Genistein is a potent inhibitor of tyrosine kinases and can interfere with signal transduction pathways. Moreover, the volume intake of these products is sufficient to account for a significant high dietary intake of isoflavones. At the moment, very limited human data are available. RAST test appears to be of poor predictive value. Many children with positive results do not react to challenge tests.
Prick tests have little predictive value.
As a consequence, these commercial extracts were less sensitive than extracts of soy flour. The challenge test with soy proteins, after an elimination diet, is the only reliable method of evaluating soy-protein intolerance. Upper or lower GI endoscopies often are performed in patients with soy protein intolerance during the workup for differential diagnosis. Findings, however, are unspecific, most commonly minimal, and, at times, even absent. Endoscopies are not considered part of the workup for soy protein because of the unspecific findings on one side and the transient nature of the disorder on the other.