Amino acids are vital to human health because the body uses them for many different biological processes. They are the building blocks for muscle growth, hormone production, and cellular repair. Amino acids are also used in the manufacturing of enzymes.
The human body utilises 21 different amino acids; most can be synthesised within the body, but nine are essential. What this means is that these nine amino acids must be obtained from the diet regularly to maintain good health.
Even if all amino acids are present and correct, poor absorption can hinder the processes they are needed for, leading to a steady deterioration in general health.
There are various disorders of amino acid absorption that leave sufferers with deficiencies in certain amino acids, producing multiple symptoms, some of which can be serious. What symptoms an individual displays depends on what amino acid is not being absorbed.
Amino acid metabolism disorders usually lead to the body being unable to break down certain amino acids so the body can use them. If this continues, vital amino acids cannot be absorbed, and symptoms of amino acid deficiency start to show.
One such disorder called Phenylketonuria or PKU is caused by a decrease in the activity of an enzyme known as phenylalanine hydroxylase, which converts the amino acid phenylalanine to tyrosine.
This ultimately results in increased amounts of phenylalanine in the body and low levels of tyrosine. If this cycle persists, then symptoms such as seizures and behavioural problems can occur.
Homocystinuria results in a build-up of homocysteine, causing symptoms such as vascular disease, osteoporosis, and psychiatric disorders.
Non-ketotic hyperglycinaemia causes underdeveloped muscle tone and developmental impairment, which is down to a build-up of the amino acid glycine.
Most causes of amino acid absorption disorders are due to enzyme defects which either leave the body deficient in an amino acid or allow certain amino acid levels to become elevated.
Both scenarios affect the amino acid balance in the body, and this is what ultimately causes symptoms to appear.
Disorders of amino acid absorption are mostly inherited, so the risk factors of developing such a condition mostly lie with parents passing on the enzyme defects to their children through their genes.
Symptoms displayed by individuals, along with blood and genetic testing, can help diagnose which amino acid absorption disorder an individual has developed. Only then can an accurate treatment program be put into action.
Treatments vary depending on what amino acid disorder is present. If too much of an amino acid is present due to an enzymatic disorder, then lowering the intake in the diet can help. The opposite can be done if depletion of an amino acid is present.
Some drug therapies can also help reduce the build-up of certain amino acids in the body due to defective enzyme activity.
Prevention is all down to screening individuals so that they do not pass down the defective genes that cause these disorders to their children.