““Chapter 3: Lipids”Chapter 3: Lipids”

Mmmmm…fat.Mmmmm…fat.

The good, the bad, and the The good, the bad, and the artery-cloggingartery-clogging

Do You Ever…Do You Ever…

Think of fats as unhealthy foods that are Think of fats as unhealthy foods that are best eliminated from the diet?best eliminated from the diet?

Wonder about the differences between Wonder about the differences between “good” and “bad” cholesterol?“good” and “bad” cholesterol?

Choose fish for health’s sake without Choose fish for health’s sake without fully knowing why?fully knowing why?

Recognize invisible fats in your foods?Recognize invisible fats in your foods?

Let’s say…Let’s say…

Your bill from a lab reads “Blood Your bill from a lab reads “Blood lipid profile: $250.”lipid profile: $250.”

Your doctor tells you that your Your doctor tells you that your blood cholesterol is high.blood cholesterol is high.

The doc also tells you to cut The doc also tells you to cut down on saturated fats.down on saturated fats.

But what does it all mean?But what does it all mean?

Intro to the LipidsIntro to the Lipids

““The lipids in foods and in the The lipids in foods and in the human body fall into three human body fall into three classes.”classes.”

Each of these are stored in Each of these are stored in different parts of the body, different parts of the body, and found in different foods.and found in different foods.

““About 95% are About 95% are triglycerides.”triglycerides.”

““The rest are phospholipids The rest are phospholipids and sterols.”and sterols.”

(Cholesterol is the best (Cholesterol is the best known)known)

Some of these names may Some of these names may sound familiar…we’ll discuss sound familiar…we’ll discuss them in more detail later.them in more detail later.

What are fat’s What are fat’s uses in the body?uses in the body?

““Fat is the body’s chief storage Fat is the body’s chief storage for the energy from food eaten in for the energy from food eaten in excess of need.”excess of need.”

Evolutionarily, if you didn’t know Evolutionarily, if you didn’t know where your next meal was where your next meal was coming from, it made sense to coming from, it made sense to store extra.store extra.

““Most cells store Most cells store limited fat.”limited fat.”

““Fat cells are Fat cells are specialized and specialized and can expand can expand almost almost indefinitely.”indefinitely.”

So the more fat So the more fat they store, the they store, the larger they grow.larger they grow.

These aren’t just sacks of fat, These aren’t just sacks of fat, though!though!

““Adipose (fat) tissue secretes Adipose (fat) tissue secretes hormones that regulate hormones that regulate appetite and influence other appetite and influence other body functions.”body functions.”

So these cells are, indeed, So these cells are, indeed, important to our health.important to our health.

Why not just store energy in Why not just store energy in carbs?carbs?

Glycogen (sugar storage) holds Glycogen (sugar storage) holds a great deal of water, so it is a a great deal of water, so it is a bulky, heavy molecule.bulky, heavy molecule.

Fats pack tightly together, and Fats pack tightly together, and store more energy in a small store more energy in a small space.space.

What else does fat do?What else does fat do? ““Pads of fat Pads of fat

surround and surround and protect our vital protect our vital organs.”organs.”

This is why we This is why we are very durable are very durable and aren’t and aren’t injured easily.injured easily.

““Fat under the skin insulates Fat under the skin insulates us.”us.”

This protects us from both hot This protects us from both hot and cold, like a thermos.and cold, like a thermos.

““It is also part of our cell It is also part of our cell membranes.”membranes.”

““Fat is needed to absorb Fat is needed to absorb vitamins A, D, E, and K, which vitamins A, D, E, and K, which are fat-soluble.”are fat-soluble.”

This means that they only This means that they only dissolve into fat.dissolve into fat.

““Our bodies make molecules Our bodies make molecules from essential fatty acids from essential fatty acids (part of fat).”(part of fat).”

So our fat is absolutely vital!So our fat is absolutely vital!

Usefulness of Fats in Usefulness of Fats in FoodFood

The energy density of The energy density of fat makes it valuable fat makes it valuable in some situations.in some situations.

A hunter or hiker can A hunter or hiker can carry fat calories carry fat calories easier than carb easier than carb calories, because fat is calories, because fat is lighter.lighter.

