The best treatment for people prone to swallowing woo is a dose of chemistry. And one of the wooiest ideas out there is the one about alkaline diets curing disease. Gives me a headache. So let’s start the discussion with a headache remedy, aspirin, or “acetylsalicylic acid.” As that name suggests, the compound is an acid and when it is absorbed into the bloodstream from the digestive tract it has an acidifying effect meaning that it lowers the pH of the blood. pH is a measure of acidity with values below 7 indicating an acidic solution and above 7 an alkaline one. Proper health requires that the pH of the blood be maintained in a narrow range, generally between 7.35 and 7.45 and to ensure that the value does not wander out of this range, our blood is equipped with a variety of compounds that can neutralize either excess acid or excess base. This makes blood a “buffer” solution, meaning that it resists large changes in pH.
The primary components of the buffer system are carbonic acid and sodium bicarbonate. Carbonic acid in the blood comes about when the carbon dioxide released from cells as they “burn” nutrients to produce energy reacts with water. Any excess base is neutralized by carbonic acid, whereas any excess acid is neutralized by sodium bicarbonate. The levels of carbonic acid are fine-tuned by the breathing rate. If respiration is very slow, carbon dioxide is not exhaled, carbonic acid builds up in the blood and the pH drops. Hyperventillation, on the other hand, causes loss of carbon dioxide, and since carbon dioxide is needed to form carbonic acid, levels of this acid drop and the pH rises. This is exactly what happens in response to an acetylsalicylic acid overdose. The aspirin causes blood pH to drop, and in response hyperventilation kicks in to raise the pH.
An influx of an acid such as aspirin, or of a large dose of an alkaline substance like baking soda, can affect blood pH, but the effect is temporary due to the blood’s rapid buffering action. There is no way to permanently alter blood pH, and in any case this would be highly undesirable because it would lead to severe complications and probably death. The reason for mentioning this is that there are all sorts of claims made by “alternative” practitioners about eating an “alkaline diet” or drinking alkaline water to change the blood’s pH in order to prevent cancer. This is based on laboratory experiments that have no relevance to a living body. When cancer cells are maintained in an acidic environment in a test tube they grow faster and chemotherapeutic drugs work more effectively in an alkaline environment. These conditions can be set up in a test tube, but not in the body. You cannot alter the acidity of the blood by any sort of diet.
The “alkaline” diet that is talked about is actually an “alkaline ash” diet that can affect the pH of the urine, but not the blood. This is determined by burning food and determining if the residue left is acidic or basic. While an alkaline diet can alter the pH of urine, it does not affect the blood. It isn’t a bad diet. It promotes the consumption of fruits, vegetables and nuts at the expense of meat, sugar, alcohol and caffeine, but the claim that this can reduce the risk of cancer is pure folly. There is absolutely no evidence that such a diet can support a sustained change in blood pH and there is no evidence of any clinical benefit. Testing the saliva or the urine with pH indicator paper is meaningless in terms of offering any clue about blood pH. None of this has stopped a variety of quacks from peddling their water alkalizers and miracle diets to cure cancer. Some even claim to cure diabetes. They are full of woo.