There are many amino acids in protein but twenty are specifically important for human health. Of the twenty that we need for proper functioning, nine are considered to be essential amino acids. Your body cannot manufacture these, so it’s incredibly important that you obtain these from your food!
1. Histidine – Inflammation Reduction
Histidine is important because your body utilizes it to make histamine. Histamine is a substance in your body that is released during an allergic reaction. It is responsible for a wide range of physiological processes, from swelling to your sex drive. Histamines also cause the swelling and reddening in asthma and allergies because histamine helps direct your body's response to foreign substances. In asthma and allergies, your body over-reacts to something that may not be particularly harmful but which has caused your immune system to react. Doctors often prescribe antihistamines in the treatment of inflammation and infections, as well as allergies. This is one amino acid you don’t want to go haywire.
Animal sources: eggs, cod, whitefish, catfish, game meat, elk, bison, boar, deer, buffalo, duck, beef, liver, chicken, turkey, pork, veal, lamb
Plant sources: sunflower seeds, brewer’s yeast, seaweed, spirulina, chlorella, apples, beets, spinach
2. Isoleucine – Oxygen Transport
Isoleucine, together with two other amino acids (Leucine and Valine), promotes muscle recovery after physical exercise, which makes it very important for athletes and bodybuilders. On its own, Isoleucine is needed to produce hemoglobin. Hemoglobin is a protein in your red blood cells that transports oxygen from your lungs to your body. Additionally, hemoglobin helps us get rid of carbon dioxide. Isoleucine also assists with regulating blood sugar and energy levels.
Animal sources: eggs, turkey, chicken, lamb, game meat, moose, buffalo, pheasant, goose, duck, elk, crab, shrimp, lobster, tuna, cod, pike, orange roughy, whitefish, smelt, milk, some cheese, pork, veal, lamb, beef liver
Vegetable sources: seaweed, spirulina, sunflower seeds, brewer’s yeast, parsley, lentils, peas, lupin beans, sesame seeds, avocados, olives
3. Leucine – Natures Fat Burner
Leucine, together with two other amino acids (Isoleucine and Valine) works to repair muscles, helps muscles recover after exercise, regulates blood sugar, and provides the body with energy. It also increases production of growth hormones and helps burn visceral fat, which is located deep inside your abdomen, surrounding your internal organs [I]. Once it’s there, visceral fat is the least responsive to dieting and exercise. Leucine also promotes the healing of skin, bones, and muscle tissue after injury and is often recommended for those recovering from surgery.
Animal sources: beef, eggs, cod, whitefish, smelt, tuna, sturgeon roe, mollusk's milk, pork, game meat, deer, elk, beef liver, buffalo, moose, rabbit, bison, lamb, veal, turkey
Plant sources: brown rice, beans, lupin beans, nuts, seaweed, spirulina, sunflower seeds, parsley, brewer’s yeast, lupins, safflower seeds, winged beans (asparagus peas), avocados, olives
4. Lysine – Immunity
Lysine is concentrated mostly in the muscle tissue and helps in the absorption of calcium from the intestinal tract. It promotes bone growth and the formation of collagen (the main protein of your skin), tendons, cartilage, bones, and connective tissue. Because of its ability to support your immune system, Lysine has also been used to prevent or treat herpes simplex infections.
Animal sources: eggs, cod, whitefish, sturgeon, tuna, salmon, yellowtail, smelt, anchovies, chicken, pork, lamb, bison, veal, beef, beef liver, elk, Parmesan and Romano cheese, mollusks, turkey, milk
Plant sources: brewer’s yeast, parsley, seaweed, spirulina, apples, beets, spinach
5. Methionine – Mental Health
Methionine contains sulphur and assists in the breakdown of fats, thereby preventing a build-up of fat in the blood vessels. It removes toxins and protects your body from free radicals that may cause clogged arteries, leukemia, and cancer. It helps your body get rid of harmful agents such as lead and other heavy metals. Methionine shows promise as an agent to assist with memory recall and is helpful for adults diagnosed with attention deficit hyperactivity disorder [III]. Methionine also works to reduce histamine levels in the body to allow your central nervous system to function properly. Deficiencies in Methionine levels can lead to mental disorders such as dementia, Alzheimer’s disease, schizophrenia, and Parkinson’s disease. Doctors often prescribe Methionine as a supplement for the treatment of those mental disorders.
Animal sources: eggs, cod, whitefish, tuna, smelt, halibut, anchovies, mollusks, elk, chicken, turkey, beef, liver, sturgeon, lamb, game meat, buffalo, salmon, buttermilk, milk
Vegetable sources: sesame seeds, sunflower seeds, Brazil nuts, brewer’s yeast, apples, kale
6. Phenylalanine – Mood
Phenylalanine is converted by your body to create tyrosine, another amino acid. It is needed to make brain chemicals including epinephrine, norepinephrine, and thyroid hormones. Norepinephrine plays a large role in mood regulation.
