A Rundown on Amino Acids: Knowing What You Need

Amino acids are organic compounds that combine to form proteins that help our bodies break down food, grow, repair body tissue, and perform many bodily functions. They are needed to help build and repair muscle in your body—an essential component of every athlete’s diet. Some athletes may take supplements of amino acids to improve athletic performance. However, according to a 2007 review published in the “Journal of the International Society of Sports Nutrition,” they don’t directly affect an athlete’s energy level.

Amino acid supplements are not tightly regulated by the Food and Drug Administration. According to the U.S. Anti-Doping Agency, there is a risk of contamination or also consuming prohibited substances that are not listed on the supplement facts label. They can also be expensive, especially when you can meet your amino acid needs by following a well-balanced diet.

Protein is made of 20 different amino acids, but your body is capable of synthesizing half of these on its own. The other half must be consume through dietary sources.

Amino acids can be classified in three categories: Essential, Nonessential, and Conditional.

Essential amino acids – cannot be made by the body, and therefore they must come from food. The 9 essential amino acids are listed below with their basic functions:

  • Leucine*
    • Primary function is energy. Also helps with muscle mass; blood sugar; stress; HGH human growth hormone; protein synthesis; bone, skin, and tissue repair (often used as a post-surgery supplement); weight loss; and blood hemoglobin.
    • Deficiency may appear as fatigue, depression, anxiety, irritability, and an inability to focus and concentrate.
    • Food Sources: eggs, beans, lentils, fish, lean meats, nuts, seeds (especially pumpkin seeds), and whole grains.
  • Isoleucine*
    • Helps maintain and repair tissue, energy, blood sugar, preventing muscle breakdown during exercise, improve endurance, and blood hemoglobin.
    • Deficiency may appear as anxiety attacks, insomnia, or depression.
    • Food Sources: eggs, lean meats, fish, beans, lentils, liver, almonds, cashews, and most seeds.
  • Valine*
    • Helps with glycogen production, muscle metabolism and repair, correcting severe amino acid deficiencies that occur with drug and alcohol addiction.
    • Deficiency may appear as trouble sleeping.
    • Food Sources: dairy, grains, lean meats, mushrooms, and peanuts.
  • Histidine
    • Helps with tissue growth and repair, producing gastric juices in the stomach necessary for digestion, protecting nerve cells, repairing stomach ulcers, removing heavy metals from the body, manufacturing red & white blood cells, lowering blood pressure, and sexual functioning.
    • Deficiency may appear as eczema in babies, cataracts, and is suspected to be associated with stomach and duodenal ulcer.
    • Food Sources: beans, brewers yeast, dairy, eggs, fish, lean meats, whole grains, rice, and wheat.
  • Lysine
    • Helps with absorbing/conserving calcium, regulating seratonin levels in the brain; improving concentration; muscle building and tissue repair; fertility; hormone and enzyme production; lowering high Triglyceride levels; boosting antibodies for the immune system; and bone, cartilage, skin, and tendon collagen formation.
    • Deficiency may appear as anxiety, stress, or depression.
    • Food Sources: fish, eggs, lean meats, dairy, cheese, lima beans, and potatoes.
  • Methionine
    • An antioxidant that helps with fat breakdown, metabolism, preventing arterial plaque build up, detoxifying and removing heavy metals from the body, collagen formation, reducing liver fat, promoting estrogen production and balance, as well as maintaining healthy hair, skin, and nails.
    • Deficiency may appear as hair loss, poor skin tone, and toxic elevation of metabolic waste products.
    • Food Sources: eggs, lean meats, liver, dairy, seeds, beans, lentils, fish, garlic, and yogurt.
  • Phenylalanine
    • Helps with reducing chronic pain, stimulating endorphin release, improving speech, alcohol and drug recovery, and reducing hunger cravings.
    • Deficiency may appear as confusion, lack of energy, depression, decreased alertness, memory problems, and lack of appetite.
    • Food Sources: lean beef, poultry, fish eggs, dairy, peanuts, almonds, and walnuts.
  • Threonine
    • Helps with forming tooth enamel, fat removal and maintaining a healthy liver, protein balance, producing antibodies for the immune system, collagen formation, bone growth, blood sugar stabalization, growth of the thymus gland, stabilizing the nervous system, brain and nervous system communication, energy production, stress.
    • Deficiency may appear as irritability and a generally difficult personality, including severe and sudden mood changes.
    • Food Sources: lean meats, eggs, dairy, nuts, fish, beans, carrots, and seeds.
  • Tryptophan
    • Helps with soothing nerves and anxiety, decreasing appetite and pain sensitivity, and niacin (B3) production.
    • Deficiency may appear as dermatitis, diarrhea, dementia, and digestion problems.
    • Food Sources: lean meats, fish, dairy, turkey, oats, bananas, and chocolate.

*The branched chain aminos play a direct role in the cell mitochondria which is responsible for health, metabolism, energy production, and longevity.

