What is Threonine?
Threonine is an essential amino acid (amino-hydroxy-butyric acid) as the body cannot synthesise it and needs to be obtained from the diet.
Health Benefits of Threonine
Supports Collagen Production muscles and connective tissue
Threonine is needed for the synthesis of glycine and serine. These amino acids are important as they are involved in the production of collagen, elastin, muscle tissue and connective tissues. Threonine is concentrated in the heart, one of the most important muscle needed to pump blood throughout the body and is needed for cardiovascular health.
Threonine is needed for regulating protein balance in the body.
Supports bones
Due to this amino acid supporting synthesis of serine and glycine, two amino acids that help with collagen and elastin synthesis it can help healthy bones. Threonine is also needed for healthy tooth enamel.
Threonine can help to recover and heal the bones following injury.
Helps heal wounds
Threonine can help speed up healing of wounds as it is involved in the formation of collagen and elastin which are important for the health of the skin, teeth and bones.
Supports the digestive system
Threonine supports a healthy digestive system due to its role in producing mucus in the intestines. Higher amounts of threonine are absorbed in the small intestines (ileum) and helps protect this portion. The mucus production acts as a barrier and provides protection against digestive enzymes that can cause damage to the intestinal walls increasing gut inflammation. This also helps absorb nutrients and thereby support digestion which is important for overall health.
Studies on animals have shown a deficiency of this amino acid can cause impaired digestion and immune system. It is very likely that this is due to poor gut health as a result of reduced mucus barrier in the intestines. Impaired gut health and digestion has been linked to a host of health problems.
Supports the immune system
The immune system relies on the thymus gland to produce T lymphocytes (T-Cells) which are needed to help fight infections. Threonine is needed by the thymus gland to help produce T-Cells and an adequate supply of this amino acid can support the immune system.
Supports Liver Health
Threonine supports liver function and can help maintain fat levels in liver by preventing excess fatty deposits [R] [R]. Other amino acids that work with threonine to support liver health includes methionine and aspartic acid. These amino acids are essential in the process of breaking down fats and are involved in the lipotropic function. Lipotropic compounds are needed to help with the digestion of fats. A deficiency of threonine can impair liver functions as it will not be able to digest fats.
Improves cognitive function
Threonine can improve certain cognitive functioning and can have calming effects.
The central nervous system has a high amount of threonine and is needed to help with CNS functions. It has been used in certain conditions such as Amyotrophic Lateral Sclerosis (Lou Gherigs Disease), Multiple Sclerosis (MS) and depression.
Threonine may help improve mental health and is essential for development and functions of the brain.
May improve sleep
One study has shown that threonine increased amount of daily sleep amount and may promote sleep. [R]
Although limited studies are currently available to confirm full effects of threonine on sleep, there are various studies on other amino acids that can be synthesised from threonine such as glycine and serine. Glycine is a non-essential amino acid and has been shown to have sleep promoting effects. Glycine has shown to increase serotonin levels an important hormone and neurotransmitter that is involved in the sleep wake cycle.
Glycine is a non-essential amino acid that can be made by the body by converting Serine (another non-essential amino acid) using a specific form of folate or from Threonine (an essential amino acid). [R]
Glycine has also been shown to promote weight loss through its ability to mitigate methionine toxicity. In addition to this methionine restriction has shown to extend lifespan of rodents though how this is done is unknown. [R]
Serine is a non-essential amino acid which the body can make from threonine. One study on serine has shown to improve sleep [R].
Although there are very little studies available on threonine and sleep, one study on fruit flies has shown to decrease latency and increase total sleep time. [R] [R]
Agonist / Synergist
Amino Acids Glycine, serine, arginine, proline
Threonine is a precursor to serine and glycine and is needed for the synthesis of these amino acids
Threonine complements arginine, glycine, proline
Escherichia coli and yeast can synthesise threonine from aspartic acid, glycine and acetaldehyde. [R] [R]
Threonine aldolase enzyme uses substrate L-threonine to produce glycine and acetaldehyde.
