NUTR Exam 2 LIPIDS

What remain the leading cause of death in the United States?

Lipids.

What are the 3 major lipid classes?

Phospholipids, sterols (cholesterol), triglycerides

Sterols stand for

cholesterol

What are the 4 functions of cholesterol?

Cell membranes, bile acid synthesis, steroid hormone synthesis, vitamin D synthesis.

What are the 2 sources of cholesterol?

Endogenous Cholesterol: Cholesterol made inside the body

Exogenous Cholesterol: Cholesterol obtained from outside the body

What is the rate limiting enzyme for Endogenous Cholesterol?

HMG CoA

Where can you obtain exogenous cholesterol?

From animal sources only

Where is endogenous cholesterol synthesized?

In the liver. (800-1500 mg/day)

What is a lipid panel?

A common blood test used in medical screening for risk of CVD.

Many products of lipid digestion are ____, whereas the interior of the enterocyte and circulatory system are ____.

hydrophobic; hydrophilic

What are lipoproteins?

Spherical particles made up of varying amounts of triglycerides, cholesterol, cholesterol esters, phospholipids, and proteins.

Which one is bad cholesterol, and which one is good cholesterol?

LDL (low density lipoprotein) is BAD cholesterol, HDL (high density lipoprotein) is GOOD cholesterol!

How do lipoproteins relate to CVD?

May impact the accumulation of cholesterol and fatty deposits in the arteries.

Which parts of the body make lipoproteins that circulate lipids in the body?

The small intestine and liver

The small intestine makes ____ for the transport of dietary fat to the cells

chylomicrons

What type of cholesterol is associated with increased CVD risk?

LDL cholesterol, the bad cholesterol.

Why is LDL cholesterol known as the bad cholesterol?

Because LDL cholesterol goes from a very low density lipoprotein delivering dietary and other fatty acids to a low density lipoprotein delivering cholesterol to the cells. Can increase build up of plaque.

T/F: The small intestine makes HDL to a greater extent to the liver.

False, it makes less.

Why are HDL’s (high density lipoproteins) considered good?

They pick up (scavenging) excess cholesterol from cells

What type of cholesterol is associated with decreased CVD risk?

HDL (high density lipoproteins)

Statin drugs increase/decrease blood cholesterol by

Decrease; inhibiting one of the enzymes (HMG CoA reductase) needed for synthesis. Lowers cholesterol by decreasing cholesterol production and increasing the liver’s ability to remove the LDL cholesterol already in the blood.

Which enzyme controls the rate of cholesterol production in the body?

HMG-CoA reductase

Triglycerides are a lipid consisting of what 2 components?

A glycerol backbone molecule attached to 3 fatty acids.

What are the 2 sources of triglycerides?

Dietary fat (oils, whatever) and adipocyte (fat cells)

What are the 3 types of fatty acids?

Saturated Fatty Acids (SFA), Polysaturated Fatty Acids (PUFA), Monounsaturated Fatty Acids (MUFA)

The structure of a saturated fatty acid has what two types of ends?

A methyl/omega end and a carboxylic acid/alpha end. The degree of saturation is a single carbon bond.

What are the dietary sources of saturated fatty acids? (SOLID)

Lard, fat in beef, pork, lamb

What are the dietary sources of saturated fatty acids? (SOFT OR LIQUID)

Milk fat (butter), coconut, palm & palm-kernel oils

A high intake of SFA increases what type of cholesterol levels in your blood, leading to an increase of risk of heart disease and stroke?

LDL (bad cholesterol)

What are the recommendations for SFA intake?

< 7-10% of total calories

< 10% of calories for general population

< 7% of calories for individuals with history of CVD

In a 2700 calorie diet, how much SFA should an individual both with and without CVD consume? IN GRAMS!!

Without CVD: 30g

2700(0.1)=270 cal/9 → 30g

With CVD: 21g

2700(0.07)=189g/9→21g

How do you convert calories to grams?

Divide calories by 9 to get grams

A 30 y/o male presents to you for general nutrition information on CVD prevention. He is particularly interested in his SFA intake. He reports a significant family history of CVD. You determine that his calorie intake needs are 3000cal/day. What would your recommendations for calories/grams of SFA be for this client based on current guidelines for SFA intake in individuals with CVD history?

23gm, 210 cal

What is the structure (the 2 ends plus the bond) of a monounsaturated fatty acid?

Omega end, one double bond, and an alpha end.

What are the dietary sources of MUFA’s (monounsaturated fatty acids)

Main sources are olive oil, canola oil, peanut oil, nuts, seed, avocado, poultry. The physical characteristic is thick liquid or soft at room temperature.

