Midterm 1 - Lecture 8 Flashcards Preview

BIBC120 > Midterm 1 - Lecture 8 > Flashcards

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
• Gluconeogenesis
• 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.


Proteins Requirements

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


Mechanism of increased CVD risk

-high in saturated fat -> increase risk of CVD
-Meat contains endotoxins and pro-inflammatory chemicals