How can you be so sure if e.g. everything we eat both prevents and causes cancer [1]? Do we have proof that exciting electrons won't do anything on a higher lev

How can you be so sure if e.g. everything we eat both prevents and causes cancer [1]? Do we have proof that exciting electrons won't do anything on a higher level like enzyme production, or one of the many metabolic pathways? 1: https://www.sciencealert.com/everything-we-eat-both-causes-and-prevents-cancer https://www.sciencealert.com/everything-we-eat-both-causes-a...