Patients with wheat allergy may be cross-sensitized to spelt, barley
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Key takeaways:
- The major allergen in wheat allergy dependent on augmentation factors is omega 5-gliadin.
- Spelt and wheat are members of the Triticum genus.
- Patients with wheat allergy are advised to avoid spelt.
Patients with wheat allergy dependent on augmentation factors, also known as WALDA, often may be sensitized to spelt and barley as well, according to a study published in Annals of Allergy, Asthma & Immunology.
Reactions such as urticaria or anaphylaxis occur when wheat is combined with exercise, nonsteroidal anti-inflammatory drugs or alcohol, Valentina Faihs, MD, of the department of dermatology and allergy, Biederstein, School of Medicine and Health, Technical University of Munich, and colleagues wrote.
90% of patients with wheat allergy dependent on augmentation factors had skin prick test results positive for spelt. Image: Adobe Stock
The major allergen in WALDA is the wheat gluten protein omega 5-gliadin. As members of the Triticum genus, wheat and spelt proteins have a high degree of homology, and patients with wheat allergy are advised to avoid spelt, the researchers explained.
“Patients with WALDA, formerly WDEIA, need to strongly adapt their diet after diagnosis. However, evidence is lacking regarding the potential tolerance or cross-reactivity of these patients to cereals other than wheat,” Faihs told Healio.
“This study was mainly driven by the fact that some patients with WALDA reported that they tolerated spelt better than wheat despite the lack of evidence for a lower allergenic potential of spelt,” she continued. “Conversely, barley may represent a good alternative to wheat in case of tolerance.”
Study design, results
The study included 40 patients (median age, 51.5 years; range, 18-82 years; 22 men) with WALDA confirmed by a challenge and a median specific IgE for omega 5-gliadin of 6.5 kU/L (range, 0.5-34.6).
Specifically, 25 patients (62.5%) had specific IgE for barley and 33 of 39 (85%) had specific IgE for spelt over 0.1 kU/L, which the researchers called the detection threshold.
The 14 patients (35%) with atopic comorbidities had significantly higher specific IgE for wheat (P < .05), barley (P < .01) and grass pollen (P < .001), the researchers continued, but not against spelt.
The researchers further noted a significant correlation between specific IgE levels for spelt and barley in addition to a correlation between specific IgE levels for barley and grass pollen (P < .001 for both).
Positive skin prick test results included 32 of 39 patients (82%) for wheat and wheat gluten, seven of 35 patients (20%) for barley, 35 of 39 (90%) for spelt and 31 of 38 (82%) for spelt gluten.
Overall, the cohort had significantly higher specific IgE levels and SPT diameters for spelt compared with barley (P < .001 for both).
Three patients had oral challenge tests for barley flakes and spelt gluten. They tolerated barley by itself and with acetylsalicylic acid, 20 mL of 95% alcohol and 20 minutes or more of intensive exercise on a treadmill with no symptoms, the researchers said, although cross-sensitization to barley was observed.
During the challenges for spelt gluten, these patients had objective reactions at thresholds that the researchers classified as similar to or below those seen in diagnostic oral challenge tests with wheat gluten.
“Three patients with WALDA who were also sensitized to barley tolerated it well on oral challenge tests, even in high amounts and in the presence of augmentation factors such as acetylsalicylic acid, alcohol and exercise,” Faihs said.
“This contrasts with the oral challenge tests of WALDA patients with spelt gluten, which triggered allergic responses similar to wheat gluten despite some patients’ beliefs in its better tolerance,” she said.
When the researchers conducted a reversed-phase high-performance liquid chromatography analysis of the spelt gluten that was used in the oral challenge tests, they found 2.5 g/100 g of omega 5-gliadin, 45.1 g/100 g of total gliadin content and 62.2 g/100 g of gluten, which they called equivalent to what typically is found in wheat gluten.
Based on these findings, the researchers said patients with WALDA frequently are cross-sensitized to spelt and, to a lesser extent, barley.
But patients with omega 5-gliadin WALDA and cross-sensitization to barley still tolerated barley even with acetylsalicylic acid, alcohol and exercise in oral challenge tests despite their immunologic cross-reactivity, the researchers continued.
Conclusions, next steps
These findings challenge the assumption that spelt might be less allergenic than wheat for patients with WALDA, Faihs said.
“The research confirmed that spelt can trigger allergic reactions comparable to those caused by wheat, which is crucial information for managing the diets of patients with WALDA and avoiding severe allergic reactions,” she said. “On the other hand, barley may represent a well-tolerated alternative to wheat in these patients.”
Finally, the researchers concluded that patients with WALDA should avoid wheat as well as spelt in combination with augmentation factors.
“Individualized dietary counselling is a key factor in the management of WALDA patients. These findings help provide more targeted dietary advice to these patients,” Faihs said. “WALDA patients should avoid not only wheat but also spelt in their diet, especially when combined with known augmentation factors. Barley could offer an alternative grain for affected patients.”
Next, Faihs and her colleagues plan on validating the barley tolerance findings in a broader group of patients to solidify its potential as a safe alternative for patients with WALDA. “Additionally, more research is needed to investigate the tolerance of other types of cereals in WALDA patients to improve their dietary management further, ” she said.
For more information:
Valentina Faihs, MD, can be reached at valentina.faihs@mri.tum.de.
Perspective
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While we can obviously see improvement in patients’ gastrointestinal and allergy symptoms when eliminating wheat, barley and/or spelt, cutting out these foods completely can make it harder to hit certain nutrition targets.
Fiber intake is often lower in those who decrease these foods, and many studies confirm that those who cut out wheat, barley, spelt and rye consume less fiber than those who can consume these grains.
There are also studies that show diets low in wheat, barley and spelt may lead to certain nutrition deficiencies, especially nutrients such as iron, folate, B-12, zinc, magnesium and thiamine.
But allergists can work with patients and other members of the health care team to ensure that patients’ diets are safe and healthy.
Informing patients where they can find these allergens first and foremost is essential. Many patients with these allergies can identify things like breads or beer as a source of wheat, barley or spelt. But many foods, especially processed foods, can leave patients in the dark and unaware of where these hidden allergens may lie.
Allergists also should educate patients about how to read a nutrition label; what ingredients contain wheat, barley or spelt; and what to ask when they are at restaurants to ensure cross-contamination and hidden allergens are not present.
I also recommend allergists refer their patients to a dietitian to make sure any nutrition gaps are addressed and ensure they are able to get in an adequate amount of fiber and micronutrients to prevent deficiency and promote good gut health.
Patients also should learn how to read labels to not only identify wheat, barley and spelt, but also to identify ingredients that these allergens may be hidden in. For example, “malt” is an ingredient that comes from barley. Soy sauce is made from wheat. Corn flakes or oats may be cross contaminated with wheat or other grains unless stated otherwise.
Allergists and dietitians should be able to provide more comprehensive education about ingredients to avoid.
It also is important to avoid cross-contamination by throwing away or separating utensils that have handled wheat, barley or spelt. This includes wooden cutting boards, cast iron pans and anything that is porous.
Finally, avoiding sauces, soups made with roux, and any restaurants with kitchens where cross-contamination is possible is essential when eating out. Some kitchens are wheat/gluten-free, so call ahead to make sure before you go out!
Food Allergy Research & Education has great online resources about what ingredients to avoid and how to avoid cross-contamination.
Gluten-free resources also can be helpful, as wheat, barley and spelt are gluten-containing foods. Find Me Gluten Free is a great website to use to identify restaurants that have gluten-free kitchens.
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