- provide energy (main fuel for muscle at rest or light exercise) - efficient storage of energy (can store up to 50x cell size) - Insulation and protection - Transport fat-soluble vitamins - Satiety (slows rate of stomach emptying): enhances fullness and slower to return hunger - Flavor and mouth feel - Variety of health benefits: Omega 3 fatty acids in particular
Explain how fat is digested once entering the small intestine (including enzymes and hormones involved)Primary site of fat digestion (~95% of fat):
- CCK hormone stimulates the release of bile and lecithin to help emulsify fat
- CCK stimulates pancreas to release pancreatic lipase enzyme
- fat is broken down into monoglycerides and free fatty acids and glycerolDescribe the transportation of digested fat (fat from food), starting with formation of chylomicron in the lymphatic system to the chylomicron remnant deposit in the liver.(see picture on slide titled "Dietary vs. Synthesized Fat")1) from the small intestine, absorbed fat travels as chylomicron
2) fat to body cells after breakdown by lipoprotein lipase
3) fat produced by the liver leaves as VLDLDescribe the transportation of synthesized fat, starting with VLDL and ending with the receptor pathway and scavenger pathway? (see picture on slide titled "Dietary vs. Synthesized Fat")1) From VLDL, fat to body tissues via lipoprotein lipase
2) VLDL remnants AKA IDL
3) LDL
4a) LDL taken up by receptor pathways (in body cells)
4b) LDL taken up by scavenger pathways (in blood vessels)Which pathway (receptor vs. scavenger) contributes to plaque formation and clogged arteries?Scavenger pathwayWhat are the three factors that affect LDL receptor synthesis and in particular, what affect does diet have on LDL receptor synthesis?- diet (excess saturated fats may decrease the number of LDL receptors)
- exercise
- genetics
replacing saturated fats with mono or polunsaturated fats may increase number of receptors and increase binding ability of LDL to receptors (replacing saturated fat with carbs does not offer the same benefit)What are the characteristics and functions of cholesterol in the body?- essential component of cell membrane
- forms important hormones (estrogen, testosterone, vitamin D)
- 40-60% of cholesterol in food absorbed
- body makes ample amount (produced by liver, found only in animal products)What is atherosclerosis and arteries in which part of the body are most susceptible?plaque buildup in arteries (generally takes 2 years to develop)
- affected by diet, exercise, and genetics
- common in arteries of the heart and brain, however arteries in the kidneys, legs, and feet can be susceptible
- plaque buildup can begin in childhoodDefine myocardial infarction.heart attack, blood flow to heart is blockedDefine stroke.blood flow to the brain is blockedWhy is it beneficial to having a high HDL level?reduces plaque buildup
- picks up cholesterol from dying cells and LDL particles and transfers back to liver
- also prevents LDL from going through oxidationWhat should blood levels for overall cholesterol, LDL and HDL levels be? (aka lab values or lipid profile)?Cholesterol: 200 or lower
LDL (bad cholesterol): 130 or lower
- 100 or lower if risk factors present
HDL (good cholesterol): men 40 or higher, women 50 or higherWhat diet measures can be taken to reduce risk of atherosclerosis?- caloric intake to maintain a healthy weight
- minimize sugar intake and increase fiber intake (results in decrease in high glycemic index foods, fiber reduces cholesterol levels, don't exceed overall carbohydrate recommendations especially if not active)
- stay within daily fat guidelines (trans fat can raise LDL levels and decrease LDL size and lower HDL levels, replace excess saturated and trans fat with mono and polyunsaturated fat)What are the daily recommendations (as grams per day) for saturated fat + trans fat?no more than 20-30 grams per day, should be
no more than 10% of total calories, trans fat as low as possibleWhy are antioxidants potentially helpful in preventing plaque build-up in arteries?because LDL is more likely to deposit in arteries when oxidized (antioxidants prevent LDL oxidation)What impact does exercise have on reducing risk of atherosclerosis?- larger and fewer LDL
- increased LDL receptor synthesis
- increases vascularity of heart
- increases HDL
- improves glucose tolerance and insulin sensitivity
- aids in weight loss and lowering blood pressure
