May 2021 Issue

Food Allergies/Sensitivities: Adult-Onset Food Allergies
By Sherry Coleman Collins, MS, RDN, LD
Today’s Dietitian
Vol. 23, No. 5, P. 14

An Assessment of the Possible Causes and Strategies for Nutrition Counseling

Historically, food allergies have been thought to affect only children. Indeed, food allergies usually are diagnosed in childhood, but recent research shows they may impact adults more often than once thought. In fact, according to a 2019 study, up to 10.8% of American adults report a “convincing” food allergy, and 48% of those were developed as adults.1

In this article, Today’s Dietitian explores the latest research and some of the important considerations when counseling adult clients with food allergies.

Food Allergy 101
Food allergies are immune-mediated reactions that occur each time someone eats an offending food. They’re most often caused by proteins in the food, but sometimes carbohydrates can be problematic, as in the rare case of alpha-gal reactions. Signs and symptoms of food allergies may impact any organ system and frequently include hives and itching or swelling of the mouth, tongue, and throat. Many reactions are mild and the individual recovers without intervention. However, a more severe reaction, often called anaphylaxis, can include difficulty breathing or wheezing, vomiting, and hypotension that can result in dizziness and syncope (ie, loss of consciousness). The only approved treatment for anaphylaxis is intramuscular injection of epinephrine.

The diagnostic process for food allergies is the same regardless of a patient’s age and always should begin with symptoms associated with eating the potentially offending food. RDs can play a critical role in gathering an accurate diet and health history to assist patients in identifying the trigger food. Asking questions such as what food did the patient eat and in what amount, how much time passed between when the patient ate the food and the onset of symptoms, and what specific symptoms occurred can help link a specific food to the reaction. The history should guide any lab or skin tests the allergist uses; panel testing, or testing against many foods at once, isn’t recommended. A positive blood or skin test indicates the likelihood of a food allergy but doesn’t diagnose food allergies in the absence of symptoms. An oral food challenge is the gold standard for diagnosis.

Differences in Adults
Researchers still have many unanswered questions about why food allergies sometimes develop in adulthood. In pediatrics, the dual-allergen exposure hypothesis has been offered as one explanation, particularly in babies with eczema. In this explanation, babies with broken skin (eg, severe eczema) are sensitized through the skin first.2 When exposure also happens in the gut (eg, by eating potential allergens at the time when complementary feeding begins), the baby develops a tolerance instead of a food allergy. This dual-allergen exposure, through the gut and the skin, promotes tolerance, but when both don’t occur, allergy is more likely to develop in childhood.

In the adult population, there have been cases of food allergy developing after an adult had avoided a food for a long time and reacted upon reintroduction and sensitization through the skin and lungs. In addition, medications that impact the gut (eg, acid suppressors) increase the risk of food allergy development.3 For adults, the most common food allergy is to shellfish, which isn’t usually eaten in childhood and so doesn’t show up until later in life.1 More research is needed to better understand how and why adult-onset food allergies happen—and how dietitians might help clients avoid them.

Those who develop food allergies in adulthood are more likely to have other atopic diseases, such as asthma and environmental allergies, as well as eosinophilic esophagitis, a condition that causes eosinophils to infiltrate the esophageal tissue causing thickening.2,3 Despite the fact many adults report having had severe reactions to food, less than 25% report having a current prescription for epinephrine.1

Mental Health and Food Allergies
Given what’s known about adult-onset food allergy, dietitians need to provide appropriate education. Motivational interviewing can be useful in helping adult patients incorporate the necessary habits to manage a new food allergy. Adults have established patterns of behavior, lifestyle, and eating that may need to change, as a food allergy will impact every part of their life. When children are diagnosed, they have the support of parents or caregivers to help them manage food allergies. However, adults generally are on their own as they learn and implement changes, and this can feel overwhelming, with good reason.

