Advertisements for products such as coral calcium or alkaline water claim that they will neutralize acid in your bloodstream, but eating calcium or drinking alkaline water does not affect blood acidity. You should not believe that it matters whether foods are acidic or alkaline, because no foods change the acidity of anything in your body except your urine.
Your stomach is so acidic that no food can change its acidity. Citrus fruits, vinegar, and vitamins such as ascorbic acid or folic acid do not change the acidity of your stomach or your bloodstream. An entire bottle of calcium pills or antacids would not change the acidity of your stomach for more than a few minutes.
All foods that leave your stomach are acidic. Then they enter your intestines where secretions from your pancreas neutralize the stomach acids. So no matter what you eat, the food in stomach is acidic and the food in the intestines is alkaline. Your bloodstream and organs control acidity in a very narrow range. Anything that changed acidity in your body would make you very sick and could even kill you.
Chemical reactions in your body are started by chemicals called enzymes. For example, if you convert chemical A to chemical B and release energy, enzymes must start these reactions. All enzymes function in a very narrow range of acidity called pH. If your blood changes its acidity or alkalinity for any reason, it is immediately changed back to the normal pH or these enzymes would not function and the necessary chemical reactions would not proceed in your body. For example, if you hold your breath, carbon dioxide accumulates in your bloodstream very rapidly and your blood turns acidic, and you will become uncomfortable or even pass out. This forces you to start breathing again immediately, and the pH returns to normal.
If your kidneys are damaged and cannot regulate the acidity of your bloodstream, chemical reactions stop and you poisons accumulate in your bloodstream and you can die.
Certain foods can leave end products called ash that can make your urine acid or alkaline, but urine is the only body fluid that can have its acidity changed by food or supplements. ALKALINE-ASH FOODS include fresh fruit and raw vegetables. ACID-ASH FOODS include ALL ANIMAL PRODUCTS, whole grains, beans and other seeds. These foods can change the acidity of your urine, but that’s irrelevant since your urine is contained in your bladder and does not affect the pH of any other part of your body.
When you take in more protein than your body needs, your body cannot store it, so the excess amino acids are converted to organic acids that would acidify you blood. But your blood never becomes acidic because as soon as the proteins are converted to organic acids, calcium leaves your bones to neutralize the acid and prevent any change in pH. Taking calcium supplements or drinking alkaline water will not change the pH of your blood. A healthful diet should include adequate sources of calcium.