Regulating the acid-base balance
The acid-base balance
Keeping the body’s pH levels in balance is a question of the acid-base balance. But what is meant scientifically by the term acid-base balance, and how can you maintain your acid-base balance?
What is the acid-base balance?
The acid-base balance is a prerequisite for the normal course of metabolic processes. Enzymes are the catalysts that control all our metabolic processes. Since their activity is pH-dependent, they require specific pH conditions to work at their best. Even a slight deviation in pH can restrict enzymes’ activity, causing functional impairments in metabolism. That is why physiological pH values must be maintained under all circumstances to ensure the metabolism functions smoothly.
The acid-base balance thus forms the basis for the normal course of metabolic processes.
Keeping pH values as stable as possible
Our body’s acid-base balance should not be seen as a rigid system, but rather as a dynamic equilibrium. It is true that the amounts of acids and bases in our body are constantly changing. However, it keeps the pH values in the various organs and types of tissue, as well as in the blood, constantly within narrow limits.
The physiological pH value
What pH value is good? There is no straightforward answer to this question, because each organ or stage of metabolism has its own optimum pH value.
- Blood plasma pH 7,35–7,45
- Gastric juices pH 1,2–3
- Bile pH 7,4–7,7
- Urine pH 5–8
- Saliva pH 6,8
- Joint fluid pH 7,4–7,8
Diet can regulate the acid-base balance
Regulation of the acid-base balance is necessary to stabilise the pH value in the blood. Many factors play a role in this. Above all, the nutrients from our diet regulate the acid-base balance, since they are metabolised as acid or as alkaline. But whenever we breathe or engage in physical activity, acid is produced as a waste product of energy production in our cells. This influences the pH value in the blood. In order to avoid an excess of acid overall, different regulatory processes run automatically in the body.
The body’s own regulation mechanisms
If the acid-base balance is upset, the body has various mechanisms at its disposal to bring acids and bases back into balance. These involve body’s own buffer systems, kidneys and lungs, connective tissue and bones.
Acid-base regulation through the body’s own buffer systems
Our body is equipped with a powerful buffer system to help it regulate our acid-base balance. These buffers are substances that serve to protect against sudden shifts in the pH values in body fluids and in cells – in particular to stabilise the pH value in the blood. Important components of this buffer system for regulating the acid-base balance are the alkaline bicarbonate dissolved in the blood and the red blood pigment haemoglobin.
Bicarbonate can bind to acid, producing carbonic acid, which breaks down into water and carbon dioxide. The latter is exhaled via the lungs. This is a quick and effective way to correct the pH value in the blood. Zinc is a cofactor for the enzyme carbonic anhydrase. It is jointly responsible for the formation of bicarbonate, which means it is also important for regulating the acid-base balance. In order for our buffer systems to regenerate regularly, the body needs alkaline minerals, which it must get from food.
Kidneys and lungs: Excretion and exhalation of acid
The most important organs for regulating the acid-base balance are the kidneys and the lungs. The kidneys are the only organs that can directly eliminate acid from the body. The lungs ensure a stable pH value in the blood for a short time via respiration. Increased exhalation of carbon dioxide allows the body to regulate acid-base balance.
Connective tissue as an acid store
If the buffer system reaches its limits and the kidneys’ capacity to excrete acid is exhausted, the body must take the acid “out of circulation” in order to maintain optimum metabolic conditions.
Storing acid in connective tissue – the physical nature of which makes it particularly suited to this task – allows the body to regulate its acid-base balance. While this does stabilise the pH value in the blood, it also decreases the ability of connective tissue to bind water. Supplying the trace element copper can help maintain normal connective tissue.
Acid balance through bases from bones
If the capacity of the buffer systems is exhausted, the body can fall back on the bones as its own alkaline deposits, regulating the acid-base balance by releasing alkaline minerals from the bones to neutralise acids. The longer this situation persists, the more it shifts the physiological balance between bone formation and bone resorption.Supplying the two minerals calcium and magnesium promotes bone health.