The Best Protein Intake

Proteins are the main structural component of every cell and tissue in your body. Proteins also act as transport mechanisms, keeping your immune system healthy, helping synthesize enzymes and hormones and aiding in acid-base balance. Proteins can also provide you with energy in the absence of carbohydrates. In order to ensure your body stays healthy, it is important to eat the right types and amount of protein every day.

Amino Acids

Every protein is composed of a combination of structures called amino acids. Amino acids are often referred to as the building blocks of protein. There are a total of 20 amino acids. Nine of these amino acids are essential, which means that your body cannot make them so they must be obtained through your diet. The remaining 11 amino acids are nonessential, which means that your body can make them and it is not necessary to obtain them through your diet. The order and combination in which amino acids come together determine the type of protein that is made.

Types of Protein

Proteins are classified based on their amino acid profile. Proteins that contain all nine of the essential amino acids as well as some nonessential amino acids are called complete proteins. Proteins that are missing one or more of the essential amino acids are called incomplete proteins. Most animal proteins are complete, whereas most plant proteins are incomplete.

Protein Scoring

Protein quality is determined by the type of protein as well as your body's ability to digest the protein. Complete proteins that are easily digested are considered the best dietary proteins. Generally, animal proteins are more easily digested than plant proteins. Plant proteins contain a cell wall that cannot be broken down by the enzymes in your digestive tract. According to "Nutrition and You" by Joan Salge Blake, 70 to 90 percent of plant proteins are digestible compared to 90 to 99 percent of protein from animal sources.

Daily Recommendations

Protein should comprise 10 to 35 percent of your daily calorie intake. Protein provides 4 calories per gram, so someone following a 2,000 calorie per day diet should consume 50 g to 175 g of protein per day. Since animal proteins are considered highest quality, most protein intake should come from eggs, lean meat, poultry, fish, low-fat milk and cheese.

Vegetarians that do not consume animal sources should aim to consume plant proteins that complement each other. Complementary proteins are those that provide all of the essential amino acids when eaten together. Rice and beans are a good example of complementary proteins.