Alkalinization and the PRAL Score of Food
Written By: Dr. Peter L. Kopko, D.C.
Measuring the pH (alkalinity or acidity) of water is easy: you simply place 2-3 reagent drops in an ounce of water and look at the color of the water. Measuring the pH of solid foods is much more difficult. Today, there are two basic methods for calculating the pH of foods.
The first method is known as ash analysis. This method requires food stuff to be incinerated at a high temperature. The ashes are analyzed for mineral content. Acidic anions in food include chloride, phosphorous, sulfates and other organic acids. Basic/alkaline cations in food include sodium, potassium, calcium and magnesium. The problem with this method is that it did not take into account the bioavailability of the food’s constituents. It was in a sense an in vitro (in a laboratory) test as opposed to an in vivo (in life) analysis.
In 1995 two researches Dr. Thomas Remer and Dr. F. Manz developed a new way to measure the acid/base effect of specific foods on the human body. This pH measuring tool is referred to as the P otential R enal A cid L oad (PRAL ). The PRAL of an ingested specific food is determined by measuring the acidity and ammonium appearing in the urine and then subtracting out the measured urinary bicarbonate. This method yields a net acid excretion score based on direct measurements of the urine. Previous to the implementation of the PRAL score method, ash analysis was utilized.
The PRAL method is far superior to ash analysis in that it takes into effect the digestion and absorption of a food and its direct effect on the kidneys and urine. However in my opinion the PRAL method has some limitations as well in that a specific food may elicit a pH homeostatic balancing mechanism and that would influence the end result in the urine. This may be evidenced by the PRAL score of coffee. Nevertheless, the PRAL method remains the best method to date.
Click here to download Table of Foods & Beverages and Their Relative PRAL Values
Let’s calculate a total PRAL score for an average Western diet meal. Take 250g (about ½ lb.) of chicken. The PRAL value for chicken is 8.7 per 100 grams. We have 250 grams which is 2.5 times 100, so we multiply 8.7 by 2.5 which equals +21.75. Add ½ pound of potatoes, that would be -4 times 2.5 which equals -10. Add 8 oz. whole milk, so multiply 1.1 by 2.5(8 oz. equals about 250g) which equals +2.75. The total for the meal would be +14.50. That is a highly acidic load and so typical of the average American diet. Using other typical foods yields the same acidic story. It is not until you incorporate several servings of vegetables and fruits and limit the amount of meat, poultry and fish before you reach a net alkaline PRAL score. Go back to the PRAL table above and look at the food group averages. The whole story is there. Meats, grains and dairy products are all highly acidic. Vegetables, fruits and nuts are all alkaline. Interesting isn’t it? All the foods you have always been told to eat because they are healthy are alkaline forming!
Eat healthy alkaline foods and drink 3-4 quarts of ionized alkaline water every day!
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