Tired or run down? Overweight, with poor digestion, aches and pains, or even more serious problems? If so, you may be suffering from chronic acidosis."
This is the health message you're likely to hear from a burgeoning new theory in alternative medicine: the acid-alkali balance. The last few years have seen a spate of books on the subject, with titles like Alkalize or Die and Sick and Tired?: Reclaim Your Inner Terrain. Their basic claim is that the key to good health is to control acidity in the body.
In the wake of these publications has come a host of new health products - acidity-testing kits, specially treated alkaline water and anti-acidity food supplements.
The pH scale
First, some basic chemistry. Acids and alkalis (opposites) are measured on a scale called the 'pH', which represents the balance between hydrogen and hydroxide ions in a liquid. A low pH corresponds to a high hydrogen-ion concentration; the more hydrogen ions, the less hydroxide ions and the more acidic the solution. A score of 1 is the most acidic and a score of 14 is the most alkaline.
The pH scale is logarithmic - every step on the scale represents a multiplication of 10. So, lemon juice, which has a pH of 2, is 10 times more acidic than soda, with a pH of 3. Water has a pH of 7 and is neutral. Common acids include lemon juice and vinegar (with a pH of around 3), and common alkalis - also called 'bases' - include baking soda (pH of 8) and milk of magnesia (pH of 10.5).
Acidity vs alkalinity
Perhaps surprisingly, despite being 75 per cent water, the human body contains a wide range of pHs, sometimes at locations that are only a few inches apart. The most acidic site is the stomach (pH 2), while the most alkaline area is the intestines (pH 8).
Hydrochloric acid in the stomach has a concentration strong enough to burn your skin, but it's kept harmless in the stomach by mucus produced in the stomach lining. Stomach acid mixes with food and breaks it down into a mush called 'chyme', which has a pH of around 4. Chyme passes into the intestines where it is rapidly made more alkaline (up to a pH of 8).
The reason for this change from acid to alkali is that the intestines need to be able to absorb nutrients, and they can't do this properly in an acidic environment. This dramatic decrease in acidity is masterminded by the pancreas, which pumps out just the right amounts of antacid bicarbonate to transform the broken-down food into the correct degree of alkalinity for absorption in the intestines.
These antacids produced by the pancreas are not to be confused with the antacid products created by the pharmaceutical industry such as Tums and Alka-Seltzer. That billion-pound industry is largely based on a myth. Their advertising claims that they can 'neutralise excess stomach acid' are a distortion of the facts, implying as they do that stomach acid is the problem.
However, on the contrary, stomach acid is vital for digestion and, indeed, it is a lack of it that may cause indigestion. Thus, the use of antacids, particularly in the long term, can produce the very problems that people with indigestion are trying to prevent. Even worse, the newer 'proton-pump' antacids such as Zantac and Prevacid can more than double the risk of stomach infections by bacteria such as Clostridium difficile, a leading cause of diarrhoea and colitis (J Am Med Assoc, 2005; 294: 2989-95).
So, what brings on the typically sour symptoms of indigestion? Most of it is thought to be due to the fermentation of foods in the stomach brought about by overeating or eating too fast.
But acid can be a problem in other respects, so the body has developed various ingenious systems for keeping it under control. The trouble is that the basic functioning of cells produces acidic waste products, and these need to be got rid of. The body's principal acidic waste-disposal units are the kidneys and the lungs. The kidneys do two jobs: they excrete excess acid into the urine and pump out ammonia (an alkali) into the blood. The lungs mix oxygen with protein to form carbonates, thus creating the body's own natural antacids.
The combined forces of the lungs and kidneys result in an overall slightly alkaline system. This suggests that, to maintain health, the body prefers to keep itself at a constant state of mild alkalinity. Blood, in particular, is kept within a very narrow pH range of 7.35-7.50, which is slightly on the alkali side of neutral. This exquisitely fine balance has been described as "among the most tightly regulated variables in human physiology" (Crit Care, 2000; 4: 6-14).
Thus, it's clear that the human body works best, and its chemistry functions most effectively, when its most vital liquid - the blood - is slightly alkaline.