Fat is naturally appealing to us, Fat is naturally appealing to us, because evolutionarily, we because evolutionarily, we needed calories!needed calories!

Fat also adds tenderness to Fat also adds tenderness to meats and baked goods.meats and baked goods.

““Fat contributes to satiety, Fat contributes to satiety, feeling full after a meal.”feeling full after a meal.”

The fat triggers a physiological The fat triggers a physiological response that slows digestion response that slows digestion and stops us from eating more.and stops us from eating more.

Although fat in the stomach Although fat in the stomach signals us to stop eating,signals us to stop eating,

The taste of fat tells us to The taste of fat tells us to keep eating, so it is possible keep eating, so it is possible to overeat easily.to overeat easily.

A Closer Look At FatA Closer Look At Fat ““FatFat usually refers to usually refers to

triglycerides.”triglycerides.” ““Made of three fatty acids and Made of three fatty acids and

one glycerol molecule.”one glycerol molecule.”

Tissues all over the body can Tissues all over the body can assemble or disassemble these assemble or disassemble these triglycerides as needed.triglycerides as needed.

““Fatty acids differ in two ways:”Fatty acids differ in two ways:” ““Chain length”Chain length”

““and degree of saturation.”and degree of saturation.” Saturated, unsaturated…Saturated, unsaturated…

more about that in a minute.more about that in a minute. Usually, triglycerides contain Usually, triglycerides contain

a mixture of different fatty a mixture of different fatty acids.acids.

““The shorter the chain, the The shorter the chain, the softer and more liquid the softer and more liquid the fat.”fat.”

So vegetable oils have So vegetable oils have shorter molecule chains;shorter molecule chains;

Beef fat has a longer chain of Beef fat has a longer chain of fatty acids.fatty acids.

This does matter!This does matter!

““Each species of animal makes Each species of animal makes different triglycerides.”different triglycerides.”

This is governed by genetics.This is governed by genetics. Fats in the diet can affect which Fats in the diet can affect which

triglycerides are made, because triglycerides are made, because the fatty acids we eat are often the fatty acids we eat are often incorporated into our incorporated into our triglycerides in the body.triglycerides in the body.

Remember, you are what you Remember, you are what you eat!eat!

Saturated vs. Unsaturated Saturated vs. Unsaturated Fatty AcidsFatty Acids

Saturation: whether or not a Saturation: whether or not a fatty acid chain is holding all fatty acid chain is holding all of the hydrogen atoms it can of the hydrogen atoms it can hold.hold.

““If every available bond is If every available bond is holding a hydrogen molecule, holding a hydrogen molecule, that chain is a saturated fatty that chain is a saturated fatty acid.”acid.”

Sometimes, in the fats of plants Sometimes, in the fats of plants and fish, this chain has a place and fish, this chain has a place where hydrogens are missing.where hydrogens are missing.

““A chain with one missing A chain with one missing hydrogen is monounsaturated.”hydrogen is monounsaturated.”

““A fat with two or more A fat with two or more missing hydrogens is missing hydrogens is polyunsaturated.”polyunsaturated.”

All of this affects the point at All of this affects the point at which that fat melts.which that fat melts.

““The more unsaturated, the The more unsaturated, the more liquid it is at room more liquid it is at room temperature.”temperature.”

So since beef fat is solid, it has So since beef fat is solid, it has lots of saturated fat.lots of saturated fat.

Since chicken fat is softer, it Since chicken fat is softer, it has less saturated fat.has less saturated fat.

A good way to tell if it is A good way to tell if it is healthy!healthy!

The CatchThe Catch Some liquid plant oils are still high Some liquid plant oils are still high

in saturated fat. (coconut, palm)in saturated fat. (coconut, palm) How do we tell?How do we tell? ““Refrigerate oil: if it turns cloudy, it Refrigerate oil: if it turns cloudy, it

has more saturated fat.”has more saturated fat.” One exception is olive oil: although One exception is olive oil: although

only mono-, good for you!only mono-, good for you!

