SPORTS NUTRITION LESSON 29 Dietary Protein WHAT IS PROTEIN Protein is a complex chemical structure containing carbon, hydrogen and oxygen. In this way it is the same as carbohydrate and fats. It is different because protein has one other essential element - nitrogen. About 16% of protein is nitrogen. Dietary Protein Carbon, Hydrogen, Oxygen and Nitrogen combine in different structures. The different element combinations are called amino acids. There are 20 different amino acids, all of which can be combined a variety of ways to form the proteins necessary for the structure and function of the body. The body may also modify the structure of amino acids converting them into the amino acid needed. Dietary Protein Proteins are created when 2 amino acids link and form a peptide bond, or a dipeptide. Most proteins are polypeptides containing up to 300 amino acids. Protein is contained in both plant and animal foods. Dietary Protein IS THERE A DIFFERENCE BETWEEN PLANT AND ANIMAL PROTEIN? Humans can synthesize some amino acids in their bodies. There are 9 amino acids that humans cannot synthesize. They are called essential amino acids. For optimal maintenance, growth and development, all 20 amino acids must be present at the same time. Dietary Protein Dietary sources of protein vary widely in their composition and nutritional value. The quality of a protein source depends on its ability to provide the nitrogen and amino acid requirements for maintenance, growth, repair, and development. Key Factors: Digestibility Ability to provide the essential amino acids Dietary Protein The National Academy of Sciences has created a method of scoring proteins. They are assessed and given a number value. Those proteins that contain an adequate content of all 9 essential amino acids are given a high score and are called complete proteins. Those that are missing one or more of the essential amino acids and are unable to adequately support life or growth are called incomplete proteins, or low quality proteins. Dietary Protein Protein from animal sources is general considered to be of a higher quality that protein from plant sources. That does not mean plant amino acids are inferior amino acids, they are the same. The difference is in the distribution. Animal protein is a complete protein because it contains each essential amino acid in the correct proportion to human requirements. All 20 amino acids are present simultaneously. Dietary Protein Plant proteins can provide you with all the protein to support growth and development. However proteins usually exist in smaller contractions, and not all 9 essential amino acids are present. People eating only plant food must be careful to choose plant foods that will supply all 9 of the essential amino acids. This is commonly known as protein complementing. Dietary Protein WHAT ARE SOME COMMON FOODS THAT ARE GOOD SOURCES OF PROTEIN? Animal Foods - All foods in the meat, milk and egg groups generally have substantial amounts of high-quality protein. Dietary Protein Plant Foods Legumes - relatively good sources of protein Black beans, garbanzo beans, lima, navy, pinto, etc. Nuts Relatively high in protein, but high in fat Fruits and Vegetables Contain some protein in varying amounts Dietary Protein HOW MUCH DIETARY PROTEIN DO I NEED? Humans do not actually need protein, they need amino acids and nitrogen. These amino acids and nitrogen are supplied in protein foods. There are a variety of ways of measuring how much protein we need. We will discuss the RDA. Dietary Protein RDA of Protein The recommended amount of protein varies with a number of factors. Stage of the life cycle Young Old Etc. Size Dietary Protein CALCULATE YOUR PROTEIN NEEDS 0.36 g protein/pound of body weight x pounds =________g protein/day Each gram of protein has 4 calorie. Calculate the number of calories provided by protein._________ Based on your calorie intake level, what % of your calories are you getting from protein.___________ How does this compare with the recommendations? Dietary Protein HOW CAN I BE SURE I GET ENOUGH OF EACH OF THE ESSENTIAL AMINO ACIDS? Well, you can count the amount in grams in each food you consume, add them up and compare them with a chart of how much you need of each. Or - you can eat a wide variety of animal and plant foods - High-quality, nutrient dense, low fat foods. Other than being a risk factor for CHD, why is it important to consume lower fat foods? Dietary Protein Go to www.ChooseMyPlate.gov Click on Food Groups Choose Protein Food Groups List what foods are the healthiest choices. Go to the Food Gallery and explain or illustrate what a serving size is for each of the healthiest choices. From the home page find “10 tips Nutrition Education Series”. Explain what you learn.