any substance that inhibits the destructive effects of
oxidation. Free radicals can cause this oxidation in the body.
Cholesterol: a fatty substance produced by
every cell in the body that is vital for health. It is a necessary
component of all cell membranes. It is the precursor to all steroid
hormone (including estrogen, testosterone, cortisol, and vitamin D). It is
the leading organic molecule in the brain and is needed for brain function.
Blood cholesterol carries antioxidant vitamins to the tissue. The majority
of cholesterol in the blood is produced by the liver. Excess of
cholesterol in the blood can contribute to heart disease.
a coenzyme that is a constituent of
every cell in the body that is
used in the production of energy. It is also a powerful antioxidant.
Fibrates: a group of cholesterol-moderating drugs in use since the
early 1960s that includes bezafibrate, gemfibrozil, and fenofibrate. Fibrates
are used primarily to treat high triglyceride levels. They can also help to
increase HDL levels.
a highly reactive atom or group of atoms with an unpaired
electron that can lead to "oxidative damage."
HMG-CoA Reductase (3-Hydroxy-3-methylgluatryl
coenzyme A reductase):
an enzyme necessary for cholesterol production.
HMG-CoA Reductase Inhibitors: synonym for
statins. Drugs that block enzyme, HMG-CoA Reductase, that catalyzes the
rate-limiting step in cholesterol production.
any of a group of organic compounds
consisting of fats, oils, and related substances that, along with proteins and
carbohydrates, are the structural components of living cells. In addition to
fats the group includes waxes, oils, sterols, triglycerides, phosphatides, and
Mitochondria: small cellular
structures, or organelles, found in the cytoplasm of eukaryotic cells (cells
with a nucleus; all plants and animals are eukaryotes, while bacteria are not). Mitochondria are responsible for converting nutrients
and oxygen into the
energy-yielding molecule adenosine triphosphate (ATP) to fuel the cell's
activities. This function, known as aerobic respiration, is the reason
mitochondria are frequently referred to as the powerhouse of the cell.
Better known as niacin (vitamin B3), nicotinic acid—in high doses—can be used as
a cholesterol-lowering drug.
Niacin lowers LDL-cholesterol and triglycerides
and also raises HDL-cholesterol. It accomplishes this by inhibiting the
production of fat and cholesterol containing proteins by the liver.
The most common side-effects of niacin are flushing, itching and
dizziness. Slow release niacin (such as Niaspan) usually prevents these
Resins or Bile Acid Sequestrants:
a group of cholesterol-lowering drugs that include
cholestyramine (Questran) and colestipol (colestid).
These medications bind bile that
was secreted into the intestine and prevent it from being reabsorbed. The liver
makes bile out of cholesterol. Since these medications cause the body to lose
bile, the liver then takes cholesterol out of the blood stream and converts it
to bile, thus lowering the serum cholesterol level.
a group of
cholesterol-lowering drugs whose generic names all end in ‘-statin.’ This group
includes lovastatin (Mevacor), pravastatin (Pravachol), simvastatin (Zocor),
atorvastatin (Lipitor), rosuvastatin (Crestor). Statin drugs are HMG-CoA
reductase inhibitors. By inhibiting the HMG-CoA reductase enzyme, statins help
to prevent the production of cholesterol within the body. (In fact, their
actual method of lowering cholesterol may be more complicated.) Since the majority of
serum cholesterol derives from this production, statins can radically bring down
cholesterol levels. The first statins became available in the late 1980s.
Definitions adapted from Microsoft® Encarta® Online
http://encarta.msn.com © 1997-2003 Microsoft Corporation. All Rights Reserved.