L-Threonine is an essential amino acid that helps to maintain the proper protein balance in the body. It is important for the formation of collagen, elastin and tooth enamel, and aids liver and lipotropic function when combined with aspartic acid and methionine. L-Threonine is a precursor of the amino acids glycine and serine. Glycine is the major inhibitory neurotransmitter in the spinal cord. Glycine itself poorly penetrates the central nervous system (CNS), but Threonine has better penetration.
Threonine is present in the heart, central nervous system and skeletal muscle, and helps to prevent fatty liver. It helps to boost the immune system by aiding in the production of antibodies, and may be helpful in treating some types of depression. L-Threonine can not be synthesized in the human body. It is nutritionally indispensable for growth as an essential amino acid, and the deficiency results in fatty liver and atrophy of the testis, even in adult cases.
Threonine may be used for multiple sclerosis, and familiar and amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease).
Published Clinical Studiescl top
The kindled amygdala model of epilepsy: anticonvulsant action of amino acid antagonists.1
Peterson DW, Collins JF, Bradford HF.
The amygdalas of rats were stimulated daily to produce kindled epilepsy. Superfusion of the ipsilateral ventricle allowed collection of amino acids before, during and after stimulation. At the stage where stimulation evoked full seizures there was a correlated increase in the extent of glutamate release. Other amino acids, including aspartate, showed no significant changes at this time. Aspartate, threonine and serine showed smaller responses not significantly different from those seen at the pre-kindled stage. Antagonists of excitatory amino acids (omega-phosphono-alpha-amino dicarboxylic acids) effectively antagonized both the behavioral and electrical components of the kindled seizures.
PMID: 6138123 [PubMed - indexed for MEDLINE]
2
Threonine requirements of healthy Indian men, measured by a 24-h indicator amino acid oxidation and balance technique.
Kurpad AV, Raj T, Regan MM, Vasudevan J, Caszo B, Nazareth D, Gnanou J, Young VR.
Department of Physiology and the Division of Nutrition, St John's Medical College, Bangalore, India. a.kurpad@divnut.net
BACKGROUND: We previously questioned the validity of the 1985 FAO/WHO/UNU upper requirement value for threonine (7 mg x kg(-1) x d(-1)) and proposed a tentative mean requirement of 15 mg x kg(-1) x d(-1). OBJECTIVE: In this study we used a 24-h indicator amino acid oxidation and balance technique, with [1-(13)C]leucine as the indicator amino acid, to assess threonine adequacy at 6 test intakes (7, 11, 15, 19, 22, and 27 mg x kg(-1) x d(-1)) with a 6-d dietary adaptation phase in healthy, well-nourished Indian men. DESIGN: Sixteen men were randomly allocated to 3 of 6 test intakes and were studied after 6 d of adaptation to the experimental diets. Diets were based on an L-amino acid mixture in which the threonine content was varied. At 1800 on day 6, a 24-h intravenous [(13)C]leucine tracer infusion protocol was conducted to assess 24-h leucine oxidation and daily leucine balances. RESULTS: Leucine balances differed significantly (P = 0.02) between the different intakes of threonine. Two-phase linear regression analysis from 12-h and 24-h leucine oxidation and 24-h leucine balance gave a breakpoint at a threonine intake of 15 mg x kg(-1) x d(-1), with 95% CIs ranging from 11 to 27 mg x kg(-1) x d(-1). There was no significant effect of threonine intake on 24-h leucine flux. CONCLUSION: The results of the 24-h indicator amino acid oxidation and balance experiments indicate that the current FAO/WHO/UNU threonine recommendation of 7 mg x kg(-1) x d(-1) is inadequate. A mean threonine intake of 15 mg x kg(-1) x d(-1) is sufficient to achieve the indicator (leucine) amino acid balance in healthy Indian men.
Publication Types:
PMID: 12324292 [PubMed - indexed for MEDLINE]