Food allergy in Honduras shows stark differences compared with the U.S.
Click Here to Manage Email Alerts
Key takeaways:
- Pineapple is one of the most common food allergies in Honduras.
- Patients with IgE peanut sensitization reported no symptoms.
- U.S. children did not have the same cross-reactivity as Honduran children.
BOSTON — A study in Honduras shows food sensitization is common among children there, according to a presentation at the American College of Allergy, Asthma & Immunology Annual Scientific Meeting.
“In the last few years, the prevalence of food allergy has really reached epidemic levels,” said Charlene M. Dunaway Altamirano, MD, PhD, allergy and immunology fellow at the University of Virginia. “This has been shown mostly in industrialized countries where most epidemiological data is coming from.”
“In less industrialized countries, such as low- and middle-income countries like in Central America, food allergies are thought to be less prevalent, but really the epidemiological data that we have is very limited,” she continued.
Dunaway Altamirano said that she and her research team hypothesized that prevalence of food allergy and IgE sensitization in lower- and middle-income countries is lower than that reported in similar populations from industrialized countries.
To test this hypothesis, they conducted a cross-sectional population-based study in San Pedro Sula, Honduras. San Pedro Sula is the second largest city in Honduras with a population of about 800,000 people, according to Dunaway Altamirano. The study recruited children aged 5 to 12 years who attended elementary schools or went to routine pediatric visits at local health clinics.
“For our recruitment strategy, we are advertising this study as a study of nutrition allergy in order to prevent bias,” Dunaway Altamirano said. “And we are recruiting children from areas that are considered low middle class with a per capita income of between $5,000 and $9,000.”
The team collected clinical data as well as data on demographics and diet. A nutritional assessment, blood sample collections and serological analysis were also conducted.
Among the 369 participants (mean age = 8.3 years; 55.7% girls), 77.2% reported having an animal in their household, 53.5% reported allergic comorbidities (most commonly allergic rhinitis), 24.2% reported a history of tick bites and 20.3% reported a history of GI parasites. The average eosinophil count in the study sample was 0.412 kcells/µL. Some participants reported a prior immediate allergic reaction to food (12.3%), and some reported a prior delayed allergic reaction to food (3.6%).
“The most commonly reported allergenic foods include — which are not very different from what we see here in the U.S. — cow’s milk but also pineapple, which was unexpected, followed by shrimp, wheat and egg,” Dunaway Altamirano said.
An IgE panel was conducted on 248 of the participants, and high levels of sensitization were found in wheat (33%), peanut (36.3%) and sesame (37.8%), which Dunaway Altamirano said was unexpected for this population.
“We’ve been looking more closely at this in terms of how common foods are consumed,” she said. “We see that cow’s milk, egg and wheat are commonly consumed. Peanut is available and it’s eaten as a snack, but not as a staple like here in the U.S., and it’s in the roasted form. Shrimp is also available but tends to be more expensive.”
More than 300 participants reported they “never” or “very rarely” eat foods like peanut or shrimp. About half of the study participants reported that they ate egg and wheat a few times a week.
IgE peanut sensitization was detected in 90 (36.3%) participants, although none of the participants reported any symptoms associated with peanut consumption.
The peanut components in peanut sensitized participants had mostly undetectable IgE levels, which commonly occur in U.S. patients, Dunaway Altamirano noted.
“The other interesting observation was that most of the peanut sensitized participants were not sensitized to peanut but to other plant derived allergens such as wheat grass, oak, sesame and even rye,” she said.
This significant correlation (P < .001) between an IgE response to peanut as well as wheat, timothy grass, oak, sesame and rye grass brought the research team to the concept of cross-reactive carbohydrates.
Dunaway Altamirano explained that cross-reactive carbohydrate determinants (CCDs) are oligosaccharides epitopes found on glycoproteins derived from plants, insects and parasites. She explained that CCDs can be recognized by IgE testing, but they do not cause clinical symptoms.
She then cited a study by Amoah and colleagues that examined peanut sensitization in a similar school-aged population in Ghana. Children in that study were also found to have higher levels of peanut sensitization than expected, which was associated with anti-CCD IgE and Schistosoma haematobium infection (not present in Honduras).
Dunaway Altamirano and her team also examined IgE binding to MUXF3 (bromelain), which is a group of enzymes found in pineapple that break down proteins and a classic CCD. They found a strong correlation between IgE response to peanut and IgE response to bromelain (P < .001).
“The most remarkable observation is when we compared these findings in patterns of desensitization with those of a similar population here in the U.S., they are strikingly different,” Dunaway Altamirano said.
The findings in the Honduras study were compared with findings in the Project Viva cohort in Boston. Dunaway Altamirano noted that children in the Viva cohort did not have the same cross-reactivity among plant or food allergies as children in Honduras.
“To summarize, food sensitization is actually common among Honduran children despite the lower rates of reported clinical food allergy,” Dunaway Altamirano said.
She also emphasized the strong correlation between IgE to peanut and IgE to other plant derived allergens and that “the pattern of sensitization seems to be driven by IgE recognition of cross-reactive carbohydrate determinants, such as MUXF3, and is strikingly different from that observed in other similar populations.”
The effects of these study results could show that cross-reactivity is a major confounder in the interpretation of IgE results for patients from Central America as well as immigrants in the U.S. that are coming from these regions, according to Dunaway Altamirano.
“A more provocative idea is whether this sensitization pattern could confer some sort of protection against symptomatic food allergy,” she said.