Amino Acids:
Amino acids are the building blocks of proteins. They are the organic compounds that contain amino and carboxyl functional groups, along with a side chain specific to each amino acid. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen, although other elements are found in the side chains of certain amino acids.
Your body needs 20 different amino acids to grow and function properly. Though all 20 of these are important for your health, only nine amino acids are classified as essential
Essential Amino Acids – This means you must get these from your diet.
They are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.
- Phenylalanine: Phenylalanine is a precursor for the neurotransmitters tyrosine, dopamine, epinephrine and norepinephrine. It plays an integral role in the structure and function of proteins and enzymes and the production of other amino acids (4).
- Valine: Valine is one of three branched-chain amino acids, meaning it has a chain branching off to one side of its molecular structure. Valine helps stimulate muscle growth and regeneration and is involved in energy production (5).
- Threonine: Threonine is a principal part of structural proteins such as collagen and elastin, which are important components of the skin and connective tissue. It also plays a role in fat metabolism and immune function
FUN FACT:
The last of the 20 common amino acids to be discovered was threonine in 1935 by William Cumming Rose, who also determined the essential amino acids and established the minimum daily requirements of all amino acids for optimal growth.
- Tryptophan: Though often associated with causing drowsiness, tryptophan has many other functions. It’s needed to maintain proper nitrogen balance and is a precursor to serotonin, a neurotransmitter that regulates your appetite, sleep and mood (7).
- Methionine: Methionine plays an important role in metabolism and detoxification. It’s also necessary for tissue growth and the absorption of zinc and selenium, minerals that are vital to your health (8).
- Leucine: Like valine, leucine is a branched-chain amino acid that is critical for protein synthesis and muscle repair. It also helps regulate blood sugar levels, stimulates wound healing and produces growth hormones (9).
- Isoleucine: The last of the three branched-chain amino acids, isoleucine is involved in muscle metabolism and is heavily concentrated in muscle tissue. It’s also important for immune function, hemoglobin production and energy regulation (10).
- Lysine: Lysine plays major roles in protein synthesis, hormone and enzyme production and the absorption of calcium. It’s also important for energy production, immune function and the production of collagen and elastin (11).
- Histidine: Histidine is used to produce histamine, a neurotransmitter that is vital to immune response, digestion, sexual function and sleep-wake cycles. It’s critical for maintaining the myelin sheath, a protective barrier that surrounds your nerve cells (12).
Branched-chain amino acids (BCAAs; valine, leucine, and isoleucine) are essential amino acids with protein anabolic properties, which have been studied in a number of muscle wasting disorders for more than 50 years.
Increase Muscle Growth
One of the most popular uses of BCAAs is to increase muscle growth.
The BCAA leucine activates a certain pathway in the body that stimulates muscle protein synthesis, which is the process of making muscle
While BCAAs can increase muscle protein synthesis, they can’t do so maximally without the other essential amino acids, such as those found in whey protein or other complete protein sources
Decrease Muscle Soreness
Some research suggests BCAAs can help decrease muscle soreness after a workout.
BCAAs have been shown to decrease muscle damage, which may help reduce the length and severity of damage muscle.
Several studies show that BCAAs decrease protein breakdown during exercise and decrease levels of creatine kinase, which is an indicator of muscle damage
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Reduce Exercise Fatigue
Just as BCAAs may help decrease muscle soreness from exercise, they may also help reduce exercise-induced fatigue.
Everyone experiences fatigue and exhaustion from exercise at some point. How quickly you tire depends on several factors, including exercise intensity and duration, environmental conditions and your nutrition and fitness level
Your muscles use BCAAs during exercise, causing levels in your blood to decrease. When blood levels of BCAAs decline, levels of the essential amino acid tryptophan in your brain increase.
In two studies, participants who supplemented with BCAAs improved their mental focus during exercise, which is thought to result from the fatigue-reducing effect of BCAAs
Prevent Muscle Wasting
BCAAs can help prevent muscle wasting or breakdown.
Muscle proteins are constantly broken down and rebuilt (synthesized). The balance between muscle protein breakdown and synthesis determines the amount of protein in muscle
Muscle wasting or breakdown occurs when protein breakdown exceeds muscle protein synthesis.
Muscle wasting is a sign of malnutrition and occurs with chronic infections, cancer, periods of fasting and as a natural part of the aging process
Therefore, it’s important that the BCAAs and other essential amino acids are replaced during times of muscle wasting to halt it or to slow its progression.
Benefit People with Liver Disease
BCAAs may improve health in people with cirrhosis, a chronic disease in which the liver does not function properly.
It’s estimated that 50% of people with cirrhosis will develop hepatic encephalopathy, which is the loss of brain function that occurs when the liver is unable to remove toxins from the blood
One review of 16 studies including 827 people with hepatic encephalopathy found that taking BCAA supplements had a beneficial effect on the symptoms and signs of the disease.
Tryptophan, an essential amino acid
Tryptophan has the lowest concentration in the body of any amino acid, yet it is vital for the production and maintenance of the body’s proteins, muscles, enzymes, and neurotransmitters that affect your mood, cognition, and behavior.
Research trials have shown it to have possible benefits when treating sleep disorders, seasonal affective disorder, premenstrual discomfort, and for reducing anxiety when quitting smoking.
Non-Essential Amino Acids
Nonessential amino acids support tissue growth and repair, immune function, red blood cell formation, and hormone synthesis. However, unlike essential amino acids, a healthy body can create these proteins if given enough protein sources with essential amino acids.
Nonessential amino acids include: alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine.
Arginine
L-arginine is an amino acid that helps the body build protein. Your body usually makes all the L-arginine it needs. L-arginine is also found in most protein-rich foods, including fish, red meat, poultry, soy, whole grains, beans and dairy products. As a supplement, L-arginine can be used orally and topically
Nitric oxide (NO) is synthesized from arginine by NO synthase (NOS), and the availability of arginine is one of the rate-limiting factors in cellular NO production.
Glutamine
It is a building block of protein and critical part of the immune system.
What’s more, glutamine has a special role in intestinal health.
Your body naturally produces this amino acid, and it is also found in many foods. Yet, you may be unsure if you need extra glutamine from supplements for optimal health.
L-glutamine can be produced naturally in your body. In fact, it is the most abundant amino acid in the blood and other body fluids
Almost any food containing protein will contain some glutamine, but amounts vary.
Tyrosine
Tyrosine is a nonessential amino acid the body makes from another amino acid called phenylalanine. It is an essential component to produce several important brain chemicals called neurotransmitters, including epinephrine, norepinephrine, and dopamine.
It also helps the body produce enzymes, thyroid hormones, and the skin pigment melanin. It also helps the body produce neurotransmitters that helps nerve cells communicate. Tyrosine is particularly important in the production of epinephrine, norepinephrine, and dopamine.
