Nutrition 2: Obesity and Starvation Flashcards
Regulation of body mass: What is the first law of thermodynamics? Energy intake =
energy intake = energy expended + energy stored
Define appetite Define satiety
Appetite = desire to eat food, felt as hunger, that regulates adequate energy intakes to maintain metabolic needs Satiety = absence of hunger
What regulates hunger and satiety? What 3 factors promote satiety?
NOT GIT! Regulated by hypothalamus - hunger centre - satiety centre High glucose, high stored fat, presence of macronutrients in GIT
- Which is the main hormone that stimulates hunger? 2. When is it released? 3. When is ghrelin release inhibited? 4. What else can inhibit appetite? 5. What are the 2 main neurotransmitters involved?
- ghrelin 2. when the stomach is empty 3. when the stomach is full 4. - CCK, PYY, GLP-1 from SI - insulin release - leptin release 5. serotonine and dopamine
What are some physiological and psychological factors can lead to loss of appetite (anorexia)?
Physiological - anaemia, cancer, liver disorders, mouth disorders, malabsorption syndrome, depression, intestinal disorders, intestinal parasites Pschological - stress, anxiety, sadness, wedding, falling in love
Most acute diseases/injuties are characterised by a ……………………… state. Most apparent sign is an abnormally high ………. ………. followed by continuous ………. ………. Symptoms will usually subside once the underlying illness of injury is treated Most common causes are:
hypermetabolic calorie intake, weight loss infections, sepsis, burns, trauma, fever, surgery, brain injury, long bone fractures, hyperthyroidsim, steroid therapy, bone marrow transplants
Why does ageing present particular problems when it comes to illness and appetite? x4
- appetite decreased - perception of taste is altered - capacity to eat is decreased - maintaining positive nitrogen balance is challenging
What are some examples of nutritional support in illness/
oral supplements enteral/parental nutrition
What is rickets a deficiency of? What does it lead to?
Vitamin D Poor mineralisation of bone, deformation of load bearing bones
What is scurvy a deficiency of? What does it lead to?
Vitamin C Destruction of collagen, damage to myelin, loss/bleeding tooth sockets, sunken eye sockets, paralysis/death
What are the 2 forms of anaemia linked to nutrition?
megaloblastic/pernicious anaemia - lack of vitamin B12 absorption iron deficiency anaemia
What are the 2 forms of inherited obesity?
monogenic mutation - leptin polygenic - Prader-Willi syndrome
What four hormones regulate fat metabolism and how?
insulin - lipogenesis glucagon, adrenaline, glucocorticoids - lipolysis
What is the problem with fructose vs glucose/
fructose is sweeter than glucose fructose absorbed differently to glucose fructose does not stimulate insulin secretion –> increase food intake More conversion into TG’s compared to glucose
What BMI defines normal weight, overweight and obese?
BMI 18.5-25 normal weight BMI 25-30 overweight BMI >30 obese
In ways can body fat be estimated/
BMI comparison with populations of same ethnic origin Bioelectric impedence DEXA scans (Xray!) MRI/CT waist circumference waist-hip ratio/skin fold thickness
What is meant by apple and pear shapes and who is most at risk of Type 2 diabetes, hyperlipidemia, hypertension, CVD
apple = visceral adiposity pear = subcutaneous adiposity apple is more at risk
What are the 4 treatments for obesity?
drugs to alter appetite - sibutramine drugs to alter absorption - orlistat restrict food intake exercise surgery
Starvation 1. Characterised by mechanism to preserve ………… ……….. to maintain ……… and ……….. ………. 2. Results in the consumptoion of ……….. to preserve …………. ………. 3. Marked by increased liver synthesis of ………. and ………… ………… . Also known and …………………… and ………………….
- plasma glucose, brain, spinal cord 2. tissues, energy production 3. glucose, ketones, gluconeogenesis, ketogenesis
Glucose in starvation: - post prandial: blood glucose and stored glycogen exhausted with …….hrs - rely on synthesis from endogenous sources beyond this e.g. ……….. and ………
24 amino acids fats (glycerol)
What is doen to maintain glucose supply to the brain? Breakdown of muscle releases ………. ………. to bolster blood glucose Breakdown of fat releases …….. DISADVANTAGEs: - muscle performance ……… - this is a ……….. resource
amino acids glycerol declines finite
Ketone Bodies Production - Produced from breakdown of ……. …… in the …….. - B oxidation produces ………-……. which can go into Krebs - Ketone bodies are ……… soluble - Can cross the ……… and be used as a source of energy by ………. in ……… as well as in ……… …. …………
fatty acids, liver acetyl-coa water BB brain starvation Type 1 diabetes
Why is villous atrophy a consequence of decreasing calorie intake? What is the impact of this?
decreased rate of cell grwoth, structures like villi are rebuilt less quickly - decreased SA for absorption - decreased absorption of nutrients - diarrohoea –> deficiencies and malnourishment
What is leptin? Where is it produced? What does it do?
hormone released from adipocytes promotes feeling of satiety
