Actually, I meant no offense to the FDA 
The FDA did not ban the compound, they banned its sale as a supplement, which means the pharmaceutical company must have patent protection on this compound essentially giving them a monoply as was mentioned earlier.
This whole concept of patenting naturally occuring materials started way back and kind of reached the peak of absurdity when they allowed companies to actually patent stem cells and DNA sequences, even though we all have them you would be infringing on the patents if you tried to market them.
No, they donāt need patent protection and there is no statement of a patent being applied for. Nor could see how they could be awarded one, as nutritional use is not novel and was anticipated, but that is a different matter.
If they had a use patent that would be an entirely different matter and they wouldnāt need the FDA to stop the sale of the supplement. The thing is, they didnāt invent either the compound or the use, but nonetheless want monopoly power and to be able to charge vast prices (I expect) for what is presently a modestly priced naturally-occurring compound for which nutritional use was already known before this company filed their drug application.
You are completely right about there being other cases which are patent based. But this is new drug application (NDA) based, which is FDA not patent office.