The calcium(especially the harder to digest forms) will buffer some HCl. Zinc requires more HCL for the body to break it down into a more absorbable form/smaller molecule. Minerals that are cultured seem to be easier to assimilate/digest than the mined minerals. I found New chapter and Megafood(cultured vitamins) to be easier to digest than the other brands. People with digestive issues or producing Low HCl should stay away from hard to digest mined minerals. Chelated minerals just help the stomach to produce a little more HCl ,but does not really change the molecular size of the mineral to make it that much easier to digest and assimilate. I’ve seen some info that most of the minerals on the market are only about 5-40% absorbed. One of the main purpose of plants is to take the raw minerals from the dirt and downsize it into a smaller size so that it can become much easier for us to utilize.