Regarding multi-vitamins, yes it may be possible.

Lets take the hypothetical example that floaters are caused by zinc deficiency.

Now zinc and copper compete against each other in the body.

Multi-vitamins will contain both zinc and copper, but they usually contain a ratio favourable to copper. Why? Because many people are deficient in copper. However, sometimes it is the other way around.

So you take the multi-vitamin and it makes you worse.


Treat taking vitamins like taking medication, each person has their unique needs and taking the wrong thing will be harmful.