What Are Fats ?
Fats are also known as lipids. They can be divided into three general categories:
- Triglycerides
- Phospholipids
- Sterols
Triglyceride Fats And Oils
Triglycerides form the main part of fat in most peoples diet. They provide us
with energy, insulate, cushion and protect internal organs
and help our bodies to use carbohydrates and proteins with more efficiency.
The following are types of triglcerides : |
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Saturated Fats
These are
usually solid at
room temperature, saturated fat contains the maximum number
of hydrogen atoms (that is "saturated" with hydrogen). Saturated
fats are said to be the least good for your health.
Monounsaturated Fats
The monounsaturated fat includes olive and canola
oils. This type of fat lowers bad
LDL cholesterol leaving the good HDL
cholesterol the same. They are liquid at room
temperature.
Polyunsaturated Fats
The polyunsaturated fat includes corn oil, safflower
oil and sunflower oil. This type of fat lowers
both bad LDL and good
HDL cholesterol. They are liquid at room
temperature,
Hydrogenated Fats
This fat results
from a process where hydrogen atoms are added back to
polyunsaturated or monounsaturated fats to protect against
going bad. This procedure effectively causes hydrogenated
fats to become saturated fats. Therefor, if
a food lists partially hydrogenated oils among its first
three ingredients, it usually contains alot of trans-fatty
acids and saturated fats.
Trans-fatty acids
In nature, most
unsaturated fats are cis-fatty acids. During
hydrogenation, the molecular structure changes from cis-
to trans-fatty acids. Trans-fatty acids increase
bad LDL cholesterol and lower good
HDL cholesterol, this in turn may increase the risk of heart disease.
Essential fatty acids
The body
uses essential fatty acids to maintain the structural
parts of cell membranes. They are also used as a component
in the production of hormone-like substances (eicosanoids)
that help regulate blood pressure, clot formation, and
maintain the immune response. Essential
fatty acids have to be supplied by the diet.
- Linoleic Acid (The Omega-6
family). Common sources for these essential fatty
acids are vegetable oils and meats. Most individuals
can get an adequate intake of Omega-6 fatty acids
by including seeds, grains, leafy vegetables, and
small amounts of vegetable oils and meats in the diet.
- Linolenic Acid (The Omega-3
family). Linolenic acid is a major component
of the communicating membranes of the brain, it is also
active in the eye's retina. It is essential
for growth and development. Fish is particularly rich in both Omega-3 and Omega-6
fatty acids.
Phospholipids
The phospholipids
help transport fat-soluble vitamins, hormones and other substances
through cell membranes. Because they can dissolve in
both water and fat, they act as an emulsifier, helping to
keep fat suspended in body fluids and blood. The liver
can produce all the body's phospholipids itself, so
it is not an essential nutrient. Lecithin is an example of a phospholipid.
Sterols
Sterols include
vitamin D, cholesterol, and sex hormones. They are a component of bile,
sex hormones (testosterone), adrenal hormones (cortisol) and
are a structural component of cell membranes. Most of
the body's cholesterol is stored in cells.
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Cholesterol
Most cholesterol is manufactured by the liver. It makes about
800-1500 mg. of cholesterol per day, which contributes much
more to total body cholesterol than diet does. The liver
can also make cholesterol from carbohydrates, proteins or
fat. Only animal foods contain cholesterol.
Excess cholesterol harms the body when it forms plaque deposits on
artery walls, leading to atherosclerosis and heart disease.
Cholesterol can be further divided into HDLs and LDLs
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