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Acid-alkaline food balance
Another potentially important factor of your diet is its metabolic acidity (not to be confused with taste-related food acidity). It is determined by the mineral-based acid-alkaline balance of foods you consume. Opinions on the importance of acid-alkaline food balance, from various sources, range from "critically important to health" to "totally irrelevant" and "quackery". What is the truth?
Knowing how critical for the proper body function is to maintain blood and cellular fluid at their optimum level of acidity, it is prudent to pay attention to factors that could affect it. Even small deviations from the optimum body acidity level result in compromised enzyme function and, with it, compromised health. A 60% increase in acidity (measured by the relative density of hydrogen ions in bodily fluids; in terms of the pH number, it corresponds to a drop from 7.4 to 7) results in death.
The popular concept of metabolic acidic-alkaline effect of foods on body's own acid-alkaline balance is based on so called mineral food residue. According to the molecular structure of its minerals, food supposedly has either acidic or alkaline effect on body fluids. It is primarily the effect of macro-minerals that matters here: those with negative electrical charge - phosphorus, sulfur and chlorine - are attracted to the positive H+ ion from bodily fluids, forming phosphoric, sulfuric and hydrochloric acids, respectively. And positively charged macro-minerals, like calcium, potassium, sodium and magnesium, will react with the negative OH- ion, to form (alkaline) calcium, potassium and magnesium hydroxides.
Western diets, in general,
favor foods with acid-producing mineral residue,
opposite to body's own alkaline bias. This doesn't seem wise to ignore. The body is under constant danger of becoming acidic, due to the very basic process of energy production, by oxidizing (breaking down) carbohydrates into carbon dioxide and water, producing acidic residue (CO2), that needs to be disposed of through cellular respiration, and then exhaled through the lungs (this is why the rate of breathing can directly affect body's acid/alkaline balance).
The body will do anything to maintain its optimum alkaline level, and that may include taking alkalizing minerals from where they are needed for other important body functions. At present, it is not known how probable, or frequent this particular nutrient-piracy is, but wide individual variations in body's compensatory mechanisms in general certainly make it possible, and likely.
Needless to say, such withdrawal of major minerals from their functional roles can adversely affect your health in many possible ways.
The fact is that elevated body acidity - so called acidosis - is typical of the state of acute and degenerative disease, as well as infections and heightened stress. But the fact is also that there is no scientific data on how exactly mineral "ash" imbalance alone does affect body's acidic/alkaline balance, not even in general, and much less individually. Thus, establishing desirable proportion of alkaline vs. acidic foods based on the mineral residue alone
may have its logical basis, but lacks factual guidance
needed to become useful measure of body's metabolic efficiency.
However, in the absence of conclusive scientific evidence specifying a complete set of factors significantly influencing body's acidity level, mineral "ash" effect certainly remains among possible - and probable - candidates. With that in mind, here is how the acid-alkaline effect of foods is determined, when based on their mineral residue alone.
The most appropriate basis for estimating near-optimum acid-alkaline proportion of the mineral food residue is the blood fluid. Its optimal acidity level, measured by its pH number (potency of hydrogen, determining the number of normal - i.e. electrically balanced - water molecules per every hydrogen ion, as 10pH) is ~7.4.
That makes it alkaline, with about 2.5 times fewer hydrogen ions in a given fluid volume than pure (unnatural, mineral-free) water, which has neutral pH of 7. According to this, the optimum proportion of alkaline versus acidic foods should also produce about 2.5 alkaline parts for every acidic part. In other words, assuming similar average potency of alkaline and acidic foods, you'd need to consume them in about 70% to 30% proportion, respectively. Not far from 80% to 20% proportion, recommended by the late Swedish nutritionist Dr. Ragnar Berg.
Following chart illustrates metabolic acidity of a number of common foods, given as an estimated relative potential of acidity (-) or alkalinity (+) per ounce (note that transforming it to a caloric proportion will change the 70/30 proportion, due to lower caloric and higher mineral and water content of typical alkaline food - vegetables - versus typical acidic food; if the latter would have, say, 50% higher average caloric level, caloric proportion of alkaline vs. acidic foods would be closer to 60/40).
ALKALINE-ACID (MINERAL) POTENCY
As mentioned, this and similar charts are based on food's mineral content alone. The actual effect on the body may differ, since body's own acidity level is a product of other factors and processes, such as the rate of mineral absorption, presence of other metabolites, and body's own acid/alkaline regulatory actions, based on the selective excretion or mobilization of acidic/alkaline substances.
It can't be predicted what mechanism is preferred by the body individually, at any given moment in time; instead of using alkalizing minerals, it can, say, retain more of highly alkaline ammonia, from breaking down proteins, as acid buffer, which could give to your sweat characteristic pungent smell; or it can use ammonia only after it runs out of alkalizing minerals, like calcium (note that buildup of ammonia can also result from liver or renal dysfunction).
Obviously, specific individual effect of different foods on body acidity cannot be determined based on their alkaline or acidic mineral residue ("ash") alone. Mineral acidity of various foods should be considered in optimizing a diet, but what makes majority of alkaline foods healthy has probably more to do with
their nutritional and fiber content,
than the acid/alkaline effect their mineral content itself.
Another problem with using food mineral acidity figures is that they do vary significantly for some foods from one source to another, probably due to varying mineral contents and/or methods of measurements. What is fairly consistent, though, is that
- vegetables, seeds and natural oils are generally alkalizing,
- fruit, grains and processed fats/oils are moderately acidic, while
- most acidic are meats, fish, shellfish, dairy, alcoholic beverages, sodas and sweeteners.
This criteria would help to further shape up the intake within three basic macronutrients: proteins (should be less than 1/4 from animal origin, since those foods create strong acidic metabolic residue), fats (natural oils favored over processed oils and fats) and carbohydrates (restricted sugar and sweets, modest proportion of grains, bakery and fruits, more liberal seeds and nuts, but predominantly vegetables and sprouts).
While it may less to do with food mineral acidity itself, maintaining acid/alkaline balance is, in fact, healthful, because it places you within the boundaries of a generally healthy diet. It should also make easier to the body to maintain its vitally important acidity level within its narrow tolerable range without causing significant metabolic stress. This makes a diet based on acid-alkaline food balance generally (remember, there are always exceptions) supportive of the optimum health.