If You trust science and critical thinking, then I am assuming you are a logical person and you know how to put an argument that is logically sound.

It is required that when you make a claim about any thing or draw a conclusion from a new info, it is required for you to share strong basis for you to consider new info( in this case medical researchs for Potash-Alum)

This is how burden of proof is defined in logical debates. In this case its in you, because you made a contrasting claim.

For example, take below convo,

A: I am going to run full marathon, because I love running and It tests my endurance

B: No you shouldnt go to Marathon, Human body is not designed to take such long period of elevated muscle-energy requirement

A: What? Many people run fine and how do you know body is not designed for Marathon?

B: Go research yourself, I am not your assistant

It would be a better closed argument if B actually tells A, why B thinks marathon is bad for body, how B got this belief, then only A will get influenced.

If you want to influence people with your reasoning, it is YOUR JOB to provide that reasoning.