In distilled water at 22 ° C, there is one gram of Hydrogen ions( H +) and one of hydroxyl ions( OH –) for every 10,000,000 liters of water; the proportion is thus 1 / 107, or 10−7. The pH of water is thus 7. Acids have a higher proportion of H +. For example, beer has a pH of 4.5, which means that there is 1 gram of H + to 150,000 liters of fluid. Stomach acid, which is very corrosive, has a pH of 1.1, or 1 gram of H + to just 10 liters of fluid. The important thing to remember is that when the numbers go down, the acidity goes up. Because water has equal amounts of H + and OH –, it is considered neutral. A pH under 7 is considered acid, while a pH over 7 is alkaline.
Is this relevant to our body? Immensely so. The pH of our blood plasma must remain at a constant between 7.35 and 7.45. The slightest deviation in either direction spells trouble. An acid pH of 6.95 results in diabetic coma and death, while an alkaline pH of 7.7 causes tetanic convulsions and eventual death. The more acid pH of the blood slows the heartbeat, whereas a more alkaline plasma speeds it up. 3 Clearly, maintaining the correct pH level of the blood is vital, and the body has several mechanisms to ensure its homeostatic balance. When the level of acids in the bloodstream is raised by the movement of the muscles and oxidation of protein and starches, these acids are then
• Broken down into water and carbon dioxide, to be eliminated through kidneys, skin, and lungs
• Utilized by the stomach for digestion as hydrochloric acid( ever notice how a walk after dinner improves digestion?)
• Neutralized and excreted as salts by the kidneys
• Neutralized or buffered by the presence of minerals left behind by the metabolism of alkalizing foodstuffs. From a nutritional standpoint, foods are classified as either acid-forming or alkalizing according to the effect they have on the body, not according to their own intrinsic acidity or alkalinity. Thus, many foods that taste“ acidic”( grapes and citrus, for example) are considered alkalizing because they leave an alkalizing residue upon being metabolized: the organic acids that affect the taste buds are dissolved and converted into carbon dioxide and water, while the minerals that are left behind serve to neutralize body acids. This is true, in fact, of most fruits and vegetables, as well as sea vegetables( dulse, kelp, hiziki, nori), all of which are high in buffering minerals( sodium, potassium, calcium, magnesium, iron). Coffee, when it is not decaffeinated, can also be alkalizing, for caffeine is an alkaloid; the rest of the coffee is highly acidic. Salt, because of its sodium content, is an alkalizing element as well. Bland-tasting foods, on the other hand,( for example flour, fish, and grains), are often, though not always, acidforming: when metabolized, they leave sulphuric, phosphoric, and hydrochloric acids behind. The only vegetable foods that are acid-forming are cranberries, plums, and prunes. I would like to add raw tomatoes with seeds to that list, as they sometimes provoke acidic reactions, such as mouth sores or bumps on the tongue( wellcooked, seeded, salted tomatoes seem more alkalizing). Sugar and other concentrated sweeteners, starches, grains, flour, fats, and most animal protein foods also create an acid condition upon being metabolized. The exceptions: potato and kuzu( kudzu) starch( see this page for more on this food) are alkalizing, and so at times are raw milk and cheese, because of their calcium content. † In chemistry, the alkalis, or bases, are also known as acid-buffers; they cushion the corrosive effects of acids. Thus we can say that the alkalizing foods will buffer the acidifying ones. In addition, there is a category of foods that belong in a separate“ buffer” category, for they can produce either effect: they will render the acid less acid by their mineral content, and the alkaline less alkaline by their protein content. These are dairy and soybean products( cream, yogurt, milk, cheeses, tofu), which combine well with either category of food. Butter, which has been found to be neutral( neither acid nor alkaline) also belongs in this category. Just think: We put butter on bread( acid) and cream in the coffee( alkaline); we eat fruit( alkaline) with yogurt; we add tofu to both grain( acid) and vegetables( alkaline), and melt cheese over meat( acid)— trying, in effect, to bring the extremes closer together and keep ourselves in balance. What is the relationship between the acid-alkaline and the expansive-contractive sets of opposites? Is acid expansive or contractive? And what is alkaline? Both are both. Sugar is an expansive acid-forming food, whereas meat is a contractive acid-forming one. Fruit is alkalizing and expansive, whereas salt is alkalizing and contractive. 6 We can see these relationships more clearly on the chart below.