Early introduction of food allergens to high-risk infants is known to reduce risk of developing food allergies in later life. While this can be done through weaning, there are commercial early introduction foods available. However, the allergen doses of these foods have not been fully established. Dr Martin D. Chapman, Indoor Biotechnologies, has been involved in the development of a modified multiplex array that is able to measure the levels of up to 17 food allergens simultaneously. Using this tool, Indoor Biotechnologies were able to demonstrate the huge variation in commercial allergen products and highlight the need for better guidelines and standardisation.
It is estimated that 1-10% of all adults and children have a food hypersensitivity. In Europe, food allergies affect between 11-26 million people – a statistic that, when extrapolated to the rest of the world, would equate to potentially 240-550 million people with a food allergy.
Food allergies in infants are a major health concern as they can often be life threatening. The incidence of food allergy in toddlers is around 5-8%, compared to 1-2% in adults. This number has increased in recent years, perhaps due to a decrease in childhood exposure to dirt and germs, more pollution or dietary changes.
Early introduction of food allergens, such as peanut and egg, during weaning may help reduce risk of allergy in later life, especially for high-risk babies who may already be predisposed to developing an allergy. These risk factors can include a family history of food allergy and babies who have eczema or existing food allergies, such as cow’s milk protein. For low-risk babies, parents are advised to introduce solid foods from around six months of age, including allergenic foods such as egg and peanut. This can be a daunting task and the more that is known about allergen loads in foods and the responses they may elicit, the better the outcome for child and parents alike.
Dr Martin D. Chapman is President and CEO of Indoor Biotechnologies, a company which provides tests and allergen molecules to help identify and manage allergy and asthma. Indoor Biotechnologies have developed a tool with the ability to simultaneously measure up to 17 specific food allergens from a single sample. The test, called MARIA® for Foods, can be used to measure specific food allergens and can also be applied to industry risk assessments and standardisation of therapeutic products for food allergies.
Quantifying food allergens
Quantification of food allergens is particularly important for characterising food preparations that may be used for treating and preventing food allergies. The ability to calculate the allergen load of a food is also crucial for food monitoring and to inform risk assessments in the food industry.
Currently, tests tend to be immunoassays which measure the presence or concentration of food proteins through the use of polyclonal antibodies. However, there are limitations to these generic immunoassays, including the need for separate tests for each individual food and their lack of ability to distinguish between all proteins and those specifically known to cause allergic reactions. It is these problems that Dr Chapman seeks to overcome.
Childhood food allergies
In 2015, the “Learning Early about Peanut allergy” (LEAP) study was published. Designed and conducted by the Immune Tolerance Network, this study was the first randomised controlled trial that showed early introduction of food allergens, peanuts in this case, was able to prevent allergy developing.
The researchers enrolled over 600 children at high risk of peanut allergy. The test group were provided with a peanut-containing snack food at least three times a week while the control group avoided peanuts. The results showed that in the control group, 17% of the high-risk infants went on to develop a peanut allergy by age 5. Remarkably, only 3% of the test group developed an allergy by the same age. A follow-on project, the LEAP-ON study, showed that even after a 12-month period of peanut avoidance, children in the test group were still less likely to develop a peanut allergy.
Other studies soon followed suit, with the “Enquiring About Tolerance” study in 2017 reporting reduction in food allergy after introducing peanuts and eggs, but not other high-risk food allergens such as milk, sesame, fish or wheat. This suggests that previous advice to avoid early introduction to food allergens may have been incorrect and could even have contributed to the increase in food allergies we see today. However, the peanut-based snack used in the LEAP study was previously the only product with a known allergen content proven to be effective against childhood peanut allergy. Dr Chapman realised that this meant a lack of understanding of allergen loads in other foods, and how they may be impacted by processing techniques or food formulation, for example food powder versus a food puff.
A modified multiplex array for food alllergens
Dr Chapman aimed to use multiplex array technology to compare specific food allergen levels in commercial early allergen introduction foods (EIF). Multiplex arrays are fast, cost-effective ways to obtain quantitative data about several samples at the same time.
EIF are single or multiple allergen containing foods that are marketed as aids to prevent food allergy in infants. The rapid commercialisation of EIF in the United States has provided consumers and families of high-risk infants with a wide range of EIF that can be used to manage the chance of developing food allergy later in life. Interestingly, EIF may be perceived as drugs or over-the-counter treatments and are expected to show significant benefit. Consumers may also consider EIF for different allergens to be equally effective, whereas in reality there can be much variation in allergen dose and effectiveness of EIF.
Using a modified “Multiplex Array for Indoor Allergens” (MARIA) technology, calibrated against purified allergen standards to ensure accurate and reliable results, the researchers were able to compare multiple EIF. The array used antibodies that recognised food allergens to bind to the molecule of interest. These antibodies were coupled to magnetic beads which had unique fluorescent molecules attached. The mean fluorescent intensities of the allergen-antibody-fluorophore complexes was then measured, and the allergen concentration derived through comparison with purified allergens.
A recent study used MARIA® for Foods to compare specific food allergen levels in commercial early introduction foods (EIF). The researchers used extracts from 32 EIF and four control foods to look at levels of 17 different allergens, including soy, peanut, egg, nuts, milk, shellfish, fish, sesame and wheat. The results showed that there was significant variation in the concentration and dose of allergens in different EIFs from nine different manufacturers. Some EIF had low, or undetectable levels of several allergens. For example, peanut allergen levels up to 26,000 μg/g were found in some peanut puffs, whereas no peanut allergens were detected in mixed food blended puffs.
The highest levels of allergens tended to be found in milk, egg or peanut powders, or a combination of all three. In contrast, mixed food blend powders, puff crackers and fruit sauces contained much lower, and sometimes undetectable allergen loads.
Food allergy regulations
Improved awareness of the doses of major allergens in EIF allows consumers and healthcare professionals to make informed choices about products. Understanding more about how processing impacts the amount of food allergen in a product also helps guide EIF manufacturers in product development strategies.
Dr Chapman calls for guidelines to standardise EIF, and to improve their formulation across the different manufacturers in order to provide better support for children and families with food allergies.
- Filep, S., & Chapman, M. D. (2021). Doses of specific allergens in early introduction foods for prevention of food allergy. The journal of allergy and clinical immunology: In practice, S2213-2198(21)00294-4. In Press. Available at: https://doi.org/10.1016/j.jaip.2021.02.051
Indoor Biotechnologies has developed MARIA® for Foods, a tool that can simultaneously measure up to 17 specific food allergens from a single sample.
European Union 7th Framework, Project No. FP7-KBBE-2012-6-312147
Dr Martin D. Chapman is President and CEO of Indoor Biotechnologies, a leading manufacturer and service provider of highly purified allergen molecules and immunoassays for research, diagnostics, and pharmaceutical product development. Indoor Biotechnologies’ mission is to improve the quality of life of patients with allergy and asthma.
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