Threonine

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]