Yes, it’s easy to become deficient in zinc, especially on a vegan diet. Which is why supplementing very modestly might be indicated. However, that does not mean every single day or above RDA. I do supplement 10mg 3 times a week, because my diet tends to be lowish in zinc.
However there are a few things to keep in mind. First, never mind all the mechanistic speculation. Look at outcome studies. Supplemental zinc, tends to fail in almost all studies. The exception were some zinc lozenges shortening the course of the common cold in some marginal study. Nothing long term. This ought to make us pause. Also remember - zinc from diet is not only bound to proteins within a food matrix, but we access it in physiological time. A bolus of near elemental zinc is an entirely different effect, even if the amount may be nominally the same.
Second, it’s very easy to accumulate excess zinc which leads to a laundry list of deleterious consequences. In view of that I would not supplement daily in RDA or close to RDA amounts, because you do get some in diet, and a bolus as in a pill is not handled by the body well. Btw. we have not evolved in conditions of abundant dietary zinc, so we have not developed physiological ways of dealing with excess, instead, as with any molecule that’s scarce, we tend to preferentially accumulate it. When there’s abundance, we can easily accumulate to excess.
So my approach is to get enough, but just enough, and not top off - and because a pill is a bolus, I would not exceed 10mg in a pill. When supplementing we often tend to go a bit extra, which is fine with many molecules (vit. C, just pi$$ it out), but zinc is not one of them - you want to get it right, not too much.
My personal caution also centers on zinc accumulation in the brain and neurotoxic effects, dementia pathologies etc. We have to be especially cautious with metals and the brain: iron, copper, zinc etc. Here’s a balanced review looking at both sides.
Zinc in the Brain: Friend or Foe?
