Our modern diet has many more acid than alkaline substances, especially compared with our historical diet. An acid-alkaline imbalance is linked to many chronic health conditions such as osteoporosis and arthritis as our body is unable to compensate for the increase in acidity. Modifying your diet to be more acid-alkaline balanced is easy to do and has a positive impact on health.
The Stone Age diet was high in alkaline-forming foods and low in acidifying foods, according to R. Curtis Morris and colleagues in an article published in 1996 in "Journal of the American College of Nutrition." This mismatch is a problem because while our modern diet has changed rapidly to become very acidic, our bodies are still designed for a much more alkaline diet.
Dr. L. Frassetto and colleagues, leading researchers in the field of acid-base balance, wrote of the importance of a diet which has an acid-base balance in a 2001 article in the "European Journal of Nutrition." They indicated that a diet which is chronically skewed towards acid-forming foods and lacking in alkaline-forming substances—particularly potassium and bicarbonate—could lead to low-grade acidity in the body.
Many health problems are linked to an imbalanced acid-alkaline diet. For example, Regina Cseuz of the Revita Rheumatology Clinic in Hungary and her colleagues found a link between acidity and symptoms of rheumatoid arthritis and presented their findings at the International Acid-Base Symposium in Germany in 2006. While Dr. David Bushinsky describes the strong correlation between acid-base imbalance and the development of osteoporosis in an article published in 2001 in the "European Journal of Nutrition."
Sources of Acids
Knowing which foods are acidic and which are alkalinizing is key to an acid-alkaline balanced diet. Research done in Germany by Dr. Thomas Remer and Dr. Friedrich Manz published in 1995 in "Journal of the American Dietetic Association" determined the acidity and alkalinity of dozens of common foods. They calculated the potential renal acid load, or PRAL, per 3.5 ounce portion to express the acidity or alkalinity of a food. A positive value is more acidic and a negative value is more alkaline.
High-protein cheese ranked the highest as a source of acid, with an average PRAL of +23.6 but some cheeses such as Parmesan have an even more acidic PRAL. Milk has a fairly neutral PRAL of +0.7. Meat on average has a PRAL of around +9.5. Bread—white or whole wheat—has a PRAL of +3.5 and white rice has a PRAL of +4.6. Pasta has a higher PRAL of +6.7. Nuts are also acidifying with peanuts having a PRAL of +8.3.
Sources of Alkaline
The best alkaline foods are fruits and vegetables. Spinach has a PRAL of -14.0, celery has a PRAL of -5.2 and fresh carrots have a PRAL of -4.9. Most other vegetables have PRAL values around -2.8.
Raisins are also strongly alkaline with a PRAL of -21.0. Other strongly alkaline fruits include black currents, apricots and bananas with an average PRAL of -5 to -6. The average PRAL for fruits and fruit juice is -3.1.
Balancing the Diet
Since fruits and vegetables are alkalinizing and meats and grains are acidifying, the key to an acid-alkaline balanced diet is to balance the different PRAL values within a single meal. If you have a 3.5 ounce portion of meat with a PRAL of +9.5, you need to balance that with enough alkaline foods to equal or surpass a PRAL of -9.5. Three ounces of spinach or 7 ounces of carrots would balance the acid in the portion of meat.
If you were to have a large sandwich with 3.5 ounces of turkey, 2 ounces of tomato and 3 ounces of cheese with 3 ounces of bread, you would have an acidic PRAL of approximately +37.0. To balance this, you could drink 8 ounces of vegetable juice and eat a banana and 3.5 ounces of raisins. Or you can cut down the acidifying foods, such as cutting down or eliminating the meat or cheese portion.
By knowing the average PRAL of foods and monitoring your portion sizes you can follow an acid-alkaline balanced diet.