Module 6- Proteins-1 (1).pptx PDF

02/10/20 20 Proteins Learning Objectives 1. List the elemental units of an amino acid. 2. Define essential, non-essential and conditionally essential amino acids. 3. Identify the essenti...

02/10/20 20 Proteins Learning Objectives 1. List the elemental units of an amino acid. 2. Define essential, non-essential and conditionally essential amino acids. 3. Identify the essential and conditionally essential amino acids. 4. Describe the functions of proteins in the body. 5. Describe the process of protein turnover in the body. 6. Identify dietary sources of complete proteins and incomplete proteins. 1  02/10/20 20 Learning Objectives 7. List nutrients and non-nutritive substances found in soy proteins. 8. List the DRIs for protein. 9. Identify individuals who may need additional protein. 10. List and define the types of vegetarian diets. 11. Identify the health benefits and potential nutrient deficits of vegetarian diets 12. Differentiate between protein energy malnutrition, marasmus, and kwashiorkor. 13. Describe the potential negative effect of too much dietary protein. Protein is a unique macronutrient. Individual units of protein made up of:  Carbon  Hydrogen  Oxygen  Nitrogen  unique to protein Protein also supplies energy:  4 kcal/g  not the primary function 2  02/10/20 20 Proteins are composed of amino acids. Amino acids  Building blocks of proteins Amino acids have a central carbon connected to four side groups  Amino group  Acid group (carboxyl)  Hydrogen group  R group (side chain) Unique in each different amino acid Amino acids are divided into two primary categories Essential amino acids  Must be acquired from our diet Nonessential amino acids Normally made by body in adequate amounts  Transamination Transfer of amine group from one molecule to another to create an amino acid Conditionally essential amino acids 3  02/10/20 20 Different proteins are composed of unique sequence of amino acids These amino acids are linked together by:  Peptide bonds 4  02/10/20 20 Shape dictates protein function. Correct AA Incorrect AA sequence sequence  predictable structure changes structure and  error in function function  Ex: Sickle cell anemia The physical properties of protein can be altered. A protein’s structure can be changed by heat, acid, enzymes, agitation, or alcohol.  Denaturation  Ex: Cooking an egg or stomach acid denatures proteins we eat 5  02/10/20 20 Functions of Protein in the Body Fluid Balance Proteins in blood maintain optimal balance between the fluids inside and outside cells and blood vessels.  Albumin  Edema developswhen blood albumin is low 6  02/10/20 20 Acid-base Balance Acids and bases constantly produced  by-products of body’s metabolic processes Body works to maintain pH, or its acid–base balance, in tight range  proteins act as buffers  neutralization of acidic and basic conditions Immune Function Foreign substances that enter our bodies and trigger an immune response  Antigen Proteins form body’s first barriers against immune invaders  Skin  Mucus present in the respiratory system and intestine Proteins produced by immune system in response to antigen  Antibodies 7  02/10/20 20 Enzymes Enzymes  Speed up chemical reactions  Strings of 100 to 1,000 amino acids  Unique shape Deficiencies in enzymes  inborn error in metabolism  non-genetic causes  illness, inadequate nutrition, and medications Hormones Hormones  Messengers that help regulate the various systems and functions of the body.  Made of lipids or proteins Ex: insulin (protein) estrogen (lipids) 8  02/10/20 20 Transport Transport substances across cell walls  Sodium-potassium pump Transporter of nutrients through bloodstream  Retinol-binding protein Proteins have water-repelling and water- attracting ends  Allows for interaction with fat and water  Ex: Lipoproteins Energy Energy production is least efficient function of proteins  Protein has no major storage form for immediate use. Body uses protein for energy as a last resource.  Energy intake from carbohydrates and fat is low  Muscle broken down amino acids used for energy 9  02/10/20 20 Protein Turnover Protein turnover includes:  protein synthesis  protein breakdown 1. Protein synthesis  requires presence of essential amino acids in adequate amounts  Limiting amino acid present in lowest amount relative to body’s needs 2. Protein breakdown  Free amino acids become part of amino acid pool Protein turnover  Deamination  required for elimination of excess amino acids occurs primarily in the liver  keto-acid used for energy production amino group converted to urea  excreted in urine Nitrogen balance  nitrogen consumed vs. nitrogen excreted  basis of many nutrition recommendations 1  02/10/20 20 Deamination of Excess Amino Acids Positive and negative nitrogen balance Intake exceeds excretion  Positive nitrogen balance  Occurs during growth, recovery from illness, and during pregnancy. Excretionexceeds intake or intake is inadequate to meet body’s needs  Negative nitrogen balance  Occurs during AIDS, cancer, starvation, and low calorie diets. 1  02/10/20 20 Food sources of protein Protein quality Complete proteins or high quality proteins  Provide all essential amino acids in amounts needed by body  Easily digested and absorbed  Includes: Animal Proteins and Soy Protein Digestibility-Corrected Amino Acid Score (PDCAAS)  Value assigned to proteins that accounts for protein quality and digestibility.  Based on scale of 0 –100 1  02/10/20 20 Protein quality Incomplete Proteins  do not contain all essential amino acids in amount required by body  examples: legumes, grains, and vegetables Complementary proteins  amino acid contents combined provide all EAA Supplemental Proteins  additional source of protein for specific populations vegetarians, highly active people, underweight people Complementary and supplemental proteins 1  02/10/20 20 Protein in health and disease Soy protein and disease Health benefits associated with soy consumption:  protection against certain cancers and CVD disease  prevention of bone loss Nutritional composition  complete, high protein source  low in saturated fat and cholesterol  B-vitamins, calcium, potassium, vitamin A, iron Other bioactive compounds  isoflavones – act as phytoestrogens 1  02/10/20 20 Soy protein sources Recommendations for protein intake DRIs for protein:  RDA: 0.8 g per kg of body weight (high-quality protein)  AMDR: 10% – 35% This recommendation is meant for healthy adults  Needs increase for: injury illness pregnancy competitive athletes 1  02/10/20 20 Forms of Vegetarianism Why do people choose to become vegetarians? Treatment of animals Hormones and antibiotics Environmental impact Health Religion 1  02/10/20 20 Health impact of vegetarianism Potential health benefits:  risk of heart disease  rates of obesity Nutrients of concern, particularly for vegans:  Vitamin B12  Zinc  Iron  Calcium  Vitamin D  Protein Protein imbalance 1  02/10/20 20 Inadequate Protein Protein energy malnutrition (PEM)  disorder that occurs with inadequate protein and/or energy consumption  most common nutrient deficiency in hospital and nursing home populations in United States  Greater concern internationally infants and young children most susceptible PEM is most lethal form of malnutrition (WHO) Types of Protein Energy Malnutrition Marasmus  condition of starvation characterized by emaciation, or skeletal appearance  causes: inadequate protein and calorie intake Kwashiorkor  characterized by swollen appearance, especially the abdomen  proposed causes: low protein intake; altered gut bacterial populations  Frequent in children being weaned from breast milk to cereal 1  02/10/20 20 Marasmus vs. Kwashiorkor Excess protein Health Benefits  Weight loss? Health Risks  risk for certain types of cancer: colon, prostate, breast, and pancreatic cancers associated with high intake of animal proteins  Kidney disease and kidney stones  Can be high in saturated fat Increased risk for heart disease 1