How proteins are digested to liberate amino acids

Digestion is obtained by actions of stomach acid (low pH) and enzymes both in the stomach & intestines (pancreatic protease). In the acidic environment of the stomach, the negatively charged side chains are removed by pepsin. In the more alkaline environment of the intestine, the positively charged side chains are removed by trypsin. In the stomach, Pepsin helps to "unwind" the proteins and breaks the bonds between the amino acids in certain places. In the small intestine other enzymes break the bonds between different amino acids than pepsin does. Because proteins are such complicated molecules it takes a long time and more than one enzyme to completely break them down into amino acids. Digestion results in about 60% small peptides (or peptide bound), which are longer chains of amino acids, and 40% free amino acids (free form). Peptides can be further broken down by hydrolysis in enterocytes (intestinal absorptive cells, simple columnar epithelial cells found in the small intestines and colon).

All proteins are naturally hydrolyzed by stomach acid during normal digestion and the amounts in mineral chelates are in milligram, not gram, strengths. Fermentation to make healthy foods like cheese, vinegar, yogurt, miso, etc. also digests proteins and liberates amino acids, which are of course essential to human nutrition.

Although the excitatory amino acids aspartic acid and glutamic acid are not essential amino acids, the body can create them from numerous sources. In fact, glutamine is the major circulating amino acid and the brain will break down muscles to get it for fuel if the blood sugar is too low to support brain function. Glutamine also fuels some intestinal cells.

Glutamine, MSG & excitotoxins, and protective nutrients

Clinicians giving several grams a day of pure L-Glutamine do not report excitotoxic reactions. The main one is for the synthetic chemical MSG. Sometimes people react to fermented foods, which indicates a problem in containment and nutritional status. Vitamin C removes glutamate from the neurons, which are additionally protected by antioxidants (tocotrienols, tocopherols, et al) and by magnesium. Branched-chain amino acids help to compartmentalize glutamates. Glutamine is fine with other aminos; the main competition is between the arginine pathway aminos (arginine, ornithine, and lysine); with another noted competition to get through the Blood Brain Barrier between the Large Neutral Amino Acids: aromatic aminos (tyrosine, phenylalanine, and tryptophan) and the BCAAs (leucine, isoleucine, and valine).

Gluten issues, allergies vs sensitivities vs digestive issues

All grains contain gluten; some forms are just more allergenic or more difficult to process than others, which can vary from individual to individual. Wheat is the most common gluten reaction; which is also possible for rye, oats, barley and buckwheat. Some people are sensitive to certain proteins because of leaky gut, a condition where digestion is impaired because of GI tract disorders. Non-allergenic "delayed sensitivity reactions" to proteins may be caused by leaky gut and the specific immune cells reacting to these specific proteins can be reprogrammed to be non-reactive to them by completely avoiding these specific foods for at least 6 weeks. Not so for true food allergies, which can be permanent and trigger ever-increasing reactions with every occasional exposure. People's abilities to digest proteins vary with genetics, immune system capacity and probiotics present in the gut. There is even current research on specific bacteria that prevent the damage caused by wheat in susceptible people's guts. Only about 1% of the population tests as truly allergic to wheat protein, between 1-2% for dairy protein. Obviously, many more are (temporarily) sensitive to these proteins based on gut dysbiosis and leaky gut tissues failing to completely digest these foods. The issue of lactose intolerance is another possible cause of gas or bloating after consuming non-fermented dairy products (except for low-lactose products like whey protein isolate). The use of antacids is a major factor reducing digestion of proteins and minerals in the stomach, as well as reducing the essential acidic barrier against pathogenic organisms that may be present in our food and water; even from dirty hands that we use to eat. Stress and improper chewing may also contribute to the presence of extra undigested proteins in the gut, composed of undigested food and undesirable microbes. Who's left to clean up the mess and try to get some badly needed nutrients into the bloodstream? The immune system, though imperfectly. A major part of immune cell counts and activity is in the GI tract for exactly this reason, consuming a lot of energy. If digestion fails and the GI tract contains an unhealthy mixture of organisms and large protein masses, the result is a significant immune challenge by every measure, leading to inflammation and fatigue. Glutamine is an amino acid present in most protein-containing foods that is essential to brain and nerve function. Magnesium, other amino acids (ie taurine) and antioxidant co-factors render it far less overexciting to neurons. MSG and aspartame are additional proteins that can cause nerve overstimulus in some circumstances. There are ways to reduce these reactions, as described thoroughly by Dr. Russell Blailock in his books, lectures and articles. The bottom line: No need for most people to avoid soy, milk or grains if they can maintain the intregrity of their digestive and GI tracts properly. Most of those whose systems aren't in such good health can utilize fairly effective means of correcting these issues and eventually resuming the use of these foods in their diets, unless they are the relatively few with true allergies.