Yes, it destroys the nutrition of grain. Stomach acid is used to digest things like road kill or large quantities of any kind of food. But when we eat very small quantities of grain, stomach acid is not supposed to be involved. I say "not supposed to be" but obviously most of us have done the vast quantity thing for so long, the stomach acid comes automatically even if we don't eat anything.
Although, admit it may give you a stomach ache or acid reflux.
Yes, by eating incorrectly for our whole lives we get excess stomach acid. Some people get stomach acid when they don't eat anything (e.g. sour stomach in the morning). That is because their body expects them to eat something through years of training. Like nearly everything else in our bodies, stomach acid is triggered in the brain.
Really? Guess my Biology 101 in the 60's was wrong about stomach acid being THE first process of digesting foods. Actually, that is exactly what stomach acid is for, to break down the initial ingredients so the intestines can break them down further and absorb the nutrients.
But then, I'm not a Doctor, but I have stayed at a Holiday Inn.