It's too bad that vitamin D isn't patented

Recent studies indicate that taking large doses of vitamin D might have huge cancer reducing effects, perhaps twice as much as quitting smoking.

So why has it taken so long for this information to be uncovered and then disseminated to the public? I suspect it's because no one owns a patent on vitamin D. As a result, no firm has much of a profit incentive to research the benefits of the vitamin.

In contrast, if a company did have the exclusive right to sell vitamin D it would probably have long ago researched the benefits of the vitamin.