By Jennifer Turley and Joan Thompson Module 1.3 Proteins By Jennifer Turley and Joan Thompson © 2013 Cengage

Presentation Overview Amino Acids in Protein Amino Acid & Protein categories Complementation Functions Dietary Recommendations

Amino Acids Amino acids are the “building blocks” of protein Amino acids (and thus proteins) contain nitrogen, carbon, oxygen & hydrogen (a few contain sulfur) Proteins are organic compounds Each of the 20 amino acids has a different variable side chain

Amino Acids Amino acids combine together to make a protein

Amino Acids There are 20 amino acids that make biological proteins Categorized as Essential and Non-essential

Categories of Amino Acids Essential: The body cannot make Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine Nonessential: The body can make from nitrogen & carbohydrate intermediates Alanine Arginine Asparagine Aspartic acid Cysteine Glycine Glutamic acid Glutamine Proline Serine Tyrosine See your textbook appendix for chemical structures

Categories of Proteins Incomplete Low Biological Value Low Quality Complete High Biological Value High Quality *Categories are based on the proportions and amounts of essential amino acids in a protein

Categories of Proteins High Quality Proteins: Contain all the essential amino acids, and are high biological value proteins or complete proteins Complete Proteins come from animal sources such as milk, yogurt, meats, eggs, and cheese Low Quality Proteins: Lack one or more essential amino acids, and are low biological value proteins or incomplete proteins Incomplete Proteins come from plant sources such as vegetables, legumes (dried beans), nuts, seeds, tofu, and grains

Protein Complementation Multiple low quality proteins can be combined in such a way that the essential amino acids lacking in one are supplied by another Example: eating rice and beans instead of meat In this way, the combined proteins can provide all of the essential amino acids of a high quality protein

Protein Complementation Protein missing black and white amino acids All the essential amino acids are present by the protein combination Protein missing pink and purple amino acids + =

Protein Complementation

Protein Complementation Grains Legumes Nuts & Seeds Vegetables Combine any 2 food groups for complementation

Functions Primarily used for tissue repair & maintenance Secondarily used for energy (4 Calories/ gram)  Not as efficiently used as carbs

Dietary Recommendations Based on body weight Adult daily recommended intake (DRI) is .8 grams of high quality protein per kilogram body weight per day AMDR: 10-35% of Calories from proteins

Summary Protein is made of 20 amino acids categorized as essential & nonessential Protein is also categorized as complete (high quality) and incomplete (low quality)  Complete: from animal sources  Incomplete: from plant sources Combining plant proteins so that all the essential amino acids are present is complementation References for this presentation are the same as those for this topic found in module 1 of the textbook

Summary The primary function of protein is tissue repair & maintenance When used for energy, protein provides 4 Calories/ gram Adults need 0.8 grams/ Kg body weight protein per day. Adults may consume 10-35% of Calories from protein. References for this presentation are the same as those for this topic found in module 1 of the textbook