Lipids are a diverse group of fats and fatlike substances.
Lipids are organic molecules that are insoluble in water. Because of this
water insolubility, lipids tend to gather together. This pattern of aggregation can
be seen in the membrane (outer portion of cells) lipids of cells and lipoproteins and in
Increased intake of dietary lipids increases the risk of developing
type II diabetes, cardiovascular problems, such as heart attacks and strokes, organ failure,
and other health problems. From this short introduction we can see that fats are essential,
and at the same time we must learn to balance intake of lipids and their specific types.
There are many different types of lipids, each with certain
characteristics. The group lipids includes fatty acids,
neutral fats, waxes and steroids. Compound lipids comprise lipoproteins, glycolipids
Lipids are essential to life. Practically every function in the human
body is in some way dependant on lipids. Structurally, lipids compose the membrane in the
outer portion of our cells. Without this
membrane, the contents of a cell would just drift away. And with the average person having
more than 170 trillion cells, we can see the importance lipids serve in this respect.
Lipids serve as energy stores. The energy content of fat is more than twice that of
carbohydrates and protein. Excess sugar can be converted to a lipid and stored
for future use. Excess lipids in the diet can also be stored. Lipids
provide padding and
insulation for us and other animals to keep warm. Some lipids act as hormones,
affecting the function of a target tissue. Lipids even perform functions that we take
such as serving as attractants to another person in courting
(eg., the curves you may find attractive on a female)
Certain lipids can also cause illness. Lipid A, the glycolipid portion
of lipopolysaccharide in certain bacteria is responsible for causing endotoxic shock.
Toxic shock syndrome, which is caused by certain bacteria multiplying on tampons, causes
life threatening decreases in blood pressure and other dangerous signs and symptoms. This
life-threatening condition is also caused by a type of lipid produced by bacteria.
The lipid highway
The best way to understand lipids is to follow their journey from
their entry into the body to their metabolism throughout. We have divided lipid
metabolism into several sections. Review
the links to learn more.
Dietary lipid metabolism of Triacylglycerols
Dietary lipid metabolism of Phospholipids
Dietary lipid metabolism of Glycolipids
Cholesterol and steroids
Classes of lipids