Chapter 5: The Lipids & Spotlight b: Lipids in Health and Disease

Fatty acids

Long chains of carbon atoms whose saturation depends on how many available bonds are filled with hydrogen. They are a major source of energy and a component of triglycerides and phospholipids.

Triglycerides

Composed of 3 fatty acids and a glycerol molecule. They are the main dietary lipids (saturated and unsaturated fats) and a storage form of fat in our bodies.

Sterols

4 fused carbon rings. Cholesterol is the most common, but plant versions also exist and help protect the heart.

Phospholipids

Composed of 2 fatty acids and a phosphate group. They are both hydrophilic and hydrophobic, making them a key component of cell membranes and the emulsification of lipids.

Functions of fat

Absorption and transportation of fat-soluble vitamins, promotes feelings of fullness, stored fat protects, cushions, and insulates, major component of cell membranes.

Saturated fats

Fatty acids with all the carbon bonds filled with hydrogen. This kind of fat is solid at room temp and some examples are; coconut oil, butter, and animal fat.

Monounsaturated fats

Fatty acids with one point of unsaturation in the carbon chain. These are usually liquid at room temp and some examples are; olive oil, canola oil, and nuts.

Polyunsaturated fats

Fatty acids with more than one point of unsaturation. These are liquid at room temp and some examples are: corn oil, safflower oil, sunflower oil, and soybean oil.

Roles of cholesterol in the body

Important for cell membranes, hormones, and bile synthesis.

2 sources of cholesterol

Produced by the liver and is found in animal products.

2 essentail fatty acids

Omega-6 (linoleic) and Omega-3 (linolenic)

How are dietary fats broken down and absorbed?

Lipase digests some of the lipids in the mouth and stomach, but since lipids are not water-soluble, they clump together in the small intestines. The cholesterol body then produces bile, which contains phospholipids that emulsify the lipids into smaller droplets. The smaller droplets can then be broken down in monoglycerides and free fatty acids. They are packaged into micelles and are delivered into the lymph.

Lipoproteins

A particle made up of an outer layer of phospholipids and proteins that transport triglycerides and cholesterol in the center core.

Chylomicrons

The least dense lipoprotein that transports dietary fats from the intestines to the rest of the body.

Low-density lipoproteins (LDL)

“Bad” cholesterol that delivers cholesterol to all cells in the body.

High-density lipoproteins (HDL)

“Good” cholesterol that transports cholesterol from the cells back into the liver.

Recommended percent of fat in the diet

20-35% of total calories

Recommended percent of saturated fats

Less than 10% of total calories

Recommendation for trans-fat

As little as possible.

Lower fat choices

Fresh produce, skinless meats, white fish, beans, non-fat produces, oats, etc.

Low-fat cooking methods

Baking instead of frying, steaming, boiling, air-drying, trimming visible fat, etc.

4% fat

Total calories = 110, fat = 0.5g

Hydrogenation

The process of adding hydrogen to unsaturated fats to make them saturated and increase shelf life.

Partially hydrogenated oils (PHOs)

The incomplete process of hydrogenation that results in added trans-fats, which was banned by the FDA In 2018.

Blood lipid profile for total cholesterol

0-200mg/dl

Blood lipid profile for HDL

40-60mg/dl is normal, 60+mg/dl is good

Blood lipid profile for LDL

0-100mg/dl

Blood lipid profile for triglycerides

0-150mg/dl

These fats raise cholesterol levels.

Saturated and trans fats.

Tropical oils

Coconut oil and palm oil.

Atherosclerosis

The long-term narrowing and loss of elasticity in blood vessels caused by the accumulation of fatty plague (cholesterol and triglycerides) in the walls of the arteries and blood vessels.

Metabolic syndrome

Metabolic syndrome is a cluster of risks associated with heart disease and type 2 diabetes. Having three of the following is a diagnostic: excessive abdominal fat, high blood pressure, elevated triglycerides in the blood, low levels of HDL, and elevated blood glucose levels.

Recommended weekly serving of fish

2 servings of fatty fish.