CFB 7 - Nutrition: Dietary Fats

1. Provide energy (9kcal/g)

2. Carrier for fat-soluble vitamins/aid absorption

3. Cell structure (bilipid membrane, integrity, permeability)

4. Physiological processes (tissue/skin/hair, hormones, vascular wall maintenance and immune response)

5. Palatability of food (taste, flavor, texture, satiety)

6. Insulation & cushion

What are the 6 functions of fats?

True - 9kcal/g vs. 4kcal/g

T/F - Fats provide more energy than CHO and protein

Made up of glycerol plus 3 fatty acids - when we say "fats" we are referring to triglycerides

What does Triglyceride mean?

Limit CHO intake to 45-50% intake (CHO raise triglycerides and lower HDL)

decrease alcohol and smoking

decrease saturated fat

increase activity

How do you improve triglyceride level

• sterols/steroids (cholesterol, estrogen, testosterone)

• phospholipids: glycerol + 2 FA + phosphate

• triglycerides (fat): glycerol + 3 FA

3 types of lipids

Saturated fats, Unsaturated (MUFA/PUFA), CIS VS. TRANS FATTY ACIDS

4 different kinds of fats

Liquid at room temp (oil), cause a bend because hydrocarbon chain on SAME side as double bond

Cis fatty acids are commonly...

Hydrocarbons are on OPPOSITE side of double bond

-increase risk of CVD

-solid at room temp

-formed during the process of artificial hydrogenation

Trans fatty acids....

Produces trans fats (ex. partially hydrogenated soybean oil)

Why?

1. cheaper to produce solid fats at room temp

2. allows fats to be heated at higher temps without smoking

3. makes flaky pies

4. increases shelf life

Natural soybean oil is polyunsaturated and liquid at room temp (bad for baking), double bonds are susceptible to oxidative attack (spoiling).

What does artificial saturation/hydrogenation produce? Why are they made?

False - means >.5g trans fat, can still contain partially hydrogenated oils!

T/F: 0g trans fat means not trans fat

Banned as of June 2018 in restaurants and grocery foods

What does the FDA say about artificial trans fats?

False - most lipids we consume are made of a combination of different percentages of saturated and unsaturated fats.

T/F: Most lipids we consume are made up of either saturated and unsaturated fats, never both

Solid at room temp & found in animal products, raises blood cholesterol, recommended

What do saturated fats do? Found where? Recommended consumption?

• Synthesized by body for cell membrane, vitamin D, bile synthesis, hormones, nerve sheath

• Body has a feedback mechanism to control amounts

• Available from shrimp, egg yolk, cheese, organ meats

• Limit to <300 mg/day

Cholesterol

FALSE - type of FA you eat affects blood cholesterol levels more!!!

T/F - amount of cholesterol you eat directly affects your blood cholesterol levels

20-35% of total calories from FAT

Dietary guidelines for fats (4 percentages)

2 years and up, limit to less than 10% daily calories from saturated fat (replace with unsaturated, PUFA is best)

5% total calories in nutrient dense foods are from saturated fat

Little room for additional saturated fats within limits of calories/fat guidelines

Trans fats and dietary cholesterol should be as low as possible without compromising nutrition

Dietary guidelines for saturated fats (4)

Sugar! Common theme in decreasing fat and having to replace it with something else

Fro-yo has less fat but more ____

Heavy cream -> whipping cream -> light cream -> half and half

Fattiest -> least fatty milk

VLDL, IDL, LDL, HDL

What are the different kinds of fats circulating the body?

Sandwiches (19%), Desserts/sweets, (11%) milk/yogurt, rice/pasta/grain, pizza, meat, chips, cheese, vegetables

What are some of the top sources for saturated fat?

Very low density lipoproteins

-eventually converted to LDL

What is this

Intermediate density lipoprotein

-converted to LDL

What is IDL

"Bad cholesterol"

Low Density Lipoprotein

Primary cholesterol transport from liver to tissues

High correlation with total serum cholesterol levels

Highly atherogenic, readily oxidized

LDL

MUFA (monounsaturated fatty acid) &

PUFA (polyunsaturated fatty acid)

Two types of unsaturated fats

1 C=C bond

Found in plant based products (olive/avocado/canola oil, peanuts, peanut butter)

What is MUFA

decrease triglcyerides/LDL

Increase HDL

Little effect on cholesterol

Effects of MUFA on triglycerides/ldl/cholesterol/HDL

2 C=C bond

-liquid at room temp

What is PUFA

1. Omega 3 fatty acids - brain, nerves, retina, immunity

2. Omega 6 fatty acids - skin, growth, reproduction

3. Trans fatty acids (ie. trans fat)

3 major PUFAs to know about

True

T/F: DECREASING saturated fat is 2x as effective as INCREASING PUFAs

Decreases cholesterol and LDL

Increases HDL

Effects of PUFA on cholesterol, LDL, HDL

Benecol

Which of two is the following description correct for: Olestra or Benecol?

