The premise of the "alkaline diet" is to alter the pH levels of your blood, in order to facilitate weight loss and fight disease. Too bad then that "alkalizing” the body is a completely nonsensical concept.
Reprinted by permission of McGill University Office for Science and Society.
The human body carefully maintains the pH of blood at about 7.35, which is slightly alkaline, or basic. This is also the pH of the cells in all our organs that depend on the blood supply for their nourishment. Should the pH drop below 7 or exceed 7.7 we are looking at a potentially catastrophic situation. Luckily, our blood constitutes a buffered system, meaning that any variation of pH is immediately compensated for. Should there be an increase in acids entering the bloodstream, we immediately start exhaling more carbon dioxide, which then reduces acidity. Should the blood start to alkalize, the lungs retain more carbon dioxide, which dissolves to form carbonic acid while the kidneys eliminate basic bicarbonate.
What all this means is that the pH of the blood cannot be altered by changing the diet. A change in diet can certainly alter the acidity of the urine but that is unrelated to the pH of the blood. Breads, cereals, eggs, fish, meat, poultry can acidify the urine while most fruits and vegetables tend to make it more alkaline. The idea of monitoring the pH of the urine to achieve optimal health by “balancing” the body’s acidity is senseless. Is it possible that some people feel better by making their urine more alkaline? That’s possible. If they switch from a heavy meat and cereal diet to one that features more fruits and vegetables they may feel better. But this has nothing to do with balancing the body’s pH.
The original McGill University OSS post can be found here.