If you are lucky enough to have a lemon tree in your backyard, by all means go ahead and use lemon zest in this recipe. Otherwise I suggest you use 2-3 tbsp of freshly squeezed lemon juice instead. And the reason is that lemons that you get a grocery store are more often than not are treated with some sort of protection coating to keep lemons fresh for longer.
And as you can guess, treated lemon zest is not a part of this recipe and should not be part of anything we eat for that matter. So for heath reason, either use non-treated lemons or replace it with a lemon juice.