‘L’ is a prefix for many of the amino acids or proteins that are the building blocks for the body. The ‘L’ denotes a left sided rotation of the molecule which is the natural form that is recognized by the human body. The other form is ‘D’ which is rotated to the right and is generally undesirable, yet is found in cheaper amino acid supplements.
There are many amino acids – some made by the body and some that must be obtained from the diet. Below is a description of the most common amino acid supplements.
L-Lysine is an essential amino acid that must be supplied by the diet as the body does not manufacture it. It is commonly found in meat, milk, cheese, egg, and beans. It is easily lost or destroyed in cooking and other processing, so it is a common deficiency. L-lysine helps with formation of healthy skin and bones, but is best known for its immune boosting properties against herpes viruses such as cold sores and shingles. For shingles or herpes, L-lysine is best taken with a good vitamin C with bioflavonoids.
L-Carnitine is another popular amino acid. It is found in meat and can be made by the body from L-lysine and vitamin C. L-carnitine helps turn fat into energy. It is a popular supplement for weight loss, heart disease and diabetes. Because L-carnitine helps with fat metabolism, it helps lower triglycerides and LDL cholesterol while raising HDL cholesterol. It provides necessary energy to muscles – particularly the heart muscle – and is popular with athletes concerned with endurance and muscle building.
L-Tyrosine is used for energy. It is a direct precursor to both adrenaline and thyroid hormones. L-tyrosine is considered an antidepressant amino acid, since it is stimulating and provides energy. L-tyrosine is found in almonds, avocados, bananas and dairy products.
L-Tryptophan is another antidepressant amino acid, but it is more calming and sedating as opposed to L-tyrosine which is energizing. L-tryptophan is a precursor to serotonin which influences moods and sleep. It is particularly effective with manic depression and depression associated with menopause. Because L-tryptophan boosts serotonin levels, it also raises the threshold for pain tolerance and is a mild pain reliever. L-tryptophan is also the precursor to niacin, or vitamin B3. Deficiencies of niacin can cause dementia, diarrhea and dermatitis. L-tryptophan along with niacin has been used successfully for these issues. L-tryptophan is found in many foods, particulary turkey.
L-Taurine is a lesser known amino acid, but an important one. It functions in electrically active tissues such as the brain and the heart. It functions as a mild sedative and has been used successfully to treat epilepsy. In Japan it is used with cardiac arrythmias and ischemic heart disease. L-taurine is a building block of bile which is needed for the digestion of fats – so it is beneficial for the liver and gallbladder. It is also a component of eye health. L-taurine is found only in animal proteins such as meat, eggs, fish and milk. It can be synthesized by the body as long as there is enough B6.
This is just a sampling of the amino acid supplements that are available. When supplementing amino acids, remember that quality counts – it is important to get the ‘L’ version of the amino acid since that is what the body recognizes and uses.
Margaret Durst is a naturopathic doctor who owns The Green House, a vitamin, herb and health food store in Mason, Texas.