What does all of this imply for our health? There's increasing evidence that lots of external factors can upset the body's delicate pH balance. For one thing, maintaining the correct acid- alkali ratio can exact quite a toll on the body. If there's too much acid for the kidneys and lungs to cope with - a state of 'acidosis' - the body becomes a thief, robbing its own bones of calcium, and turning it into an alkaline calcium carbonate. As an emergency measure, this won't do much harm. But if the acidosis is chronic or long term, the bones can become depleted of essential minerals. "Even subtle chronic acidosis could be sufficient to cause appreciable bone loss over time," says professor of anatomy Dr Tim Arnett of University College, London (Proc Nutr Soc, 2003; 62: 511-20).
What are the causes of chronic acidosis? A major one is simply growing old. As we age, most bodily functions become less efficient, and that includes the kidneys and lungs. So the natural acid-alkali regulation system starts to break down, forcing the bone-store robbery system to kick in more often. Some experts now believe that this could be a main cause of osteoporosis (Swiss Med Wkly, 2001; 131: 127-32).
Acidosis can also result from things that put stress on bodily functions, such as ill-health or infections, anorexia, prolonged exercise like running marathons, diabetes and the menopause (Proc Nutr Soc, 2003; 62: 511-20).
But perhaps the most common cause of acidosis is the food we put into our stomachs. It's hardly surprising that what we eat has an effect on our acid-alkali balance. But it's not nearly as simple as 'acidic foods cause acidosis'. In fact, the actual acidity of the food itself is irrelevant; for example, oranges and lemons - full of citric acid - don't increase blood acid at all. In fact, they do the reverse, as almost all fruits turn out to be alkali-producing (see box above). If you do get an 'acid stomach' from consuming citrus fruits, it's almost certainly not because of the acid in the fruit, but most likely due to an allergy or intolerance to citrus.
So what are considered the acid-forming foods? In many people, these are mainly proteins - meat, fish, poultry, eggs and most nuts. This is mainly the result of their high sulphur, phosphorus and iron contents. At the other end of the spectrum, carbonated soft drinks are also high acid-formers due to their high phosphate content. But milk, high in protein and thus acidic, also contains calcium, which acts as an alkaline buffer - making it, in effect, neutral.
The alkali-forming foods are primarily fruits and vegetables. These are rich in potassium, calcium and magnesium - minerals that create alkaline reactions in the body.
According to one theory, it's no accident that our blood prefers to be alkaline rather than acidic: it's all to do with our ancestral past. Professor Lynda Frassetto and her colleagues at the University of California have analysed the diets of man's ape-like forebears for acid-alkali content, and discovered that their diet of wild plants and fruits would have been highly alkalinising - a factor almost certainly incorporated into our genes over thousands of years of human evolution.
However, with the rise of agriculture 10,000 years ago, the human diet changed dramatically in favour of high-protein grains and farmed meat, a trend that has accelerated over the last 200 years. What's more, processing our foods has dramatically reduced its potassium (alkali-forming) content, and artificially increased its sodium (acid-forming) content (J Nutr, 2004; 134: 2903-6), condemning us to what Frassetto calls "chronic low-grade metabolic acidosis and its pathophysiological sequelae" (Eur J Nutr, 2001; 40: 200-13).
The question is, just what are these pathological consequences?
This is where conventional medicine shrugs its shoulders. If there is a problem at all, say most doctors, acidosis will increase the risk of only two conditions: kidney stones and osteoporosis.
But 150 years ago, that wasn't the tune being sung. At that time, there was a movement among some cutting-edge medical researchers that claimed that acidosis isn't just a minor medical problem, but the primary cause of all disease, period.
Pasteur vs Bernard
One of the chief protagonists of this movement was Dr Claude Bernard (1813-1878), an eminent French physiologist and contemporary of Louis Pasteur (1822-1895). It was unlucky that these two men were contemporaries, as they each arrived at opposite ideas as to the cause of ill-health.
Pasteur believed that disease was caused by invading microbes. Bernard, however, pointed out that, although Pasteur's 'germ theory' may well be true, it was not the whole story. Bernard stressed what he called le milieu int'erieur - the internal environment, or the basic health of the body. If the body is healthy, disease won't gain a foothold. Bernard is reputed to have proved his point by drinking a glassful of cholera microbes - without harm.
