Could this Be a True Food Allergy? Recognizing the Signs and Symptoms

with Sayantani B Sindher, MD, and Jay A. Lieberman, MD

Does your mouth, tongue, throat, or skin get itchy after you eat a certain food?  Do you get severe stomach cramps or hives? You just might have a true food allergy.

This is not to be confused with a food intolerance or a food insensitivity, which are often lumped together with food-related allergies. The difference is that a food allergy is a physical response to an IgE-mediated immune reaction. The body essentially views the food as an invader, prompting a protective reaction in which histamine is released in response to an offending food or food ingredient.

The five most common food allergies in order of frequency are: shellfish, peanuts, tree nuts, milk, and fin fish. 

Sorting Out Accurate Food Allergies from More Minor Reactions and Food Insensitivities

According to a recent cross-sectional survey of adults in the United States, nearly 11% of respondents say they have experienced a negative reaction to at least one food, and  nearly twice as many believe they had an allergy to a particular food or foods.1 Surprisingly, a group of Stanford University investigators believe that among adults who report having had at least one food allergy, approximately half of them developed this new reaction to food as an adult.

The survey was conducted using phone and online surveys to evaluate symptoms that would offer credible food allergy rates among adults;1 the findings were published in the Journal of the American Medical Association Network Open.

“Food allergies were considered to be convincing if the most severe reaction reported includes at least one symptom on the stringent symptom list developed by our expert panel,” according to the authors.

Stringent Symptoms Indicative of a Convincing Food Allergy1

  • Skin and Oral Symptoms: Hives/rash, Rash, Swelling, Difficulty Swallowing, Throat tingling 
  • Respiratory: Chest tightening, Trouble breathing, Wheezing
  • Gastrointestinal: Vomiting
  • Cardiovascular: Chest pain, Rapid heart rate, Light-headed or dizzy, Low blood pressure

The researchers found that credible food allergies occur nearly twice as often in woman as in men (13.8% versus 7.5%., respectively).1 And, individuals int their 30s have the highest prevalence of new onset food allergies, which the authors suggest offers a greater possibility that adults can outgrow a food allergy over time—with the exception of shellfish as people are least likely to overcome this food allergy.

Other groups that appear more vulnerable to developing food allergies as adults include non-white adults and adults who have asthma and/or eczema.

Is a Food Allergy Always Life-Threatening? 

“If it is not a genuine food allergy, then the reported reaction is not likely to become an issue of life or death, rather it may be an issue of quality of life,” says Sayantani B Sindher, MD, clinical assistant professor of medicine and pediatrics at the Sean N. Parker Center for Allergy and Asthma Research at Stanford University in California in Palo Alto.

This clinical assessment is not meant to undermine the impact of food intolerances or food insensitivities but is intended to differentiate food allergies from oral food reactions in order to emphasize then importance of accurate testing, Dr. Sindher tells EndocrineWeb.

According to the Stanford researchers,1 “approximately one-quarter of adults with food allergies possess a current epinephrine prescription.” Epinephrine is considered necessary to treat food-induced anaphylaxis, and is often life saving, and three-quarters of adults with a diagnosed food allergy do not have a prescription for an epi pen. The prevailing misunderstanding of food allergies can be dangerous, Dr. Sindher says.

Challenges of Managing a Food Allergy When Eating at a Restaurant

Since eating out presents a heightened challenge for anyone who has an allergy to a food (or foods), Adrian Loebroks, PhD, MSc, MSH, a senior researcher at the University of Düsseldorf in Germany and colleagues set out to learn how restaurant workers view customers who mention having a food allergy when placing their order.2 The investigators conducted 295 face-to-face interviews with restaurant staff from 15 randomly selected districts in Düsseldorf. 

They found that restaurant workers generally have a poor understanding of food allergies and this lack of knowledge manifests as a negative attitude towards people who mention a food allergy when placing their order;2 the full results appear in the journal PLOS One,

“Our shared ignorance and confusion around food allergies and intolerances can create a dangerously dismissive environment,” they say.

Swapping Out a Problem Food Isn’t So Straightforward or Obvious

A misdiagnosed food allergy can present further problems if you replace that food improperly, says Dr. Sindher. She believes our modern diet of highly processed foods may partially account for the increased prevalence of food allergies, food insensitivities, and a growing intolerance to food ingredients in adults. 

A varied gut microbiome is the best way to assure that you have a strong immunity and eating a diet that focuses primarily on whole foods stimulates a healthy bacterial gastrointestinal environment. Conversely, a diet that is comprised of highly processed food products is likely to lead to bacterial imbalances in this vital microbiome and may explain the rise in food allergies in adults.

According to a report in “Markets and Markets,3 the gluten-free product market is expected to grow from 4.18 billion USD in 2017 to 6.41 billion USD in 2023. Much of the wheat-free products are highly processed, replacing wheat with starches from rice, potato, corn, and tapioca, which may is not likely to support a healthy bacterial environment and may actually lead to a decline a the gut microbiome, reducing your overall health.

