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This article explains the benefits and food sources for including essential amino acids in your diet.
Amino acids, often referred to as the building blocks of proteins, are compounds that perform many important functions in your body.
They are needed for vital processes such as building proteins, hormones and neurotransmitters.
Amino acids are concentrated in protein-rich foods such as meat, fish and soybeans.
Some people also take certain amino acids in the form of dietary supplements to naturally enhance their athletic performance or improve their mood.
They are classified as essential, conditionally essential or non-essential depending on various factors.
In this article you will find all the basic information about essential amino acids, including how they work, food sources rich in essential amino acids and the potential benefits of taking supplements.
Amino acids are organic compounds made up mainly of nitrogen, carbon, hydrogen and oxygen.
Your body needs 20 different amino acids to grow and function properly. Although all 20 are important for health, only 9 are considered essential.
These are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.
Although the body can make non-essential amino acids itself, it cannot make essential amino acids, so you have to get them from food.
The best sources of essential amino acids are animal proteins such as meat, eggs and poultry. However, some plant foods, such as the soy products edamame and tofu, contain all nine essential amino acids. This means that they are "complete" sources of protein.
After eating protein, the body breaks it down into amino acids and then uses them for various processes, such as building muscle and regulating immune function.
Conditionally essential amino acids
Several non-essential amino acids are classified as conditionally essential.
They are only essential under certain circumstances, e.g. illness, pregnancy, infancy or trauma.
Arginine, for example, is considered non-essential, but your body can't make as much of it as you need when you're recovering from a serious injury or fighting certain diseases like cancer.
For this reason, people may take arginine supplements to meet their body's needs in certain situations.
In addition, certain amino acids, including glycine and arginine, are considered conditionally essential during pregnancy because a pregnant woman needs more of these amino acids to support her own health and that of the fetus.
SUMMARY
Your body cannot make the nine essential amino acids itself, so you need to get them from food. Conditionally essential amino acids are non-essential amino acids that become essential under certain circumstances, such as illness or pregnancy.
There are nine essential amino acids, each of which performs a number of important functions in the body:
1. phenylalanine. The body turns this amino acid into the neurotransmitters tyrosine, dopamine, epinephrine and norepinephrine. It plays an essential role in the structure and function of proteins and enzymes, as well as in the production of other amino acids.
2. valine. This is one of the three branched chain amino acids (BCAAs) on this list. This means that it has a chain that branches off from one side of its molecular structure. Valine helps promote muscle growth and recovery and is involved in energy production.
3. threonine. It is a major component of structural proteins such as collagen and elastin, which are important components of skin and connective tissue. It also plays a role in fat metabolism and immune function.
4. tryptophan. Tryptophan is often associated with sleepiness and is a precursor to serotonin, a neurotransmitter that regulates appetite, sleep and mood.
5. methionine. This amino acid plays an important role in metabolism and detoxification. It is also necessary for tissue growth and the absorption of zinc and selenium, minerals that are important for health.
6. leucine. Like valine, leucine is a BCAA that is crucial for protein synthesis and muscle repair. It also helps regulate blood sugar levels, stimulates wound healing and produces growth hormones.
7. isoleucine. The last of the three BCAAs, isoleucine is involved in muscle metabolism and is highly concentrated in muscle tissue. It is also important for immune function, haemoglobin production and energy regulation.
8. lysine. Lysine plays an important role in protein synthesis, calcium absorption and the production of hormones and enzymes. It is also important for energy production, immune function and the production of collagen and elastin.
9. histidine. The body uses this amino acid to produce histamine, a neurotransmitter important for immune response, digestion, sexual function and sleep-wake cycles. It is crucial for maintaining the myelin sheath, a protective barrier that surrounds your nerve cells.
As you can see, essential amino acids are central to many vital processes.
Although amino acids are best known for their role in muscle building and repair, your body needs them for so much more.
Therefore, a deficiency of essential amino acids can have a negative impact on the entire body, including the nervous, reproductive, immune and digestive systems.
However, most people take in all the amino acids they need through their diet.
SUMMARY
All nine essential amino acids perform important jobs in your body. They are involved in many processes, including tissue growth, energy production, immune function and nutrient absorption.
Health benefits of taking supplements with essential amino acids
Essential amino acids are found in a variety of foods, but taking concentrated doses in supplement form has been linked to several health benefits.
May improve mood
Tryptophan is necessary for the production of serotonin, a chemical that acts as a neurotransmitter in the body.
Serotonin is an essential regulator of mood, sleep and behaviour.
Low serotonin levels are associated with depressive moods and sleep disorders. Several studies have shown that taking tryptophan supplements can reduce symptoms of depression and improve mood (16
A review that included 11 high-quality studies found that taking 0.14 to 3 grams of tryptophan per day can help reduce anxiety and improve positive mood in healthy people
May improve athletic performance and recovery
Many people take valine, leucine and isoleucine, the three essential BCAAs, to relieve fatigue, improve athletic performance and promote muscle recovery after exercise.