• stanols and sterols

• plants that extract lower cholesterol

• low in sat/trans fat

• Not recommended for pregnant, breastfeeding, children under 5

Olestra

Olestra or Benecol?

-sucrose/fatty acid composition

-found in most fat-free chips

-no calories

-binds fats & excretes them

-has disadvantages: greasy stools, deficiency in fat soluble vitamins, cramping

True

T/F Emulsification by bile acids essential in interaction with lipases & for lipid digestion and absorption

High density lipoprotein

"Good cholesterol"

Scavenges lipids from artery walls

Associated with LOWER risk of heart attack

What is HDL

Can interfere with blood clotting

- be careful with fish oil supplements

Can reduce risk of sudden death

Best sources: fatty fish from cold water, canola oil, soy oil

Omega 3 fatty acids

• Periodontal disease (inflammatory disease, omega 3 fatty acid can be helpful for anti-inflammatory/anti-bacterial)

• Dental caries: fats act as a protective layer of tooth surface

  • Prevent adherence of carbohydrates

  • Enhances clearance of sugars from mouth

How do fats impact oral health?

True

T/F: fats can prevent adherence of carbohydrates to teeth & clearance of sugars from mouth

False, Saturated fatty acids more prevalent in solid fats

T/F: MUFA and PUFA dominated in solid fats

True

T/F: MUFA and PUFA more prevalent in oils at liquid form

1. Linoleic acid - Omega 6

2. Linolenic - Omega 3, precursor for DHA and EPA (supplemented in baby products)

3. Arachidonic acid - synthesized from linoleic

What are the three essential fatty acids?

Visual probs, neuropathy, dry skin, decreased growth in children, infection susceptibility, poor wound healing

Essential FA deficiency characterized by...(6)

INTAKE OF FATTY ACIDS:

SOURCES: fish, vegetable oil, nuts, flax seeds (Aka omega 6 & omega 3)

Essential FA deficiency can be resolved by

False - they are important for growth!!

T/F: Kids under age 2 can be put on low fat diets

1. eat

2. chew (mechanical digestion, small component)

3. stomach (gastric lipase, small component)

4. emulsification in duodenum by bile acids (essential, interaction with lipases)

- Bile from gallbladder breaks up the "blob"

- Lipases from intestine and pancreas can easily break down the fat into FAs

Four steps in fat digestion/absorption

False, duodenum

T/F Emulsifcation by bile acids occurs in the stomach

Chylomicron -> liver -> VLDL —> adipose tissues-> LDL -> other tissue -> HDL -> back to liver

Pathway of fat to other tissues

Passive diffusion into enterocyte -> package into chylomicron -> delivery of triglyceride to tissue

Steps of absorption

LDL (bad cholesterol, from VLDL & IDL)

- primary cholesterol transport from liver to tissue, readily oxidized

- high correlation with total serum cholesterol levels

HDL (good cholesterol)

Which types of lipoproteins have the most cholesterol?

Won't dissolve in blood (surrounded by cholesterol, protein, and phospholipids) - blood and oil don't mix well

Why are fats packaged into chylomicrons?

More protein - higher density

More lipid - lower density

Serum lipid levels named based on the ratio!

What does high/low density mean?

Increased by excercise, weight loss, antioxidants

What can increase HDL?

Alpha linolenic acid

Lineolic acid is to omega 6, as ______________ is to omega 3

False, require FDA approval

T/F fat substitutes require FSIS approval

corn syrup (sugar), partially hydrogenated vegetable oil

In non dairy creamer, fat is replaced with what?

Increase: trans fats!! & saturated fats

Decrease: MUFA & PUFA

What types of fats increase mortality? Decrease mortality?

Carries excess cholesterol back to the liver

Why is HDL the "good cholesterol"

Carries cholesterol TO the cells

Why is LDL the "bad" cholesterol?