Proteins are the building blocks of cells; everything in your body is made of proteins, including your muscles, skin and organs. Additionally, proteins comprise the enzymes required for all the biochemical reactions that constitute life. Because proteins are so critical, you need protein in your diet in order to maintain a healthy body. Different foods contain different types of protein, and you should pay attention to the types of protein you eat to make sure you meet your nutritional needs.
Complete Proteins
Proteins are made up of molecules called amino acids. Of the 20 different types of amino acids, nine cannot be made by your body and must be consumed through food in order to be available in the body. These nine are known as the essential amino acids. Certain types of proteins, known as complete proteins, contain all nine of these amino acids. Complete proteins are most often found in animal sources of protein, including poultry, meat, fish, eggs, milk, cheese and yogurt. Soy protein is the only plant protein that contains all nine essential amino acids.
Incomplete Proteins
Most proteins founds in plant material are missing one or more of the nine essential amino acids and are known as incomplete proteins. Plants that are rich in incomplete amino acids include peas, beans, nuts, grains and seeds. Many of the incomplete proteins are missing different essential amino acids, and combining these together can provide all the essential amino acids. For example, beans contain the essential amino acids missing from rice, and rice contains the essential amino acids missing from beans, so eating beans and rice together provides all the essential amino acids.
Daily Intake
The recommended dietary allowance (or RDA) of protein for men ages 19 years and older is 56 g per day. For women of the same age group, the RDA is 46 g. The different sources of protein contain different amounts of protein. For example, a 3-oz. piece of meat contains 21 g of protein, 1 cup of milk contains 8 g, 1 cup of beans contains 16 g and an 8-oz. container of yogurt provides 11 g. Most people in developed countries eat more than enough protein each day and do not require protein supplements, according to the U.S. Centers for Disease Control.
Nutritional Considerations
Different sources of protein also contain different amounts of fat and cholesterol, which can be detrimental to your health. For example, a 6-oz. steak contains about 38 g of protein but also 44 g of fat. In contrast, a 6-oz. portion of salmon contains 34 g protein but only 18 g of fat. One cup of lentils contains 18 g of protein and less than 1 g fat. To avoid excess fat, you should try to find lean cuts of meat and low-fat dairy products.
Member Comments