Nonessential amino acids – our bodies can produce these amino acids, even if we don’t get it from the food we eat. The 4 nonessential amino acids are listed below with their basic functions:

  • Alanine
    • Helps with protecting muscle cells during high-intensity workouts, improving muscle mass, improving endurance, improving prostate health, producing neurotransmitters to the brain essential for the functioning of the nervous system, regulating blood sugar levels, maintaining energy levels, eliminates toxins from the liver, produces antibodies for the immune system.
    • Food Sources: lean meats, poultry, eggs, dairy, fish, and avocados.
  • Asparagine
    • Helps with maintaining balanced control of cell function in the brain and nervous system, converting other amino acids into those the body requires, detoxifies ammonia from the body,
    • Food Sources: eggs, fish, dairy, nuts, beans, whole grains, and red meat.
  • Aspartic Acid
    • Helps with chronic fatigue, maintaining Ph balance and metabolism, increasing stamina and endurance, increasing testosterone levels, enhancing production of antibodies for the immune system, minimizing drug withdrawal symptoms, raising NAPH levels in the brain that are necessary for function,
    • Food Sources: dairy, lean beef, poultry, sprouted seeds, avocados, asparagus, and oats.
  • Glutamic Acid
    • Glutamic Acid is the most abundant neurotransmitter in the body. It excites or stimulates the nuerons in the nervous system enhancing brain nervous system interaction. It also helps with cognitive function, turning sugar and fat into glucose, assisting ammonia from the body, and preventing prostate enlargement.
    • Food Sources: lean red meats, fish, eggs, poultry, and dairy.

Conditional amino acids – usually not essential, except in times of illness and stress. The 7 conditional amino acids are listed below with their basic functions:

  • Arginine
    • Helps with increasing sperm count, reducing cancerous tumor growth, building bone tissue, promoting collagen production, building muscle mass, releasing HGH (human growth hormones), improving mental awareness, opening clogged arteries, reducing blood pressure, converting nitrous oxide, expanding blood vessels in the extremities, increasing endurance, stimulating insulin release from the pancreas, neutralizing ammonia and promoting liver detoxification, as well as regulating enzymes and hormones.
    • Food Sources: lean meats, fish, dairy, nuts, whole grain cereals, whole wheat products, and wheat germ.
  • Cysteine
    • An antioxidant that helps with producing white blood cells, detoxification, reducing damage caused by drugs and alcohol, removing heavy metals from the body, aids in iron absorption, relieves respiratory congestion by breaking down mucus, collagen production, and hair growth.
    • Food Sources: eggs, lean meat, dairy, cereals, granola, oats, and wheat germ.
  • Glutamine
    • Helps with improving brain function, stabilizing blood sugar levels, restoring the digestive tract, protein synthesis, maintaining normal acid/alkaline levels, eliminating ammonia from the brain and body, reducing inflammation, muscle enhancement, minimizing sugar and hunger cravings, supporting pancreatic function, and producing Glutathione to fight disease.
    • Food Sources: lean beef, poultry, fish, eggs, and dairy.
  • Tyrosine
    • Helps with forming Thyroid hormones; converting dopamine and norepinephrine, essential to mental function and health; and producing melanin, a pigment that produces color in the eyes and skin.
    • Food Sources: eggs, cheese, yogurt, fish, poultry, red meat, pork, spinach, and mustard greens.
  • Glycine
    • Helps with forming and conducting RNA and DNA strands, promoting electrical-chemical signals through the brain, regulating bile acids, preventing an enlarged prostate, inhibiting neuro-transmitter seizure activity, absorbing calcium, supplying glucose for energy, regulating blood sugar levels, repairing damaged tissue, digestion, preventing melanoma or cancerous tumor growths, and collagen formation.
    • Food Sources: fish, lean meats, beans, and dairy.
  • Proline
    • Helps with collagen creation, lubricating muscles and joints, strengthening the heart, as well as preventing soft tissue damage and muscle breakdown during exercise.
    • Food Sources: eggs, chicken, poultry, fish, dairy, and lean red meats.
  • Serine
    • Helps with DNA and RNA cell function, producing antibodies for the immune system, aiding in brain-nervous system exchange, muscle growth, production of tryptophan, and maintaining metabolism.
    • Food Sources: lean meats, dairy, wheat germ, and peanuts.

You do not need to eat essential and nonessential amino acids at every meal, but getting a balance of them over the whole day is important. Animal-based foods such as meat, fish, poultry, diary products, and eggs are considered complete proteins, because they contain all the essential amino acids. Plant-based foods contain a variety of amino acids, but with the exception of soybeans and quinoa, do not contain all 10 amino acids at once. Such foods are considered incomplete proteins. Plant-based sources of amino acids can be found in a variety of vegetables, corn, beans, rice, legumes, lentils, nuts, and grains. If Vegetarians and Vegans are eating a well-balanced diet including these foods, then you will meet your protein and amino acid needs. Protein deficiencies are more commonly a result of poverty. Cornell University notes that protein-energy-malnutrition, or PEM, occurs in parts of the world where food supply limits the opportunity to obtain all of the essential amino acids. Severe PEM can cause liver deterioration, anemia, and skin inflammation.

For more information on how much protein you should consume per day, and how much protein can be found in different animal and plant-based foods, read my post on Protein here.

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“Phenylalanine.” (Jun. 17, 2011.) University of Maryland Medical Center. Retrieved Jan. 1 2015 from

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