NUTR 202 1nd Edition Exam 2 Study Guide Lectures 11 17 Ch 6 Proteins and Amino Acids Discussion Disadv Of Atkins Diet high protein positives negatives need supervision because don t want to limit carbs to much for brain activity and RBCs Try to maintain macronutrient distributions May not be sustainable because limits majority of foods Should you intake as much protein as possible to encourage muscle growth Proteins are not stored Carbs fats are equally important Not only in animals Plants are also a great source of protein Proteins are the predominant structural and functional material in every cell Proteins contains carbon hydrogen oxygen and a unique element Nitrogen Elemental component of proteins are amino acids each has a carbon center amine group NH 2 acid group COOH hydrogen unique side chain Twenty different amino acids found in proteins Nine amino acids are essential Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan and Valine Eleven amino acids are nonessential Can be synthesized in the body from other amino acids or by adding nitrogen to C containing structures Some amino acids are conditionally essential amino acids Cannot be made in the body in adequate amounts under certain condition Ex Tyrosine is syn in liver from phenylalanine Ppl with PKU cannot convert Phe to Tyr therefore tyrosine is now a conditional essential aa Connected by peptide bonds Side chains can interact with each other Can attract repel interact Some side chains are hydrophilic or hydrophobic Form specific 3D shapes due to interactions between the side chains of amino acids Shape is critical to protein function Definition of denaturation alteration of a protein s 3D structure includes Heat cooking Mechanical Agitation cooking digestion Acids Salt Enzymes What happens to the proteins you eat Pepsin in stomach and HCl breakdown food Absorption of AA requires Active Transport requires energy and carrier molecule This allows amino acids to move from area of high concentration to low concentration Protein Absorption Competition in Brush Border purple green use same transport system if consume more green larger amt of green will limit the absorption of the purple ones If body uses 100g from diet and 200g from breakdown of different body proteins body is going to on avg use 300g Majority is obtained from protein breakdown If intake is more eliminated AA and proteins are not stored become apart of pool for anabolic catabolic reactions Can be used to syn new proteins AA can be converted to glucose or catabolized complete to generate E When E intake exceeds converted to FAs and stored in adipose tissue Must have amino acid pool first Need to produce hemoglobin syn enzymes syn antibodies main fxn Synthesize new proteins DNA in nucleus contains instructions for protein synthesis First step Transcription location in nucleus then Translation location ribosomes 1 Make mRNA 2 mRNA joins ribosome protein maker 3 tRNA delivers amino acids Protein Functions reiterate that proteins are needed for energy necessarily has many other important functions 1 Provide structural mechanical support to body tissues 500 000 different proteins Key components of muscles bones skin hair nails Collagen is the most abundant protein in your body connective tissues Tissues and organs in our body are constantly broken down and repaired protein turnover We need structural proteins for growth and repair of tissues severe burns 2 Transport substances throughout the body 3 Build most enzymes and hormones 4 Contribute to a healthy immune system Abs 5 Maintain Fluid Balance Proteins help maintain acid base balance Protein improves satiety and appetite control Blood clotting Movement of muscles actin myosin Regulate chemical signals hormones Can provide energy 4kcal gram yet we want proteins for their other functions How much do you need Healthy adults should consume enough dietary protein to replace the amount they use each day whereas pregnant women people recovering from surgery and growing children need more protein to supply the necessary amino acids and nitrogen to build new tissue Healthy adults have nitrogen balance injury illness cause negative balance and might have a lot of nitrogen in urea secreting more than consuming growth and development you have a positive balance infancy adolescence As you get older unless you re an athlete the amount of protein you need will decrease Endurance athletes 1 2 to 1 4 g kg Strength Athletes 1 6 to 1 7 g kg RDA 0 8 g kg of body weight day for adults With more weight more protein is needed To convert weight in pounds to kilograms kg Weight in lbs 2 2 Increased needs Infancy Pregnancy lactation Injury Problem Calculate 140 pound adult female healthy not pregnant or lactating regular physical activity no competitive Convert weight in to kg 140 lbs 63 6 kg 63 6 kg x 0 8 g kg 51 g day anything above excreted converted to triglycerides Remember AMDR is 1035 Rec for women is 50g and for men its 60g Animal Foods Most concentrated sources of Protein Eggs Meat Fish and Poultry one ounce equals 7 grams of protein Dairy Products 1 serving 1 cup of milk 8 grams of protein Low in fiber high in cholesterol saturated fats Source of B vitamins iron zinc calcium absorbable form Plant Foods Less conc sources of protein Nuts Legumes Grains Vegetables Low in fiber high in cholesterol saturated fats Source of some B vitamins iron zinc calcium less absorbable form Excellent sources of fiber phytochemicals and unsaturated fats Protein quality Is a measure of how good the protein in a food is at providing the essential amino acids the body needs to synthesize proteins Digestibility amino acid profile determine protein quality 70 90 from plant digested vs 90 99 from animal Proteins that contain all of the essential amino acids with some nonessential ones Complete dietary proteins High Quality Examples Animal proteins soy possibly quinoa not animal but contain those 2 factors to be considered high quality Incomplete Proteins low in one or more essential aa like plant proteins and can be upgraded or made complete with complementary proteins Like PB sandwich pita bread with humus rice and beans MOST FOOD GROUPS ARE SOURCES OF PROTEIN except fruit avoid high saturated fats eat both animal and plant sources eat beans chickpeas and unsalted nuts Inadequate protein intake If poor energy intake continues for prolonged periods over time may exhibit symptoms of protein deficiency ex Edema lack of