Aspartic acid is known in two forms, L-aspartic acid and D-aspartic acid. L-aspartic acid is the only form incorporated directly into proteins, while the biological role of D-aspartic acid is more limited. L-aspartic acid is often referred to as L-aspartate, or simply aspartic acid.
This non-essential amino acid has an important role in the Krebs cycle, also known as the citric acid cycle. During this process biochemical and other amino acids are synthesised, such as lysine, arginine, asparagines, threonine, methionine, isoleucine, and several nucleotides.
Thus, L-aspartic acid is essential for energy production and plays a key role in metabolism. L-aspartic acid is classified as an excitory amino acid neurotransmitter and is needed to stimulate central nervous system synapse.
Aspartic acid and energy production
Aspartic acid is vital for generating cellular activity. It transports coenzyme nicotinamide adenine dinucleotide (NADH) molecules from the cell into the mitochondria. Here NADH is used to produce adenosine triphosphate (ATP). This coenzyme is needed to transport chemical energy throughout the cell, facilitating metabolism.
Therefore, the higher the availability of NADH within the cell, the more ATP can be produced which leads to a healthy metabolism. This translates into more energy for the body.
Aspartic acid and immune function
Aspartic acid is needed for the production of immunoglobulines and antibodies. These are glycoprotein molecules produced by white blood cells (plasma cells). They are a critical component of the body’s immune function.
Immunoglobulines and antibodies are responsible for recognising and binding to antigens, such as viruses and bacteria. They also help to destroy these foreign bodies. There are many different immunoglobulin isotypes and without L-aspartic acid many of these compounds cannot be synthesised.
RNA and DNA requires aspartic acid
For the body to produce healthy RNA and DNA it requires aspartic acid. This amino acid assists with the transportation of the mineral needed by cells to replicate DNA and RNA.
In the absence of L-aspartic acid, genetic mutations may arise.
Aspartic acid and cognitive function
Aspartic acid is important for cognitive function as it supplies the brain with NADH. This help to support the brain in maintaining the necessary levels of specific chemicals and neurotransmitters needed to uphold normal mental functioning.
Aspartic acid and toxin removal
The body continues to produce toxins as a by product of cellular activity. L-aspartic acid helps to remove toxins such as ammonia. If ammonia levels are not regulated it can cause damage to the liver, nervous system, and brain.
Aspartic acid and reproduction
Aspartic acid is also involved in the neuroendocrine system. This amino acid plays an important role regulating the production and release of certain hormones. In the pituitary gland, L-aspartic acid stimulates the secretion of prolactin, enabling milk production in mammals. It also is involved in the production of the luteinizing hormone required for testosterone synthesis in males and regulation of the menstrual cycle and ovulation in females. This amino acid is also needed to regulate the synthesis and release of growth hormone (GH).
Symptoms of an aspartic acid deficiency
As the body is able to manufacture its own L-aspartic acid, deficiencies are often rare. They are usually only associated with people with a diet low in protein or suffering from malnutrition or an eating disorder. There also may be periods of illness which can increase the demand for aspartic acid.
When aspartic acid is deficient there are is a deterioration of physical ability. Metabolism and other functions within the body decline. One of the common symptoms of low aspartic acid levels is chronic fatigue and reduced stamina.
Several studies have suggested that athletes or people suffering from chronic fatigue may benefit from increasing their intake of L-aspartic acid1, 2. Not only can this help to elevate energy levels, it can also assist with the removal of excess ammonia as a byproduct of exercise3.
High levels of ammonia and low levels of L-aspartic acid can also lead to damage to the brain, liver, and nervous system. Some of the common symptoms include irritability, poor concentration, loss of energy, chronic headaches, and intolerance to high-protein foods.
Low L-aspartic acid levels are also associated with deficiencies in magnesium and calcium. This can contribute to other health concerns.
Dietary sources of aspartic acid
As aspartic acid is a non-essential amino acid it can be produced by the body. This amino acid is also found in beef, dairy, sugar cane, poultry, sea food, sugar beet molasses, asparagus, avocado, sprouting seeds, and oats.
This amino acid is often incorporated into dietary supplements. It may be present in the form of aspartic acid itself, or as a form of salt, such as magnesium aspartate.
Many athletes, including body builders, take supplements containing this amino acid and it is often found in whey protein powder bars and drinks marketed as energy boosters.
Dosage of aspartic acid
For people involved in athletic sports where physical endurance is important supplements of aspartic acid salts are often taken regularly. Tablets containing natural L-aspartic acid are preferred for high bioavailability.
The usual dose is 500mg take one to three times a day with fruit juice or water on an empty stomach, approximately 30 minutes before mealtime. Protein should not be consumed at the same time as the supplement as it can interfere with the body’s ability to utilise this amino acid.
Excessive doses of this amino acid may have the same effects as consuming too much protein. Ti can damage the kindness and liver, increasing the risk of developing gout. As with any supplementation, it’s recommended to consult a professional health care practitioner before taking aspartic acid supplements.
- Wesson, M. et.al. (1987). Effects of oral administration of aspartic acid salts on the endurance capacity of trained athletes. Research Quarterly for Exercise and Sport, Volume 59, Issue 3, (pp. 234-9).” ↩
- Formica P. (1962). The housewife syndrome. Treatment with the potassium and magnesium salts of aspartic acid. Current Therapeutic Research, Clinical and Experimental. Volume 4, (pp. 98-106).” ↩
- “Barns, R. et.al. (1964). Effects of exercise and administration of aspartic acid on blood ammonia in the rat. American Journal of Physiology. Volume 207, Issue 6, (pp.1242-6).” ↩