Transcript LIPIDS

LIPIDS
Dr. Thomas J. Montville
1
Our plan for the day…
•
•
•
•
Good things about “fat”
Bad things about “fat”
Lipid Chemistry (ugh)
Carbon chains can be saturated or
unsaturated, cis or trans
• Problems with saturated and trans fatty acids
Dr. Thomas J. Montville
2
Good Things About Fats
•
•
•
•
•
•
Concentrated energy source
Stores energy for long term use (fat cells)
Flavor carrier
Heat Transfer - frying
Imparts texture – plasticity, flakiness
Mouthfeel – creamy, smooth
Dr. Thomas J. Montville
3
More good things about fat
•
•
•
•
•
Essential fatty acids (linoleic, linolenic)
Phase transition (solid ↔ liquid)
Carries fat soluble (A,D,E,K) vitamins
Satiety- gastric inhibitory protein
Major component of membranes
Dr. Thomas J. Montville
4
Bad Things About Fat
• Makes you fat!
• Heart disease, high blood pressure, cancer
• Unsaturated fats are reactive free radicals
Dr. Thomas J. Montville
5
Stop and discuss carbon
chemistry
Dr. Thomas J. Montville
6
Fat Structure
Fatty acids are either
saturated, monounsaturated
(contain one C=C double
bond) or polyunsaturated
(contain two or more C=C
double bonds)
Saturated fatty acids
stack closely and are
more solid. Unsaturated
fatty acids are more fluid.
“Hydrogenating”
unsaturated fatty acids
makes them more rigid.
Dr. Thomas J. Montville
7
Fat Structure
1 Saturated Fat – Primarily animal
3. Polyunsaturated Fat - Primarily plant
sources: meat, poultry, milk, butter,
sources: vegetable oils (corn, safflower,
cheese, egg yolk, lard
soybean, sunflower, canola, etc.), margarine
Plant Sources: chocolate, coconut,
(most), mayonnaise, certain nuts (almonds,
coconut oil, palm oil, vegetable
filberts, pecans, walnuts)
shortening
Animal Sources: fish
Dr. Thomas J. Montville
8
Fat Structure
2. Monounsaturated Fat
Sources: avocado, peanuts, peanut butter,
olive/olive oil
Dr. Thomas J. Montville
9
Trans fats, what were they thinking?
Polyunsaturated > monounsaturated
Dr. Thomas J. Montville
10
Trans Fats
• Time Article “Fessing Up to Fats”
Dr. Thomas J. Montville
11
Trans Fat
• Men’s Health Article “The Hidden Killer”
• “It’s a fat that’s difficult to digest so it increases
the amount of bad cholesterol in your blood and
can dramatically boost your risk of heart disease.
If saturated animal fats are unhealthy, trans fats
are far worse.”
• “You’re almost better off eating butter and
bacon.”
• “Harvard scientists estimate that trans fats may
contribute to more than 30,000 premature
deaths per year.”
Dr. Thomas J. Montville
12
Linolenic Acids
Alpha – linolenic acid (omega 3)
Structure of omega-3 fatty acids and omega-6 fatty acids. These fatty acids are
defined by the location of the first double bond.
Dr. Thomas J. Montville
13
Summary of Fats
Saturated
Unsaturated
Single bond (straight)
Solid
Animal (cholesterol)
Flaky
“Unhealthy”
Double bond (kinked)
Liquid
Plants (cholesterol free)
Tenderization
Essential Fatty Acids
and ώ-3s
D.B.s reactive, free
radicals
Chemically stable
Cooling as Solidliquid
Dr. Thomas J. Montville
14
Nutritional Overview of Lipids
• Classification
– Triglycerides – 95% of dietary fat
• 1 glycerol + 3 fatty acids
– Fatty acids
» Short, medium, or long chains
» Saturated (no double bonds)
» Monounsaturated (one double bond)
» Polyunsaturated (> one double bond)
• Omega 3
• Omega 6
– Cholesterol
– Phospholipids
– Energy value 9kcal/g
Dr. Thomas J. Montville
15
Nutritional Overview
• Functions
– Provide energy
– Serve as energy reserve
– Assist in transport and adsorption of fat-soluble
vitamins
– Serve as source of essential fatty acids
– Insulate and protect organs
– Maintain cell walls and play role in making
Vitamin D
Dr. Thomas J. Montville
16
Nutritional Overview
• Food Sources
–
–
–
–
Oils, sauces, spreads, butter
Meat, poultry, fish, eggs, nuts (fish oil for omega 3s)
Milk, cheese, dairy
Breads cereals and grains with added fats
• Recommended Intake
– Less than or equal to 30% of calories from total fat
– Less than or equal to 10% of calories from saturated
fat
– No more than 300 mg cholesterol
Dr. Thomas J. Montville
17
Fats In Food
•Milk: (8 oz. serving)
•Whole: [3-4 % (legal 3.2%)] 150Kcal
•2%: 120 Kcal
•1%: 100 Kcal
•Skim: [<.5%] 90 Kcal
•Cream:
•Heavy (Whipping): 36%
•Light: 18%
•½ & ½ : 10.5%
•Others:
•Mayo: 65% oil, vinegar, sugar, salt, egg yolk
•Salad Dressing: 40% oil
Dr. Thomas J. Montville
18
Dr. Thomas J. Montville
19
Fat Substitutes
• Simplex
– Egg white and milk protein
– very small 0.1 – 0.3uM
– microencapsulated
• Oatrium – from oat bran or flour
• Avicel – microcrystalline cellulose (from wood)
(0 calories)
• Olestra (Olean) polyester sucrose
Dr. Thomas J. Montville
20
Fat Substitutes
• Olestra
– Indigestible
– Lack of ADEK
– Digestive issues
– Anal leakage
Dr. Thomas J. Montville
21
“On the seventh day of Olestra…”
Dr. Thomas J. Montville
22
http://www.zug.com/pranks/olestra
+
Day 1
=
Day 3
Day 5
Dr. Thomas J. Montville
Day 7
23
Take Home: Fats, Oils, Lipids
• Good things about fats
– Concentrated source of energy 9 cal/g
– Flavor carrier
– Imparts texture
– Imparts mouthfeel, phase transiition
– Carries fat soluble vitamins, ADEK
– Major component of membranes
– Satiety
Dr. Thomas J. Montville
24
Take Home: Fats, Oils, Lipids
• Bad things about fats:
• Saturated – solid, animal, leads to cholesterol
• Unsaturated, polyester sucrose,
non-digestible, loss of ADEK
– Makes you fat
– Coronary disease
– Heart disease
– Cancer
Dr. Thomas J. Montville
25
Take Home Points
• Know the good and bad characteristics
of fats and oils
• Saturated vs. unsaturated
– where found, why used
– cis vs. trans
• Fat in Food
–
–
–
–
How much?
What foods?
Different types of oil (general)
Fat free does not equal calorie free
• Fat Substitutes
Dr. Thomas J. Montville
26