The point is they developed these symptoms after incorporating large amounts of soy into the diet.How to test if soy is not causing these issues? remove it from their diets for 1-2 weeks and observe the changes.
Where is their proof that these symptoms even occurred and even if they did that they were caused by soy? You are taking a biased article based on the biased bogus propaganda by a foundation funded by industries that are threatened by soy sales as fact with no proof. Being that the Weston Price Foundation has been proven to be making up their "facts" I seriously doubt that these symptoms ever occurred, or that they were occurring long before soy was being fed to the prisoners. If the Weston Price Foundation had not been shown to be making stuff up to support their financial sponsors I would maybe take the article a little more seriously. But as it stands they have shown me that nothing they claim can be considered even slightly credible.