What are amino acids?

You can get enough essential amino acids through eating a diet rich in protein. These proteins are available in both plant foods and animal foods.
You can get enough essential amino acids through eating a diet rich in protein. These proteins are available in both plant foods and animal foods.

Amino acids are an important nutrient required for life and good health maintenance. They are sometimes called macronutrients and combine to form proteins. Proteins and amino acids are the building blocks of life.

Amino acids are long-chain molecules that make up protein. You have protein in your body in muscles, bones, skin, hair, and almost every tissue or body part. They also make enzymes that drive important chemical reactions in the body. 

Your body doesn’t store amino acids, so it makes them from scratch or from others instead. There are more than 20 amino acids, which fall into three groups:

  • Essential amino acids
  • Nonessential amino acids
  • Conditional amino acids

Your body cannot make essential amino acids from scratch or from other amino acids, so you must get them from food. These include:

  • Histidine
  • Lysine
  • Isoleucine
  • Leucine
  • Tryptophan
  • Valine
  • Threonine
  • Methionine
  • Phenylalanine

If you’re an adult, your body can make nonessential and conditional amino acids. Children’s bodies can’t produce enough conditional amino acids to meet their needs. 

Benefits of amino acids

Amino acids are required for life. Your body uses amino acids to build protein in your muscles, skin, hair, organs, and tissues and as a source of energy. Amino acids are important to:

  • Build muscle
  • Grow
  • Break down food
  • Repair tissues
  • Balance nitrogen in the body
  • Regulate appetite
  • Regulate blood pressure
  • Build brain chemicals
  • Regulate the immune system

Amino acids are responsible for many other processes and functions in the body.

Foods high in essential amino acids

You can get enough essential amino acids through eating a diet rich in protein. These proteins are available in both plant foods and animal foods. 

Some foods contain complete proteins. These are foods that contain all 20 or more types of amino acids. Some foods are incomplete proteins and they may be missing one more of the nine essential amino acids. 

Animal and plant foods that contain complete proteins or all amino acids include:

  • Red meat
  • Chicken
  • Fish
  • Seafood
  • Eggs
  • Milk
  • Cheese
  • Yogurt
  • Quinoa
  • Chia seeds
  • Tofu

Plant foods that contain some amino acids include:

  • Grains
  • Nuts
  • Seeds
  • Beans
  • Legumes
  • Fruits
  • Vegetables

QUESTION

According to the USDA, there is no difference between a “portion” and a “serving.” See Answer

How much protein do you need?

The Recommended Daily Allowance for protein is 0.8 grams of protein per kilogram of body weight per day in the United States, or about 7 grams for every 20 pounds of bodyweight. That means if you weigh 140 pounds, you should eat about 50 grams of protein in a day.

Most healthy people who live in a developed country get more than enough protein in their diet. However, millions of people, especially children and those who live in developing countries, do not get enough protein because of food insecurity.

The best way to get all the amino acids you need is to eat a variety of foods throughout the day that contain amino acids. People who do not eat animal foods may need to eat more and a greater variety of plant foods that contain amino acids to reach their recommended daily intake.

Risks and outlook

Protein is required for your health to maintain healthy body functions. Children need extra protein as they grow, and pregnant or breastfeeding women need good amounts of protein as they grow a baby. 

Risks of not enough protein

People who live with food insecurity may have difficulty getting enough protein and essential amino acids. People who do not eat animal foods may also be at risk for not enough protein or a variety of proteins. Too little protein and malnutrition can lead to:

  • Poor growth
  • Loss of muscle mass
  • Weakened heart
  • Weakened respiratory system
  • Decreased immunity

Severe malnutrition and a lack of protein can lead to death.

Risks of certain types of protein

Eating high amounts of red or processed meats or eating these foods often can lead to:

People who have liver disease, kidney disease, or gout need to be careful with the amount and type of protein they eat.  

People who have allergies may also have to avoid certain foods that may be rich in protein. These include grains, nuts, seeds, fish, soy, and dairy. Eating high amounts of these foods is also linked to other health problems like breathing and digestive problems. 

Outlook

Remember that protein isn’t bad, despite the risks. People who get protein from plant foods, fish, or chicken and replace red or processed meat with these foods can lower the risk of developing diseases and premature death.

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Medically Reviewed on 2/8/2021
References
British Nutrition Foundation: “Protein.”

Harvard School of Public Health T.H. Chan: “Protein.”

Nutrients: “Food Products as Sources of Protein and Amino Acids—The Case of Poland.”

Recommended Dietary Allowances: “Protein and Amino Acids.”