In a small 2017 study, strength-trained athletes took BCAAs at a dose of 0.039 grams per pound (0.087 grams per kg) of body weight, with a 2:1:1 ratio of leucine, isoleucine and valine.
Those taking BCAAs showed improved performance and muscle recovery and reduced muscle soreness compared to those taking a placebo.
A review of eight studies found that taking BCAAs was better at promoting muscle recovery and reducing muscle soreness after a strenuous workout than rest.
Another review that included nine studies concluded that taking BCAAs reduced muscle damage and soreness after resistance training in active men.
Intake of BCAAs has also been shown to reduce ratings of perceived exertion - how intense a person feels they are working during exercise - in people performing high-intensity training
May be helpful in wound healing and during surgery
Taking amino acid supplements may be helpful for people who need to heal after surgery.
A study of 243 people with pelvic or long bone fractures found that those who conditionally consumed essential amino acids for 2 weeks after surgery had a lower rate of death and medical complications than those who received a standard diet.
A review of 20 studies on the effects of taking BCAAs in cancer patients undergoing surgery found that those taking BCAAs at the time of surgery had fewer postoperative complications from infection and fluid retention in the abdomen.
In addition, taking supplements with essential amino acids may help reduce the loss of muscle mass in older adults recovering from knee replacement surgery, according to one study.
SUMMARY
Taking certain essential amino acids in supplement form can help improve mood, support athletic performance and recovery, and improve health outcomes after surgery.
Food sources and recommended intake
Because the body cannot make essential amino acids itself, it is important to get them from the diet.
Many foods are rich in essential amino acids, so it is easy to meet your daily needs
Below are the daily intakes of essential amino acids recommended by the World Health Organisation. These values apply to adults per 1 kg of body weight (2.2 pounds)
- Histidine: 10 mg
- Isoleucine: 20 mg
- Leucine: 39 mg
- Lysine: 30 mg
- Methionine: 10.4 mg
- Phenylalanine in combination with the non-essential amino acid tyrosine: 25 mg
- Threonine: 15 mg
- Tryptophan: 4 mg
- Valine: 26 mg
To find out how much you should take per day, you can multiply the above figures by your weight in kilograms. For example, a person weighing 60 kg (132 pounds) should consume 1,200 mg (1.2 grams) of isoleucine per day.
In most diets, it is very easy to meet this requirement, so it is usually not necessary to track the intake of individual amino acids.
For example, a 174 gram piece of braised chicken breast provides 55.9 grams of complete protein, easily meeting or exceeding the above requirement.
Food sources
Foods that contain all nine essential amino acids are called complete proteins.
The following foods are complete protein sources:
- Meat
- Seafood
- Poultry
- Eggs
- Dairy products
Soy and pea protein are complete vegetable protein sources (2
Other plant protein sources such as beans, nuts and certain grains are considered incomplete proteins because they lack one or more of the essential amino acids.
If you eat a plant-based diet, you can still ensure an adequate intake of all nine essential amino acids by eating a variety of plant-based proteins each day.
For example, by eating a variety of plant proteins such as beans, nuts, seeds, whole grains and vegetables, you can meet your essential amino acid needs even if you avoid animal products in your diet.
SUMMARY
Many animal and plant foods, such as meat, eggs, quinoa and soy, contain all nine essential amino acids and are considered complete proteins
Most people get enough essential amino acids through their diet.
However, taking supplements with essential amino acids has some advantages. Athletes, for example, often take them to improve their performance and recovery.
A review that included 10 high-quality studies found that BCAAs in doses of up to 115.6 mg per pound (255 mg per kg) per day can help reduce delayed-onset muscle soreness in trained individuals after exercise (32
In addition, people may choose to take individual amino acids rather than a blend to support certain aspects of health, such as mood.
A review that included 11 high-quality studies found that taking 0.14 to 3 grams of tryptophan per day can improve mood in healthy people.
As you can see, the dosage depends on the type of amino acid you are taking and what your goal is.
Amino acid supplements are considered safe for most people. However, they are not usually necessary if you are getting enough protein in your diet.
However, amino acid supplements may offer certain benefits for certain groups of people.
If you are interested in taking supplements with essential amino acids, you should talk to a healthcare professional who knows about supplements, such as your doctor or a registered dietitian.
They can recommend a specific dosage and tell you how best to take your supplement, depending on your health goals. They can also help you choose a supplement from a reputable brand whose products have been tested by independent organisations.
SUMMARY
The dosage of amino acid supplements depends on the particular amino acid and the reason for taking it. If you are interested in taking supplements containing essential amino acids, you should consult a qualified health care professional.
The bottom line
There are nine essential amino acids that you need to get from your diet: Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan and Valine.
They are vital for functions throughout the body, including protein synthesis, tissue repair and nutrient absorption.
Some may also help prevent muscle breakdown, aid recovery after surgery and improve mood, sleep and athletic performance.
These vital compounds are found in many animal and plant foods, so most people can meet their daily needs through a healthy, balanced diet. You can also take essential amino acid supplements if needed.