Recommended Daily Allowance for Protein

What is Protein?

Protein is an essential nutrient for bodily growth and repair. It makes up 15-20 percent of our body mass. Protein is made from differing combinations of substances called amino acids. Twenty two amino acids can be used by the body to manufacture protein. Composed of carbon, hydrogen and oxygen atoms, as well as nitrogen, they fall into two types: non-essential and essential. See also: Health Benefits and Sources

Amino Acids: Essential and Non-Essential

Both types of amino acid are widely available in food. However, while non-essential amino acids can be produced by the body itself from fats, carbs and other amino acids, the essential ones can't, so they must be obtained from dietary sources. The eight essential amino acids are: isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. The non-essential amino acid group includes: alanine, arginine, aspartic acid, cystine, glutamic acid, glycine, hydroxyproline, proline, serine and tyrosine.

Functions of Protein in Diet

We use dietary protein to create new cells throughout the body (eg. in organs, muscles, bones) and to maintain or repair existing cells. In addition, dietary proteins are used to produce enzymes, agents that act as a catalyst for a wide variety of biological and chemical processes in the body, including: digestion, cell-building, energy metabolism and fat storage. In fact, nearly all the body's chemical reactions are regulated by enzymes. Protein is also used in the production of neurotransmitters, the chemicals used in the transmission of messages between body cells.

Protein Synthesis - How We Use Dietary Protein

When we eat proteins, our digestive system breaks them down into their basic amino acids, and then our cells rebuild them again, in a different order, to form the particular type of proteins they need. Chemicals left over after protein synthesis are converted to glucose and used for energy. Due to the body's demand for protein, it is essential to include enough in our daily diet. Otherwise we start digesting the proteins in our muscle tissues.

Calorie Content of Protein

One gram of protein contains roughly 4 calories, the same caloric value as carbohydrate, but less than half the calories of fat (9 calories per gram).

Protein: Recommended Daily Allowance (RDA)

According to the US National Academy of Sciences, healthy people need about 0.8 grams of high quality protein, per kilogram of bodyweight - that's just under 0.4 grams for every pound. For example, a 150 pound woman needs about 55 grams of protein per day, while a 170 pound man needs about 62 grams.

People Who Need More Protein in Diet

Individuals who are building new tissue quickly, need more than the standard recommended amount of protein. For example, children need up to 2 grams per kilogram of weight, while young teenagers need up to 1.2 grams. Pregnant women typically need an extra 10 grams of protein a day, while nursing mothers need about 15 grams extra per day for the first six months, and an extra 12 grams a day during the second six months. People suffering blood loss or injuries also need extra amounts of protein.

Nutrition Resources About Protein

Food Sources
Health & Weight Benefits

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