by a woman consuming 2,000 calories a day and no
more than 28 g saturated fat should be consumed by a
man consuming 2,500 calories a day. A product is
considered low in saturated fat if it contains less than
1.5 g per 100 g and high in saturated fat if it contains
more than 5 g of fat per 100 g.
Monounsaturated fatty acids
Monounsaturated fatty acids have a hydrocarbon
chain that contains one unsaturated carbon bond that
is not fully saturated with hydrogen atoms. Instead, it
has a double bond to the adjoining carbon atom.
Double bonds are either in acisortransformation.
In thecisformation the hydrogen atoms bonded to the
carbon atoms in the double bond are positioned on
the same side of the double bond. This creates a kink in
the hydrocarbon chain. There is also a free electron or
slightly negative charge surrounding the double bond
causing them to repel each other. The molecules are
not packed closely together and become liquid (oil) at
room temperature. In thetransformation the hydro-
gen atoms are on opposite sides of the carbon-carbon
double bond resembling the characteristics of a satu-
rated fatty acid. There is less kinking of the hydro-
carbon chain and the fat is more solid at room
temperature.transbonds are rarely seen in nature.
Monounsaturated fatty acids are named accord-
ing to the number of carbons they contain and the
position of their double bond. Like saturated fatty
acids, they each have a common name, a systematic
name, and a notational name. Fatty acids with double
bonds in the ninth position are sometimes called n-9s
or omega-9s.
The most concentrated sources of monounsatu-
rated fatty acids in the diet are olive oil and rapeseed
oil. They are present in many other foods including
nuts and seeds, avocados, eggs, fish and meat fat.
MONOUNSATURATED FATTY ACIDS AND HEALTH.
Monounsaturated fatty acids reduce the level of total
and LDL cholesterol. It also has a significant effect on
increasing and maintaining the body’s level of high
density lipoprotein (HDL) cholesterol. HDL choles-
terol is commonly known as ‘good’ cholesterol
because it removes cholesterol from the blood trans-
ferring it to body tissues where it is used to make
hormones and other substances the body needs.
Therefore, higher levels of HDL cholesterol are asso-
ciated with a reduction in the risk of cardiovascular
disease. Between 10–20% of dietary energy should
come from monounsaturated fat.Polyunsaturated fatty acids
Polyunsaturated fatty acids have a hydrocarbon
chain containing two or more double bonds not fully
saturated with hydrogen atoms. The double bonds
may either be in thecisortransformation. The major-
ity of naturally occurring polyunsaturated fats are in
thecisform. In this form the hydrogen atoms bonded
to the carbon atoms in the double bond are positioned
on the same side of the double bond. This creates a
kink in the hydrocarbon chain. There is also a free
electron or slightly negative charge surrounding the
double bond causing them to repel each other. The
molecules are not packed closely together and become
liquid (oil) at room temperature. The presence of one
or more double bonds with free electrons and a neg-
ative charge makes them unstable molecules ready toFatsType of fat Dietary source Effect on cholesterol How often to choose
Trans fat • “Hydrogenated” or “partially hydrogenated” oils Raises LDL Less often- Vegetable shortenings, stick margarine, deep fried foods,
some fast foods and snack foods (i.e., cookies and crackers)
Saturated fat • Tropical oils such as palm and coconut oils, cocoa butter, Raises LDL Less often
coconuts and coconut milk - Red meat, the skin from chicken and other birds, butter, whole
milk and milk products (i.e., cheese and ice cream)
Monounsaturated fat • Avocados, olives, certain nuts Lowers LDL when More often - Olive, canola, and peanut oils substituted for saturated fat
Polyunsaturated fat • Plant oils like corn, sunflower, and safflower Lowers LDL when More often
(includes omega-3 and • Fish (especially salmon, trout, and herring) substituted for saturated fat
omega-6 fatty acids) • Flaxseed oil
SOURCE: Division of Nutrition Research Coordination, National Institutes of Health, U.S. Department of Health and Human Services
(Illustration by GGS Information Services/Thomson Gale.)
Fats