Conditionally essential amino acids are usually not essential for healthy adults, meaning our bodies can typically produce them. However, they become essential—meaning we need to obtain them from our diet—under certain conditions like illness, stress, or during periods of rapid growth.
The Seven Conditionally Essential Amino Acids
The seven amino acids generally classified as conditionally essential are:
- Arginine: Important for wound healing and immune function. It may become conditionally essential during illness or injury. [1, 9, 10]
- Cysteine: Plays a role in antioxidant defense and the synthesis of proteins. Its production can be insufficient during certain conditions. [1, 3]
- Glutamine: A major fuel source for cells of the immune system and the gut. It can become conditionally essential during stress, illness, or trauma. [1, 2, 3, 4]
- Tyrosine: A precursor to several neurotransmitters. Its production relies on the availability of phenylalanine; deficiencies can make it conditionally essential. [1, 3]
- Glycine: Involved in various metabolic processes and collagen synthesis. Its production may not meet demands during periods of stress or illness. [1]
- Proline: A key component of collagen and other connective tissues. Its production may be limited during periods of increased need. [1]
- Serine: Plays a crucial role in numerous metabolic pathways. While typically non-essential, its synthesis can be compromised under certain conditions. [1, 8]
It's important to note that the need for these amino acids as conditionally essential can vary based on individual factors, such as age, health status, and nutritional intake. While healthy individuals usually produce sufficient amounts, those with specific health conditions or increased physiological demands may require additional intake through diet or supplementation. [5, 6, 7]
References:
[1] Conditionally essential amino acids are usually not essential, except in times of illness and stress. Conditionally essential amino acids include: arginine, cysteine, glutamine, tyrosine, glycine, proline, and serine.
[2] https://pubmed.ncbi.nlm.nih.gov/2080048/
[3] https://www.ajinomoto.com/amino-acids/what-are-amino-acids
[4] https://www.bu.edu/aldolase/biochemistry2/ConditionallyEssentialAA.pdf
[5] https://medlineplus.gov/ency/article/002222.htm
[6] https://www.sciencedirect.com/topics/medicine-and-dentistry/essential-amino-acid
[7] https://en.wikipedia.org/wiki/Essential_amino_acid
[8] https://pmc.ncbi.nlm.nih.gov/articles/PMC9105362/
[9] https://www.ncbi.nlm.nih.gov/books/NBK525313/
[10] https://www.healthline.com/nutrition/essential-amino-acids
