Soybean oil is not allergenic to soybean-allergic individuals

Abstract

Rationale Soybean-allergic individuals may be instructed by clinicians to avoid all foods derived from soybeans including soybean oil. However, highly refined soybean oil contains extremely low levels of protein. Previous work suggested that soybean oil was not allergenic, but the number of subjects challenged was small and the protein content of the oil was unknown. These deficiencies are rectified in this study. The study objective was to determine the allergenicity of highly refined soybean oil in soybean- allergic individuals. Methods Soybean-allergic subjects were selected by convincing history, positive skin test and positive radioallergosorbent test (RAST). Challenge materials consisted of a mixture of 4 soybean oils with the highest protein level from a group of 30 highly refined oils obtained from 30 different worldwide processors. Subjects consumed increasing doses of 1, 5, and 10 grams soybean oil (test material) and canola oil (control material) in a double-blind placebo controlled food challenge. Prepared oatmeal was the challenge vehicle. Results Twenty-eight soybean allergic subjects were challenged. No untoward reactions were encountered to either soybean or canola oils. No reaction with this number of subjects indicates with 95% certainty that 89.85% of soybean allergic individuals would not react to this soybean oil. Conclusions The lack of reactions to commercially available soybean oil supports the previous claim that hot solvent-extracted, bleached and deodorized soybean oil is not allergenic for soy-allergic individuals and avoidance of soybean oil of the type used in this study is unwarranted. The allergenicity of cold-pressed or expeller-pressed soybean oil remains uncertain.