Sarah H. Short, Ph.D.,Ed.D.,R.D., Prof of Nutrition, Syr U.
NSD225 CHOLESTEROL and more Lipids
Introduction and functions
1. Cholesterol is a fat soluble complex alcohol of high molecular weight.
It is found only in ANIMAL tissue.
2. Cholesterol is an essential nutrient manufactured in your liver. You need
cholesterol to make bile acids & salts(needed to emulsify fat), some of
the sex hormones, adrenal hormones, vitamin D, and as part of
Cholesterol and heart disease
1. Cardiovascular diseases (CVD) are the leading causes of death in the USA.
CVD is a general term for all diseases of the heart and blood vessels.
Coronary heart disease (CHD) is atherosclerosis in the arteries feeding the
heart muscle. Atherosclerosis is an artery disease where there are patchy
nodular thickenings of the inner walls of the arteries ( called plaques).
2. Since the mid 60s, there has been a decline in heart disease mortality.
Of the 550,000 heart attack deaths occurring each year, 36% occur in
people over the age of 80 which certainly cannot be called premature
3. The primary cause of atherosclerosis is unknown. It may be injury to
the artery wall, virus infections, infiltration of the inner arterial walls by fatty
compounds in the blood.
4. Factors which may lead to an increased risk are: male gender, family
history of heart attack under age 55, smoking more than 10 cigarettes a
day, high blood pressure, HDLcholesterol below 35, diabetes
mellitus, impaired circulation to brain or legs, being 30% or more
overweight, lack of exercise .
1. Since chol is not water soluble, it is transported through the
bloodstream as lipoproteins, which are lipids surrounded by a thin layer of
proteins. The lipoproteins are named by their relative density. High density
lipoproteins (HDL) may reduce the risk of CHD while low density lipoproteins
(LDL) are associated with increased risk of CHD.
2. LDL carry cholesterol through the system, dropping it off where it is
needed for cell building and leaving any excess in arterial walls and other
tissue. HDL pick up these cholesterol deposits and bring them to the liver
for reprocessing or excretion, so HDL is called the "good" chol and LDL the
1. The association between blood chol and CHD is statistical and not
necessarily one of cause and effect.
2. Epidemiology is the study of relationships between environmental
factors and disease. It does not provide proof of causation. These studies
are first steps in developing evidence relating to cause and effect. Because 2
of this and the difficulty of doing long term human studies, scientific opinion
is divided on the association of environmental factors with CHD.
3. A study of 12,000 men from 7 countries over 10 years found that men
eating the most SATURATED fats had the highest CHD rate.
4. However, combined records of 7000 men found no evidence of more
CHD among those eating high saturated fat diets.
6. Blood cholesterol levels do not necessarily reflect dietary practices.
The Framingham Heart Study (monitoring 5,200 residents of Framingham,
MA since 1948) revealed that the intake of eggs was unrelated to blood chol
levels or to CHD incidence. In only about 20% of those with high blood chol
do chol levels return to normal as a result of dietary modification.
7. British scientists state that there should be no recommendations on
diet cholesterol because its effects on serum cholesterol are MINIMAL.
There are many reports in this country indicating that CHD is inherited and
dietary cholesterol intake may have little to with increased risk. The
amount of saturated fat in the diet probably has much more risk attached to
NOTE: Even if no cholesterol is consumed, the body can
manufacture from 800 1500 mg per day. Only about 10 50% of
dietary cholesterol is absorbed.
1. Most guidelines want you to have no more than 300 mg of dietary
cholesterol per day and no more than 30% of kcal from fat (and of this 30%,
no more than 10% from saturated fat).
2. The National Institute of Health (NIH) grouped blood levels into
mg chol/dl blood Desirable borderline high
Total cholesterol <200 (5.2) 200 239 >240
LDLcholesterol <130 (3.4) 130 159 >160
Total chol/HDL <4.5 >4.5
Triglycerides 30175 250 500
Note: There is a debate about triglycerides (TG) levels. Some people with
TG more than 150 and HDL under 40 are at high risk.
Cholesterol levels now are reported in SI units (Systeme International);
200 mg/dl equals 5.2 mmol/L (divide mg by 38.7).
Dietary Sources of Cholesterol
1. The average diet contains about 500 mg of cholesterol per day.
Cholesterol is found only in animal sources , so there could not possibly be
any cholesterol in vegetable oil, cereals, bread, fruit, vegetables.
2. Food sources of cholesterol are liver (370 mg/3 oz), egg 213),shrimp,
3 oz (130 mg), chicken, skin off 3 oz (72 mg); lean beef, 3oz (62 mg);
haddock, 3 oz (63); 1 Tblsp butter (31); 1 cup whole milk (33); skim milk (4).
Other areas of dietary research
1. Fish oils Large studies conducted in the Netherlands found a direct 3
link between the amount of fish in the diet and the rate of death from
heart disease. Cold water fish such as cod, salmon, sardines,
mackerel contain polyunsaturated oils that are rarely found in other
foods (called omega 3 fatty acids). Further studies indicated that
moderate intake of fish oils can lower plasma triglycerides but has
very little effect on lowering plasma LDLcholesterol. However these
fatty acids have been found to increase bleeding time. Another
problem is that fish oil pills were marketed before enough testing was
done. The fish oil in the pills comes from the liver which may be too
high in fat soluble vitamins, cholesterol and water contaminants as
well as interfering with blood clotting. Am.Heart Assoc: NO