Acid-Alkaline Balance

Posted by Blog Saturday, March 5, 2011

The blood must be maintained in a narrow range of acidity. Acidity is measured on a pH (potential of hydrogen) scale. Normal values for blood are between 7.35 and 7.45 on the pH scale. Water is used as a reference as pH 7, which is considered neutral. Values higher than pH 7 are considered alkaline (also known as base). Baking soda has an alkaline pH of 9. Values lower than pH 7 are considered acid. Vinegar has an acidic pH of 3. If the blood deviates from its narrow range of normal acidity, delicate proteins can be damaged. Enzymes need normal acidity to perform their functions and are vital to life. In hospitals the acidity of intravenous solutions is carefully adjusted for proper pH.

The concentration of hydrogen ions (H+) determines the acidity of a solution. The higher the concentration of hydrogen ions, the higher the acidity. Hydrogen ions are generated during normal energy metabolism in the cells. Other acids are also generated during normal energy metabolism. These acids must be neutralized. There are three different systems in the body that work together to normalize acidity. The kidneys, the lungs, and pH buffers in the blood keep our blood at the correct, neutral acidity

Three Systems to Maintain Blood Acid-Alkaline Balance
Kidneys release acidity.

Lungs release carbon dioxide.

Blood buffers neutralize blood.

The kidneys are the most important regulators of acid-alkaline balance.

The kidneys decide which ions to keep and which ions to reject. The acidity of urine is adjusted so that the acidity of blood stays at the proper level. Protein in excess of the adult daily requirement of 46 to 56 grams is burned for energy. When this excess protein is burned for energy, metabolic acids are formed. This puts an extra strain on the blood buffering systems. Vegetables, which leave an alkaline residue, help to offset excess metabolic acids.

Lungs also regulate the acidity of blood. During normal metabolism, carbon dioxide is formed. This carbon dioxide forms carbonic acid in the blood. This acidic influence on the blood must be neutralized. Carbon dioxide is released during respiration. If acid builds up in blood, breathing accelerates to release more carbon dioxide, thus lowering the carbonic acid levels in the blood. Conversely, if blood acidity is a little too low, respiration slows to allow more carbonic acid to build up again to regain neutral acidity in the blood. The lungs release an average of thirty liters (about eight gallons) of carbonic acid each day to keep the blood neutral.

Lungs release enough carbon dioxide each day to neutralize eight gallons of carbonic acid.


Blood acidity is also regulated by blood buffers. These buffers come in pairs that work together. One pair of buffers consists of bicarbonate (alkaline) and carbonic acid (acid). Buffers can be used up if a continuous supply of extra acid or alkaline substances is added to the blood. It is more common for excess acidity to be a problem since many metabolic wastes are acidic. If too much acid enters the blood, the bicarbonate may become depleted. Respiration may be temporarily increased to release more carbonic acid and restore the ratio of bicarbonate to carbonic acid.

Another pair of blood buffers consists of phosphoric acid and dihydrogen phosphate. This pair of blood buffers also consists of an acid-alkaline pair. Proteins in blood also can act as blood buffers by donating or accepting positive hydrogen ions. A healthy body does an excellent job of adjusting fluids, acidity, and the balance of minerals.

More about Macro Minerals:

Macro Minerals

Water and Electrolytes

Water Output-Water Input


Blood Pressure and Blood Volume

Fluid and Electrolyte Balance in the Cells

Movement of Electrolytes

Fluid and Electrolyte Balance in the Body

Acid-Alkaline Balance


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