Can magnesium, vitamins & minerals, omega 3 incur any negative side effect or damage to your organism, if taken daily for 3 months or even more ?

Occ.mild side effect: Vitamins ; minerals (including mag.) ; omega 3's are very safe; millions have taken them for decades without harm. But they can cause side effects; too much mag. Causes loose stools, b vits can get people wired, b vits, zinc ; omega 3's may cause stomach upset etc. Synthetic vit. E may harm health ; should be avoided. People may be harmed by addtives/fillers ; binders; choose quality- see comment:.