One last question: It's a hypothetical, so relax. Let's say…

One last question:
It's a hypothetical, so relax.
Let's say a supermarket is selling a vitamin supplement and experts agree that it is beneficial.
But then someone compares people who take it with people who don't take it and finds that while the supplement does what it is meant to do, lower the risks for a certain disease, the people who take it die 4 times more often from other diseases and are sick more often.
Should that supermarket stop selling g the supplement until all doubts have been cleared up?
Or should it keep selling the supplement because without it people might be at a higher risk to get the disease it is meant to prevent?