I agree with you that the foods I am eating may be of poor quality.
But the problem is I am not planning on growing my own fruits and veggies anytime soon. So, even if I end up buying a refractometer, Im only going to have fewer produce options since other places (HEB, Walmart etc have even poorer produce). Also, the kelp as wombat suggested may be compounding the problem as I see it. Guess, I will cut back on the kelp and see what happens.