The acid-base balance of human plasma and other tissues is of vital importance. Acidosis and alkalosis are medically accepted terms, and can be found in any textbook of medical physiology. Acidosis refers to an excess of acid in the body or a low pH, while alkalosis refers to an excess alkalinity in the body or too high a pH. Acidosis is far more common than alkalosis and can result from diabetes, uncontrolled respiratory disorders, heavy loss of fluids from diarrhea for example, or through renal insufficiency. These relatively short term, serious and easily diagnosable conditions of acid-base imbalance are well characterised and understood. However a chronic, subtle and more insidious deviation from normal homeostatic acid-base balance is thought to occur through regular consumption of low quality foods containing too many acid forming foods. Such a nutritional disorder is now recognised as a likely cause of Western lifestyle diseases, particularly osteoporosis.
When food in metabolised it produced an ‘ash’ residue that is a reflection of the mineral content of the foods. Plant foods contain high amounts of potassium and this produces potassium salts that can alkalinise the blood. In contrast the sulphur containing amino acids present in animal protein for example leave an acid residue that can acidify the blood. Alkaline foods include most fruits and vegetables, nut and some cereal grains such as millet. Acid foods include fish, meat, eggs, wheat, peanuts and lentils. Neutral foods that do not affect the acid-base balance include milk, butter and vegetable oils. It is recommended that between 20 and 50 % of foods are acid forming, whilst 50 to 80 % are alkaline forming foods. The ability to alkalinise the blood may be ones of the reasons for the beneficial effects of fruits and vegetables. Traditional diets tend to provide more alkalinising that acidifying foods, which may be one of their key benefits. Drinking mineral rich water may also be able to lower the acidity of the tissues and thus restore health.