Let me start by saying my question was genuine. 30 year old research in medicine triggers scepticism in me.
“Yes, that says quite bad things about the medical community that they are only focused on things that can be patented to make money. It’s another reason to be distrustful of doctors.”
Sorry, I don’t subscribe to this. “The medical community” is vastly diverse and merit is not only gained through patentable research.
Which is proven by the point there actually has been ongoing research into the effect of chicken soup on influenza as well as the effect of supplements. The latest study I could find was a 2025 meta-study. One of the underlying studies supports the claim of a 1-2.5 reduction. All support “modest benefits”. All in all I would say the result is not as “extremely huge” as you portray but I do agree further research is warranted to verify and explore the exact mechanisms at play.
The nutritional supplements industry does have those millions necessary for clinical trials. A peer-reviewed clinical study is likely to further boost their sales. We don’t know exactly why there hasn’t been another study commissioned. One likely explanation to me seems to be that there is low confidence in achieving results that prove the suggested “extremely huge” impact, and an inherent risk of being reduced to the efficiency level of chicken soup.
There is a case to be made to amend the DSHEA of 1994 (or equivalent legislation in the EU) to enforce more clinical studies for nutritional supplements, which would close this gap in verified knowledge.