react with other chemicals. Polyunsaturated fatty
acids are susceptible to chemical changes or oxidation
within food leading to cell damage in the body.
Polyunsaturated fatty acids are named similar to
other fatty acids. They have a common name, a sys-
tematic name, and a notational name. Fatty acids with
double bonds starting in the sixth position are com-
monly known as n-6s or omega-6s.
POLYUNSATURATED FATTY ACIDS AND HEALTH.
Polyunsaturated fatty acids are divided into two
groups, omega-6s and omega-3s. There is one essential
fatty acid in each of these groups from which all other
fatty acids can be made in the human body. These
essential fatty acids cannot be made by the body and
must be obtained from the diet. They are a necessarycomponent of the diet; without them deficiency symp-
toms and poor health would result. Linoleic acid
(omega-6) and alpha-linolenic acid (omega-3) are the
essential fatty acids. Linoleic acid should provide at
least 1% of dietary energy and alpha-linoleic acid
should provide 0.2% dietary energy. These essential
fatty acids are converted into longer chain fatty acids
that form important substances in the body such as
hormones, blood clotting agents, and compounds
involved in immune and inflammatory responses.
These long chain fatty acids are not technically
essential, but they have an important role in the body.
Examples of long chain fatty acids include aracha-
donic acid (AA), eicosapentaenoic acid (EPA), and
docosahexanoic acid (DHA). Long chain omega-3KEY TERMS
Antioxidant—A chemical that has the ability to neu-
tralize free radicals and prevent damage that would
otherwise occur through oxidation.
Atherosclerosis—A thickening of the artery walls
that impedes the flow of blood supplying the heart,
brain, and other organs.
Bile acids—Produced by the liver, from cholesterol,
for the digestion and absorption of fat.
Carboxyl group—The carbon atom at the end of a
fatty acid hydrocarbon chain is attached by a double
bond to oxygen and by a single bond to hydrogen
forming the chemical structure carboxyl.
cisformation—The arrangement of atoms where
hydrogen atoms sit on the same side of the carbon
to carbon double bond.
Electron—A component of an atom or molecule. It
has a negative charge when a free or unpaired elec-
tron exists making it chemically unstable and likely
to initiate chemical reactions.
Essential fatty acid—A molecule that cannot be
made by the body and must be supplied by food in
order to prevent deficiency.
Fatty acid—A molecule consisting of mainly carbon
atoms joined together to form a carbon chain to
which hydrogen atoms are attached. Fatty acids
vary according to their degree of saturation (i.e., the
number of hydrogen atoms attached and the length
of the hydrocarbon chain).High density lipoprotein (HDL)—One of several
proteins in the blood that transports cholesterol to
the liver and away from the arteries.
Hydrogenated—Usually refers to partial hydrogena-
tion of oil, a process where hydrogen is added to oils
to reduce the degree of unsaturation. This converts
fatty acids from acistotransfatty acids.
Omega-3—Polyunsaturated fatty acid where the first
double bond occurs on the third carbon-to-carbon
double bond from the methyl end of the hydrocar-
bon chain.
Omega-6—Polyunsaturated fatty acid where the first
double bond occurs on the sixth carbon-to-carbon
double bond from the methyl end of the hydrocar-
bon chain.
Omega-9—Polyunsaturated fatty acids where the
first double bond occurs on the ninth carbon-to-
carbon double bond from the methyl end of the
hydrocarbon chain.
Oxidation—A chemical reaction in which electrons
are lost from a molecule or atom. In the body these
reactions can damage cells, tissues, and deoxyribo-
nucleic acid (DNA) leading to cardiovascular dis-
ease or cancer.
transfatty acids—Monounsaturated or polyunsatu-
rated fats where the double bonds create a linear
formation. They are formed largely by the manufac-
ture of partial hydrogenation of oils, which converts
much of the oil intotransfat. Hydrogenated fats and
transfats are often used interchangably.Fats