182. Starvation and Metabolic Adaptation Flashcards
How does core body temp respond to starvation?
Decreases
Hormones that __ during starvation:
- leptin
- insulin
- T3/T4
- LH, FSH
- Estrogen, testosterone
Decrease
Volitional reduction in energy intake (below needs), with adequate intake of protein and micronutrients
Caloric restriction
Primary deficit is in protein intake
Low or normal body weight
- edema may mask weight loss
Distended abdomen
Fatty liver/liver dysfunction
Marked hypoalbuminemia
Skin and hair changes
Kwashiorkor
__ changes seen in normal volunteers during __:
- preoccupation with food
- hoarding and stealing food
- abnormal taste preferences
- binge eating
- depression, apathy, irritability, and other personality changes
Behavior
Starvation
Determinants of __:
- Body composition
- Age (decreases w/ age)
- Gender (women have higher in luteal phase)
- Nutritional status
- Health status
BMR
Metabolic adaptation to starvation spares __ mass
- d/t use of alternative fuels: FFA and KB
Lean
Life-threatening condition that can occur during eating a lot in an individual with malnutrition who previously was unable to eat
Electrolyte abnormalities may occur when the availability of glucose produces shifts of electrolytes into cells for use in synthesis of ATP and new tissue
- arrhythmias and decreased cardiac contractility can result
- heart size is reduced due to malnutrition and eating once again leads to increased circulatory blood volume –> heart failure can result
Refeeding Syndrome
On day _ of starvation, one switches from main source of fuel being glucose to fatty acids and ketones
- allows us to survive longer
3
Enzyme that is sensitive to insulin
Activated when insulin levels are low to produce free fatty acids
- site of action is in adipose tissue
Kind of like Type 1 DM
HSL
Close to pure-simple starvation
Primary deficit is in low calorie intake
Very low body weight
Wasted appearance with loss of both fat and muscle
Liver function is usually normal
+/- hypoalbuminemia
Dry, inelastic skin
Marasmus
Can be seen in babies when they are removed from breastfeeding all of a sudden
- loss of protein
Can also be seen in ppl w/ GI surgery that hurts protein absorption or ppl on low protein diets
Kwashiorkor
__ increases in illness d/t:
- catecholamines and sympathetic nervous system stimulation
- fever
- inflammation and cytokines
May increase by 30-100% or more
BMR
2 main ways to provide nutrition support to patients who can’t or won’t eat
Enteral nutrition (G-tube) Parenteral nutrition (IV)
Where do ketone bodies come from?
Liver
With weight loss, __ levels decrease in obese patients
leptin
It has been postulated that decreased levels of __ leads to HPA axis activation of cortisol that leads to increase in free fatty acid production along with ketone bodies
Leptin
2 substitutes for glucose that are used for energy in a starving state
Free fatty acids and ketone bodies
In illness, you see increase __ __ d/t:
- inflammation and cytokines
- increased cortisol
- insulin resistance
Dietary needs may double in some patients
Protein metabolism
What causes increased energy expenditure and markedly increased protein catabolism?
Glucose does not suppress protein catabolism in this case
- no protein sparing
Can present as cachexia
Differs from starvation
Illness
Fuels used by the brain in late starvation
Ketone bodies and glucose
Just __ g of dietary carbohydrate per day can suppress ketosis and gluconeogenesis
- protein sparing
100
“Flaky paint” rash and depigmentation of hair are clues to a patient w/ what?
Kwashiorkor
Becomes more important as a source of new blood glucose when starvation continues
Kidneys
Hormones that increase during starvation (2 of them)
Ghrelin and glucagon
Changes in \_\_ \_\_ during starvation: TEE: down arrow, down arrow BMR: down arrow, down arrow TEF: down arrow EEPA: down arrow, down arrow
Disproportionately goes down more than we’d expect, not explained just by amount of weight loss
energy expenditure
Occurs with illness; characterized by increased protein catabolism, induced by inflammatory cytokines
Disease-associated malnutrition (cachexia)
Metabolic and hormonal changes with weight loss in __:
- Decreased:
- energy expenditure
- leptin
- T3/T4
- core body temp
- Increased:
- Ghrelin
- Muscular efficiency
Modified:
- Neural activity
Obesity
Adipose produces __ in times of starvation that leads to:
- Free fatty acids being produced from adipose tissue and sent to muscle, liver, and kidney
HSL (hormone-sensitive lipase)
