Quinoa (Chenopodium qunoa) is a plant used for centuries in South America, but is more recently gaining popularity in North America. Quinoa is technically considered a fruit, although many use its seeds as a grain supplement. We tested the hypothesis that sensitization to quinoa is associated with increased apple sensitization.
We reviewed the patient research database at Children’s Mercy Hospital, which included patients who were deemed by allergist to need IgE testing (performed by the ImmunoCAP method). We found 212 patients were tested for IgE of quinoa, apple, wheat, and soy. We queried for allergen specific serum IgE of apples, and used wheat and soy as comparisons. Spearman correlation (p) was determined for each variable. Sensitization was defined as an IgE level of 0.35 kU/L or higher.
Of the 212 tested, 64(30.1%) were positive for quinoa with a mean(SD) of 4.32(1.29). 71 were positive for apple sensitization(33.5%)with a mean(SD) of 6.09(1.83). We found that 54 patients(25.4%) were positive for all 4 variables. Apple had a correlation of 0.656 with quinoa(p-value<0.0001). Wheat and quinoa had a correlation of 0.646(p-value<0.0001), and quinoa and soybean had a correlation of 0.713(p-value<0.0001). These associations were consistent with chi-square testing completed. Pairwise comparison of test results showed highest percentages in double negative test results; however, double positive results were also strong at ~30% of sample for all comparisons.
These findings demonstrate that in this group of patients sensitization to quinoa is associated with sensitization to apple. This association has not been demonstrated in previous literature.