Science, Tech, Math › Science Essential Amino Acids and Their Role in Good Health Amino Acids You Must Add To Your Diet Share Flipboard Email Print PASIEKA/Getty Images Science Chemistry Biochemistry Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated January 09, 2018 An essential amino acid may also be called an indispensable amino acid. This is an amino acid that the body cannot synthesize on its own, so it must be obtained from the diet. Because each organism has its own physiology, the list of essential amino acids is different for humans than it is for other organisms. The Role of Amino Acids for Human Beings Amino acids are the building blocks of proteins, which are essential to forming our muscles, tissues, organs, and glands. They also support human metabolism, protect the heart, and make it possible for our bodies to heal wounds and repair tissues. Amino acids are also essential for breaking down foods and removing waste from our bodies. Tryptophan and tyrosine are amino acids that produce neurotransmitters. Tryptophan produces the mood-regulating chemical serotonin and can make you sleepy. Tyrosine is essential for the production of norepinephrine and adrenaline and makes you feel more energetic.The amino acid arginine is essential to the production of nitric oxide which lowers blood pressure and helps to protect the heart.Histidine makes the enzymes needed to produce red blood cells and healthy nerves. ]Tyrosine is used in the production of thyroid hormones.Methionine makes a chemical called SAMe which is essential for the metabolism of DNA and neurotransmitters. Nutrition and Essential Amino Acids Because they cannot be produced by the body, essential amino acids must be part of everyone's diet. It isn't critical that every essential amino acid be included in every meal, but over the course of a single day, it's a good idea to eat foods that include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. The best way to ensure that you are eating a sufficient quantity of foods with amino acids is to complete proteins. These include animal products including eggs, buckwheat, soybeans, and quinoa. Even if you don't specifically consume complete proteins, you can eat a variety of proteins throughout the day to ensure that you have enough essential amino acids. The recommended dietary allowance of protein is 46 grams daily for women and 56 grams for men. Essential Versus Conditionally Essential Amino Acids The essential amino acids for all people are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. Several other amino acids are conditionally essential amino acids, meaning they are required at some stages of growth or by some people who cannot synthesize them, either because of genetics or a medical condition. In addition to the essential amino acids, babies and growing children also need arginine, cysteine, and tyrosine. Individuals with phenylketonuria (PKU) need tyrosine and also must limit their intake of phenylalanine. Certain populations need arginine, cysteine, glycine, glutamine, histidine, proline, serine and tyrosine because they either cannot synthesize them at all or else are unable to make enough to meet the needs of their metabolism. List of Essential Amino Acids Essential Amino Acids Non-Essential Amino Acids histidine alanine isoleucine arginine* leucine aspartic acid lysine cysteine* methionine glutamic acid phenylalanine glutamine* threonine glycine* tryptophan proline* valine serine* tyrosine* asparagine* selenocysteine *conditionally essential Amino Acids: Structure, Groups and Function What Is an Essential Amino Acid? What Is an Amino Acid? Definition and Examples Tryptophan: The Antidepressant Lurking in Your Turkey Why a Big Turkey Dinner Makes You So Sleepy These Are the Amino Acid Structures Chemical Structures of Acids Decoding the Elements of Your Genetic Code Review Vitamin Chemical Structures Different Types of Cell Proteins and What They Do What Do You Know About Amino Acids? 4 Types of DNA Mutations and Examples What Is Collagen? Facts and Functions What Are Proteins? How Amino Acid Chirality Works What Is Aliphatic Amino Acid?