Biochem- starvation and malnutrition Flashcards
Post-absorptive period fuels produced/used
Produced: glucose from hepatic glycogenolysis and gluconeogenesis
Fatty acids from adipose tissue
Used: glucose by all
Gluconeogenesis begin and when fully active
4-6 hours after last meal begins
fully active at 10-18 hours after last meal – glycogen stores depleted
Fuel production and usage in early starvation (24 hours last meal)
Produced: glucose from gluconeogenesis
Fatty acids from adipose tissue
Used:
Brain: glucose – can used ketone bodies
Muscles and other tissues: some glucose, mostly fatty acids
Fatty acid breakdown
FA -> acetoacetate – +NADH to NAD+ –> b-hydroxybutyrate
Ketone bodies
Urine test for ketones only detects acetoacetate, not b-hydroxylbutyrate
Fuel production and usage in intermediate starvation (48 hrs after last meal)
Produced:
Glucose
Fatty acids
Ketone bodies from liver
Used:
Brain: mostly glucose, some ketone bodies
Muscles, other tissues: fatty acids, some ketone bodies
Metabolic scenario favoring synthesis of ketone bodies
When production of acetyl CoA from b-oxidation of FA exceeds oxidative capacity of the TCA cycle
Fuel production and usage in prolonged starvation (5 days after last meal)
Produced:
Glucose
Fatty acids
Ketone bodies
Used:
Brain: ketone bodies -> 2 acetyl CoA -> TCA cycle
Other tissues: fatty acids, some ketone bodies and glucose
Overnight fast vs 3 day fast glucose to ketone body usage
Overnight: 90% glucose, 5% ketone body
3 day: 60% ketone body, 40% glucose
Ethanol metabolism effect on gluconeogenesis
NAD+ regeneration by liver
When liver metabolizing ethanol it can’t perform gluconeogenesis -> severe fasting hypoglycemia when consume a lot of alcohol in a fasting state
Fate of Aceytl CoA
TCA cycle
Fatty acid synthesis
Cholesterol synthesis
Ketone synthesis
Refeeding syndrome
Negligible nutrient intake at least 5 days
Cells intracellular depleted
Eat -> nutrients pulled back into cells, drops serum levels of Mg2+, phosphate, K+
-> arrhythmias and neurological problems
monitor electrolytes closely
slow feeding
phosphorylate to keep in cells -> depletion of ATP
Kwashiorkor
“FLAMES”
Fatty Liver disease – can’t make apoB100 -> lipid accumulation
Anemia
Malnutrition – protein
Edema – lack serum proteins
Skin lesion s- depigmetnaiton of skin and hair
Marasmus
Total energy malnutrition
Muscle wasting
SQ fat loss
Edema