October 2015 Issue

Geriatric Nutrition: Late-Onset Food Allergies
By Larissa T. Brophy, MS, RDN, LD
Today's Dietitian
Vol. 17 No. 10 P. 76

Elderly patients are at higher risk of food allergy due to their aging immune systems.

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's 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 aren't limited to manifestation in the pediatric population. Foods commonly associated with adult food allergy are fruits, vegetables, tree nuts, peanuts, and seafood (shellfish), but aren't limited to these foods. The prevalence of fruit and vegetable allergies are thought to be a result of cross-reactivity with aeroallergens (oral allergy syndrome) to birch, ragweed, and grass.

In the elderly, confounding factors for food allergy development 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.

How to Detect a Food Allergy
Skin Prick Test Measures the presence of immunoglobulin E (IgE) antibodies to specific food allergens. A solution containing the food allergen is applied to the back or forearm and then the skin is exposed through a small scratch or prick. A response is typically recorded within 30 minutes and detects the severity of the reaction. Delayed hypersensitivity usually occurs within two hours, but is often not detected as the test is concluded after 30 minutes. Oral antihistamines need to be discontinued before testing.
Blood Test Previously referred to as RAST (radioallergosorbent tests) testing. Also detects IgE-mediated response by incubating blood in a plate coated with potential food allergens. Results are not immediate, do not determine the severity of the reaction, and are not affected by oral antihistamines.

Celiac: Specific antigen testing for tissue transglutaminase antibodies (tTG-IgA), which are positive in 98% of celiac patients on a gluten-containing diet.
Oral Food Challenge If skin and blood testing are inconclusive, a physician may perform an oral food challenge (OFC) in a medical facility. During the OFC, increasing doses of the potential food allergen are fed to the person and the response is monitored. It is a highly accurate diagnostic test for a specific food allergen but should be completed only under medical supervision. It also may be done to determine whether an individual has outgrown a food allergy. Can be completed as a double-blind/placebocontrolled food challenge (gold standard), single-blind food challenge, or an open food challenge.
Trial Elimination Diet A physician may ask an individual to temporarily eliminate specific foods from the diet. This method is generally combined with skin and blood testing and used to confirm IgE-mediated food allergens or related disorders (see Table 2 online). The elimination diet typically lasts for two to four weeks. If the correct food allergen or offending food has been eliminated, then all symptoms should disappear.
Unproven and Nonstandardized Tests Includes applied kinesiology (muscle testing), cytotoxicity testing, electrodermal testing (vega testing), Nambrudipad's Allergy Elimination Technique (natural elimination of allergy treatment), IgG/IgG4 testing (blood), hair analysis, and pulse testing. For more information, go to www.foodallergy.org/document.doc?id=238.

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 also has 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.

Common Food Threats
Eight Common Food Allergens* The common eight food allergens are cow's milk, eggs, fish, peanuts, shellfish, soy, tree nuts, and wheat. These account for 90% of all food allergies. By law, labeled foods must identify these allergens.
Oral Allergy Syndrome Also referred to as pollen-food syndrome. Symptoms are usually isolated to the mouth. This reaction is caused by a crossover reaction from pollen to similar food proteins.

Birch: apple, carrot, peach, plum, cherry, pear, almond, hazelnut, and kiwi
Grasses: tomato
Ragweed: melons, zucchini, cucumber, and banana
Latex-Fruit Syndrome Approximately 30% to 50% of individuals with an allergy to natural rubber latex are also allergic to several plant-based foods. These foods can include avocado, banana, chestnut, kiwi, peach, tomato, bell pepper, and potato.
Eosinophilic Esophagitis Results in an inflamed esophagus, contributing to swallowing issues ("getting stuck"). May cause early satiation and reduced food intake. Often triggered by certain food allergens; should include food allergy testing as part of the diagnosis and treatment.
Food Protein-Induced Enterocolitis Syndrome (FRIES) Typically presents in young children, but outgrown by age 3. A severe, non-IgE–mediated reaction to food ingestion within two to three hours. An oral food challenge is needed for diagnosis; usually triggered by milk and soy proteins.
Celiac Disease An autoimmune response to gluten (protein found in wheat, rye, and barley) within the gastrointestinal tract. One-third of new diagnoses are in the elderly. If undiagnosed, will cause malnutrition from malabsorption of nutrients (including iron, zinc, and vitamin D) due to disease pathophysiology.
Food Intolerances Food intolerance is simply maldigestion of carbohydrates, causing undesirable symptoms, but not an immune response. Examples include lactose, although yogurt, hard cheese, and Lactaid milk are well tolerated, and FODMAPs (fermentable oligo-, di-, monosaccharides and polyols) for irritable bowel syndrome.
Food Aversion An intense dislike for a food; may even provoke pseudosymptoms. Does not involve the immune system or digestion.

