NUTR 470 1st Edition Lecture 19-Protein is made up of amino acids.-Function of protein in our body• Growth of body tissue• Repair of body tissue• Red blood cells• Proper functioning of antibodies that resist infection• Regulation of enzymes and hormones-Protein in foods provides the body with aminoacids-Amino acids are the basic structural building units of proteins • Essential amino acids-histidine, isoleucine, leucine,lysine, methionine, phenylalanine, threonine, tryptophan, and valine. (Branched-chain amino acids )• TV TILL PM (plus) H-Foods of high protein quality include allof the essential amino acids• Sources of high-quality protein-Animal sources of proteins have thecomplete complement of all twentyamino acids. • Plant sources of protein-With the exception of soybeans, plantsources of protein do not provide all nineessential amino acids. -Combinations of plant foods, such asgrains and seeds with dried beans,however, yield high-quality protein.-The protein RDA is high, to cover most person’s needs• RDA for protein-The average requirement for protein is 0.6grams per kg body weight; the RDA is 0.8grams per kg body weight, which meet97.5% of the population's needs.• Get a good mix of proteins-Ensure getting all of the amino acids.• Balance proteins and carbohydrates-The most recent evidence appears tosupport the beneficial nature of a high-protein,low-carbohydrate diet.• Issues of Protein Nutrition-Excessive protein intake may cause severalproblems.• Overreaction within the immunesystem• Loss of bone density• Liver dysfunction due to increasedtoxic residues-Nitrogen Balance• Definition: -Nitrogen balance expresses the balancebetween anabolism and catabolism ofnitrogen.• Determination: -Nitrogen balance is measured by assessingdietary N intake vs. urinary N output (asurea).• Positive balance-Positive nitrogen balance indicates netstorage of nitrogenous compounds• Childhood growth• Pregnancy• Muscle building• Healing• Negative balance-Negative nitrogen balance indicates netbreakdown of stored nitrogenous compounds.• Illness• Uterine resorption• Starvation• Amino acid deficiency• Wounding-Topics in Amino Acid Nutrition• Branched-chain amino acids refer to the aminoacids having aliphatic side-chains that are nonlinear.• Branched-chain amino acids-Leucine, Isoleucine, and Valine• BCAA supplementation may prevent muscleloss at high altitudes and prolong enduranceperformance in the heat.• BCAA have an overall benefit for the symptomsof encephalopathy-Macronutrients and HealthyFoods• Carbohydrate, lipid, and protein aremacronutrients-Healthy foods• Low glycemic index, high in fiber• High in n-3 fatty acids, low in trans fat• High proteins• Minerals + vitamins-Junk Foods • Any food that has poor nutritional value isconsidered unhealthy and may be called ajunk food.-High in fat, sodium, and/or sugar-Easy to carry, purchase and consume-Attractive appearance-Being added with food additives and
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