Have you ever heard someone say that amino acids are the building blocks of nature, in fact, of all life? Well, it’s true. Amino acids are compounds that — when ingested or created by the body — allow us do all the important things like grow, heal, move and think. According to the National Library of Medicine, amino acids are a natural energy source as well as necessary for all the functions of life.
Those who are concerned they aren’t getting the proper amount of amino acids from their daily nutrition can rest easy, however. Many essential amino acids can be boosted in the body by taking daily supplements.
Amino Acids Definition: What Are They?
Amino acids are organic compounds found in nature or in the body. When they join together, they form proteins, which allows human beings to function properly both physically and mentally. Proteins, which are just complex chains of amino acids, are broken down by the body to create energy and allow for other functions.
There are actually three kinds of amino acids. These include essential amino acids, nonessential amino acids and conditional amino acids. Essential amino acids must be gained through eating foods or taking supplements. This is because they are not naturally synthesized by humans and must be ingested daily. Nonessential amino acids are created by the body, and therefore, do not need to be monitored for intake. Conditional amino acids are more necessary during certain, high-stress period such as when a person is sick, under extreme mental or physical pressure or dealing with another serious problem.
Also Known As…
Amino acids are sometimes called proteins, essentially because, as previously stated, they are the building blocks of proteins. If you hear someone say you need more protein in your diet, they’re saying you need to bring more essential amino acids into your body. But which are essential amino acids, which are nonessential and which are conditional?
Essential, Nonessential and Conditional Amino Acids
There are nine essential amino acids. You are likely to hear about these more than any other, simply because it's our job to monitor our intake of these compounds because our body cannot do it for us. These nine amino acids include
There are five nonessential amino acids that we do not need to take supplements or eat food in order to gain because our body actually makes them. These include
- Aspartic acid
- Glutamic acid
Finally, there are ten conditional amino acids, which we do not need a certain amount of every day in order to be healthy, energetic and well. However, those who are struggling with either a physical issue, a mental issue or both might benefit from taking one of these conditional amino acids, which include
Getting to a point where you understand what each of these compounds for your body is how you can start to draw distinctions between these 20 amino acids.
What Are Amino Acids Made Of?
When you’re learning about the way amino acids work, you need to look at them on a molecular level. Amino acids are made up of several different building blocks called molecules. These include
- A carbon atom, often called a carbon, which is central to the amino acid’s makeup
- A carboxylic acid, which contains a carboxyl group
- The carboxyl group consists of another carbon atom and two oxygen atoms. This group is negatively charged.
- An amino group or an NH2 group
- In amino acids, hydrogen atoms will move from one side of the molecule to the other, which creates a positive charge.
- The negative charge of the carboxyl group and the positive charge of the amino group allow the pH of the amino acid to be neutral, also known as the isoelectronic point.
- A hydrogen atom that is bonded to the central carbon atom
- A distinctive R-group, also known as the side chain
- The R-group is bonded to the central carbon atom, and this group will be different depending on which type of amino acid it makes up.
For those hoping to learn more about the building blocks of each amino acid — and the R-groups that make each one special — NCBI Structures highlights the different chemistries of all 20. When you are able to see amino acids broken down to their simplest forms, you can see how each of them is individually unique.
Beyond amino acids, nucleic acids are also necessary to creating proteins. Two types of nucleic acids — DNA and RNA — achieve protein biosynthesis by building a protein chain made up of amino acids. These two types of natural compounds come together to create the proteins you need to survive and to feel your best. When you are not getting enough amino acids from your diet in order to achieve this effect, you may need to take supplements to help it along.
As you probably guessed, different amino acids have different benefits for your body, mind and overall wellbeing. Some are completely free amino acids — that is, the ones your body creates itself. Nonessential amino acids are made by the body and contain their own important benefits like the ability to work with essential amino acids to create proteins, and if your diet is healthy, the ability to create glucose or fatty acids.
Histidine does quite a lot for your body because it is metabolized to create the neurotransmitter histamine. Histamine is essential to a number of functions in your body including immunity, sexual functions and maintaining the myelin that protects your nerve cells. PubChem states histidine should definitely be obtained by children from ingesting food, but it can also be used as a supplement to treat arthritis, inflammation, allergies, and in some cases, even sexual dysfunction in women1.
Isoleucine is used to synthesize hemoglobin in the body, and it is found in large quantities in the muscular tissue. It regulates the levels of muscle metabolism in the body, as well as the levels of blood sugar and energy. Some people take isoleucine as a supplement in order to develop their muscles and heal injuries more quickly, but it’s important to be aware the University of Rochester Medical Center cites these effects are a mostly unsubstantiated claim.
