1. Lipids and Lipids and Lipids – Oh My!
Fat
Fatty acid
Steroids
Palmitic acid
Testosterone
Triacylglycerol
Estrogen
Triglyceride
Waxes
Saturated fatty acid
Lard
Unsaturated fatty acid
Omega-3-fatty acids
Monounsaturated fatty acid
Free fatty acids
“Trans fatty acid”
“Butter”
Polyunsaturated fatty acid
“Margarine”
Stearic acid
Olive oil
Oleic acid
Flax seed oil
Oil
“Toasted Sesame oil”
Phospholipid
Bile salts
Cholesterol
“Vegetable shortening”
“Hydrogenated vegetable shortening”
“Partially hydrogenated oil”

2. Lipids Lipids Lipids Relatively insoluble in water (hydrophobic)
Consist mostly of carbon & hydrogen (hydrocarbons)
very few oxygen molecules (thus hydrophobic)
Greasy/oily consistency
Some solid at room temp,
others liquid at room temp
Nutritionally significant forms:
1. Triglycerides (Fats & Oils)
2. Phospholipids
3. Sterols
4. Carotenoids

3. 1) Triglycerides
A.k.a. Are the most abundant lipids (95%) in living organisms
Consist of a glycerol backbone + 3 fatty acids (FA)
Efficient storage form of fuel
Yields twice as many Calories (9 Calories/gm) as carbs
Excess Carbs and excess proteins are converted
into fat and stored as fat
Functions:
Cushion / pad
Retain heat
Make up 50% of cell mem.
Make up certain hormones
Store vitamins A, D, E, K
Provide satiety

4. FAs may be saturated or unsaturated
Solid at room temp
Liquid at room temp
Polyunsaturated FA

5. Lipids contain 2X Calories of Carbs and Proteins.
9 kilocalories/gm

6. extra Calories add up…

7. Most lipids are a mixture of saturated, monounsaturated, and polyunsaturated FAs

8. Making a good thing bad… Hydrogenation
Lipids w unsaturated FAs
typically cheaper
shorter shelf life due to oxidation at points of unsaturation
Tend to be too oily for some recipes
E.g. cookies, muffins, breads…
The Solution: add Hydrogen (by hydrogenation) and “saturate” the unsaturated FAs
Longer shelf life. Slower to turn rancid.
Thicker, more spreadable.
Higher “smoking point.” Less likely to burn.
Sometimes creates trans-fatty acids
Classic e.g. = margarine

9. 2) Phospholipids
Consist of glycerol & 2 fatty acids and a phosphate group
“heads” and “tails”
1o function is to serve as a cell membrane component
Also plays role in emulsification of lipids for digestion
E.g. Lecithin in bile
E.g. transport of lipids in blood

10. 3) Sterols) Consist of rings of carbon atoms Examples: Cholesterol
stabilizer of cell membranes
emulsifier in bile
Some hormones
Testosterone, Estrogen, Progesterone, & Cortisol

11. 4) Carotenoids Plant pigments: usually Orange and yellow
E.g. beta-carotene, lycopene, lutein, many others
Often act as anti-oxidants
May help prevent cell damage leading to cancers
Some are the basis of Vit. A used to produce visual pigment retinal for both day and night vision