Antacids, acid blockers and acid inhibitors can be very destructive. They not only cause deficiencies in B12, iron, calcium and protein, but a host of other problems.

Food doesn't digest well enough.
Nutrients aren't absorbed into your small intestines as much.
Undigested food sits in the large intestines, putrefying and rotting.
That can lead to a leaky gut and loads of immune problems.
Bad bacteria builds up, overcrowding the good bacteria.
Infections (sinus, too) are easier to catch and harder to cure.
Immune complexes begin to multiply, attempting to fix you.
After that, you can have all sorts of problems, such as allergies, diseases, even more digestive problems, etc.

And inflammation. Inflammation can lead to infections can lead to cancer.

One thing leads to another. Get your B12 and D checked.