The enzyme threonine dehydrase may deaminate Threonine to form ketobutyric acid. Ketobutyric acid is involved in the metabolism of many amino acids.
The enzyme L-threonine dehydrogenase converts threonine to glycine [R]
Catabolism of threonine needed to form Acetyl-Coenzyme A which is needed for acetylcholine synthesis
DAO or histaminase enzyme participates in various metabolic pathways which includes threonine metabolism
Antagonists
Minerals Cu
Antagonizes copper
Medications used for Alzheimer’s disease (NMDA antagonists) interacts with threonine. Threonine might decrease how well medication such as memantine (Namenda) for Alzheimer’s disease works
Food Sources of Threonine
Food sources of this essential amino acid are found in higher amounts in animal based protein rich food which includes fish, meat, pork, eggs and dairy. It can also be found in plant based foods but in much lower concentrations. Plant based foods include nuts, seeds, beans, some fruits and vegetables. It is found in fair amounts in cashew nut, sesame seeds, sunflower seeds, beans, carrots, maize, rice, wheat germ, lettuce, spinach, bitter gourd, cauliflower, jackfruit, apples, bananas and persimmons.
Recommended Daily Allowance
Adults need around 10mg to 14mg per kg of body weight per day from dietary intake for optimal functioning.
Up to 4g of daily threonine has been used safely for up to 12 months.
Children need more amino acids that adults as their body is still developing. The recommended daily amount for children over the age of three increases by 10% to 20% more than what is needed by adults. For infants the amount required increases by 150% more than what is needed by adults.
The requirements may change on individual basis and highly dependent on existing health. [R]
Threonine Supplementation
Threonine can be found in tablet, capsule, powder and liquid form. This amino acid can be found in many full spectrum amino acid supplement and can be found in some protein bars.
Only recommended dosage should be taken which may be found on supplement label or if in doubt ask a health professional.
Most threonine supplements are suitable for vegans or vegetarians and are indicated on supplement packaging. Threonine is available as a single amino acid or in combination amino acid supplements. It can also be found in some multivitamin supplements and food supplements.
Taking single amino acid supplements are not always recommended and may be harmful for those with damaged liver or kidneys.
Deficiency Symptoms of Threonine
A deficiency of this amino acid is unlikely as it is readily available in a healthy and balanced diet. However in the case of strict vegan, vegetarian diets or diets low in protein deficiencies are likely to occur.
Symptoms of threonine deficiency include:
- Digestive problems
- Emotional agitation
- Confusion
- Fatty liver
- Obesity
- Heart failure
Causes of deficiency include:
- Inadequate protein intake
- Vegan vegetarian diets
Vegans and vegetarian diets are likely to cause a deficiency due to this amino acid being more abundant and readily available in animal based food and diets lacking animal based protein it may be supported with an amino acid supplement that contains threonine under the supervision or guidance of a qualified health practitioner.
A deficiency of threonine causes irritability in children.
Levels of deficiency can be checked through an amino acid profile analysis.
It may be helpful to supplement with threonine which converts to glycine as animal based proteins such as meats may contain low ratios of glycine:methionine than in collagen or plant based protein, which can be insufficient.
Toxicity Symptoms of Threonine
Threonine toxicity can occur if excess threonine supplements are taken.
Too much threonine can become concentrated in the heart, where it is normally found in significant amounts. This means excess amounts may cause problems with the heart.
Excess threonine levels can lead to liver damage and ammonia toxicity.
Causes of threonine toxicity:
- High intake of threonine
- Impaired or insufficient metabolism
Threonine supplementation may cause side effects which includes:
- Headache
- Nausea
- Stomach upset
- Skin rash
Excess amino acids are excreted by the liver through liver cells releasing urea and water which are transported to the kidneys to filter the blood and then excreting urea through urine.