27-14 Some Derivatives of Carboxylic Acids 1083CC Our Daily Lives
HEMISTRY IN USE
Butter, Margarine, and transFats
Humans had consumed butter for thousands of years before
France introduced the world to margarine in the late 1860s;
by 1874, margarine had reached the United States. Margarine
consumption has increased rapidly, due in part to an increased
risk of heart disease that has been associated with consump-
tion of butter.
Both butter and margarine are primarily fats, but they
contain different kinds of fats. The main ingredient in but-
ter is cream, the concentrated fat from milk, whereas the main
ingredient in margarine is vegetable oil, the concentrated fat
from plants. Although it is widely accepted that animal fats
pose a greater risk for heart disease than vegetable oils, most
vegetable oils used in margarine and processed foods are
modified by hydrogenation.
The hydrogenation process adds hydrogen atoms to
unsaturated vegetable oils; this causes vegetable oils to solid-
ify, which makes them creamier and prolongs their shelf life.
Unfortunately, the hydrogenation process changes about
40% of the naturally occurring cismolecules of vegetable oil
into transisomers; the resulting fat molecules are referred to
as transfats. Oils produced in nature contain only cisisomers
and are considered healthful, but the transfats have been
linked to many thousands of deaths due to heart disease. Diets
high in hydrogenated vegetable oil may be as unhealthy as
those high in saturated animal fats.
To understand the different effects produced by animal
fats, vegetable oils, and transfats, we need to know a little
about blood cholesterol. Medical specialists recognize several
types of cholesterol, two of which are HDL (high-density
lipoproteins) and LDL (low-density lipoproteins). Because
high levels of HDL reduce the risk of heart disease, HDL
has become known as “good” cholesterol; because high lev-
els of LDL increase the risk for heart disease, LDL has
become known as “bad” cholesterol. In the average U.S.
adult, the total amount of cholesterol (including HDL and
LDL) circulating in the blood is about 200 mg per 100 mL
of serum.
A diet high in animal fats usually increases blood choles-
terol levels beyond 200 mg per 100 mL of serum, thereby
increasing the risk for heart disease. When animal fats
increase the total blood cholesterol level, however, they
increase the levels of both HDL and LDL. In contrast, veg-
etable oils decrease the total blood cholesterol level, whichmakes them healthier foods than other fats. Transfats (from
hydrogenated vegetable oils) also decrease the total blood
cholesterol level, giving the appearance of being healthy, but
unfortunately they accomplish this reduction by simultane-
ously reducing the desirable HDL levels and increasing the
undesirable LDL levels.
The damage done by hydrogenated vegetable oils is par-
ticularly disturbing because margarine is one of the largest
sources of calories in the U.S. diet; approximately 40% of
margarine fat is the transisomer. Hydrogenated vegetable oils
are widely used in shortening, cookies, crackers, chips, and
other processed foods. Ironically, most of these foods are
touted as being healthy because they contain no cholesterol
or saturated fats.
What can we do to protect our health? For many years,
nutritionists have been telling us what appears to be the “best
solution”: reduce your total fat intake to 20% of your daily
calories, and reduce your consumption of animal fats by sub-
stituting vegetable oils. Whenever possible, use vegetable oils
that have not been hydrogenated.Ronald DeLorenzo
Middle Georgia CollegeBlood pressure check.