Overview
Essential amino acids, such as threonine, are those that are not synthesized in the body so they must be taken in through the diet. Threonine is an important component in the formation of protein, collagen, (1) elastin, and tooth enamel and is found in the central nervous system, skeletal muscles, and the heart. (2) Threonine enhances the production of antibodies. It is an important constituent of many body proteins and neurotransmitters and is necessary for the formation of glycine and serine. Threonine is metabolized into glycine, serine and glucose. It acts as a lipotropic in controlling fatty accumulations in the liver.
Strict vegetarians are at higher risk for deficiency, however deficiencies are still possible even on a non-vegetarian diet. Reasons for deficiency include stress, infection, impaired absorption, and age. Various problems can arise with insufficient amounts of amino acids due to their interactivity in so many metabolic processes.
Dosage Info
Dosage Range
100mg – 7.5 grams daily.
Most Common Dosage
1 gram, 2 times a day.
Dosage Forms
Tablets, capsules, and powder.
Adult RDI
None established
Adult ODA
None established
RDA
- : None established
Interactions and Depletions
Interactions
Active Forms
DL-threonine and L-threonine.
Absorption
The absorption of amino acids occurs along the entire length of the small intestine. Some free forms can be found in the bloodstream.
Toxicities & Precautions
General
There is no known toxicity associated with threonine.
Side Effects
One study noted increased hypertension on threonine supplementation. (3)
Functions in the Body
Collagen and Elastin:
Component of many body proteins.
Glucose-sparing Effect:
Precursor to amino acids glycine and serine.
Lipotropic:
Inhibits fat accumulation in liver.
Immune System:
Assists in production of antibodies, thereby enhancing immune system.
Clinical Applications
Multiple Sclerosis
Enhancement by threonine of glycinergic postsynaptic inhibition of the motor reflex arc in the spinal cord may represent a non-sedating, nontoxic approach to the management of spasticity in multiple sclerosis. Results demonstrated no therapeutic difference between doses of 3 or 6 grams daily
Depression
Inadequate levels of threonine and certain other amino acids are associated with depression. (4)
Immune Enhancement
A study noted an increase in the weight of the thymus on threonine supplementation and suggested the effects were due to specific needs of the thymus for threonine. (5)
ALS
L-threonine has been shown to improve some symptoms and signs of ALS. (6)
Symptoms and Causes of Deficiency
Threonine is classified as an essential nutrient. It is found in high amounts in newborns, and the body’s requirement for it tends to decrease with age. Deficiency can result in hypoglycemic symptoms, particularly if glycine or serine are also low. Threonine deficient diets may result in neurological dysfunction, (7) skin disorders, or weakness. (8) Excess methionine supplementation may induce threonine deficiency and result in fat deposition in the liver. (9)
Dietary Sources
There are high levels of threonine in most meats, dairy foods, and eggs, and moderate levels in wheat germ, many nuts, beans, and seeds, as well as some vegetables.
References
- View Abstract: Kamata T, Takada Y, Wright R. Critical Threonine and Aspartic Acid Residues within the I Domains of Beta 2 Integrins for Interactions with Intercellular Adhesion Molecule 1 (ICAM-1) and C3bi. J Biol Chem. May1995;270(21):12531-35.
- View Abstract: Vasdev S, Whalen M, et al. Ethanol- and Threonine-induced Hypertension in Rats: A Common Mechanism. Can J Cardiol. Oct1995;11(9):807-15.
- View Abstract: Vasdev S, Whalen M, et al. Ethanol- and Threonine-induced Hypertension in Rats: A Common Mechanism. Can J Cardiol. Oct1995;11(9):807-15.
- View Abstract: Maes M, et al. Serum Levels of Excitatory Amino Acids, Serine, Glycine, Histidine, Threonine, Taurine, Alanine and Arginine in Treatment-resistant Depression: Modulation by Treatment with Antidepressants and Prediction of Clinical Responsivity. Acta Psychiatr Scand. Apr1998;97(4):302-08.
- Lotan R, et al. The Effect of Lysine and Threonine Supplementation on the Immune Response of Growing Rats Fed Wheat Gluten Diets. Nutr Teports Inter. 1980;22(3):313-18.
- Blin O, et al. A Double-Blind Placebo Controlled Trial of L Threonine in Amyotrophic Lateral Sclerosis. La Presse Medicale. Sep1989;18(30):1469-70.
- View Abstract: Rogers QR, Tichenal CA, et al. Threonine Imbalance, Deficiency and Neurologic Dysfunction in the Kitten. J.Nutr. 1980:110(12):2444-59.
- View Abstract: Kamata T, Takada Y, Wright R. Critical Threonine and Aspartic Acid Residues within the I Domains of Beta 2 Integrins for Interactions with Intercellular Adhesion Molecule 1 (ICAM-1) and C3bi. J Biol Chem. May1995;270(21):12531-35.
- Leclerc J. Fatty Liver Induced by Methionine Supplementation of Low Protein Diet: Effect of Inositol Supply. Journal of Nutrition. Jul1991;121(7):1139.