* Although there are eight common food allergens, many other foods have been associated with allergic reactions. These include but are not limited to corn, gelatin, meat (beef, chicken, mutton, and pork), seeds (sesame, sunflower, and poppy are the most common), and spices (caraway, coriander, garlic, mustard, etc).

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.

Taking Action
Once a food allergy has been diagnosed, the only approved method for effective management is avoiding the allergen. It's important to note that once a food allergen is totally eliminated from the diet, reactions can become more obvious and will usually increase in severity. As to avoidance, some foods are easier to eliminate than others. Food labels containing ingredient lists are essential tools for prepackaged foods. However, when older adults dine out or visit well-intentioned friends and family, avoidance becomes a bit more challenging.

Lack of knowledge and cross-contact 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's 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-contact 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-contact is highly probable.

• Bring safe food to a function, outing, cookout, or holiday dinner. If shared, discard any leftovers, as cross-contact is likely. Eat a snack or meal before attending.

Additional Considerations
There's a lack of evidence on food allergy development and alternative therapies in the elderly; therefore, more research is needed. However, there are strategies and safe practices that may improve food allergy sensitization and management. First, health care professionals must correct any nutritional deficiencies patients may have, especially iron, zinc, and vitamin D plus consider the following supplements:

• a daily multivitamin (providing the antioxidant vitamins A, C, and E; B-complex vitamins; and trace minerals) as a prophylactic measure, which also may correct deficiencies that food allergy avoidance may cause.

• coenzyme Q10, an antioxidant that may be deficient in individuals with recurrent food allergy and that may decrease with age.

• omega-3 fish oil (if individuals are unable to get adequate amounts in their diet) that specifically provides DHA, which changes cell membrane composition, potentially reducing histamine release and promoting food allergy sensitization, especially in females.6,7

• L-glutamine and probiotics, containing Lactobacillus acidophilus and Bifidobacterium. Probiotics and glutamine may promote intestinal health, specifically preventing a leaky gut.8 Probiotics also help balance the microbiome, which together with L-glutamine could avert food allergy development by inhibiting absorption of allergenic epitopes9,10 (an amino acid sequence of an absorbed protein peptide that the body recognizes as foreign).

Always use caution when recommending supplements to the elderly population. It's important to prevent overdosing (recommending nutrients more than 100% of DV), unless a patient is deficient and avoiding any nutrient-drug interactions. As with any supplement, dietitians should address contraindications while stressing that taking higher doses isn't better and actually may be harmful.

Although it is a controversial suggestion, the University of Maryland Medical Center recommends supplementing with certain herbs, such as green tea, bromelain, turmeric, and cat's claw, for their immune-enhancing and anti-inflammatory effects,11 but patients should use extreme caution because of the potential for interactions. Milk thistle has been shown to possibly decrease environmental allergy symptoms when combined with antihistamines,12 which potentially could help with cross-reactive foods from oral allergy syndrome. Milk thistle may be contraindicated in individuals with ragweed allergy.

As a good practice for potentially reducing food allergy symptoms, sufferers should consume foods rich in omega-3 fats, including fatty fish such as salmon, tuna, mackerel, sardines, and herring, and plant-based sources such as flax, chia seeds, walnuts, canola oil, and fortified foods to reduce inflammation caused by food allergy.6,7,11,13 Moreover, individuals should try to drink six to eight glasses of water each day, increase daily probiotic intake by consuming yogurt or kefir, and choose fiber-rich foods. Plant-based foods are sources of phytochemicals, compounds that may help reduce the proinflammatory effects of a food allergy.

Other dietary and lifestyle recommendations include avoiding trans fats and reducing saturated fats, both of which are proinflammatory and may exacerbate food allergy reactions; aiming for 30 minutes of physical activity, five days per week, which may reduce inflammation and help maintain a healthy immune system; 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 oz of beer, 5 oz of wine, or 1.5 oz 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. In addition, patients should use proton pump inhibitors and antacids with caution, since these will either further decrease stomach acid production or neutralize stomach acid, reducing digestion of protein in foods. When protein is incompletely digested (not denatured and broken apart into smaller peptides), the body is exposed to more allergenic epitopes. Once the immune system programs against the food epitope, the food allergy develops.

Dietitians who specialize in food allergy management may assist in the detection of potential offenders by comparing detailed food logs with self-reported symptoms. A specialized RD can ensure nutritional adequacy and balanced menu planning.

— Larissa T. Brophy, MS, RDN, LD, is an assistant professor at Mount Carmel College of Nursing, an adjunct faculty member at Columbus State Community College, and continues to provide nutrition counseling at Mount Carmel Home Care. A dietitian for more than 20 years, she suffers from severe adult-onset food allergies.

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