What Are Essential Amino Acids?
November 15, 2012
Amino acids are the building blocks of protein. And protein is essential to the proper function of every cell, muscle, and organ in the body. Your body breaks down the protein you consume into amino acids, which are then used to repair and replace damaged proteins.
If amino acids are so important to repairing and maintaining your body, then why are certain amino acids deemed “essential” while others are not?
There are 21 naturally occurring amino acids used by the human body. However, your body cannot synthesize 9 of these 21 amino acids. The 9 amino acids you cannot synthesize are called “essential amino acids.” If you don’t ingest them as part of your diet, your body has no way to make them.
The Essential Amino Acids
Histidine makes red and white blood cells and transports oxygen through the blood. It’s also essential for the growth and repair of tissue. Histidine is found in dairy, meat, poultry, fish, rice, and wheat.
Leucine regulates blood sugar and enhances human growth hormone (HGH) production. It promotes the growth and repair of skin, bone, and muscles, as well. Leucine is found in brown rice, beans, nuts, and whole wheat.
Isoleucine is similar to leucine because it promotes muscle repair and HGH production. It also creates hemoglobin, which transports oxygen through blood. Chicken, cashews, fish, almonds, eggs, and liver are rich sources of isoleucine.
Lysine increases calcium absorption and maintains nitrogen levels. It also produces antibodies, hormones, and collagen. Cheese, eggs, milk, yeast, and potatoes are excellent sources of leucine.
Methionine improves digestion and breaks down and utilizes fat. It is one of three amino acids needed to make creatine. Methionine comes from fish, beans, garlic, lentils, onions, and yogurt.
Phenylalanine treats depression and reduces pain. It works by increasing levels of epinephrine, norepinephrine, and dopamine. Phenylalanine is naturally found in dairy products, almonds, avocadoes, nuts, and seeds.
Threonine creates collagen and elastin and balances protein levels. It’s most important function is enhancing the absorption of other nutrients. The main sources of threonine are meat, dairy, and eggs.
Tryptophan improves sleep quality and elevates mood. Chicken, soy, tuna, turkey, and salmon have the most tryptophan.
Valine enhances brain function and stimulates muscle growth. It can be found in dairy, meat, grain, mushrooms, soy, and peanuts.
Isoleucine, leucine, and valine are also known as “branched-chain amino acids” (BCAAs). Besides building muscles, BCAAs increase energy. Naturally, BCAAs are bodybuilders’ 3 favorite essential amino acids, but anyone can appreciate stronger muscles and higher energy.
Essential Amino Acids and Protein Synthesis
You’ve been told countless times that protein is important. So, although you may not know the “how”, you make protein a staple of your diet. Eggs fill your fridge and protein supplements line your shelves. Well, it’s time you learned why protein is so important.
When you consume protein-rich foods or supplements, your body digests them into amino acids. While most of the amino acids in the body come from the foods you eat, your body can and does synthesize non-essential proteins as needed.
So, if your diet does not contain enough non-essential amino acids, your body will compensate by creating them itself. However, if your diet does not contain enough essential amino acids, you will be compromising your ability to repair and maintain your body.
After digestion, amino acids are single and unattached. Then, protein synthesis happens. The single, unattached amino acids hook up to form polypeptides, and a protein molecule is created.
As long as you consume enough essential amino acids, your body can make all the protein it needs for the maintenance and repair of tissue, organs, and muscle. As an added benefit, amino acids unused by the body will be converted into energy.
4 Proven Benefits of Essential Amino Acids
It’s not just nerdy science. Essential amino acids have been proven to speed up recovery time, reduce muscle soreness, build muscle, and increase endurance and power. Here’s the evidence:
- Essential amino acids speed recovery. Study participants consumed 6 grams of essential amino acids 1 and 2 hours after resistance exercise. The result: muscle breakdown was reduced and people recovered faster.
- Essential amino acids reduce soreness. When men took essential amino acid supplements during a study, their muscle soreness was significantly lower 48 to 72 hours after exercise.
- Essential amino acids build muscle. In one study, people were given a drink (6 grams essential amino acids and 35 grams sucrose) 1 or 3 hours after resistance exercise. The result: protein synthesis increased and muscles growth was enhanced.
- Essential amino acids increase endurance and power. After taking essential amino acid supplements, study participants had more endurance and greater upper body power.
The Safety of Essential Amino Acids
Consuming protein-rich foods is the best and safest way to get essential amino acids. Supplements contain naturally-derived essential amino acids, which are usually safe. However, there are a few things you should be aware of when taking supplements:
- Essential amino acid supplements may cause insomnia because they increase energy
- Essential amino acid supplements may aggravate preexisting liver and kidney problems
- Essential amino acid supplements may disrupt amino acid balance in the body
- Supplements with high essential amino acid dosages may increase heart rate and cause damage over time
- Supplements with high essential amino acid dosages may cause a blood disorder; eosinophiliamyalgia syndrome
How to Get the Best Results
When it comes to ingesting essential amino acids, “how” and “when” you take them makes all the difference. First of all, let’s talk about the recommended intake of essential amino acids. Because ingesting too much can cause negative side effects, it’s important to get this right.
The “How”. The best way to get amino acids is by eating foods in which they are found. But sometimes, getting the right amount from your diet is a challenge. This is where essential amino acid supplements come in handy.
According to research, 6 grams of essential amino acids is a safe, effective total dosage for a supplement serving. However, here are the individual amounts of each essential amino acid you should be getting from diet or supplements:
Essential Amino Acids: Building Blocks of Health
Whether you’re looking to build muscle, lose weight, increase energy, or live a healthy lifestyle, essential amino acids are crucial to achieving your goals.
Knowing what essential amino acids are and how they work doesn’t just make you book-smart. It’s the key to choosing the best amino acid supplements and foods and consuming them at the right time. This in turn helps you improve your health and get into great shape.
-  Borsheim, E, KD Tipton, et al. “Essential amino acids and muscle protein recovery from resistance exercise.” American Journal of Physiology, Endocrinology, and Metabolism. 283.4 (2002).
-  Jackman, Sarah R, Oliver C Witard, et al. “Branched-Chain Amino Acid Ingestion Can Ameliorate Soreness from Eccentric Exercise.” Medicine and Science in Sports and Exercise. 42.5 (2010): 962-70.
-  Rasmussen, BB, SL Miller, et al. “An oral essential amino acid-carbohydrate supplement enhances muscle protein anabolism after resistance exercise.” Journal of Applied Physiology. 88.2 (2000): 386-92.
-  Crowe, MJ, JN Weatherson, et al. “Effects of dietary leucine supplementation on exercise performance.” European Journal of Applied Physiology. 97.6 (2006): 664-72.
-  World Health Organization. Protein and amino acid requirements in human nutrition. Switzerland: WHO Press, 2007.