I was just speaking with a lab testing company that runs two types of tests. One is based on which medications match up best with the genes tested. One is based on which supplements and diet - 'wellness' - match up best with the genes tested.
The company rep told me that the medication based one is well-researched and highly specific, whereas the 'wellness' one ranges from loosely to highly researched (i.e. thus more ambiguous).
I asked why that is. The rep responded that he guessed it was due to more funds being allocated toward the medications. He then proceeded to tell me that the founders of the lab company were two MDs.
Although he was not entirely certain, this was the answer that I figured. It is significant progress to match genes to medication. But understand when someone says to you that nutrition and supplements are not well researched, keep in mind that we live in a healthcare environment that is not always trying to research natural alternatives with the same amount of effort as it does medications. That does not mean their efficacy is any less potent when used appropriately by an expert.