The Lipids: Triglycerides, Phospholipids, & Sterols

Lipoprotein Lipase (LPL)

An enzyme that hydrolyzes triglycerides passing by in the bloodstream & directs their parts into the cells, where they can be metabolized for energy or reassembed for storage.

Cardiovascular Disease (CVD)

A general term for all diseases of the heart & blood vessels. Atherosclerosis in the main cause of CVD. When the arteries that carry bood to the heart muscle become blocked, the heart suffers damage known as coronary heart disease (CHD).

Choline

A nitrogen-containing compound found in foods & made in the body from the amino acid methionine. Choline is part of the phospholipid lecithin & the neurotransmitter acetycholine.

Eicosanoids

Derivatives of 20-carbon fatty acids; biologically active comounds that help to regulate blood pressure, blood clotting, & other body functions. They include prostaglandins , thromboxanes, & leukotrienes.

Trans-Fatty Acids

Fatty acids with hydrogen on opposite sides of the double bond.

Oils

Lipids that are liquid at room temperature. (77 F or 25 C)

Fats

Lipids that are solid at room temperature. (77 F or 25 C)

Monoglycerides

Molecules of glycerol with one fatty acid attached. A molecule of glycerol with tow fatty acids attached is a diglyceride.

Cis

On the near side of; refers to a chemical configuration in which the hydrogen atoms are located on the same side of a double bond.

Trans

On the other side of; refers to a chemical configuration in which the hydrogen atoms are located on opposite sides of a double bond.

Lecithin

One of the phospholipids. Both nature & the food industry use lecithin as an emulsifier to combine water-soluble & fat-soluble ingredients that do not ordinarily mix, such as water & oil.

Cholesterol

One of the sterols containing a four-ring carbon structure with a carbon side chain.

Blood Lipid Profile

Results of blood tests that reveal a person's total cholesterol, triglycerides, & various lipoproteins.

Conjugated Linoletic Acids

Several fatty acids that have the same chemical formula as linoleic acid (18 carbons, two double bonds) but with different configurations (the double bonds occur on adjacent carbons).

Oxidation

The process of a substance combining with oxygen; oxidation reactions involve the loss of electrons.

Hydrogenation

A chemical process by which hydrogens are added to monounsaturated or polyunstaurated fatty acids to reduce the number of double bonds, making the fats more saturated (solid) & more resistant to oxidation (protecting against rancidity). Hydrogenation produces trans-fatty acids.

Phospholipid

A compound similar to a triglyceride but having s phosphate group ( aphosphorous-containing salt) & choline (or another nitrogen-containing compound) in place of one of the fatty acids.

Lipids

A family of compounds that includes triglycerides, phospholipids, & sterols. Lipids are characterized by their insolubility in water. (Lipids also include the fat-soluble vitamins).

Omega-6 Fatty Acid

A polyunsaturated fatty acid in which the first double bond is six carbons from the methyl end on the carbon chain.

Omega-3 Fatty Acid

A polyunsaturated fatty acid in which the first double bond is three carbons away from the methyl end on the carbon chain.

Olestra

A synthetic fat made from sucrose & fatty acids that provides 0 kcalories per gm; also known as sucrose polyester.

Hydrophobic

A term referring to water-fearing, or non-water-soluble, substances; also known as lipophilic (fat loving)

Hydrophilic

A term referring to water-loving or water-soluble, substances.

Atheroclerosis

A type of artery disease characterized by plaques (accumulations of lipid-containing material) on the inner walls of the arteries.

Lipoproteins

Clusters of lipids associated with proteins that serve as transport vehicles for lipids in the lymph & blood.

Sterols

Compounds containing a four-ring carbon structure with any of a variety of side chains attached.

Low-Denity Lipoproteins (LDL)

The type of lipoprotein derived from very-low-density lipoproteins (VLDL) as VLDL triglycerides are removed & broken down; composed primarily of cholesterol.

Very-Low-Density Lipoprotein (VLDL)

The type of lipoprotein made primarily by liver cells to transport lipids to various tissues in the body; composed primarily of triglycerides.

High-Density Lipoproteins (HDL)

The type of lipoprotein that transports cholesterol back to the liver from the cells; composed primarily of protein.

Micelles

Tiny Sherical complexes of emulsified fat that arise during digestion; most contain bile salts & the products of lipid digestion, including fatty acids, monoglycerides, & cholesterol.

Essentail Fatty Acids

Fatty acids needed by the body but not made by it in amounts sufficient to meet physiological needs.

Fat Replacers

Ingredients that replace some or all of the function of fat & may or may not provide energy.

Adipokines

Proteins synthesized & secreted by adipose cells.

Adipose Tissue

The body's fat tissue; consists of masses of triglyceride-storing cells.

Artificial Fats

Zero-energy fat replacers that are chemically synthesized to mimic the sensory & cooking qualities of naturally occuring fats but are totally or partially resistant to digestion.

Antioxidants

As a food additive, preservatives that delay or prevent rancidity of fats in foods & other damage to food caused by oxygen.

Docosahexaenoic Acid (DHA)

An omega-3 polyunsaturated fatty acid with 22 carbons & six double bonds; present in fatty fish & synthesized in limited amounts in the body from linolenic acid.

Arachidonic Acid

An omega-6 polyunsaturated fatty acid with 20 carbons & four double bonds; present in small amounts in meat & other animal products & synthesized in the body from linoleic acid.

Plaque

An accumulation of fatty deposits, smooth muscle cells, & fibrous connective tissue that develops in the artery walls in atherosclerosis. Plaque associated with atherosclerosis is known as atheromatous plaque.

Hormone-Sensitive Lipase

An enzyme inside adipose cells that respond to the body's need for fuel by hydrolyzing triglycerides so that their parts (glycerol & fatty acids) escape into the general circulation & thus become available to other cells for fuel. The signals to which this enzyme responds include epinephrine & glucagon, which oppose insulin.

Linoleic Acid

An essential fatty acid with 18 carbons & double bonds.

Linolenic Acid

An essential fatty acid with 18 carbons & three double bonds.

Eicosapentaenoic Acid (EPA)

An omega-3 polyunsaturated fatty acid with 20 carbons & five double bonds; present in fatty fish & synthesized in limited amounts in the body from linolenic acid.

Triglycerides

The chief form of fat in the diet & the major form of fat in the body; composed of a molecule of glycerol with three fatty acids attached; also called tricylglycerols.

Chylomicrons

The class of lipoproteins that transport lipids from the intestinal cells to the rest of the body.

Omega

The last letter of the Greek alphabet, used by chemists to refer to the position of the first double bond from the methyl (CH3) end of the carbon chair.