General Description
Cholesterol is a waxy, fat-like, steroid alcohol found in all parts
of the body. It is essential for health because it helps make cell
membranes, steroid hormones, and vitamin D. However, when blood
cholesterol levels are too high (hypercholesterolemia), they can
cause fatty buildup in the arteries (atherosclerosis), which increases
a person's risk for developing coronary heart disease (CHD). Cholesterol
is transported through the bloodstream in carrier molecules known
as lipoproteins. The two main lipoproteins in the bloodstream are
low-density lipoprotein (LDL), which carries most of the cholesterol
in the blood, and high-density lipoprotein (HDL). High LDL levels
contribute to atherosclerosis, which is why LDL is known as the
"bad" cholesterol. HDL transports cholesterol to the liver for metabolism
and excretion, removing it from the bloodstream, which is why HDL
is often called the "good" cholesterol. Blood LDL levels are considered
a more accurate indicator of heart disease risk than total blood
cholesterol, which includes both HDL and LDL.
In adults, total blood cholesterol levels under 200mg/dL are
considered "desirable" because they lower the risk for heart disease.
Levels between 200 and 239 mg/dL are considered "borderline high"
and indicate an increased risk for heart disease. Levels of 240
mg/dL or greater are considered "high." A person with high cholesterol
has more than twice the risk of heart disease compared to someone
whose cholesterol is 200 mg/dL or lower. For LDL, levels less
than 130 mg/dL are considered "desirable," levels from 130 to
159 mg/dL are considered "borderline-high risk," and levels of
160 mg/dL and above are considered "high risk."1
For people with CHD, it is recommended that LDL levels be reduced
below the normal "desirable" level, to 100 mg/dL or less.2
Contributing factors
Blood cholesterol levels are influenced by diet and by the rate
that the body makes LDL cholesterol and disposes of it. The liver
produces all the cholesterol the body needs, therefore it is not
necessary to take in any additional cholesterol through foods.
Saturated fat raises LDL cholesterol more than anything in the
diet. In fact, eating too much saturated fat and cholesterol is
the main reason for high cholesterol levels and the high rate
of heart attacks in the United States.2 Genetic
factors can influence LDL levels by affecting how fast LDL is
made and removed from the body. Other factors that contribute
to high cholesterol levels include obesity, stress, and the hormonal
changes associated with menopause.2
Conventional treatment
In most cases, high cholesterol levels can be reduced without
medication by decreasing saturated fat and cholesterol in the
diet, increasing physical activity, and controlling body weight.
When diet and exercise alone are inadequate, a doctor may prescribe
cholesterol-lowering medications. In many cases, high cholesterol
levels are treated with a combination of diet, exercise, and medication
tailored to the individual patient profile.
Nutritional/lifestyle considerations
While a diet low in cholesterol and saturated fat is essential
for lowering blood cholesterol levels, there are other nutritional
factors that can also have a positive impact. Studies have shown
that regular consumption of oat bran3 and
soybeans4 can help reduce cholesterol levels.
Several dietary supplements, including niacin,5-7
lecithin,8-12 flaxseed oil,13-16
chromium,17 and chitosan,18
have demonstrated cholesterol-lowering abilities, as have herbs
such as garlic,19-23 fenugreek,24-26
and ginger.27-28 Although they don't reduce
cholesterol levels, antioxidant nutrients may be helpful because
they protect LDL from oxidation,29-31 and
oxidized LDL can be particularly damaging to arterty walls. |
