I had a personal trainer in north London who could recite all the amino acids by heart. He was a competitive bodybuilder as well as personal trainer, and his knowledge of nutrition was inspiring.
Put simply, amino acids are the building blocks of protein. When you digest protein, it is broken down into amino acids, ready for absorption and use by the body.
There are two categories of amino acids. The essential amino acids (also known as indispensable amino acids) you can only get from food. The non-essential amino acids can be synthesised by your body from the essential amino acids. There are 20 amino acids in total. 9 are essential, and 11 are non-essential.
They all have specific roles to play, as I’ll summarize below.
The Essential Amino Acids
Leucine
Helps reduce catabolism (muscle protein breakdown), promotes skin healing, helps heal broken bones, and can be used for energy.
Isoleucine
Used for energy, helps prevent muscle wasting in hospitalised patients, and forms part of haemoglobin in the blood for oxygen transport.
Lysine
Inhibits viruses, delays fatigue, assists bone growth.
Valine
Influences brain uptake of neurotransmitter precursers such as tryptophan (see below).
Histadine
Crucial for the blood, in production of red and white blood cells. Used medically for treatment of a range of conditions from stomach ulcers to rheumatoid arthritis.
Methionine
Helps reduce blood cholesterol levels, and helps liver remove toxic wastes.
Phenylalanine
Boosts memory, learning skills, mood, levels of alertness. A crucial brain amino acid.
Threonine
Fights against ‘fatty liver’ disease. Vegetarians are sometimes deficient in this amino acid.
Tryptophan
Precursor to neurotransmitter serotonin, which has a pacifying effect. Also stimulates growth hormone, so foods rich in tryptophan are popular with bodybuilders.
The non-essential amino acids
Arginine
Helps with hormone release, particularly insulin. Boosts recovery from injury, and stimulates immune system.
Cysteine
Helps detoxify harmful chemicals in the body, such as alcohol and chemicals from cigarette smoking. Stimulates white blood cell activity, so it’s a crucial amino acid for your immune system.
Tyrosine
Precursor of a range of neurotransmitters and hormones. Boosts your mood.
Alanine
Key component of connective tissue (ligaments, tendons, fascia). Boosts immune system.
Aspartic Acid
Key amino acid in energy production: helps convert glucose into muscle energy.
Cystine
Together with alanine, helps form connective tissue. Also essential in forming your skin and hair.
Glutamic acid
Precursor of glutamine, and helps brain function.
Glutamine
This is the most abundant amino acid, crucial for your immune system. A source of energy for your kidneys and intestines, and also for the brain. Lack of glutamine impairs your powers of concentration.
Glycine
Another haemoglobin-component. Produces glucagon, a hormone which instructs the liver to release glucose into the bloodstream when blood sugar levels are low. Has a pacifying effect, so it’s used medically to treat aggression disorders.
Orthinine
Helps immune system, and wound healing.
Proline
Building block of connective tissue, and your heart muscle. One of the first amino acids to be used as energy, when other energy sources become low.
Serine
Helps produce antibodies, aids nervous system. Also key to energy production within cells.
Taurine
Helps absorption of fats.
Protein in your diet and in your body
Now you can see how crucial protein is for your health and for almost every structure and function in your body, not just your muscles. The top 3 sources of protein are eggs, meat, and fish. For strict vegetarians and vegans the best sources of protein are nuts, lentils, beans, and quinoa.
Different proteins in the structures and functions of your body are made up of different amino acids, connected in a vast range of lengths and shapes, depending on the structure or function in question. The unique chemical component of amino acids and proteins (not found in fats or carbohydrates) is nitrogen.
Some proteins in the body are hollow, which transport and store materials. Some are strong and rigid (found in tendons and ligaments), others are more elastic (muscles and fascia). Some protein structures in the body are very small (such as enzymes) and others are large (muscle tissue). And all are built from the 20 amino acids.
Dominic Londesborough is a personal trainer in London.