Glycine can be produced in the body from other amino acids and is the smallest amino acid with a simple structure. It is a component of haemoglobin metabolism (haemoglobin transports oxygen in the blood), is involved in the energy supply in creatine metabolism and plays an important role in skin regeneration, hair formation and cartilage formation. Glycine is also required as a component of DNA and is involved in the regulation of blood sugar levels.
Proline can be produced by the body from glutamic acid and ornithine and therefore does not necessarily have to be taken in with food. It is needed in the body for collagen production and is involved in the formation of body tissues. In chronic or long-term illnesses, proline can no longer maintain its protective function of collagen and must be supplied in greater quantities.
Meat and dairy products are rich in proline, whereas plant products contain hardly any portions of this amino acid. A deficiency can lead to joint problems and a general decline in performance. In addition, the stability of the artery walls can suffer from proline deficiency. Proline can only develop its full effect when there is sufficient vitamin C in the body, so there should always be enough vitamin C in the diet.
The last non-essential amino acid is serine. Serine can be produced from threonine, glycine and glucose and does not necessarily have to be taken in with food. It is not only a component of many proteins, but also belongs to the ingredients of many membranes in the human body.
Especially in the brain it is found in higher concentrations in the cell walls (cell membranes) and plays a decisive role in the transmission of stimuli to the cells. A lack of serine can lead to various symptoms. Concentration disorders as well as inattention are among the consequences of a serine deficiency in the body.
Two other amino acids (cysteine and tryptophan) can be produced from serine. Acetylcholine is also produced on the basis of serine and, as a hormone, has effects (lowering blood pressure, increasing glandular function and accelerating intestinal movements) on various human organs. A lack of serine can only occur if there are far too few proteins in the diet.
A large part of the serine is produced in the body itself. If the production of serine in the body is too low, soybeans, peanuts and cereals are the main sources of serine.