Lecture 14 & Lecture 15 - Nutrition I & II (2 lectures) Flashcards
What are the fuel sources during early fasting and after 5 week of semi-starvation?
- Fasting:
- glucose for CNS and RBC/WBC
- fatty acids & ketones for heart, kidney , and muscle - 5-6 Weeks of Semi Starvation:
- decreased use of glucose
* * increase in ketone as fuel for CNS,
- glucose fuel for RBC/WBC, fatty acids fuel for heart, kidney muscle
What are the signs and symptoms of PEM?
Which is chronic mild PEM and which is acute PEM ( Stunting or Underweight)?
What is the difference between Marasmus and Kwashiorkor?
Protein–energy malnutrition (PEM) or protein–calorie malnutrition refers to a form of malnutrition where there is inadequate calorie or protein intake.
- Stunting = chronic mild PEM
* * mean height for age** - Underweight = acute mild PEM
WASTING = acute, severe PEM ** WEIGHT FOR HEIGHT**
Marasmus: severe wasting with loss of subcutaneous fat & skeletal muscle
Kwashiorkor: wasting of fat and muscle WITH EDEMA and skin and hair color changes, fatty liver, and impaired renal function
State the structural differences and health consequences of saturated, monounsaturated, and polyunsaturated fatty acids.
- SFA
- MUFA
- PUFA
- SFA
- NO DOUBLE BONDS (hence, saturated)
- associated with increased risk of CVD
= hypercholesterolemia (decreased catabolism of LDL) - MUFA
- SINGLE double bond (hence, mono unsaturated)
- not associated with increased CVD
- not associated with increased LDL or decreased HDL! - PUFA
- multiple double bonds
- associated with LOWER LDL levels
ex: linoleic (omega 6 –> 2 DB) and alpha-linolenic (omega 3 –> 3 DB)
BUT CAN ALSO LOWER HDL!! (not good)
Identify the essential fatty acids and signs of EFA deficiency.
- Linoleic Acid - omega 6 fatty acid
- Linolenic Acid - omega 3 fatty acid
EFA deficiency: infertility, scaly dermititis
Describe the structure, function, and health consequences of trans fatty acids.
- Structure:
- manufactured** changed the double bond from cis to trans (less rotation = solid at room temp)
HYDROGENATION REACTION!!
- Function:
- increased viscosity of vegetable oils & stability of baked goods - Health consequences:
- found to increase LDL and lower HDL
Explain by which mechanisms dietary fiber may impact plasma cholesterol levels. (3)
- Sequester bile in gut, decreasing reabsorption
- Slow carb absorption and subsequent rise in plasma insulin levels (thereby slowing cholesterol synthesis)
- Stimulate SCFA synthesis thereby inhibiting cholesterol synthesis
** this is from SOLUBLE FIBERS** - pectins & gums (legumes & fruit associated with lowering cholesterol)
Describe the functions of the following FAT SOLUBLE vitamins:
- Vitamin A
- Vitamin D
- Vitamin E
- Vitamin K
- Vitamin A
- required for optimal vision
- retinoic acid essential for cellular growth and differentiation
- also required for cell - mediated & antibody mediated immune responses
- ** epidermal differentiation** –> allopecia - Vitamin D
maintain serum Calcium & phosphorous levels - Vitamin E
- antioxidant in cell membranes - Vitamin K
- cofactor for proteins involved in coagulation and some bone associated proteins
Define the symptoms of deficiency & excessive intake for the following:
- Vitamin A
- Vitamin D
- Vitamin E
- Vitamin K
- Vitamin A
- night blindness, stages of xerophthalmia, immune dysfunction & poor growth
TOXICITY: nausea, vomiting, headache, & bright red gingiva
- Vitamin D
- rickets, osteomalacia
TOXICITY: kidney stones, dehydration, thirst - Vitamin E
- ataxia with progressive peripheral neuropathy
TOXICITY: extremel rare - Vitamin K
- hemorrhagic disease of newborns
TOXICITY: unreported
Explain the general mechanism by which retinoids regulate cellular differentiation.
Retinoid Acid binds to receptor on response element in promoter region of target genes resulting in activation of transcription
What are 3 ways that Vitamin D maintains plasma calcium levels?
- Increase intestinal absorption of Calcium
- Increase renal calcium reabsorption
- Increase calcium reSORPTION from bone (breakdown)
What is the mechanism by which Vitamin E protects cell membranes from oxidative damage?
- Acts as an antioxidant and peroxide scavenger particularly for cell membrane PUFAs and lipoproteins
- Breaks chain reaction of oxidation preventing propagation of free radical damage
- Regeneration to reduced Vitamin E by Vitamin C
Explain etiologic factors contributing to hemorrhagic DISEASE OF THE NEWBORN. (3)
- Placenta poorly transmits vitamin K
- Liver is immature regarding prothrombin synthesis
- Intestine is sterile at birth (synthesized by intestinal bacteria normally) and breast milk is low in vitamin K
** given prophylaxis of Vitamin K at birth to prevent this**
Describe the primary function of the following water soluble vitamins:
- Thiamin
- Niacin
- Folic acid
- Thiamin
- coenzyme required for metabolism of carbs and branched chain amino acids - Niacin
- coenzyme for multiple redox reactions
- ATP synthesis & ADP ribose transfer
- significant amount of dietary tryptophan metabolized to NAD - Folic acid
- coenzyme in methyl group transfer reactions such as purine & pyrimidine synthesis and methylation of transfer RNA
Describe the primary function of the following water soluble vitamins:
- Vitamin B 12
- Vitamin C
- Vitamin B 12
- coenzyme for 2 critical enzymes involved in methyl group transfer - Vitamin C
- coenzyme for some redox reactions
- hydroxylation of collagen
- water soluble antioxidant
- neurotransmitter & neuropeptide synthesis
- corticosteroid synthesis
- seratonin synthesis
How much kcal/gram are contained in the following:
- Proteins
- Carbs
- Fats/lipids
- Ethanol
- Proteins - 4
- Carbs - 4
- Fats/lipids - 9
- Ethanol - 7
<1% trans fats)
~ 15% kcal from protein
55-60% kcal from carbohydrate
