Protein
Protein is made up of long chains of amino acids. These amino acids are linked together to make up different proteins. When proteins are consumed from food they are broken down into their individual amino acids, which are then absorbed to use by the body.
Essential and non-essential amino acids
There are 22 types of amino acids which are divided into two groups: There are essential amino acids and non-essential amino acids. 14 of these are non-essential which means that they are manufactured in the body and do not have to be derived from food.
The remaining 8 essential amino acids, cannot be derived from the body and therefore need to be derived from the food we eat. All these amino acids are important for the body.
Complete and Incomplete proteins
Some foods contain all of the essential amino acids. If a food contains all of the 8 amino acids, they are considered “complete” proteins. Complete proteins usually come from animal sources such as meat, dairy, eggs, fish and poultry.
Incomplete proteins are lacking one or more of the essential amino acids. These tend to come from vegetable products such as fruits, vegetables, grains and nuts. When combining two or more “incomplete proteins” a complete source of essential amino acids is available.
Roles of Proteins:
- growth and maintenance, such as skin, tendons, membranes, muscles, organs, bones
- enzymes- proteins facilitate chemical reactions
- hormones- proteins which regulate body processes
- acid-base balance- proteins help to maintain the acid-base balance in the body
- transportation- proteins transport substances (vitamins, lipids, minerals, oxygen)
- antibodies- protein invade foreign invaders
- energy and glucose- proteins provide some fuel and glucose if needed for the body’s energy
What foods are good sources of proteins?
The best sources of complete protein are found in animal foods such as meat, fish, shellfish, poultry and dairy products. Lean meats are the best source in addition to low-fat and non-fat dairy products.
