Flashcards in Midterm 1 - Lecture 8 Deck (20):
Fxns of proteins
• Building blocks of body components
• Maintain fluid balance
• Building block for hormones and enzymes
• Immune function
• Energy yielding
• Source of N & essential amino acids (EAA)
Effect of Protein Deficiencies
-Diarrhea and poor absorption
-Impaired immune function
-Increased gut inflammation
Describe edema. How does protein deficiency result in edema?
-Loss of fluid homeostasis
-Proteins in capillaries draw fluid into blood vessels. If not enough protein, fluid remains in tissue and causes swelling.
How does protein deficiency result in diarrhea and poor absorption?
-GI regeneration is impaired -> loss of villi -> diarrhea & poor absorption
How does protein deficiency result in increased gut inflammation?
-Low trp -> low antimicrobial peptides -> increased gut inflammation.
lactating woman>pregnant woman>man>woman;
Adult in general: 0.8 g/kg body weight
UL & Typical Intake of proteins
most Americans get enough protein; too much puts extra burden on kidneys to excrete excess urea
What is protein quality?
-a function of the abundance and ratio of essential AA in the food source and how well the protein is digested & assimilated.
How many essential amino acids are there? Which two AA's are most important to consider?
phe is essential and tyr is semi-essential (Remember PKU)
Three non-essential AAs and precursors
pyruvate -> alanine
oxaloacetate -> aspartate
α-ketoglutarate -> glutamate
What is the Protein Efficiency Ratio?
measure of how a protein supports growth & maintenance of body
• Used by FDA to set standards for baby food
PER = Weight gained (grams)/protein consumed (grams)
What is a complete protein?
Has all 9 Essential AAs; e.g. an egg
Protein Digestibility Corrected AA Score
• Most widely used (on food labels)
• Maximum value is 1.0 (e.g. milk, eggs)
Chem. Score x (~0.9-1.0) range of digestibility
Chemical Score of a protein
mg of lowest ratio EAA per gm of protein/ same for egg
Summary of protein quality
Animal sources are best; Mixed foods (Grains plus beans/nuts) are complete
Celiac's disease mechanism and gluten
Parts of gluten are resistant to digestion. Stable oligopeptides cross epithelial barrier of SI, react with transglutaminase -> activate immune system -> inflammatory response.
What is Celiac's disease?
Autoimmune, inflammatory disorder of the small intestine; NOT an allergic reaction;
-Causes GI distress, lactose intolerance, depression & fatigue.
-Left untreated -> anemia, osteoporosis & cancer in GI tract
-specific HLA genes responsible, found in 0.5-1% of population
Food sources and fatal heart attacks
animal-based foods increase risk of fatal heart
attacks while plant-based foods decrease the risk
Who is most at risk from red meat (especially processed) overconsumption?
women from CVD: 50% increased risk