I really think that we're onto something including plant-enzymes and probiotics in products and vitamins, etc. It really seems obvious in hindsight, but truly, our bodies need those enzymes to appropriately absorb the components of our makeup. Most supplements and vitamins are wasted because nothing in them becomes bioavailable.
In truth, that's probably why vegetarians and vegans feel and age the way that they do. It's not that necessarily cutting out meat is important (though i believe decreasing the amount that we eat to be), it's the a d d i t i o n of all of those raw vegetables, nuts, and fruits, etc. that our bodies need to function. Foods are full of enzymes (good foods, anyway). That's why they even taste the ways that they do. Mineral-ineffecient foods have less flavor because, essentially, they are full of less life.
And again, it's not that meat is necessarily bad, per se, it's that the enzymes found in the flesh of other animals is harder to break down without the proper enzymes to help our bodies absorb what they need to adequately maintain themselves.
One of the biggest things that this generation is facing (that includes all and anyone reading this) is that we are magnesium deficient from all of the chemical fertilizers, pesticides, and other artificial nonsense that we currently are so fascinated with. These products strip most soils of magnesium (and it doesn't help they we constantly crop the same soils, either), which leads to plants being deficient, which, of course, effects everything else. I would wager that we are seeing depression and anxiety on such a rise because of a lot of these deficiencies.
My recommendation:
get on a good magnesium supplement, support companies that produce more holistically, avoid any and all unnecessary chemical products when you can (including in your own home), and look into a company called Garden Of Life, which is just one that I seem to be really appreciative of (though there are other great companies out there as well). Remember, i am recovering (my mate also) from the effects of a prolonged eating disorder. It has taught me a lot, actually, about my body and how things function.
"From the dust you were made, and to the dust you shall return."
Namaste.