Late-Onset Food Allergies
As individuals age, so do their immune systems. With the significant increase in life expectancy, it's projected that by 2050, more than 80 million adults will be aged 65 or older while another 20 million adults will be aged 85 or older. This rapidly growing geriatric population will experience immunosenescence, the aging of the immune system.
Immunosenescence affects the innate and adaptive immune system, causing specific changes in the various cell types of the immune system. For mast cells, a key cell type involved in the food allergy reaction, aging reduces degranulation and causes dysregulation in function. The latter change can result in new food allergy development, whereas the former may diminish physical symptoms of a food allergy and delay medical attention. Food allergy is an increasing health concern in the geriatric population.
In the elderly, the prevalence of food allergies is estimated at 5% to 10%,1,2 but is likely underestimated and underdiagnosed, and thus undertreated. A study reported that 24.8% of geriatric nursing home patients (mean age of 77) were positive (skin test) for food allergens.3,4 It is speculated that 25% to 30% of adults self-diagnose food allergies, but the true prevalence is approximately 5% in industrialized countries.4,5 Notably, food allergies can develop at any time and are not limited to manifestation in the pediatric population.
In the elderly, confounding factors include decreased stomach acid (leading to decreased protein digestion and increased in vivo exposure to absorbed allergenic epitopes) and an age-related decrease in total serum immunoglobulin E (IgE).
Conversely, alcohol consumption greater than 14 units per week significantly increases total serum IgE concentrations, which correlates with positive food allergen tests. These various factors may induce de novo sensitization to food allergens, increasing the need for continuous screening and diagnosis. In the geriatric population, typical diagnostics may be insufficient to detect a food allergen but should continue to be the starting point as shown in Table 1. Self-diagnosis needs to be eliminated because the subsequent self-management may lead to nutritional inadequacy, potential nutrient deficiencies, and increased frailty from over-restricting food intake.
Malnutrition, another significant concern in the elderly, plays a critical role in immune system maintenance and efficiency. The three micronutrients of concern are vitamin D, zinc, and iron. An insufficiency or deficiency in calcitriol, the active form of vitamin D, may negatively affect food-related IgE reactions (nonlinear association). Poor zinc bioavailability (absorbed from food) and in vivo homeostasis may further alter the immune efficiency, favoring the development of food allergies. Iron deficiency has also been associated with immune system issues, decreasing antibody responses and increasing the risk of food allergy. In these cases, correcting any deficiencies through vitamin and/or mineral supplementation should improve outcomes and possibly reduce the incidence of any deficiency-related allergies. Blood measurements for zinc, iron, and vitamin D are easily obtainable. (Note: zinc measurements may not indicate a deficiency and should be coupled with risk factors and symptoms.)
Symptoms of food allergies can range from mild to severe. A person experiencing anaphylaxis will seek immediate medical attention that results in an easier diagnosis. However, the elderly are less likely to experience anaphylaxis, making detection more difficult. The elderly report mild symptoms that are often nonspecific and can be related to numerous causes. The most common food threats are shown in Table 2.
Health care professionals may not identify the reported symptoms as potential food allergies. Symptoms can involve the skin, nasal passages, eyes, mouth/lips, ears, gastrointestinal tract, or respiratory and cardiovascular systems. The specific symptoms can be incorrectly mistaken for problems with medication(s), sleep deprivation, environmental allergies, gastrointestinal issues, viruses, autoimmune disorders, or attributed to general aging effects. Undiagnosed food allergies (and celiac disease) can contribute to malaise, malabsorption, and inflammation, further exacerbating the risk of frailty. The keys are an accurate diagnosis and appropriate management in the elderly.
Lack of knowledge and cross-contamination of foods can lead to a reaction. Caution is necessary and may require an individual to ask various questions. Requesting to see an ingredient list from a package or in a recipe may be crucial. If the establishment or the individual is unable to answer questions or produce the requested food label, then it is best to avoid the unknown unless the individual is prepared to deal with a reaction.
For anaphylaxis, injectable epinephrine is required, followed by immediate medical treatment after exposure. For more mild symptoms, antihistamines can be effective in reducing symptoms, but only time will heal. Food allergy management requires vigilance and due diligence to remain safe at all times. Proper food tip recommendations to ensure patients' safety include the following:
• Read all food labels and recheck periodically, as ingredients will change. It's important to avoid if uncertain.
• Modify recipes. Many websites provide appropriate substitutions and/or modified recipes.
• Ask questions. Knowledge is essential for management.
• Avoid cross-contamination by cleaning food preparation areas, utensils, dishes, pans, and kitchen appliances. Consider safe equipment when needed (eg, toaster).
• Check out a restaurant's menu before arrival. If several menu items contain the food allergen, cross-contamination is highly probable.
• Bring safe food to a function, outing, cookout, or holiday dinner. If shared, discard any leftovers, as cross-contamination is likely. Eat a snack or meal prior to attending.
Some herbs are recommended for immune-enhancing and anti-inflammatory effects, such as green tea, milk thistle, bromelain, turmeric, and cat's claw, but patients should use extreme caution because of the potential for interactions.
Patients should consume diets rich in omega-3 fats, such as fatty fish including salmon, tuna, mackerel, sardines, and herring, and plant-based sources such as flax, chia seeds, walnuts, canola oil, and fortified foods. In addition to drinking six to eight glasses of filtered water daily and increasing daily probiotic intake by consuming yogurt or kefir, patients should choose fiber-rich foods. Plant-based foods also are sources of phytochemicals, which are compounds that may help.
Other recommendations include avoiding trans fats, which are found in commercial baked goods, processed foods, and stick margarine; aiming for 30 minutes of physical activity, five days per week; and reducing alcohol intake to moderate levels or abstaining altogether. Moderate alcohol intake is defined as one drink per day for women and two drinks per day for men. One drink equals 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of 80-proof liquor.
Advise patients to monitor nonfood substances for the food allergen, which can be present in lotions, cosmetics, medications, and hair products. Additionally, patients should use proton pump inhibitors and antacids with caution.
Dietitians who specialize in food allergy management may be able to assist in detection of potential offenders by comparing detailed food logs with self-reported symptoms. A specialized dietitian can ensure nutritional adequacy and balanced menu planning.
— Larissa T. Brophy, MS, RDN, LD, is an assistant professor at Mount Carmel College of Nursing, adjunct faculty at Columbus State Community College, and continues to provide nutritional counseling at Rite for You Nutrition Center. A dietitian for more than 20 years, she suffers from severe adult-onset food allergies.
2. Ventura MT, D'Amato A, Giannini M, Carretta A, Tummolo RA, Buquicchio R. Incidence of allergic diseases in an elderly population. Immunopharmacol Immunotoxicol. 2010;32(1):165-170.
3. Diesner SC, Untersmayr E, Pietschmann P, Jensen-Jarolim E. Food allergy: only a pediatric disease? Gerontology. 2011;57(1):28-32.
4. Bakos N, Scholl I, Szalai K, Kundi M, Untersmayr E, Jensen-Jarolim E. Risk assessment in elderly for sensitization to food and respiratory allergens. Immunol Lett. 2006;107(1):15-21.
5. Vierk KA, Koehler KM, Fein SB, Street DA. Prevalence of self-reported food allergy in American adults and use of food labels. J Allergy Clin Immunol. 2007;119(6):1504-1510.