Many alternative practitioners believe that following an alkaline diet,
which consists mostly of fruits and vegetables, prevents health
problems such as cancer. Proponents of the alkaline diet claim that a
diet high in meat increases the acidity of your body, which can have
negative health effects. But while a diet high in acidic foods such as
meat may increase the acidity of your urine, it won't increase the
acidity of your blood.
The Importance of pH
The
term pH means "potential of hydrogen" and refers to the amount of
hydrogen in a substance. A pH of 7 is considered neutral; anything below
is acidic, while anything above a 7 is alkaline. The pH in your blood
must remain within a very narrow range, between 7.35 and 7.45 or you
become sick and can die. Both metabolic factors and respiratory factors
control pH in your blood. Metabolic factors include the breakdown and
elimination of waste products normally created by your body. Respiratory
factors include the amount of carbon dioxide you elimination from the
lungs when you breathe; excess carbon dioxide acidifies your blood.
Foods and pH
The
foods you eat do not affect the pH of your stomach, which normally
remains extremely acidic, with a pH of around 2.0. Foods also don't
affect the pH of your intestines, which remains alkaline due to
pancreatic secretions. Foods do produce either an acidic or alkaline
ash, which your kidneys eliminate. Foods you eat can have an effect on
the pH of your urine. Meats leave an acidic ash, which your kidneys must
eliminate through the urine. Not all acidic foods leave an acidic ash.
Before slaughter, animals have a pH of around 7.1. After slaughter the
pH drops to a low of between 5.4 and 5.8, which is acidic. However,
many fruits and vegetables have a similar pH. The difference is that
most fruits and vegetables leave an alkaline rather than an acidic ash.
Acid Ash
An
acidic ash, according to proponents of an alkaline diet, depletes
essential minerals such as from the body to eliminate the ash. To
neutralize large amounts of acid, for example, your body may remove
calcium from your bones to buffer the urine and make it more acidic.
This can result in loss of calcium in the urine, which some scientists
think may contribute to osteoporosis,
according to author and physician Dr. Gabe Mirkin, who does not support
the alkaline diet. Urine normally has a lower pH than blood, around
6.0.
Effects of High Acid Foods
Registered
dietitian Stephanie Vangsness of the Dana-Farber Cancer Institute says
that no studies have proven that alkaline diets prevent or treat cancer,
although laboratory studies have shown that cancer cells grow faster in
an acidic environment. However, meat and other high-acid foods do not
increase your risk of cancer or other diseases because they don't change
the pH in your body anywhere but the urine, according to Mirkin. While
cancer cells can't live in an alkaline environment, neither can any of
the other cells in your body, Mirkin states.