NSC 170C1 1st Edition Lecture 14 Outline of Last Lecture I Proteins Outline of Current Lecture I Protein in foods II Personal need for protein A Too little protein B Too much protein Current Lecture I High quality protein A Digestible i In general animal proteins are more digestible than plant proteins 90 to 99 percent of animal proteins are digestible 70 to 90 percent of plant proteins are digestible B Has a complete amino acid profile i The amino acid profile of a protein is the types and amounts of amino acids it contains ii Complete proteins provide all nine of the essential amino acids along with some of the 11 nonessential amino acids iii Proteins from animal sources are typically complete while proteins from plant sources are incomplete a Exceptions Gelatin an animal protein lacks tryptophan Soy is a complete plant protein C Complemented proteins incomplete proteins coupled with animal proteins soy or other plant proteins rich in the limiting amino acids II Determining your personal protein needs A Daily dietary protein for healthy adults should equal the amount of protein the body uses daily B Nitrogen balance i Nitrogen balance studies can help determine daily protein needs ii Measure the nitrogen consumed against nitrogen excreted iii Healthy adults are typically in nitrogen balance iv Positive nitrogen balance occurs during periods of growth in infancy childhood and adolescence and during pregnancy v Negative nitrogen balance can occur when healing from a traumatic injury fighting fever or during illness Tissues will be broken down to meet needs when dietary intake is inadequate C Dietary protein can be expressed as percent of total calories or grams of protein eaten per day i Recommendations ii 10 to 35 percent of total calories from protein iii 0 8 g protein per kg of body weight for adults 19 and older iv Most Americans easily meet or exceed dietary protein needs v Competitive athletes participating in endurance or resistance exercises need 50 to 100 percent more protein to meet their needs a Protein is abundant in dairy foods meat fish poultry and meat alternatives such as dried beans peanut butter nuts and soy b Grains and vegetables provide less protein but can aid in meeting your daily needs III Eating too much protein can be harmful A A diet too high in protein can be associated with risk of i Heart Disease ii Many protein rich foods are higher in saturated fats creating a kidney stones b osteoporosis poor bone density c Cancer Large amount of meats especially red meats can increase the risk of colon cancer IV Eating too little protein can also be harmful A Protein energy malnutrition PEM A lack of dietary protein and or calories i Most frequently seen in infants and children ii Causes include poverty poor food quality insufficient food intake unsanitary living conditions ignorance of how to properly feed children and stopping breast feeding too early iii Can lead to life threatening health problems including compromised immunity infection and diarrhea B Kwashiorkor PEM disorder caused by severe protein deficiency i Protein deficiency causes fluid accumulation in the spaces surrounding the cells ii Characterized by edema in the legs feet and stomach decreased muscle strength and tone dry and peeling skin infection and water and electrolyte imbalances C Marasmus PEM disorder resulting from deficiency of calories i Characterized by a frail emaciated appearance thin and dry hair low blood pressure and body temperature and risk of infection and dehydration
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