Report from AAAAI/WAO 2018: New studies on folic acid exposure, EoE and more
This weekend, representatives from FARE are attending a joint congress of the American Academy of Allergy, Asthma & Immunology (AAAAI) and the World Allergy Organization (WAO) in Orlando, FL. We’re reporting on selected abstracts from the meeting that address diverse topics in food allergy. Read on to learn more about some of these featured findings.
This research was supported by FARE through a 2014 Howard Gittis Memorial Research Award to its lead author, Dr. Emily McGowan. The researchers looked for a relationship between folate levels in infants at birth and subsequent risk for food allergy.
Folate, one of the B vitamins, is an essential molecule that humans can’t make. To get enough folate, we need to eat a diet rich in natural folate or supplement our diet with a synthetic form of folate called folic acid. Pregnant women need adequate folate to help protect developing children from neural tube defects like spina bifida, but many modern diets are poor in sources of natural folate, such as leafy green vegetables, citrus fruits and beans. To compensate, pregnant women are given folic acid supplements. In addition, enriched cereal grain products have been fortified with folic acid since 1998 in the U.S.
Adding folic acid to enriched grain products correlates with the growing prevalence of food allergy in children, which increased by 50 percent between 1997 and 2011. In addition, as Dr. McGowan explained in 2014, “folic acid is also known to change the expression of certain genes, which may contribute to the development of food allergy”.
To investigate this question, researchers turned to data from the Boston Birth Cohort, established in 1998. Extensive data and biosamples are available for this group of largely minority children enrolled at birth.
A subset of children in the cohort were tested at birth and early in life for levels of unmetabolized synthetic folic acid, as well as 5-methyltetrahydrofolate (5-MTHF), which is the main folate metabolite involved in biochemical processes in the body. Sources for 5-MTHF include naturally occurring dietary folate and metabolized folic acid from prenatal vitamin supplements and fortified foods.
Diet, clinical history and blood serum levels of food-specific IgE were also assessed in early life. Out of the 1,394 children included in this study, 507 were sensitized to a food, and 78 had a food allergy.
Researchers found that, compared to their peers without food allergies, the children who developed a food allergy had lower average levels of total folate at birth, but higher levels of unmetabolized synthetic folic acid. More research may reveal the underlying reasons for these differences between the children with and without food allergies, which could reflect genetic differences or increased exposure to synthetic folic acid before birth. Read more here.
Abstract 274: Eosinophilic Esophagitis is a Late Manifestation of the Atopic March
Eosinophilic esophagitis (EoE) is a chronic condition in which the esophagus – the tube that connects the mouth to the stomach – is inflamed and contains many eosinophils, a type of white blood cell that is active in immune defenses and allergies. Most cases of EoE are associated with harmful immune responses to food. EoE is much less common than food allergy, affecting 1 or 2 people per 2000.
Researchers studying a cohort of more than 130,000 children found that having EoE is associated with increased odds of having other allergic conditions. This fits a disease model called the atopic march, in which multiple allergic (atopic) diseases can emerge over time, typically starting with atopic dermatitis (eczema) and possibly food allergy in early childhood and leading to later asthma and allergic rhinitis (hay fever). In this proposed model, EoE is a late-emerging manifestation of the atopic march.
It should be noted that diseases associated with the atopic march don’t always develop in the typical order, and this predisposition to allergies does not result in each patient developing each allergic disease. Read more here.
Compared to children allergic to peanut or tree nut, children with allergy to cow’s milk have significantly lower height and weight. The two groups did differ significantly in body mass index (BMI), a calculated value based on height and weight measurements. Reviewing medical records that included at least one clinic visit each at ages 2 to 4, 5 to 8, and 9 to 12 years, researchers found that weight differences were greater for the two groups of older children than for the preschoolers. The differences were not affected by other allergic conditions, early-onset eczema, or inhaled corticosteroid use. Read more here.
In oral immunotherapy (OIT), food allergy patients attempt to become desensitized to their allergen by consuming gradually increasing doses of allergen, up to a daily maintenance dose. Many peanut allergy patients can become desensitized through peanut OIT, but some patients are not able to tolerate the 3,000-mg daily dose (about 10 peanuts) that is considered large enough to enable unlimited peanut consumption. Researchers in Israel followed 11 patients who were unable to tolerate 3,000 mg peanut protein per day as they continued OIT at a lower, tolerated daily dose of peanut protein (range, 600 to 1,500 mg; median, 1,200 mg). Five patients experienced reactions during treatment at home, including one reaction treated epinephrine. During long-term follow-up, 6 to 68 months later (median, 14 months), 10 of the 11 patients were able to tolerate an oral food challenge (OFC) dose of 3,000 mg peanut. The patient who did not pass the 3,000-mg OFC had consumed the lowest daily maintenance dose (600 mg) and reacted at 2,100 mg peanut. Read more here.
Stay tuned to learn more about the research being presented at the 2018 AAAAI-WAO meeting on the FARE blog.