Undernutrition (Negative Energy Balance)

what are the core causes of undernutrition

market failure, conflict, central planning failures, natural disasters

how do market failures lead to undernutrition

poor households can’t access food, breakdown in entitlement not food supply

how does conflict lead to undernutrition

war disrupts food systems & humanitarian aid

how do central planning failures cause undernutrition

authoritarian policies in Soviet Union, Maoist China, & North Korea caused massive famines

how do natural disasters lead to undernutrition

floods & droughts destroy crops & infrastructure

what is anthropometry

measuring the size & shape of the human body (like weight & height) to see if someone is growing normally

what is stunting

low heigh for age (short, old)

what is wasting

low weight for heigh (slim, tall)

what is underweight

low weight for age (slim, older)

what are the types of protein-energy malnutrition

Marasmus, Kwashiorkor

what is marasmus

severe calorie & nutrient deficiency

what is characterized by extreme wasting (loss of fat & muscle)

marasmus

In Marasmus, serum albumin levels are

normal

what is kwashiorkor

protein deficiency with adequate calorie intake

what is often triggered by infection or toxin stress

Kwashiorkor

what is characterized by edema, hypoalbuminemia, dermatoses

kwashiorkor

what are clinical signs of undernutrition

fatigue, weakness, low body temp, hair/skin changes, stunted growth, swelling, frequent infections

what are developmental markers of undernutrition

bone age, mental age, head cirrcumference

during undernutrition, energy stores are mobilized after __ depletion

glycogen

how does macronutrient usage change during undernutrition

transition to fatty acid oxidation & ketone body production

after the transition to FA oxidation, once fat is insufficient:

protein catabolism increases for gluconeogenesis

what are the 4 phases of starvation

postabsorptive, early, intermediate, adapated

when does the postabsorptive phase of starvation occur

12 hr

what is the postabsorptive phase of starvation

glycogenolysis

when does the early phase of starvation occur

2-3 days

what is the early phase of starvation

gluceoneogenesis from amino acids

when does the intermediate phase of starvation occur

2-3 weeks

what is the intermediate phase of starvation

increased ketogenesis & fat use

when does the adapted phase of starvation occur

after 3 weeks

what is the adapted phase of starvation

minimal proteolysis, reliance on ketones

how does body composition change during undernutrition

reduced physical activity to conserve energy, growth halts; lean tissue loss becomes irreversible if prolonged

what happens to muscle & protein metabolism during undernutrition

decrease protein synthesis due to lower energy intake, enhanced Cori cycle & glucose-Ala cycle for glucose production

what regulates protein breakdown

ubiquitin-proteasome system (UPS) & autophagy

which micronutrients have an effect during undernutrition

zinc, iodine

Zn is needed for

growth, transcription, & cell repair

iodine deficiency lowers

thyroid activity & metabolic rate causing cretinism

how does leptin respond to undernutrition

levels fall with fat loss leading to reduced TRH, TSH, T3, T4, & RMR

how do thyroid hormones respond to undernutrition

reduced conversion of T4 —> T4, reduced RMR, protein turnover, & UCP activity

how does growth hormone respond to undernutrition

increased GH secretion to mobilize FA & preserve lean body mass; stimulate protein synthesis, reduces glucose use; increases aa transport & RNA/DNA activity

how do glucocorticoids (cortisol) respond to undernutrition

stimulate muscle protein breakdown & lipolysis; promote gluconeogenesis to maintain glucose for vital organs

how does the AMPK-SIRT1 pathway respond to undernutrition

It is activated by energy depletion, decreased anabolic pathways (synthesis), increased catabolic pathways (breakdown)

what is the emergency treatment protocol for undernutrition

start w F-75 (low osmolality, low lactose) —> F-100 for catch-up (higher protein & fat); small frequent feeds