Obesity Flashcards
What is obesity?
A condition of extremely high levels of adiposity. BMI over 30.
How can obesity be measured?
Skin fold thickness. Waist to hip ratio. DXA MRI CT
Name 4 factors that increase chances of successful dietary management.
- setting realistic goals
- Having a support network
- Eating a balanced diet
- Safe rate of weight loss is encouraged.
Name two problems with fad diets.
- Lead to macronutrient imbalance (eg. Atkins diet is low carb, high protein and fat)
- Restriction of healthy foods
What are the co morbid conditions associated with obesity? (10)
- CVD
- type 2 diabetes
- hypertension
- obstructive sleep apnoea
- dyslipidaemia
- gall stones
- gout
- osteoartheritis
- infertility
- cancer
How does generalised obesity cause cardiac problems?
Obesity alters total blood volume.
What methods can be used to manage obesity?
- dietary restriction
- physical exercise
- behaviour modification
- bariatric surgery
- drugs
Define the two types of bariatric surgery.
Malabsorptive –> reduces size of intestine to prevent nutrient absorption. More invasive
Restrictive –> induces early satiety
Describe roux-en-Y gastric bypass surgery.
Form of maladaptive surgery.
The stomach is stapled at the top to create a small pouch. This small pouch is attached to the end of the intestine, bypassing the rest of the stomach and duodenum.
The bypassed duodenum is connected to the end of the intestine so bile and digestive juices can pass through.
Describe biliopancreatic diversion surgery.
Maladaptive.
Stomach is stapled along the vertical to create a large pouch. The stomach is attached to the end of the intestine, bypassing the duodenum and most of the intestine.
The rest of the small intestine is attached to the end of the small intestine so digestive juices can flow through
Describe gastric banding.
Band is placed over the opening of the stomach and tightened, reducing the stomachs capacity and inducing early satiation.
What modes of action do drugs for obesity use?
- reducing food intake
- reducing fat intake
- increasing energy expenditure
Which neuropeptides increase food intake? (7)
- NPY
- Agouti related peptide
- melanin concentrating hormone (MCH)
- galanin
- growth hormone releasing hormone
- opioids
- orexins
How to neurotransmitters affect intake?
They usually reduce intake
What are the two types of drugs and how to they act?
- monoamine releasing agents
- releases more neurotransmitter, increasing response
- monoamine reuptake inhibitors
- Prevents reuptake of neurotransmitter into secretory synapse, amplifying response
What type of drug is Sibutramine and how does it reduce weight?
- SSRI
- reduces weight by increasing satiety and increasing energy expenditure
What are the side effects of Sibutramine?
- dry mouth
- insomnia
- constipation
- small increase in blood pressure and pulse
Why was Sibutramine banned?
Morbidity due to CVD
What new drugs have been developed from Sibutramine?
Lorcaserin –> serotonin receptor agonist
Osymia –> approved in US, not EU
Bupropion –> SSRI
What type of drug is Rimonabant?
Endocannabinoid, opposite of cannabinoids
What did trials of Rimonabant show?
- reduced body weight and abdominal obesity
- improved plasma lipid and glucose levels
- reduced prevalence of metabolic syndrome
Why was Rimonabant banned?
Psychiatric effects, leading to suicide.
What peptide does Liraglutide mimic?
Glucagon line peptide-1
Why was Liraglutide developed and what are its effects?
- developed to treat type 2 diabetes
- also reduces food intake
How does Liraglutide differ from GLP1?
Liraglutide has a far longer half life than GLP1
How is Liraglutide administered and why?
IV, because it’s a peptide
What is Liraglutide approved for?
Diabetes treatment only
What does Orlistat/alli do?
reduces fat absorption by inhibiting pancreatic lipase
What is Orlistat derived from?
Synthetic derivative of lipostatin
What are the side effects of orlistat?
- liquid, oily stools
- fat soluble vitamin deficiency
What is DNP?
Dinitrophenol
Why was DNP used?
Clinically significant and sustained weight loss
Why is DNP toxic?
DNP shuttles protons across inter mitochondrial membrane
- this dissipates proton gradient, bypassing ATP synthase, leading to uncoupling –> lack of ATP and dangerous rise in temperature
