Plasma amino acid testing is used to determine the adequacy of dietary proteins and the balance of amino acids in the body, factors that lurk in many chronic pathological conditions.
Amino acid testing shows the level of amino acids available in the body to produce structural, transport, and storage proteins and the synthesis of immunoglobulins and enzymes. Amino acids also play an essential role in many other body functions, such as the synthesis of neurotransmitters, the metabolism of carbohydrates and cholesterol, and the organism's detoxification processes.
Why is Amino Acid testing necessary?
Amino acid imbalance can often be the first sign of many diseases, from depression to obesity. Amino acid balance disorders and deficiencies are common in people with poor nutrition. Since stress, age, inflammation, and various other factors, including exercise, can affect amino acid levels, people with good nutrition may also have deficiencies.
Plasma and urine amino acid analysis are valuable diagnostic tools for identifying inherited metabolic diseases (e.g., phenylketonuria) and examining patients on chronic parenteral nutrition.
Amino acid balance disorders are observed in certain conditions of the gastrointestinal tract, food intolerances, vitamin and mineral deficiencies, renal and hepatic impairment with reduced ability to detoxify the body, psychiatric disorders, chronic inflammation, oxidative stress, and many other inherited and acquired disorders of amino acid metabolism.
Who should test for Amino Acids?
Amino acid testing can help patients investigate the causes of diseases such as:
- Attention Deficit Hyperactivity Disorder (ADHD)
- Autism spectrum disorders
- Depression and stress
- Epileptic seizures
- Chronic fatigue syndrome
- Insomnia
- Cardiovascular diseases
- Hypertension
- Digestive disorders
- Infertility (in men and women)
- Nutritional deficiencies
- Rheumatoid arthritis and other autoimmune diseases
More information
Amino acids are organic compounds that contain nitrogen and are the building blocks of proteins. More than 500 amino acids have been identified in nature, but only 22 are used in protein synthesis, and only 20 are encoded by our genetic code in DNA. These 20 amino acids are classified as essential and non-essential. The human body cannot synthesize essential amino acids, which must be included in the daily diet. Some amino acids are essential because they may be necessary under specific conditions, usually age or certain pathological conditions. For example, arginine can be synthesized by adults but not by children.
Many critical amino acids, including those used in protein synthesis and some not used in protein synthesis, play critical roles in the body. For example, in the human brain, glutamic acid and gamma-amino-butyric acid (GABA) are the major stimulant and inhibitory neurotransmitters. Hydroxyproline (an essential component of connective tissue collagen) is synthesized from the amino acid proline, glycine synthesizes porphyrins in red blood cells, and carnitine transports lipids.
Many people have "hidden" disorders in amino acid metabolism that often go undiagnosed. These disorders can have specific symptoms and, in many cases, do not have any particular signs or symptoms and can increase a person's susceptibility to various degenerative diseases.
Amino acid testing provides essential information about nutritional adequacy, including the quality and quantity of dietary proteins, indirect information about digestive disorders and malabsorption syndromes, and indirect information about deficiencies and the metabolism of vitamins and minerals. In addition, the amino acid analysis provides important diagnostic information regarding hepatic and renal function, the availability of neurotransmitter precursors, the ability to detoxify, and many inherited disorders of amino acid metabolism.
Plasma Amino Acids and Urine Amino Acids
Plasma amino acid analysis measures levels at the time of sampling. To reduce the effect of dietary protein, the sample should be taken after a 12-hour fast. Comparing the measured levels with established reference values can cause possible anomalies.
Urine amino acids analysis is more likely to detect abnormalities if renal function is normal. The 24-hour sample collection detects amino acid levels throughout the day, reflects the levels and reserves of amino acids in the blood and tissues, and is unaffected by the circadian (daily) rhythm. Normal kidney function effectively maintains essential amino acids in the body. Therefore, the levels of amino acids in the urine are affected earlier and give signs of deficiency before their plasma levels are even disturbed. Analyzing amino acids in the first-morning urine sample is an alternative when the complete collection of 24-hour urine is impossible.