Where the Fatty Acids are Where the Fatty Acids are FoundFound

““fish, veggies: polyunsaturated”fish, veggies: polyunsaturated” ““some veggies (canola, olive): some veggies (canola, olive):

monounsaturated”monounsaturated” ““meat: most saturated”meat: most saturated” Beware: veggie fat can contain Beware: veggie fat can contain

trans fat…dangerous! (More trans fat…dangerous! (More later)later)

What’s so great about olive What’s so great about olive oil?oil?

Rich in Rich in antioxidant antioxidant phytochemicalsphytochemicals

Excellent Excellent replacement replacement for butter and for butter and other animal other animal fatsfats

““Some Special Fats”Some Special Fats”

““Phospholipids (PPLs) and Phospholipids (PPLs) and Sterols”Sterols”

““PPLs have two fatty acid chains PPLs have two fatty acid chains instead of three, and a instead of three, and a phosphorus molecule.”phosphorus molecule.”

Why does this matter?Why does this matter? ““It is water- and also fat-It is water- and also fat-

soluble.”soluble.” So it dissolves in both water and So it dissolves in both water and

fat. Why do we care?....fat. Why do we care?....

““Manufacturers use PPLs Manufacturers use PPLs as an emulsifier to blend as an emulsifier to blend fats and water.”fats and water.”

One of the most One of the most common on labels: common on labels: lecithinlecithin

Used in mayo to blend Used in mayo to blend vinegar and eggsvinegar and eggs

““Sterols are rings of carbon Sterols are rings of carbon atoms with hydrogens and atoms with hydrogens and oxygens attached.”oxygens attached.”

Cholesterol is the best known.Cholesterol is the best known. Good cholesterol is vital to cell Good cholesterol is vital to cell

membrane structure; bad membrane structure; bad cholesterol clogs arteries.cholesterol clogs arteries.

What is the difference?What is the difference? ““Low-density lipoproteins Low-density lipoproteins

(LDL) are carriers of (LDL) are carriers of cholesterol to the tissues.”cholesterol to the tissues.”

These are larger, lighter, and These are larger, lighter, and richer in cholesterol.richer in cholesterol.

““High-density lipoproteins High-density lipoproteins (HDL) carry cholesterol away (HDL) carry cholesterol away from tissues, to the liver for from tissues, to the liver for disposal.”disposal.”

These are lighter, smaller, These are lighter, smaller, and contain more protein.and contain more protein.

So both contain the same So both contain the same cholesterol…what’s with the cholesterol…what’s with the goodgood and and badbad??

We’ve come to call them We’ve come to call them good and bad cholesterols, good and bad cholesterols, when cholesterol is when cholesterol is cholesterol.cholesterol.

The key is, “LDL carries lipids The key is, “LDL carries lipids that trigger inflammation and that trigger inflammation and contribute to heart disease.”contribute to heart disease.”

““HDL proteins oppose HDL proteins oppose inflammation and protect inflammation and protect against heart attack.”against heart attack.”

Therefore, elevated LDL in Therefore, elevated LDL in the blood warns of an the blood warns of an increased heart attack risk;increased heart attack risk;

Elevated HDL points to a Elevated HDL points to a reduced risk.reduced risk.

These numbers are SO These numbers are SO important to health!important to health!

So how do we change our So how do we change our numbers?numbers?

““LDL can be lowered by LDL can be lowered by avoiding saturated fat and avoiding saturated fat and trans fat.”trans fat.”

Happily, the national Happily, the national cholesterol level is dropping!cholesterol level is dropping!

But heart disease is still this But heart disease is still this country’s top killer.country’s top killer.

““We should choose a diet We should choose a diet with less than 10% of calories with less than 10% of calories from saturated fat.”from saturated fat.”

LDL Cholesterol RisksLDL Cholesterol Risks

How do we raise HDL?How do we raise HDL?

““Diet rarely raises HDL; regular Diet rarely raises HDL; regular exercise works better.”exercise works better.”

Although some foods, like olive Although some foods, like olive oil, fiber, fish, and nuts can help.oil, fiber, fish, and nuts can help.

Remember HDL = Happy DL Remember HDL = Happy DL

Coming soon…Coming soon…

More about fat!More about fat!