Midterm 1 - Lecture 8

Question 1

Fxns of proteins

Answer 1

• 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)

Question 2

Effect of Protein Deficiencies

Answer 2

• Edema
• Diarrhea and poor absorption
• Impaired immune function
• Increased gut inflammation

Question 3

Describe edema. How does protein deficiency result in edema?

Answer 3

• Loss of fluid homeostasis
• Proteins in capillaries draw fluid into blood vessels. If not enough protein, fluid remains in tissue and causes swelling.

Question 4

How does protein deficiency result in diarrhea and poor absorption?

Answer 4

-GI regeneration is impaired -> loss of villi -> diarrhea & poor absorption

Question 5

How does protein deficiency result in increased gut inflammation?

Answer 5

-Low trp -> low antimicrobial peptides -> increased gut inflammation.

Question 6

Proteins Requirements

Answer 6

lactating woman>pregnant woman>man>woman;

Adult in general: 0.8 g/kg body weight

Question 7

UL & Typical Intake of proteins

Answer 7

most Americans get enough protein; too much puts extra burden on kidneys to excrete excess urea

Question 8

What is protein quality?

Answer 8

-a function of the abundance and ratio of essential AA in the food source and how well the protein is digested & assimilated.

Question 9

How many essential amino acids are there? Which two AA’s are most important to consider?

Answer 9

9;

phe is essential and tyr is semi-essential (Remember PKU)

Question 10

Three non-essential AAs and precursors

Answer 10

pyruvate -> alanine
oxaloacetate -> aspartate
α-ketoglutarate -> glutamate

Question 11

What is the Protein Efficiency Ratio?

Answer 11

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)

Question 12

What is a complete protein?

Answer 12

Has all 9 Essential AAs; e.g. an egg

Question 13

Protein Digestibility Corrected AA Score

Answer 13

• 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

Question 14

Chemical Score of a protein

Answer 14

mg of lowest ratio EAA per gm of protein/ same for egg

Question 15

Summary of protein quality

Answer 15

Animal sources are best; Mixed foods (Grains plus beans/nuts) are complete

Question 16

Celiac’s disease mechanism and gluten

Answer 16

Parts of gluten are resistant to digestion. Stable oligopeptides cross epithelial barrier of SI, react with transglutaminase -> activate immune system -> inflammatory response.

Question 17

What is Celiac’s disease?

Answer 17

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

Question 18

Food sources and fatal heart attacks

Answer 18

animal-based foods increase risk of fatal heart

attacks while plant-based foods decrease the risk

Question 19

Who is most at risk from red meat (especially processed) overconsumption?

Answer 19

women from CVD: 50% increased risk

Question 20

Mechanism of increased CVD risk

Answer 20

• high in saturated fat -> increase risk of CVD

- Meat contains endotoxins and pro-inflammatory chemicals