Obesity and metabolic syndrome Flashcards
where is the hunger centre located in the hypothalamus?
lateral area
where is the satiety centre located in the hypothalamus?
ventro-medial nucleus
what do positive signals to the satiety centre stimulate a felling of?
fullness
what are the circulating hormones that makes you feel hungry?
orexigens
what are the circulating hormones that makes you feel full?
anorexigens
where are orexigens produced?
neuroendocrine cells in stomach, neuropeptide in brain
name some anorexigens
SST, CCK, Peptid YY (ileal break), oxyntomodulin, GLP-1
are foodstuffs like AAs lipids and glucose anorexigens or orexigens?
anorexigens
what does ghrelin stimulate?
hunger
where is the arcuate nucleus found and where does it receive messages from?
medulla, receives central and peripheral messages and messages from annorexigens
what does the arcuate nucleus communicate with?
hunger centre in the hypothalamus
What do anorexigenic neurones release?
POMC (–> aMSH) and CART
go to hypothalamic areas
what do orexigenic neurones release?
AGRP and NPY that modify function
what effect does AGRP have on melanocortin receptors?
inhibitory
What hormones are involved in the overall long term integrating signal for eating?
leptin and adipokines
which cells produce leptin?
adipocytes
what is the effect of leptin?
potentiates insulin
central effects
which hormone is similar to leptin?
adiponectin
which pro-inflammatory cytokines inhibit leptin and insulin and therefore worsen obesity
TNF-a and IL-6
which neurones does leptin stimulate?
anorexigenic neurones –> feel full so don’t eat
what is the order of metabolites used in starvation?
glucose fat (ketone bodies to brain glycerol to gluconeogenesis) muscle (AAs to gluconeogenesis)
what happens in severe starvation?
apathy, decreased heart rate, muscle wasting, muscle fatigue, decreased respiratory capacity, decreased exercise capacity, cardiac failure, respiratory failure, infection, decreased heat generating capacity
which 3 out of 5 conditions are required to have the metabolic syndrome?
DMT2, obesity (waist circumference), low HDL cholesterol, hypertension, high plasma triglycerides
what disease is the metabolic syndrome associated with?
CVS disease
why is visceral fat around organs more dangerous?
less responsive to insulin, hyperlipolytic state, more NEFAs produced, less adiponectin produced, more pro-inflammatory cytokines produced
what effect do non-esterified fatty acids (NEFA) have on the body?
liver is less sensitive to insulin, alters lipid handling, impairs beta cell insulin release
which pro-inflammatory cytokines does visceral fat increase the levels of?
TNF-a, IL-6, IL-1 (amplified by invading macrophages)
Why does insulin resistance lead to protein glycation?
increased plasma glucose levels results in advanced glycation endproducts (AGEs)
what is the term for glycated proteins?
AGEs (advanced glycation endproducts)
via which receptor do AGEs induce an inflammatory response?
RAGE
how do AGEs increase the risk of CHD and atheroma?
via the RAGE receptor –> induce an inflammatory response –> reactive oxygen species –> CHD, atheroma
which other factors contribute to CHD and atheroma formation?
dislipidaemias, oxidative stress
which hormone do obese mice lack?
leptin
which receptor do diabetic mice lack?
leptin receptors
What do most obese people have high levels of?
ghrelin and low leptin
how is the energy used for an activity per day calculated?
PAR (physical activity ratio) x BMR/hr x hours
how is BMI calculated?
weight/ height^2
what are the risks associated with obesity?
DMT”, CHD, gout, hypertension, sleep apnoea, cancer, stroke, MI, osteoarthritis, retinopathy, hypertension, reproductive and urological problems, musculoskeletal problems
What are the 3 factors that characterise anorexia nervosa?
active maintenance of low body weight,
What are the characteristics of anorexia nervosa?
peaks at 15-18years, 0.5% girls 15-18 years get it, 95% female
how is bullimia nervosa distinguished from binge eating bisorder?
no compensatory behaviour after binge
what binge frequency is required to diagnose bullimia nervosa?
frequency of one per week for 3 weeks
what are the characteristics of bulimia nervosa?
recurrent binge eating, compensatory behaviours, extreme shape and weight concern
What are the characteristics of binge eating disorder?
recurrent binge eating, binge episodes, marked distress regarding bingeing, no compensatory behaviour, no BN or AN
who typically gets bulimia nervosa?
late adolescents, 1-3% or 18-25, 95% female
what is OSFED?
Other specified feeding and eating disorders
disordered eating such as bingeing or restriction but criteria for AN or BN not met
AN but >85% body weight
BN but less frequent episodes
what are the common features of eating disorders?
behaviour around food, levels of distress, overvaluation of shape and weight
Who devised the Socio-cultural model and what are the 4 main components of it that increase the likelihood to dieting?
Stice, 1994
socio-cultural environnment, carriers (peers media), mediators (self esteem body weight), individual
who devised the theory that dieting is a main pathway leading to eating disorders?
Patton et al 1999
2000 15 year olds over 3 year cohort study
moderate dieting increased risk 5x severe dieting increased risk 18x
in the study by patton et al 1999 what effect did poor mental health have on the frequency of eating disorders?
increased risk 6x
who devised the model for specific and non-specific risk?
connors, 1996
what are the non-specific factors that contribute to risk of eating disorder?
self-regulatory risk factors that lead to low self esteem, affective dysregulation and insecure attachment
what are the specific factors that contribute to risk of eating disroders?
body dissatisfaction risk factors leading to negative body image and weight preoccupation
what is an eating disorder a combination of in regard to the specific and non-specific risk theory?
body dissatisfaction and low self esteem or other psychological problems
Why are eating disorders a particular problem with adolescent girls?
shape and weight concern acted out through food, often framed as ‘healthy’, food autonomy from parents, peer impression management
why might eating disorders develop?
as a way of managing a problom for example feeling in control by stopping eating, bingeing to regualate negative emotional state
what was the minnesota experiment?
ancxel keys
starved men during the war to look into physical and psychological effects of starvation
who delevoped the motivated eating restraint theory?
palmer 2000
what is motivated eating restraint?
pre-cursor to AN and BN with similar motivations of “sitting on top of hunger” AN is successful BN breaks out with binges
what are the negatives associated with eating diorders?
prevents socialising, lost freedom, moody, guilty, controls life
when are drugs considered to reat obesity?
BMI 25-30 and high waist crcumference and co-morbidities
when is bariatric surgery recommended?
BMI > 40 or 35-40 with co-morbidities and other significant disease, generally fit for surgery and anaesthesia., commits to long term follow up
how did the foresight report of 2007 change the way we tackle obesity?
treating obesity as physiology
highlighted an obesogenic environment
what were the 7 main themes outlined by the foresight report of october 2007?
passive weight gain is a biological adaptation to biology, food consumption, individual psychology, activity environment, societal influences, food production, individual activity, activity environment
what 5 factors are required before a person can begin weight loss treatment?
- physical and emotional circumstances 2. eating disorders 3. own initiatives/ pressured? 4. realistic expectations (10% loss) 5. understanding of what’s needed