Leucine is also known to build up muscle mass, heal wounds more quickly and promote growth. According to a 1999 study published in the American Journal of Sports Medicine2, leucine has been studied more thoroughly for its supplemental values than the other branched-chain amino acids — valine and isoleucine — because it has a higher oxidation rate than the other two. If you’re looking for amino acids information because you want to increase and maintain your muscle mass, these are the essential supplements for this effect.
Lysine boosts energy production as well as the immune system. It is also essential to creating collagen and elastin in the body, producing hormones and producing enzymes. In addition, it makes it easier for the body to absorb necessary amounts of calcium. Though not all individuals can benefit from lysine supplements, it has been known to help prevent flare-ups3 of the herpes simplex virus.
Methionine makes skin and hair more pliable, strengthens nails and creates the sulphur4 necessary to protect cells from age and pollutants. Because methionine keeps fat from stacking up in the liver, methionine supplements are sometimes taken to liver problems or disorders. They can also help to fight viral infections.
Phenylalanine has many jobs inside your body: It helps to create tyrosine, epinephrine, norepinephrine and dopamine, which are all essential neurotransmitters; it helps produce other, nonessential amino acids in the body; and it builds essential enzymes and proteins in the body. Because it can help make the neurotransmitters that affect mood, it can sometimes be taken as a supplement to help treat depression.
Threonine helps build tooth enamel, collagen and elastin in the body. It is also important to the body’s immune system, preventing fatty buildup in the liver and metabolism. However, one of the most important aspects of threonine is how it can affect the nervous system, which is why it is often used as a supplement to treat depression and anxiety5.
Tryptophan is essential to adults and children to promote growth and balance nitrogen in the body, respectively. Tryptophan is used to create essential nutrients and chemicals like niacin, serotonin and melatonin (which is part of the reason why it’s associated with making you sleepy!). As a supplement, it can be used to reduce mood swings, anxiety and other unwanted behavioral and psychological effects.
Valine is another of the branched-chain amino acids, which means it helps aid muscle growth, repair tissues and stimulate the body. Those who take it as a supplement are usually athletes like weightlifters or bodybuilders who need to build muscle.
Conditional Amino Acids
Conditional amino acids — like arginine, tyrosine and glutamine — can be effective to take as supplements at certain, high-stress times in your life. For example, they can help boost immunity or make it easier for you to deal with stress. However, you should not be taking conditional amino acid supplements all the time. They aren’t necessary, and it’s possible that doing so can negatively affect your body in the long run6.
Daily Recommended Allowance of Amino Acids
Although proteins are good for you, it’s important not to take in more than your body can handle. If you decide to take supplements to increase your intake of one of these amino acids, go by this handy amino acids chart for the daily recommended allowance of protein:
- The recommended dietary intake of protein for adult men is 0.84 g/kg (grams per kilogram of bodyweight).
- The recommended dietary intake of protein for adult women is 0.75 g/kg.
- The recommended dietary intake of protein for pregnant or breastfeeding individuals as well as adults over 70 years of age is 1 g/kg.
Children’s needs can be different based on variables like their age and weight. In some cases, adult recommendations can vary as well, so it's best to check with a doctor. Essentially, though, it helps to stick with these rules of thumb.
How to Use Amino Acids
People take amino acid supplements for a number of reasons: to produce protein in the body, to improve psychological functioning, to improve sleep, to boost performance when exercising7, to build muscle and to assist in weight loss. All of these effects can be desirable, but it is important to remember that taking amino acids to produce an effect like one of these listed above is like taking medicine. You shouldn’t do it without talking to your doctor first, and you should never take more than the recommended dose.
Amino Acids for Sports Performance
When many individuals consider the use of amino acids, they are either professional or amateur athletes thinking of taking them as supplements for enhanced sports performance. When used in this way, amino acids can offer many benefits, including but not limited to, increased muscle mass, decreased fatigue, protection against sports anemia and increased nitrogen retention. If this is your aim, you'll want to consider taking one or a combination of the amino acids listed below.
BCAAs stands for branched-chain amino acids. These proteins are actually metabolized by the cells of the skeletal muscles in order to give an individual more energy during physical activity. They also help build muscle mass and increase strength. While there isn't much evidence that BCAAs help those hoping to engage in aerobic workouts, they can be incredibly helpful for endeavors like weight training. The three BCAAs are leucine, isoleucine and valine, and they are often packaged together as supplements.
