Lipids Pre midterm Flashcards
What are the seven functions of lipids?
- Energy! 9kcal/g; takes less energy to store and holds less water than carbohydrates
- Protection
- insulation for body and axons (myelin sheath)
- carries and stores fat soluble vitamins (ADEK) and essential fatty acids
- conversion to other molecules needed by the body such as amino acids, phospholipids, lipoproteins, hormones
etc - makes up the lipid bilayer in the cell
- adds taste, texture and smell to food and aids in satiety (in mouth and stomach) and slows gastric emptying due to release of CCK
What are the basic building blocks of a lipid?
fatty acid; omega end and acid end with carbon chain in
between; can be short, medium, long chain or very long >22
What are lipids made of?
made of carbon, oxygen and hydrogen but less oxygen than carbohydrates
What is the structure of fatty acids?
chains of carbon molecules; every C always has 4 bonds either to C, H, O, or OH
What does it mean when a C chain is saturated?
A C chain is “saturated” eg. when all 4 bonds linked
with all possible hydrogens
When does a C chain become unsaturated
Remove 1 or more H, then a double bond is made (to
keep the 4 bonds) so now it is an unsaturated FA –
(can be mono or poly unsaturated, depending on # of
double bonds)
What is considered a short chain fatty acid?
< 6 C
What is considered a medium chain fatty acid?
6-12 C
What is important to know about medium fatty acids?
not naturally occuring in foods except coconut; can be made synthetically; helpful for lipid malabsorption
What is considered a long fatty acid?
> 12 C
What is considered a very long fatty acid chain?
> 22 C
What are some things to know about saturated fatty acids?
- solid at room temperature (can stick to artery walls)
- found mostly in animal products
- generally less healthy
- can use in frying etc.
- food don’t spoil as easily; more stable
What are some things to know about unsaturated fatty acids?
- liquid at room temperature less tendency to oxidize on artery walls
- found mostly in plant foods
- generally more healthy
What is an example of naming of a fatty acid?
C18 omega 3 polyunsaturated fatty acid
Which fatty acids are essential in a diet? why?
- omega 3 and 6 FA
- body can’t make the double bonds at the 3 and 6
carbon
How are trans fatty acids made?
made by the process of hydrogenation
What does hydrogenation do?
Hydrogenation makes a liquid oil into a semi
solid (spreadable fat) by breaking bonds and adding H in a trans formation
What does hydrogenation do to food?
Increases shelf life and improves consistency of foods but increases health risks
What are some pros of Butter compared to margarine?
- All natural, right from the cow, maybe salt added
- Tastes great!
- CLAs (conjugated linoleic acid; naturally occurring trans fats found in dairy products and help prevent
cancer)
What are some cons of Butter compared to margarine?
Animal fat; saturated
What are some pros of margarine compared to butter?
- Non-hydrogenated
- mostly veg. oil with a bit of saturated fat added; beta
carotene added for colour - Plant fat; unsaturated
- Choose ones made with plant oils with more omega 3
fats and less omega 6 eg. canola
What are some cons of margarine compared to butter?
Hydrogenated; trans fats! (don’t buy these ones!)
Which fatty acids should you have more often?
- all plant food sources such as oils, nuts, seeds, avocados, except tropical oils as more saturated
- choose lean meats, poultry, eggs, fish, cheese, dairy
Which fatty acids should you have less often?
processed meats such as bacon, salami, hot
dogs and sausages, high fat cheeses, any foods with
hydrogenated oils and tropical oils
Why is omega 3 fatty acid essential for our body?
- makes hormones involved in heart and immune system functioning
- parts of cells of cerebral cortex and retina
- heart health, mental/brain health, and decreased inflammation
Where is omega 3 found?
found in canola, soybean, flax and walnut oils, human milk, cold water fatty fish and fortified foods
Why is omega 6 fatty acid essential for our body?
- play a role in cell membrane formation
In what foods can omega 6 fatty acids be found?
-found in nuts, seeds, whole grains, leafy greens, vegetable oils eg. sunflower, safflower, corn oils
- in processed foods
What happens if you have too much omega 6 fatty acids
too much fosters systemic inflammation and
increased health risk
What does it mean that Omega 3s are more unstable?
can’t heat as high eg. canola but high omega 3 oils like flax need to be kept in dark and cold
Concerns re fish oil supplements?
Possible contaminants, unbalanced, “food first
approach”
What is the best source of Omega 3?
FISH
What are the best oils for omega 3?
- flax
- fish
- canola
- walnut
- grapeseed
Cis vs trans fatty acids formation?
Cis fatty acid has both hydrogen atoms located on the same side. On the contrary, trans fatty acid has the two hydrogen atoms on opposite sides. Fatty acids with cis configuration are typical in natural foods. Most of the trans fatty acids are formed during the process of hydrogenation of vegetable oils.
Omega 3 fortified foods?
margarine, yogurts, eggs, soy milks,
granola bars, breads, juices etc.
What are the “family” of omega 3 fatty acids that foods can be fortified with?
ALA, DHA, and EPA
What is there to know about ALA, DHA, and EPA?
- ALA easier to get in diet but it must be converted in body
- DHA and EPA harder to get in diet but are the best kind as they are readily usable by the body
What do ALA, DHA, and EPA stand for?
- Alphalinolenic acid
- Docosahexaenoic acid
- Eicosapentaenoic acid
What is a weekly recommendation to get enough omega 3 in the diet?
2 servings of cold water fatty fish recommended per week
Lables with how much trans fat are allowed to say they are trans fat free? What is the issue with this?
< .2
- people who eat a lot of pkg food then could still consume quite a bit during a day
What are triglycerides? How are they made and stored? Are high tri levels bad?
- most common type of fat in food and stored in the body
- 3 fatty acids + 1 glycerol
- made from excess carbohydrates, fats, and/or protein
- stored in fat tissue
- high triglyceride levels in blood are a health risk