Proteins are vital, complex substances made from chains of smaller compounds called amino acids. Dietary sources of these substances include animals and animal products, as well as grains, beans, nuts and seeds. Your body requires proteins and their constituent amino acids to create and maintain a wide array of structures, including your internal organs, muscles, body fluids, glands and skin.
Amino Acids
Amino acids can combine to make thousands of distinct forms of protein, according to the Nemours Foundation. Although many different types of amino acids exist, only 22 are vital to your health. Your body creates 13 of these amino acids internally, while the remaining nine must come from sources in your diet. Since you must have these dietary amino acids for the healthy function of your body, scientists call them essential amino acids.
Complete and Incomplete Proteins
Dietary sources may contain either complete or incomplete proteins, according to the U.S. National Library of Medicine's Medline Plus. Complete protein sources contain all nine essential amino acids, while incomplete sources contain less than nine. In most cases, complete proteins come from various forms of meat or animal products such as milk, cheese, eggs and yogurt. You can also get complete proteins from foods that contain soybeans. In addition to seeds, grains, nuts and beans, you can obtain incomplete protein from peas. Vegetables also contain small amounts of incomplete protein. You can create complete proteins from incomplete proteins by mixing complementary dietary sources such as rice and beans, or corn and beans.
Protein Use
In addition to creating and maintaining body structures, protein is necessary to replace body tissue, the Nemours Foundation reports. You also need protein for basic general processes such as growth and development. When you eat food sources that contain protein, digestive juices in your stomach and small intestine break down the food and release its constituent amino acids. Your body then uses these acids to create various new proteins that are specialized for internal functions, including the construction of hemoglobin, the component in your blood that carries vital oxygen to all parts of the body.
Adequate Intake
You can obtain an adequate protein supply by eating a well-balanced diet, Medline Plus reports. Although specific daily protein requirements vary with factors such as health and age, you can typically get sufficient protein from two or three daily servings of high-protein foods. Examples of appropriate serving sizes include one egg, half a cup of beans and two to three ounces of lean pork, fish, poultry or beef.
Choosing Sources
When picking protein sources, you also need to consider other food components such as fat and saturated fat, according to the Harvard School of Public Health. In some cases, the protein benefit of foods such as meat can be equaled or outweighed by the health risks of high fat intake. Non-animal sources of protein typically have a low fat content, in addition to containing vitamins, minerals and fiber. Good choices of animal protein include poultry, fish and lean red meat in moderate portions.
Member Comments