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What is threonine?

Threonine is an essential amino acid [1]. In foods, threonine is incorporated into proteins.

Threonine abbreviation (symbol): Thr

Threonine Functions in the Human Body

Threonine is [1,2]:

  • A building block of proteins
  • A precursor of the amino acids serine and glycine; the later acts as an inhibitory neurotransmitter in the brain, which reduces spasticity
  • A glucogenic amino acid — it can be converted into glucose [5]
  • A ketogenic amino acid — it can be converted into ketones [5]

Threonine Rich Foods

  • ANIMAL FOODS: meat, fish, cheese [3]
  • PLANT FOODS: beans, lentils, wheat germ, seeds, baker’s yeast, spirulina [3]

Foods low in threonine include cereals (except wheat germ), fruits and vegetables [3].

Threonine Deficiency

Threonine deficiency in humans seems to be rare.

Threonine Supplements

Oral L-threonine supplements without prescription (over-the-counter) are available.

Threonine Health Benefits

Threonine supplements are POSSIBLY EFFECTIVE in the treatment of spinal spasticity [2], phenylketonuria [4] and tyrosinemia type I [4].

Threonine supplements are POSSIBLY INEFFECTIVE in the treatment of amyotrophic lateral sclerosis (Lou Gehrig’s disease) [2].

There is INSUFFICIENT EVIDENCE about the effectiveness of threonine supplements in the prevention or treatment of anxiety, depression, multiple sclerosis and familial spastic paraparesis or in boosting immune system [2].

Threonine Safety: Side Effects, Toxicity

Threonine in doses up to 4 g/day for 12 months is POSSIBLY SAFE [2].

Side effects may include nausea, stomach upset, headache, skin rash [2].

During Pregnancy

Not enough studies have been done about the safety of threonine supplements during pregnancy and breastfeeding, so women in these periods should better avoid them [2].

Threonine-Drugs Interactions

Threonine supplements may reduce the effectiveness of memantime–a drug used in Alzheimer’s disease [2].

Who should avoid threonine?

Individuals with the following conditions may need to limit their threonine intake from foods and supplements:

  • Methylmalonic acidemia [4]
  • Propionic acidemia [4]

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