What You Need to Know about Food Allergies in Adults (Part 1)

Food allergies are often considered a childhood condition since they are most often diagnosed in young children. However, the reality is that not all children with food allergies will outgrow their condition; they then become adults with food allergies. Moreover, food allergies can be diagnosed at any age throughout the lifecycle. But, just as with diagnosing food allergies in childhood, accurate diagnosis is essential at every age.

A new paper published in the Journal of the American Medical Association (JAMA) has shed new light on the issue of adults with food allergies. According to the paper, 40,443 surveys were completed and included a variety of questions about food allergies. Responses indicated that 19% of responding adults believed they had food allergies, however only 10.8% of those reported convincing symptoms of food allergy. This means that nearly half of respondents who believed they have a food allergy were likely to have had true food allergy.

According to the survey responses, shellfish (2.9%) was most commonly reported, followed by milk (1.9%), peanut (1.8%), tree nut (1.2%), and fin fish (0.9%). More than 45% of respondents reported having multiple food allergies. Severe reactions were common with 51.1% reporting having had one. The primary limitation for this study is that the data is self-reported, resulting in potential bias.

The NIAID Guidelines for the Management of Food Allergies in the U.S. states – 50% to 90% of presumed food allergies are not allergies.

Why does accurate diagnosis matter? Because an individual may not get the care necessary if they don’t have a food allergy and have a different condition instead. For instance, inflammatory bowel disease, such as Crohn’s or colitis, and irritable bowel disease may both present with symptoms similar to food allergies, but require very different treatment. In these cases avoidance won’t treat the underlying disease conditions.

Unnecessary avoidance can also lead to increased financial burden. Often “free from” foods, such as gluten-free flours, are more expensive and harder to find than traditional foods like wheat flour. Individuals who believe they are food allergic, but who are not, may carry anxiety and stress about exposure unnecessarily.

Finally, over-restriction can lead to nutrition deficiencies. A liberal diet that includes as much variety as possible leads to a diet that contains more nutrients. However, restricting specific foods and food groups can result in poorer nutritional status. It is essential to avoid unnecessary elimination of nutrient-rich foods, of which all of the most common food allergies are.

Diagnosing food allergies begins with a visit to a board-certified allergist. An allergist familiar with food allergies can help uncover potential food allergies, while also identifying signs and symptoms that do not indicate food allergy, but could indicate another condition.

A detailed food and symptom history is the first step to an accurate diagnosis. By connecting consistent symptoms of a reaction with the consumption of specific food, a skilled professional will identify a pattern. If reactions don’t occur every time a food is eaten, food allergy is unlikely.

Laboratory tests, such as skin prick testing or serum IgE levels can help with diagnosis, but are not diagnostic alone. These tests have high negative predictive value (meaning if they are negative, they are probably correct), but poor positive predictive value (with 50% or higher false positive rates).

The gold standard for diagnosis is an oral food challenge. In a supervised setting, the suspect food is consumed in small and increasing doses until either a reaction occurs or a full serving is eaten.

Once an accurate diagnosis has been made, the newly diagnosed individual with food allergies has a lot to learn. Learning to live with a food allergy can be a life-changing condition. Food and interactions that include food are an integral part of our culture, yet it takes time for the newly diagnosed individual to learn all of the areas where food can be an issue. Other things he or she will have to learn include navigating restaurants, cooking substitutions, label reading, and managing the emotional and social aspects of food allergies. It takes time, planning and attention, but life with food allergies can be healthy and satisfying.