What are the health effects of MUFA’s (monounsaturated fatty acids)

Increase the HDL-C levels in the blood and reduce your risk of heart disease and stroke

Why is olive oil something good to eat?

B/c it’s a MUFA, meaning it raises HDL-C levels (good cholesterol) and reduces risk for CVD and stroke.

To get the benefits of olive oil, ___ may be best

fresh

What diet do you follow to increase your MUFA intake?

Mediterranean diet. The traditional diet features olive oil as the main fat, abundant fruits and veggies, whole grains, beans, nuts, and seeds, a daily intake of small amounts of cheese and yogurt, weekly fish intake, limited use of eggs and red meat, regular exercise and rest, moderate wine intake.

What is the structure of a PUFA? (The ends + the bonds)

Omega end, more than.2 double bonds, and an alpha end.

What are the dietary sources of PUFA’s (polyunsaturated fatty acids)?

Sunflower oil, corn oil, safflower oil, fish oil, nuts oils. Physical characteristic is a liquid.

What are the 2 essential PUFA’s?

Omega-3 fatty acids and omega-6 fatty acids

What are eicosanoids?

Signaling molecules which regulate many physiological processes.

Essential fatty acids serve as precursors to

Eicosanoids: Signaling molecules which regulate many physiological processes.

Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA)

Eicosapentaenoic acid (EPA) is derived from what and then converted to what?

Omega-3 fatty acids (alpha linoleic acid) is converted to omega 3 eicosanoids, which are anti inflammatory and inhibit platelet aggression

What is another name for omega-3 fatty acids and omega-6 fatty acids? How can you remember?

Omega 3 Fatty Acids: Alpha-linoleic acid (the first double bonds is located on the 3rd carbon) (alphas are always first)

Omega 6 Fatty Acids: Linoleic acid (the first double bonds is located on the 6th carbon)

What are the sources of omega 3 fatty acids?

ALA (flaxseed, walnuts, chia seeds, avocado, oils: soybean, canola)

EPA/DHA (cold water fish: salmon, tuna, sardines, mackerel)

The benefits of Omega 3 FA in the world of heart disease are that

They are

• Anti-inflammatory

• Decrease platelet aggregation (excessive blood clotting)

• Decrease LDL levels

• Increase HDL levels

What is the precursor of omega-6 fatty acids?

Arachidonic acid

The function of omega-6 eicosanoids are that ____ acid is derived from omega 6 fatty acids and converted to omega 6 eicosanoids to be

Arachidonic Acid; Pro inflammatory and pro aggregatory

What are food sources for omega-6 fatty acids?

• Vegetable oils: safflower, sunflower, and corn

• Beef/Poultry

• Nuts/seeds

ARA and EPA compete for ____ for conversion into eicosanoids

enzymes

Why should you emphasize omega-3 fatty acids in the diet?

Omega 3 fatty acids reduce inflammation and inhibit platelet aggregation. In contrast, omega 6 fatty acids promote inflammation and increase platelet aggregation.

What is hydrogenation?

Adding hydrogen to polyunsaturated fats. Decreases potential for oxidation and increases shelf life.

What differs in the structure of a cis fatty acid vs a trans fatty acid?

Cis fatty acids have hydrogens on the same side of the fatty acid backbone, whereas hydrogens are on opposite sides of the fatty acid backbone.

T/F: Trans fatty acids do not increase the risk of CVD.

F. Trans fatty acids DO increase the risk of CVD

What do trans fatty acids do in relation to increasing the risk of CVD?

Increase LDL, lower HDL, and increase inflammation.

How can you decrease trans fats in your diet?

Choose processed foods that don’t use trans fats and are low in saturated fat.

Is it possible for a good product to list the amount of trans fat as 0g on the nutrition facts label if the ingredient list indicates that it contains “partially hydrogenated vegetable oil”?

Yes.

What are some sources of trans fat?

Packaged snacks like cookies, chips, crackers

Fried foods

Fast food

Baked goods made with stick margarine or shortening

Frozen foods

Non dairy creamers

What FA’s increase LDL levels?

SFA, trans fatty acids

What FAs and Type of Fiber decrease LDL levels?

MUFA, PUFA (omega 3 fatty acids), Dietary soluble fiber

How can you increase HDL levels?

Adequate omega 3 fatty acids intake

Emphasize use of MUFA fats in the diet intake

Moderate red wine consumption

What occurs during a myocardial infarction?

Necrosis of myocardial cells secondary to ischemia. Necrotic cardiac cells do not regenerate and are replaced by scar tissue.

T/F: Damage to the myocardium is irreversible.

T.

Who are the chief contributors of saturated and omega-6 fatty acids in the US?

animal products, LDL, increased inflammation