Having a food allergy can impact an individual’s emotional and mental health. Research has shown there’s a high burden of anxiety and decreased quality of life in mothers of children with food allergies.4 Other studies have found that adolescents and young adults also are at risk of anxiety.5 Little research has been done to understand the emotional impact on those with adult-onset food allergies, but it’s likely to be significant. Referring clients to a therapist, counselor, or other mental health professional can be an important part of managing food allergies in the short and long term. Tamara Hubbard, LCPC, who specializes in food allergy counseling in the Chicago area, encourages her clients to identify at least one person in each major area of their lives to educate about their allergy (eg, coworkers, family members, friends). Hubbard helps clients consider what they may be losing now that they’re managing a food allergy. “[It’s important to] acknowledge and validate those uncomfortable feelings, while also empowering clients to identify ways in which their lives can still be full [and] also allergy friendly,” Hubbard says. RDs can work with local therapists or those offering virtual counseling who are versed in food allergy-related issues.

Unique Challenges for Adults
Currently, there are no treatments for food allergies for adults other than avoiding the trigger food. There’s one FDA-approved food allergy oral immunotherapy treatment available to treat peanut allergies, but it’s only indicated for use in children aged 4 to 17. Therefore, the focus of nutrition counseling should center around teaching patients skills to manage their food allergy in the context of an established lifestyle. Clients may need to learn how to make allergen-safe food for themselves while still serving allergenic foods to family members, as in the case of an adult with peanut allergies who has a weaning infant.

According to Beth Doerfler, MS, RDN, a clinical research dietitian in the digestive health center at Northwestern Medicine in Chicago, “adults and children face similar risk of cross-contamination from restaurant meals and improperly labeled foods, but the scenarios surrounding these events might differ.” Adults tend to eat out more frequently, may participate in business-related eating events, and may struggle with the social aspects of managing food allergies. There’s also the issue of alcohol and food allergies, which is a hot topic, Doerfler says. To that end, it’s important for dietitians to remind patients that alcohol can lower inhibitions and increase the risk of anaphylaxis. Learning to manage food allergies while dating and traveling are two additional issues to discuss with patients experiencing adult-onset food allergies.

When performing the nutrition assessment and plan, RDs should consider potential nutrient shortfalls when foods are eliminated. “Remember that dietary patterns and supplementation of key nutrients, such as B vitamins, vitamin D, and iron, need consideration when adults must eliminate dairy and wheat,” Doerfler says. “Some allergy-free products aren’t fortified and can cause patients to come up short.” So providing patients with food substitutions that are safe and equally nutritious is vital.

Practice Considerations
Counseling adult clients who have food allergies is different from working with children and their families. While there’s some crossover in patient education, such as label reading, identifying the allergen, cooking and food substitutes, and preventing nutrient deficiencies, there are important differences. According to Doerfler, RDs can ensure adult patients succeed in following an allergy-free lifestyle by helping them “develop a wellness-based lifestyle plan that works for the whole family.”

— Sherry Coleman Collins, MS, RDN, LD, is president of Southern Fried Nutrition Services in Atlanta, specializing in food allergies and sensitivities, digestive disorders, and nutrition communications. Find her on Twitter, Instagram, and Facebook at @DietitianSherry, via the Southern Fried Girlfriends podcast, and at


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2. du Toit G, Tsakok T, Lack S, Lack G. Prevention of food allergy. J Allergy Clin Immunol. 2016;137(4):998-1010.

3. Sicherer S, Warren CM, Dant C, Gupta RS, Nadeau KC. Food allergy from infancy through adulthood. J Allergy Clin Immunol Pract. 2020;8(6):1854-1864.

4. Feng C, Kim JH. Beyond avoidance: the psychosocial impact of food allergies. Clin Rev Allergy Immunol. 2019;57(1):74-82.

5. Ferro MA, Van Lieshout RJ, Scott JG, Alati R, Mamun AA, Dingle K. Condition-specific associations of symptoms of depression and anxiety in adolescents and young adults with asthma and food allergy. J Asthma. 2016;53(3):282-288.