The Best Protein For Your Body

Proteins provide structure and support, help create enzymes and hormones and aid in maintenance of acid-base and fluid balance. Proteins also help transport nutrients between cell membranes and ensure that your immune system stays healthy. Proteins can also provide you with energy in the absence of carbohydrates. Not all proteins are created equal, however. Some proteins are considered better than others.

Amino Acids

Each protein is com composed of a series of units called amino acids. Amino acids contain the elements carbon, hydrogen, oxygen and nitrogen. There are a total of 20 amino acids, which combine in different patterns to determine which protein is made. The combination of amino acids is important when determining which protein is the best for your body. Amino acids are classified as either essential or nonessential.

Essential Versus Nonessential

The term essential amino acid refers to the amino acids that your body cannot make. Because your body cannot make these amino acids, they must be consumed in the diet, thus making them essential. There are nine essential amino acids.

Nonessential amino acids are the amino acids that your body can make. Because your body can make nonessential amino acids, it is not necessary that you consume them in your diet. There are a total of 11 nonessential amino acids.

Protein Quality

Protein quality, which determines which proteins are the best for your body, is dependent on two major factors: the types and amounts of amino acids that the protein contains and how well your body can digest the protein, or the protein's digestibility. According to "Nutrition and You" by Joan Salge Blake, animal proteins are more digestive than plant proteins because some plant proteins cannot be broken down in your intestines. In this aspect, animal proteins are considered of higher protein quality.

Proteins are further divided into two classes based on their amino acid profile. Proteins that contain all of the nine essential amino acids, as well as some of the nonessential amino acids are considered complete proteins. A protein that does not contain one or more essential amino acid is considered an incomplete protein. Because they contain all of the essential amino acids, complete proteins are considered higher quality. Animal protein sources are usually complete proteins, whereas plant sources are incomplete proteins.

Protein Scoring

Proteins are also assigned a number, or score, based on their digestibility and amino acid profile. This score is called the protein digestibility corrected amino acid score, or PDCAAS. Milk, which contains all of the essential amino acids and can be easily digested, is rated 100 percent, according to "Nutrition and You" by Joan Salge Blake. Chickpeas have a score of 87 percent, whereas wheat scores only 44 percent because it does not provide all of the essential amino acids.

Protein Needs

Protein should contribute 10 to 35 percent of your daily calorie intake. In general, adults require 0.8 g of protein per kg of body weight. For a woman that weighs 135 lbs., this would be equal to 49 g of protein per day.