The nine essential amino acids for humans are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. While many sources list nine, some research suggests a tenth, arginine, may also be considered essential, particularly for infants and growing children. It's important to note that "essential" means our bodies cannot produce these amino acids, so we must obtain them through our diet.
Understanding Essential Amino Acids
Amino acids are the building blocks of proteins, vital for numerous bodily functions, including:
- Muscle growth and repair
- Enzyme production
- Hormone synthesis
- Immune function
Because our bodies can't synthesize essential amino acids, we must consume foods containing them to ensure adequate protein synthesis. A deficiency can lead to various health problems.
The List: Nine Essential + One Potentially Essential
Here's a breakdown, incorporating information from various sources:
- Histidine: Important for growth and repair of tissues.
- Isoleucine: Plays a crucial role in muscle metabolism and healing.
- Leucine: Essential for muscle protein synthesis.
- Lysine: Involved in calcium absorption and collagen formation.
- Methionine: Important for the production of other amino acids and helps with detoxification.
- Phenylalanine: A precursor to several neurotransmitters.
- Threonine: Essential for collagen and elastin production.
- Tryptophan: A precursor to serotonin, a neurotransmitter influencing mood and sleep.
- Valine: Important for muscle metabolism and tissue repair.
- Arginine: While often considered non-essential in adults, its essentiality, particularly for infants and growing individuals, is supported by research showing a decreased growth rate when arginine is restricted in the diet. (Reference: Essentiality of amino acids for the growing kitten. https://pubmed.ncbi.nlm.nih.gov/430271/)
Numerous sources highlight the nine essential amino acids for adults, while the inclusion of arginine as potentially essential, especially during growth periods, is supported by studies. Always consult a healthcare professional for personalized dietary advice.
