Obesity Flashcards
Prevalence of obesity in Canada?
23%
What percentage of Americans are overweight or obese?
70%
What is the MOA behind obesity increasing cancer risk?
increased insulin resistance means more insulin in the blood as well as increased IGF1; their receptors are stimulated on target cells, increasing cell proliferation and decreasing apoptosis –> tumour development
biochemical factors that inhibit appetite?
serotonin dopamine cholecystokinin corticotropin releasing factor neurotensin bombesin calcitonin gene related peptide amylin adrenomedullin glucagon glucagon-like peptide 1
biochemical factors that increase appetite?
noradrenaline opioids GHRH galanin melanin-concentrating hormone neuropeptide Y
cortisol decreases _________ sensitivity by receptor cells
insulin
and therefore glucose uptake
cortisol increases urinary excretion of _________
magnesium
important in synthesis of healthy PGs
cortisol competes with thyroid hormone for the amino acid __________, which is involved in thyroid hormone formation.
tyrosine
therefore limits amount of thyroid hormone –> decreased energy and increased body fat
T or F: insulin crosses the BBB
true
binds to receptors in hypothalamus - activates appetite centre within brain
Leptin acts in hypothalamus to…?
suppress food intake and increase energy expenditure
sends satiety signals to the brain
levels high in nearly all obese people
what is the action of ghrelin?
appetite stimulant
secreted by stomach and duodenum
levels rise before meals
suppressed after eating
dopamine plays an important role in which physiological functions
motor control motivation arousal cognition reward lactation sexual gratification nausea
does not cross BBB
PET scans of obese individuals demonstrate a difference in dopamine receptors in obese and lean people. What is the difference?
less dopamine receptors found in obese people as compared to lean
obese individuals need to eat more to derive pleasure and reward from food
MOA of obesogens?
- alter action of metabolic sensors
- disregulate sex steroid synthesis
- inappropriate modulation of nuclear receptor function (mimic hormones in the body, alter normal homeostasis)
Overweight BMI?
25-29.9
Morbidly obese BMI?
higher than 46-47
Obese BMI?
30 or more
how many calories per day must be cut in order to lose 1-2 lbs per week?
500 cals
for adults, success in weight loss is defined as?
losing at least 10 percent of initial weight without regaining more than 6 or 7 lbs. in 2 yrs.
Maintenance of a lower waist circumference (at least 2 inches lower than before weight loss)
natural supplements to increase satiety?
guar gum
glucomannan
psyllium
garcinia cambogia
Theory:
Soluble fiber can absorb water within the gut
Causing increased satiety and lower caloric intake
Fiber also may improve control of diabetes and hyperlipidemia
Findings:
Guar gum versus placebo for weight loss showed no benefit.
Glucomannan in dosages of 3 to 4 g per day may be well tolerated and yield modest weight loss
Psyllium improved glucose and lipid parameters significantly more than placebo in 125 overweight patients with type 2 diabetes, but there were no differences in weight loss
describe leptin
the “satiety hormone”
made by adipose cells that helps to regulate energy balance by inhibiting hunger. Leptin is opposed by the actions of the hormone ghrelin, the “hunger hormone”. Both hormones act on receptors in the arcuate nucleus of the hypothalamus to regulate appetite to achieve energy homeostasis. In obesity, a decreased sensitivity to leptin occurs, resulting in an inability to detect satiety despite high energy stores.
