Lecture Discovering nutrition - Chapter 5: Lipids, not just fat

After studying this chapter you will be able to understand: What are lipids? fatty acids are key building blocks, triglycerides, phospholipids, sterols, lipid digestion and absorption, transportation of lipids in the body, recommendations for fat intake, lipids and health.

Chapter 5

Lipids:

Not Just Fat

What Are Lipids?

throughout the body

food

Lipids Include…

Fatty Acids Are Key Building Blocks

Fatty Acids Are Key Building Blocks

Fatty Acids Are Key Building Blocks

Fatty Acids Are Key Building Blocks

– Saturated fatty acids

• All single bonds between carbons – Unsaturated fatty acids

• One or more carbon bonds is a double bond

– Fats with more double bonds are generally

more liquidy

Fatty Acids Are Key Building Blocks

Trans Fat

LDL (“bad”) cholesterol, and lower HDL

(“good cholesterol”), promote systemic

inflammation, and increase triglycerides in

your blood

substitute for soldiers

“healthier and cheaper butter”  food

scientists decided to hydrogenate

vegetable oil to solidify them

Fatty Acids are Key Building Blocks

Fatty Acids Are Key Building Blocks

– Omega-3 (alpha-linolenic acid)

– Omega-6 (linoleic acid)

adipose tissue

food

flavor, odor, and texture

Triglycerides in Food

increases availability of calorie-rich oils

extend shelf life

Triglycerides in Food

phospholipids, plant sterols, and other phytochemicals

increases the proportion of trans fatty acids

• Functions

membranes

environments of blood and cell fluids

water-soluble substances into the cell

carry lipid particles to their destinations

in the body

emulsifier to combine

two ingredients that

don’t ordinarily mix,

such as oil and water

salad dressing to mix

well and remain

mixed, for example

Phospholipids in Food

much smaller amounts than triglycerides

peanuts

Sterols

Sterols in Food

250-700 mg of cholesterol and 250 milligrams of plant sterols per day

Lipid Digestion and Absorption

diglycerides and free fatty acids

break down the fats for absorption

acids into the bloodstream

Lipid Digestion and Absorption

core

fatty acids to microvilli

enterohepatic circulation

Lipid Digestion and Absorption

cells and liver

Lipid Digestion and Absorption

cholesterol

absorption

Transportation of Lipids in the Body

lipoprotein carriers in order

to travel in the bloodstream

density, and the

composition of their lipid

cores

Transportation of Lipids in the Body

raw material for

very-low-density lipoproteins

Transportation of Lipids in the Body

Transportation of Lipids in the Body

Transportation of Lipids in the Body

Transportation of Lipids in the Body

Recommendations for Fat Intake

cholesterol

fat

Recommendations for Fat Intake

calories

acids

• Seafood (fatty fish), canola or soybean oil

Recommendations for Fat Intake

fat

Americans consuming more total grams of fat

• Cheese, pizza, grain-based desserts, chicken, sausage, etc

Recommendations for Fat Intake

• Role of fat replacers

• Sucrose + fatty acids

• Indigestible— provides no calories

• Reduces absorption of fat-soluble vitamins

Lipids and Health

Lipids and Health

• Reducing heart disease risk

– AHA diet and lifestyle recommendations

• Consume an overall healthy diet

• Aim for a healthy body weight

• Aim for a desirable lipid profile

• Aim for normal blood pressure

• Aim for normal blood glucose levels

• Be physically active

• Avoid use of and exposure to tobacco products

Lipids and Health

• Reducing heart disease risk

– AHA recommendations

• Balance calorie intake and physical activity

to achieve or maintain a healthy body weight

• Consume a diet rich in fruits and vegetables

• Choose whole-grain, high-fiber foods

• Consume fish, especially oily fish, at least twice a week

• Limit your intake of saturated and trans fat

and cholesterol

Lipids and Health

• Reducing heart disease risk

– AHA recommendations (cont.)

• Minimize your intake of beverages and foods with added sugars

• Choose and prepare foods with little of no salt

• If you consume alcohol, do so in moderation

• Follow the AHA recommendations when eating outside of the home

Lipids and Health

adolescents

Lipids and Health

• Excess abdominal fat

• High blood glucose

• High serum triglycerides

• Low HDL cholesterol

• High blood pressure

Lipids and Health

hereditary, and environmental factors

poor food choices and physical inactivity

while others serve a protective role

Lipids and Health

cancer risk

Lipids and Health

– Healthy People 2020 objectives target

reducing deaths from heart disease and stroke and reducing the number of adults with high blood cholesterol levels