Amino acids, also called the building blocks of proteins, are compounds that perform a large number of essential functions in the body. They are needed for vital processes such as building proteins and synthesising hormones and neurotransmitters.
Some may also be taken in supplement form to naturally enhance sports performance or improve mood. They are categorised as essential, conditionally essential or non-essential, depending on various factors.
Amino acids are organic compounds made up of nitrogen, carbon, hydrogen and oxygen, together with a variable side chain group. Your body needs 20 different amino acids to grow and function properly. Although these 20 amino acids are important for your health, only nine are classified as essential. These are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.
Essential amino acids cannot be synthesised by the body and must be obtained through diet. The best sources of essential amino acids are animal proteins such as meat, eggs and poultry. When you eat protein, it is broken down into amino acids, which are then used to help your body with various processes, such as building muscle and regulating immune function.
There are several non-essential amino acids that are categorised as conditionally essential. These are considered essential only under specific circumstances such as illness or stress. For example; although arginine is considered non-essential, your body cannot meet demands when fighting certain diseases such as cancer. Therefore, arginine must be supplemented through diet to support your body's needs in certain situations.
The 9 essential amino acids fulfil a number of important and diverse tasks in your body:
While essential amino acids can be found in a wide range of foods, taking concentrated doses in supplement form has been linked to several health benefits.
Foods containing all 9 essential amino acids are called complete proteins. Complete protein sources are meat, seafood, poultry, eggs and dairy products. Soya, quinoa and buckwheat are plant foods that contain all 9 essential amino acids, making them complete sources of protein.
Other plant-based sources of protein such as beans and nuts are considered incomplete because they lack one or more of the essential amino acids. However, if you follow a plant-based diet, you can still ensure a good intake of all essential amino acids as long as you eat a variety of plant-based proteins every day.
For example; choosing a variety of incomplete proteins such as beans, nuts, seeds, whole grains and vegetables can ensure that your essential amino acid needs are met, even if you choose to exclude animal products from your diet.