn
    • Headaches
    • Skin flushing
    • Irritability or anxiety
    • Fatigue

Symptoms tend to increase as the amount of the food consumed increases. They may appear suddenly or over a matter of hours, in some cases lasting for days afterwards.

Other Conditions

Some people have adverse reactions to food from other health conditions, making it difficult to diagnose. Some examples of this include:

    • Eosinophilic Esophagitis (EoE) – inflammation in the esophagus, caused by a variety of factors
    • Food Protein Induced Enterocolitis Syndrome (FPIES) – a rare and potentially severe reaction to food proteins that causes delayed vomiting and diarrhea
    • Food Protein-Induced Allergic Proctocolitis (FPIAP) – a condition that presents in otherwise healthy infants with mucus or blood in the stool, most often triggered by milk or soy proteins in breast milk and generally resolves by 12 months
    • Celiac Disease – a genetically predisposed condition in which ingestion of gluten leads to damage in the small intestine
    • Eczema – causes itchy and rough skin due to a variety of factors
    • Oral Allergy Syndrome (OAS) — pollen associated food allergy syndrome, often due to a cross-reactivity between plant proteins from pollen and fruits or vegetables, rarely can trigger anaphylaxis
    • Food Dependent Exercise Induced Anaphylaxis (FDEIA) – certain foods are well tolerated unless ingested around excise, can trigger severe life threatening allergic reactions

What’s the Difference Between Food Sensitivity/Intolerance and Food Allergy?

The difference between a food sensitivity/intolerance and a true food allergy isn’t always clear, as some symptoms may be shared. There are two key characteristics to keep in mind when diagnosing a food sensitivity or intolerance: 

    • It often triggers a reaction in the digestive system or gastrointestinal tract, leading to various forms of stomach upset and discomfort. 
    • Small amounts can be consumed without causing life-threatening problems.

While certainly uncomfortable and disruptive in its own right, food sensitivity/intolerance is not life-threatening. A food sensitivity will not cause anaphylaxis, no matter how much of the offending food is consumed. Conversely, there are two defining characteristics that help distinguish a food allergy:

    • It triggers an immune system reaction, releasing antibodies (IgE) and causing the body to react as if to a threat.
    • Even small amounts may trigger serious or life-threatening reactions, such as anaphylaxis.

Food allergies can be extremely dangerous when left untreated or undiagnosed. A severe reaction, triggering anaphylaxis, may include constriction of the throat, difficulty breathing, rapid pulse, dizziness, or fainting. Without immediate treatment, anaphylaxis can be fatal. 

This is a crucial difference between a food intolerance and a food allergy: unlike food intolerances/sensitivities, food allergies can be life-threatening and those with a food allergy must carry two epinephrine autoinjectors (such as an EpiPen) at all times. A recommended best practice is to create an anaphylaxis treatment plan with family members and friends to enable quick action in case of accidental contact or ingestion. With severe and potentially life-threatening allergic reactions, any potential allergy must be properly diagnosed to determine whether it is a food intolerance/sensitivity or a true food allergy. 

How is Food Intolerance/Sensitivity Diagnosed?

In order to properly diagnose a food intolerance/sensitivity, it’s crucial to first determine whether a food allergy is present. The gold standard approach to determine if someone has a food allergy considers key information, gathered in four steps: 

Skin Prick Test

This is a safe and low-risk test in which the skin is lightly brushed with a suspected allergen. Most reactions appear as bumps or hives, with mild itchiness as the most common side effect that self resolves. Any skin reactions are closely observed and monitored by a clinician.

Blood Test

A blood test will measure the amounts of specific IgE antibodies that the immune system has deployed as a response to a suspected allergen. Once drawn, the blood is sent to a lab to be evaluated. Blood tests are safe for both infants and children, as well as adults. While the results of a skin prick test are immediate, the results from a blood test often take a few days.

Component Test

A component test is a form of a blood test that assesses whether a patient can tolerate certain components of a suspected allergen. This test provides heightened clarity to a clinician and pinpoints specific aspects that may be less harmful. For example, a component test may determine that you are allergic to a food in a certain form, but can safely tolerate it when it’s in another such as straight egg vs. baked egg. Reliable component testing is currently available for milk, egg, peanut, walnut, cashew, hazelnut and Brazil nut. 

Oral Food Challenge

This test is particularly useful as the final step when skin and blood tests are inconclusive. It can also aid in determining whether a previous allergen has been outgrown (such as a childhood allergy to milk and dairy products). An oral food challenge can determine, with certainty, whether a suspected allergen may safely be consumed. This step is only taken after a full review of patient history and only in cases where a clinician determines that a patient is likely to pass. Under close supervision and observation, the patient will consume very small amounts of the suspected allergen in increasingly larger amounts over a three- to four-hour time period.

Do At-Home Food Allergy Tests Work?

Simply put: no. The availability and convenience of these tests  may seem appealing, but you will not get reliable, accurate results. And for those with an undiagnosed food allergy, inaccurate results could be life-threatening. 

Non-standardized and at-home tests typically look for IgG antibodies to assess food allergies. These IgG antibodies are produced by your immune system and are based on memory: once you’ve consumed a certain food in the past, your body recognizes it and stores that memory in IgG antibodies — meaning if you have eaten a food before, it may unnecessarily show up as a positive result with IgG testing. Unfortunately, this is far from a dependable or accurate process when determining whether you have a food allergy. There is a reason that many of these tests are considered non-standardized and aren’t usually covered by insurance. Studies show that IgE antibodies are directly correlated to immune system responses from food allergies — not IgG.

A non-standardized test may be able to tell you if your body recognizes whether you’ve consumed a certain food in the past, but it won’t be able to tell you with certainty whether you have a true food allergy. Left undiagnosed, the consequences of coming into contact with or ingesting a food that you are allergic to can be severe, causing anaphylaxis and putting your life at risk. Relying on non-standardized test results can lead to unnecessary avoidance of foods, resulting in inadequate nutrition and overall decreased quality of life.

If you suspect that your food intolerance or sensitivity may be due to an allergy, the best next step is to make an appointment with a trained clinician who specializes in food allergy testing and diagnosis.

Are you or someone you love impacted by a food sensitivity/intolerance? Improve your quality of life and unlock a better future with Latitude Food Allergy Care. Latitude offers comprehensive food allergy care, including prevention, diagnosis, and treatment, for babies, children, and adults. Contact us today to schedule a no-obligation conversation with one of our Patient Care Coordinators.

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