Unit 18 Flashcards
Fats and cholesterol in health
What are the 3 lipid classes?
- triglycerides
- phospholipids
- sterols
What is the structure of a triglyceride?
glycerol + 3 fatty acids
Where do we see phospholipids?
cell mebrane (lipid bilayer)
What is the structure of phospholipids?
hydrophilic head on with hydrophobic tails (
What class of lipids are cholesterol and vitamin D in?
sterols
What type of lipid makes up 98% of our dietary fat intake and majority of body fat stores?
triglycerides
What are triglycerides used for by cells?
- energy
- tissue maintenance
What part of the triglyceride determines its type?
the fatty acids
What is the difference between saturated and unsaturated triglycerides?
saturated: fully saturated with hydrogen (no double bonds)
unsaturated: not fully saturated with hydrogen (has double bonds)
What is the difference between monounsaturated and polyunsaturated triglycerides?
mono: only 1 point of unsaturation (double bond)
poly: more than 1 point of unsaturation
What state do we normally find saturated fats in? Unsaturated?
saturated: solid (butter)
unsaturated: liquid (canola oil)
List the saturated fats.
- animal fats
- butter
- lard
- coconut oil
- palm kernel oil
What type of fats are omega 9 fats?
monounsaturated fats
List the monounsaturated or omega 9 fatty acids.
- olive oil
- avocadoes
- peanuts
- almonds
- canola
What are the 2 categories of polyunsaturated fats?
omega 3 and omega 6 fatty acids
List the omega 6 fatty acids.
corn oil
safflower oil
sunflower oil
List the omega 3 fatty acids.
- fish
- shellfish
- flaxseed, soybean, walnut and rapeseed oils
Which of omega 3,6,9 needs to be consumed with caution? Why?
omega 6 (too much of these fatty acids can lead to inflammation)
What do healthier fats do?
lower LDL and raise HDL
What is the ‘bad’ cholesterol?
low density lipoprotein (LDL)
What is the good cholesterol?
High density lipoprotein (HDL)
What are the 2 essential fats?
both polyunsaturated
alpha-linoleic acid (omega 6 fatty acids)
alpha-linolenic acid (omega 3 fatty acids)
Where do we get alpha-linoleic acid from?
sunflower, corn and safflower oils
Where do we have high amounts of alpha-linolenic acid?
brain and other nervous system tissue
Where can we get short-chain n-3’s?
- walnuts
- flaxseed and canola oil
- soybeans
- dark, leafy green vegetables
all plant sources
Where can we get long chain omega-3?
- fish oils
- EPA
- DHA
animal sources
What are benefits and consequences of long-chain omega-3?
- reduces heart disease risk
- reduce tendency for blood clot
- high consumers can have imaired blood clotting (puts them at risk fo uncontrolled bleeding and hemmorrhagic stroke)
How often should you eat fish?
2x per week
Where is DHA found in our bodies?
- structural component of the brain
- retina
What does DHA promote?
intellectual and visual development during last 3 months of pregnancy and during infancy
DHA is now added to many infant formulas
What is the suggested ratio of n6 - n1? What is canadians ratio?
4:1 or less
Canada: 9:1 (need to increas intake of n3 fatty acids)
What is the relationship between omega 6 and omega 3?
functions of one are adversly modified by high amounts of the other
What do less healthy fats elevate?
LDL cholesterol
What are examples of less healthy fats?
- meat
- block margerine
- lard
(trans and saturated fats)
Why did make hydrogenated fats?
because unsaturated fats are unstable and turn rancid with time, oxygen and heat. solid fats last longer than oils during frying
How does hydrogenation work?
Adds hydrogen to unsaturated fats to make them more saturated and solid (improves shelf life, cooking properties and taste)
What are the 2 drawbacks of hydrogenation?
- hydrogenated vegetable oils have more saturated fat (corn oil - 6%, coil margerine - 17%)
- hydrogenation changes structure of the unsaturated fatty acids (convertes some fats into trans fats
Where do trans fats come from?
hydrogenated vegatable oils
Why are trans fats bad?
- they raise blood cholesterol levels more than all other types of fat and promote inflammation
- increase LDL and lower HDL
- not made by body (small amounts can be found naturally in beef and dairy, but it’s a different configuration)
- increases risk of heart disease, stroke, sudden death from heart disease and type 2 diabetes (2g/day)
List common food sources of trans fats.
- margarine, shortening, PB
- deep-fired fast foods
- salad dressing and mayonnaise
- cookies, cakes, crackers, doughnuts
- fried snack and chips
When did Health Canada prohibit partially hydrogenated oils in food in canada?
Sep 15th, 2017 (can longer contain after september 2020)
Where is the only place you can find cholesterol?
Animal products
What 2 sources reflect blood cholesterol? In what amounts?
Endogenous: 2/3 produced by the liver
Exogenous: 1/3 comes from the diet
Is cholesterol an essential nutrient?
No
What has a more severe effect on LDL, dietary cholesterol or saturated fat?
saturated fats
Where is cholesterol found?
in every cell in our body
What does cholesterol do?
- serves as the bulding block for estrogen, vitamin D and testosterone
- major component of brain and nerves
- cannot be used for energy
What is the biggest sources of dietary cholesterol?
Meat
What 2 foods have the most cholesterol?
- 3oz Liver (408mg)
- 1 egg (213mg)
what is the recommended intake of cholesterol?
300 mg/d