Animal sources: eggs, cod, whitefish, smelt, milk, cheese, gelatins, mollusks, pork, chicken, veal, beef, roe, salmon, lamb, game meat, beef liver, bison, moose
Plant sources: seaweed, spirulina, sesame seeds, sunflower seeds, brewer’s yeast, pumpkin seeds, parsley, mung beans, lupin beans, butter, nuts, winged beans, peanuts, kidney beans, black-eyed peas, apples, beets, spinach
7. Threonine – Healthy Skin
Threonine is an important part of many proteins in the body and is necessary for the formation of elastin and collagen, which are needed for both healthy skin and wound healing. Threonine has a mild glucose-sparing effect, which means it leaves glucose (blood sugar) available for cells that rely on blood sugar. It is useful in the stabilization of blood sugar. When combined with aspartic acid, Threonine assists in liver function and may prevent fat from accumulating in the liver. A fatty liver is associated with diseases of the liver such as cirrhosis.
Animal sources: beef, beef liver, game meat, buffalo, elk, moose, eggs, turkey, tilapia, orange roughy, tuna, cod, haddock, smelt, mollusks, salmon, pork, roe, gelatins, Parmesan cheese
Plant sources: watercress, seaweed, spirulina, pumpkin seed, brewer’s yeast, kale, lupin beans
8. Tryptophan – Natures Sleep Aid
Tryptophan is known for its role in the production of neurotransmitters (nervous system messengers), especially those related to relaxation, restfulness, and sleep. Your body can convert tryptophan to serotonin, a neurotransmitter that helps regulate appetite, sleep patterns, and mood. Because of its ability to raise serotonin levels, tryptophan has been used therapeutically in the treatment of a variety of conditions, most notably insomnia, depression, and anxiety. Because of its ability to raise serotonin levels, tryptophan is a routine part of most protein-based foods or dietary proteins. Many people believe that turkey contains high levels of tryptophan, which is why we get sleepy after our Thanksgiving meal. In reality, the amount of tryptophan in turkey is the same amount found in most poultry. Your post-meal drowsiness is more likely attributed to the carbohydrates and the large meal, which result in a surge of insulin and post-meal fatigue.
Animal sources: eggs, cod, pork, mollusks, whitefish, smelt, roe, salmon, Parmesan cheese, game meat, elk, goose, duck, beef, beef liver, goat, milk, chicken, lamb
Plant sources: sesame seeds, seaweed, spirulina, winged beans, sunflower seeds, chia seeds, pumpkin seeds, brewer’s yeast, parsley, spinach, fenugreek seeds, oats, dates
9. Valine – Healthy Muscles
Valine, along with Leucine and Isoleucine, is found in high concentrations in your muscles. Valine, Leucine, and Isoleucine account for 70 percent of the amino acids present in proteins. Valine helps repair damaged tissues, promotes normal growth, provides energy to cells, and regulates blood sugar levels. Valine also stimulates the central nervous system and thus plays an important role in mental functioning. “Maple syrup urine disease” is a disorder passed down through families in which the body cannot break down Leucine, Isoleucine, and Valine. Urine in individuals with this condition can smell like maple syrup [II]. The amino acid deficiencies that result cause problems with the nervous system, seizures, and a condition known as “failure to thrive.”
Animal sources: egg, cod, cheese, milk, gelatins, mollusks, pork, veal, lamb, pork, game meat, bison, salmon, milk, liver, beef, turkey
Vegetable sources: seaweed, spirulina, sunflower and sesame seeds, brewer’s yeast, parsley, apples, beets
As you can see, proteins are absolutely essential for skin, mood, mental health, brain function, immunity, and blood sugar regulation! Choosing the right proteins means the difference between mental clarity and brain fog, healthy skin and dull skin, strong muscles and weak fatty muscles. Hormonal balance, sexual function, inflammation, immunity, and so much more can be improved simply by choosing good quality proteins.
Browse our All-Star Foods section to read more about some of our favorite whole-food protein sources!
[I] Layman D, Walker D. "Potential Importance of Leucine in Treatment of Obesity and the Metabolic Syndrome". The Journal of Nutrition, January 2006, vol. 136 no. 1 319S-323S, 2006. Web. May. 2016.<http://jn.nutrition.org/content/136/1/319S.long>.
[I] "Maple Syrup Urine Disease". Genetics Home Reference. U.S. National Library of Medicine, 2016. Web. May. 2016. <https://ghr.nlm.nih.gov/condition/maple-syrup-urine-disease>.
Reeds, Peter J. "Dispensable and Indispensable Amino Acids for Humans". The Journal of Nutrition. July 1, 2000. vol. 130 no. 7 1835S-1840S. Web. May. 2016. <http://jn.nutrition.org/content/130/7/1835S.full>.
[III] Shekim WO, Antun F, Hanna GL, McCracken JT, Hess EB . "S-adenosyl-L-methionine (SAM) in adults with ADHD, RS: preliminary results from an open trial." Psychopharmacol Bull. 1990;26(2):249-53. Web. May. 2016. <http://www.ncbi.nlm.nih.gov/pubmed/2236465>.