Acid And Alkaline Foods: The Real Story

Although the alkaline diet is generally healthy, the body's pH management and cancer–acid relationship have been poorly understood by its promoters.

- Robert G. Smith, Phd, And Andrew W. Saul

Alkalising foods are sometimes believed to behealthier because they prevent acid build-up in thebody. This is a myth.1–3 Alkalising foods such as vegetables, fruits and nuts are healthy—not because they prevent acid build-up, but because they contain more essential nutrients, fibre, and a healthy balance of carbohydrates and fats.3

Foods in the diet contain a variety of biochemicals and essential nutrients. Some foods are acid, some neutral, and some alkaline. During digestion, all foods are acidified by very powerful stomach acid. In the metabolic process, some foods such as meat, cheese, fish, and eggs generate acid (low pH). Other foods such as vegetables, fruits, and nuts cause alkalinity (high pH).

How Your Body Manages pH

The pH of the blood and body organs is kept within very tight limits near 7.4 (between 7.35 to 7.45). This is accomplished by several mechanisms. The pH of blood and body organs is largely controlled by the level of carbonic acid (H2CO3), which is in equilibrium with the bicarbonate ion (HCO3-). More carbonic acid in the blood plasma causes lower pH, and less carbonic acid causes higher pH.4

CO2 <=> CO2 + H2O <=> H2CO3 <=> H+ + HCO3(gas) (dissolved)

On the scale of seconds to minutes, pH is regulated by the rate of breathing. Faster breathing exhales more carbon dioxide from the lungs. Since carbonic acid in the blood is in equilibrium with carbon dioxide in the lungs, faster breathing removes acidity from the body, causing higher pH.