Bernard's major contribution to medicine was to show that, although a healthy immune system is important, it is not the major player in the picture of disease. Before, beyond and beneath the immune system lies the state of the body itself - le terrain. If the terrain is healthy, the immune system will never have to be called upon, as it is merely a second line of defence. The primary one is the state of the body itself.
Bernard identified two major factors as comprising a healthy 'ground': a negative electrical charge, and a state of alkalinity. He laid stress on good nutrition and the avoidance of toxins as the best way to achieve those foundation stones of a healthy body.
And what of Pasteur? After a lifetime of scientific combat with Bernard, Pasteur is reported to have recanted on his deathbed in a final acknowledgement that Bernard was right after all.
Curiously, at about the same time as Pasteur, German pathologist Rudolph Virchow also came to the same conclusion. Virchow was Europe's other great proponent of the germ theory of disease - and yet he wrote: "If I could live my life over again, I would devote it to proving that germs seek their natural habitat - diseased tissue - rather than being the cause of the diseased tissue."
It took years for the connection between the acid-alkali balance and le milieu int'erieur to come into public awareness. It was not until as late as 1933 - when New York doctor William Hay (of Hay diet fame) published his popular book, A New Health Era, in which he maintained that all disease is caused by 'autotoxication' (self-poisoning) due to acid accumulation in the body. .
Thirty years later, Professor George Watson, a psychologist at the University of Southern California, discovered that that small changes in blood acidity had major effects on his patients' moods. As a result, he was able to determine that the ideal blood pH was exactly 7.46. Armed with this information, he set about producing dramatic cures in his patients simply by giving them foods that altered the pH of their blood (Watson G. Nutrition and Your Mind: The Psychochemical Response. Harper & Row, 1972). But this work was largely ignored.
It took another American pioneer, Rudolf Wiley, PhD, to develop the concept of blood pH still further. With a background in physics, Wiley discovered that not only did psychological conditions improve on balancing blood pH, but so did a number of physical problems such as fatigue, allergies, obesity and cardiovascular disease (Wiley RA. BioBalance. Essential Science Publishing, 1998). Wiley carried out a huge amount of basic medical hard slog to determine which foods caused blood acidity or alkalinity (see box, page 8).
However, Wiley only had part of the story. Cancer specialist William Kelley proposed that an individual's reaction to any food depended entirely upon how his body metabolised its fuel. William Wolcott, who took up Kelley's mantle, further discovered that people had a tendency to either burn or store food (see Viewpoint, page 3), and certain foods or nutrients had opposite biochemical effects depending on a person's metabolic type.
Most nutritionists maintain that certain foods are inherently acidic and that others are inherently alkalising. However, this ignores the simple fact that a food's effect on the body does not derive from any inherent quality of the food itself, but on how the body's numerous homeostatic controls - the rate of food conversion to energy; the autonomic nervous system, the master controller of metabolism; oxygen metabolism within the cells; immune responses; electrolyte balance - are influenced by the qualities of the food.
"The way in which any given food or nutrient affects a person's biochemistry is always relative to that individual's metabolic type," says Wolcott.
In his experience, vegetables can alkalinise an autonomic-dominant person - whose metabolism is mainly controlled by the autonomic nervous system - but acidify an oxidative-dominant type - whose oxidative sys-tem is the controlling force.
For the latter type of person, meat can have an alkalising effect (see box below). Kelley discovered this fact when his wife, who was extremely ill, failed to get better on a 'healthy' vegetarian diet. In desperation, he fed his wife beef broth and, 24 hours later, she experienced a dramatic recovery.
So, to maintain a slightly alkaline status, the best route may be to deter-mine and eat for your metabolic type.
The acid-alkali balance theory is being explored by a growing number of alternative physicians - particularly for cancer. The reasoning goes like this: cancer cells are highly acidic with a very low pH, and are also highly anaerobic (they can only live without oxygen). Therefore, to stave off cancer, alkalinise the body, which not only reduces acidity, but also oxygenates the body.
As yet, no one has done the research. But as people move away from the one-size-fits-all diet towards individualised regimes, the more enlightened will be considering pH as part of the package.
Tony Edwards and Lynne McTaggart