Theanine is a conditional amino acid that can help with mental and physical performance. In fact, it is one of the only supplements that can both relax the mind and avoid causing drowsiness8. As such, many people like to use it during physical activity to keep their minds engaged but calm, which is a perfect sweet spot for sports performance. Theanine can be found in tea, but it can also be found as a supplement sold on its own.
Like phenylalanine, phenylalaine highly affects the way the brain works, allowing an individual to produce the neurotransmitters responsible for regulating and stabilizing moods. This often translates into more energy and better mental outlooks for athletes.
Carnitine directly affects energy levels as well as metabolism9. It helps to burn the fatty acids the body needs to use as fuel. Carnitine does not need to be taken by healthy adults and children, but some athletes take it to increase energy levels and to ensure that they do not become carnitine deficient, which can dramatically affect weight gain.
Tartrate is formed by the organic tartaric acid compound. In many cases, it is paired with carnitine for supplemental use. In a 2003 study, L-carnitine and L-tartrate were found to be effective for helping people recover more quickly after exercise routines where their muscles were not receiving enough oxygen10.
Citruline can boost your immune system, increase the amount of nitric oxoide in your body and potentially even help with erectile dysfunction11. People often take this nonessential amino acid for sports performance specifically because it can lower blood pressure while also increasing athletic performance and allowing for muscle building.
Who Is at Risk of an Amino Acid Deficiency?
Usually, amino acid deficiency is not an isolated problem. In most cases, people who experience this issue do so because they are not taking in their essential dietary amount of amino acids. Those who do not intake enough tryptophan and valine, for example, will sometimes experience psychological issues12 as a result, and this is the root of the problem, rather than a physical issue causing the deficiency.
In most cases, those with amino acid or protein deficiencies are living in third world countries, very poor and unable to intake enough amino acids—like methionine, phenylalanine, threonine and so on—to be able to build the essential proteins they need. This is a much more serious problem in underdeveloped countries, which is why you don’t hear of too many cases of protein deficiency in the US.
Still, some individuals can experience this issue while living in a country like ours. Sometimes, people who are very old and/or ill may not receive proper medical treatment and/or dietary offerings, which can lead to a protein deficiency. People with eating disorders like anorexia can also experience amino acid deficiency because they aren’t taking in enough of these essential compounds to help their bodies function properly.
This type of deficiency can sometimes occur in individuals who choose to follow vegetarian or vegan diets, but again, because of the widespread knowledge of protein deficiency and the body’s need for this component, it is a rare effect. Many vegan or vegetarian individuals get their sufficient protein intake from supplements or from eating different types of foods than meat.
Symptoms of Amino Acid Deficiency
As echoed by the Better Health Channel, the symptoms of amino acid deficiency include
- Loss of muscle tissue
- Iron deficiency
- Swelling of the feet and ankles because of fluid buildup
- In children, slowed growth
It is also important to be aware that a diet with too much protein intake can also be a problem. People who are so focused on protein may forget other essential nutrients like carbohydrates, fiber and calcium. In addition, taking in too much protein can put a strain on the kidneys, liver and heart. Always remember that one must balance their intake of amino acids as well as every other type of nutrient.
Food that Contains Amino Acids
Aside from taking supplements, most people can also get their daily recommended amount of protein from simply eating foods that are rich in amino acids. The NLM lists a number of foods that, at one ounce, contain at least seven grams of protein each. These include
Making sure to eat these protein-rich foods regularly will help you keep to your daily recommended amount of amino acids. If you are vegan or vegetarian, the Vegetarian Resource Group offers a number of options for protein-rich foods that do not contain animal products, such as
- Oatmeal (6 grams of protein per 1 cup)
- Tofu (12 grams of protein per 5 ounces)
- Soybeans (31 grams of protein per 1 cup)
- Lentils (18 grams of protein per 1 cup)
- Almonds (4 grams of protein per 2 tbsp)
- Whole wheat bread (7 grams of protein per 2 slices)
- Soy milk (7 grams of protein per 1 cup)
- Brown rice (5 grams of protein per 1 cup)
- Peanut Butter (8 grams of protein per 2 tbsp)
Your Amino Acids and You
Making sure to stay on top of your amino acid intake is essential to living a healthy life. Whether you take supplements for histidine, isoleucine, leucine, lysine or another essential amino acid or you make sure to eat foods that are rich in protein, you are focused on giving your body the fuel it needs—not to mention giving your mind the tools it needs—to keep you going and feeling healthy all day.