A lot of its diet, not enough essential minerals or vitamins. The American diet often being so poor in quality produce and high in crap and GMO ingrediants is to blame for a lot of things...
Thing is, all mass produced food, organic or not, is lacking in minerals, especially trace minerals, so go look into supplements for this!
Thing is, all mass produced food, organic or not, is lacking in minerals, especially trace minerals, so go look into supplements for this!