Chapter 6 Lipids

Chylomicrons

A large lipoprotein formed in intestinal cells following the absorption of dietary fats. A chylomicron has a central core of triglycerides and cholesterol surrounded by phospholipids and proteins.

Obesity

Excessive accumulation of body fat leading to a body weight in relation to height that is substantiall greater than some accepted standard.

Small intestine

Fat in the small intestine stimulates the gallbladder to contract, sending bile down the bile duct to the small intestine.

Essential fatty acids

Fatty acids that the body needs but cannot synthesize and must obtain from the diet.

Non-essential fatty acids

Fatty acids that your body can make when they are needed. It is not necessary to consume them in the diet.

HDL

High-density lipoproteins (HDL)-The blood lipoproteins that contain high levels of protein and low levels of triglycerides. Synthesized primarily in the liver and small intestine, HDL picks up cholesterol released from dying cells and other sources and transfers it to the other lipoproteins. Sometimes called "good cholesterol."

Micelles

Tiny emulsified fat packets. They are composed of emulsifier molecules (phospholipids) oriented with their fat-soluble part facing inward and their water-soluble part facing outward toward the surrounding aqueous environment.

VLDL

Very-low-density lipoproteins (VLDL)- The triglyceride-rich lipoproteins formed in the liver. VLDL enters the bloodstream and is gradually acted upon by lipoprotein lipase, releasing triglyceride to body cells.

Sterols

A category of lipids that includes cholesterol. Sterols are hydrocarbons with several rings in their structures.

Cancer

A disease in which abnormal cells multiply out of control, spread into surrounding tissues and other body parts, and disrupt normal functioning of one or more organs.

Monosaturated

A fatty acid with one carbon-carbon double bond.

Polysaturated

A fatty acid with two or more double bonds.

Cholesterol

A type of fat made by the body from saturated fat; a minor part of fat in foods.

Cis fatty acid

An unsaturated fatty acid with a bent carbon chain. Most naturally occurring unsaturated fatty acids are cis fatty acids.

Trans fatty acid

An unsaturated fatty acid with a straighter chain than a cis fatty acid, usually as a result of hydrogenation; trans fatty acids are more solid than cis fatty acids.

Heart Diese

Any group of cardiac disorders that together constitue the leading cause of death in the US

Fatty Acids

Compounds containing a long hydrocarbon chain with a carboxyl group(-COOH) at one end and a methyl group(-CH3) at the other end.

Phospholipids

Compounds that consist of a glycerol molecule bonded to two fatty acid molecules and a phosphate group with a nitrogen-containing component. Have both water-soluble and fat-soluble regions, which makes them good emulsifiers.

Bile

Contains a large quantity of bile salts and the phopholipid lecithin. These key elements emulsify fat, breaking globules into smaller pieces so water-soluble pancreatic lipase can attack the surface.

Triglycerides Functions

Energy source, energy reserve, insulation and protection, carrier of fat-soluble compounds, and sensory qualities.

Mouth

In the mouth a combination of chewing and the work of the lingual lipase starts the digestive process rolling, with the small amount of dietary phospholipid providing emulsification.

Stomach

In the stomach, gastric liase joins in, and the stomach's churning and contractions keep the fat dispersed. After two to four hours in the stomach, digestion has broken down about 30 percent of dietary triglycerides to diglycerides and free fatty acids.

LDL

Low-density lipoproteins (LDL)-The cholesterol-rich lipoproteins that result from the breakdown and removal of triglycerides from intermediate-density lipoprotein. Sometimes called "bad cholesterol."

Fat replacers

Olestra, Olean, Caprenin, Salatrim

Saturated

Pertaining to fats and fatty acids whose hydrocarbon chains contain the maximum number of hydrogens and therefore have no double covalent bonds. Saturated fats and fatty acids solidify at room temperature.

Phytosterols(Plant sterols)

Sterols found in plants. Phytosterols are poorly absorbed by humans and reduce intestinal absorption of cholesterol. They recently have been introduced as a cholesterol-lowering food ingredient.

AMDR

The acceptable macronutrient distribution range for fat is 20-35 percent for adults. Because children have higher energy needs the levels are more liberal.

Triglycerides Structure

The major lipids in the diet and in the body. Adds flavor and texture(and calories) to foods that are an important source of energy. Consists of three fatty acids attached to a glycerol backbone. Glycerol is a thick smooth liquid. Two fatty acids attached to a glycerol form a diglyceride.

Chain Length

The number of carbons that a fatty acid contains. Foods contain fatty acids with chain lengths of 4 to 24 carbons, and most have an even number of carbons.