Food Sensitivity vs. Food Allergy: Key Differences

Food sensitivity or food intolerance can cause significant stress on your day-to-day life and overall well-being. You may not be able to eat your favorite foods without side effects or may feel nervous about eating in restaurants. While most food sensitivity or food intolerance symptoms in adults range from mild to moderate, food allergy symptoms can be severe — and in some cases, life-threatening.

If you suspect that you are having reactions to a specific food, determining whether you have a food allergy is vital to ensuring your safety, health, and quality of life.

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

What is a Food Sensitivity or an 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 a stuffy nose.

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 ingest or digest 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 from a gastroenterologist or a consultation with a specialized nutritionist may be helpful in understanding the causes, symptoms, and solutions for IBS.

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 That May Cause Reactions to Food

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 is the Difference Between Food Sensitivity/Intolerance and Food Allergy?

The difference between a food sensitivity and a true food allergy is not always clear, as some symptoms may be shared. There are two key characteristics to keep in mind when diagnosing a food sensitivity:

    • Sensitivities often trigger a reaction in the digestive system or gastrointestinal tract, leading to various forms of stomach upset and discomfort.
    • With a food sensitivity, small amounts can usually be consumed without causing symptoms.

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, a food allergy 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.

The crucial difference between a food sensitivity and a food allergy is that 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 for those with diagnosed food allergies, is to create an anaphylaxis treatment plan for family members and friends to enable quick action in case of accidental contact or ingestion. Talking to a board certified allergist can help you determine if what you are experiencing is a food sensitivity, or something more serious.

How is Food Intolerance/Sensitivity Diagnosed?

Currently, there are no reliable or proven diagnostic tests for food sensitivities or intolerances — as highlighted in this story on The Today Show. However, a board certified allergist can determine if testing for food allergy would be helpful to rule out the potential of a life-threatening issue, identify whether referral to another specialist could be relevant, or recommend an elimination diet guided by a registered dietitian.

How Food Allergy is Diagnosed

If you are experiencing symptoms of a food allergy such as hives, swelling, or breathing issues, the gold standard approach to diagnose a food allergy includes four important steps. These steps begin with a full clinical history — what happens when a person ingests the suspected food either intentionally or accidentally. The next steps to test for a food allergy include skin prick testing and blood tests measuring specific IgE antibodies. After a full review of patient history and testing, if the clinician determines that a patient is likely to be able to eat the food safely, an oral food challenge may be recommended.

What if Symptoms are Related to Another Medical Issue

A food allergy specialist may determine that symptoms are not specific to a certain food, but instead could indicate another underlying medical issue. There are auto-immune diseases, gastroenterology and skin disorders that can all have symptoms that may mimic a food sensitivity. A food allergy specialist can provide a referral to another specialist, such as a gastroenterologist, a dermatologist, or a general allergist.

How Can Nutrition Counseling Help Diagnose Sensitivities

An elimination diet, where one or more foods is temporarily removed from the diet, can be a powerful diagnostic tool to help identify food triggers for certain food sensitivities. However, undertaking an elimination diet without proper guidance of a trained clinician can put you at risk of nutrient deficiencies, difficult to adhere to rules, and unclear results. A registered dietitian experienced in elimination diets can guide you through this process safely and effectively to best diagnose and manage a food sensitivity.

Do At-Home Food Sensitivity 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 — which are often sold to diagnose food sensitivities — typically look for IgG antibodies. 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. Relying on non-standardized test results can lead to unnecessary avoidance of foods or misdiagnosing broader health issues, 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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