 “At the end of the day, if you don’t feel well after eating a specific food, you should stop eating that food” says Dr. Sindher. For example, many of her patients say they feel better when they avoid gluten-containing products. So she encourages individuals to try a simple elimination diet. “In general, if you want to avoid wheat-based foods for a few weeks, then try adding these foods back into your diet, there’s no great risk in trying.”

 Either you will feel more sluggish and may experience other symptoms, or you will not really notice any difference; that’s the best way to determine if you have a food insensitivity to gluten-containing foods (non-Celiac gluten sensitivity or NCGS) or even just wheat. Wheat is often the greatest offender because it has been modified to have a higher gluten content in current crops, which appears harder for some people to digest.

This is not to be confused with someone who has Celiac disease, which is an autoimmune condition that triggers an inflammatory response at the intestinal walls when gluten is present.4 The presence of Celiac disease is confirmed with a blood test and/or endoscopy. However, no test is 100% accurate; and there is no test for NCGS.

“What I tell my patients is to move away from the label of gluten. Adding more fiber into your diet that would be better than consuming gluten-free products and potentially falling into the routine of eating even more processed foods, which can cause you harm,” she says.

Differentiating a Food Allergy, Food Intolerance, Food Sensitivity 

How do you know if the symptoms you are experiencing are related to a food allergy rather than a food intolerance or a food sensitivity? First and foremost, if you suspect you have a food allergy, go to a food allergist to get tested, says Jay A. Lieberman, MD, an allergy and immunology specialist at Le Bonheur Children’s Hospital in Memphis, Tennessee,

He tells EndocrineWeb that credible food allergies may be extremely serious, even life-threatening. While Dr. Sindher acknowledges a significant risk of anaphylaxis (shock) when facing a life-threatening food allergy.  

For most people who suspect a new food allergy, she recommends beginning with a process of ruling out the problem food by avoiding it for a week or two to see if the symptoms you were experiencing continue or stop. Then you can reintroduce the food to see if any indications of discomfort arise. Often people may do this with wheat, dairy, and soy as these are the foods that most commonly produce an adverse reaction.

Degrees of Reaction—Identifying a Life-Threatening Food Allergy  

All food allergies arise in response to an immune response to a protein in the food, and all forms of this food are likely to trigger the same reactions to a food allergy. Food intolerances are typically a reaction to a sugar in the food, such as lactose intolerance. 

According to Dr. Lieberman, common symptoms of a food intolerance are belly pain, bloating, foggy headedness, gas, and sometimes vomiting. You will appreciate the differences in food allergies and food intolerances by understanding a few key points. Dr. Lieberman explains that there are two primarily two types of allergies: fast food allergies and slow food allergies.

An immediate food allergy is felt instantaneously, for example, just by smelling the allergen or coming in contact with the problem food is enough to set off a severe reaction. In comparison, a slow food allergy is one in which a person might be allergic to soy but the reaction may vary based on the amount consumed and the form (raw or cooked).

To clarify, Celiac disease is actually an autoimmune disorder—not an immune or allergic reaction—whereby physical damage to the intestines occurs when gluten is consumed. This food issue is an inability to digest the protein, gluten, which causes inflammation in the gut of a person with this condition. https://www.aaaai.org/conditions-and-treatments/library/allergy-library/celiac-disease

Managing a Credible Food Allergy Wisely

“If you are allergic to a particular food, the best course simply is to avoid it and you should carry an ephedrine (epi pen) prescription. When the problem is a food intolerance, patients often tell me they don’t have symptoms every time, it is more dose dependent.” says Dr. Sindher, and every person will have a difference tolerance level to the amount of a problem food their body can handle before the symptoms become intolerable.         

Can a person with a food intolerance can still have small amounts of that food? Dr. Lieberman weighs in on this, going back to gluten, as an example: “If you accidentally eat breaded cutlets, for example, you might slightly nauseous, a bit lightheaded, and experience some abdominal discomfort but these symptoms will pass.”

Food intolerances as well as food insensitivities are much more a matter of quality of life, and very individualized, and may change over time.

New Approach to Treating Food Allergies—Direct Challenge

Immunotherapy has been used for years to treat non-food allergies, but until recently have not been considered for food-related allergies.

“Until recently, we thought food allergens had to be avoided completely,” Dr. Singher explains, “but now there is a focus on therapeutics—immunotherapy— that can help to manage and potentially treat allergies.”  Now, someone with a peanut allergy, for example, will be treated with small doses of the allergen to help build up an immunity, essentially desensitizing the person over time with repeated exposures.5

According to the American Academy of Allergy, Asthma, and Immunology, “Phase 3 development programs of a standardized form of oral immunotherapy as well as epicutaneous immunotherapy for peanut allergy are complete, suggesting that Food and Drug Administration approval and widespread use may be expected in the near future.”5,6

Bottom line: Choose foods that make you feel good.

If you have a negative reaction, such as tingling lips, an itchy throat, mild diarrhea, foggy headedness, to a certain food start by removing that food from your diet and replace it with a high-quality unprocessed food. If you have symptoms such a rash (hives), coughing, vomiting, abdominal pain, prolonged diarrhea, or other more severe discomfort after eating any certain food, make an appointment with an allergist as soon as possible.

Food is a crucial part of life, and your food preferences are personal; being properly informed helps us all make better choices, says Dr. Singher.

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