Cholesterol critical to life

As I sit, writing, I can almost hear my arteries hardening. Cholesterol is out to get me! Cholesterol is a word which strikes fear in our hearts. It is connected to coronary heart disease or CHD. Strokes, heart attacks, and other arterial diseases resulting from the development of plaques in our blood vessels are collectively the number one killer of people in both North America and worldwide.

Consequently, low cholesterol or no cholesterol diets are all the rage for the prevention of CHD. There are also a number of treatment options available ranging from drugs to surgery.

Yet, at the same time as we try to reduce our dietary intake, this naturally occurring compound infuses all of the cells of our body.

Without it, we would die. We make it in our livers and transport it from there to our nether regions.

The average 70 kg adult has about 35 g of cholesterol in the cells of their body. Their liver produces about one gram per day and they typically consume about 0.3 grams per day as part of their diet. Our bodies balances production with consumption to roughly keep the total constant.

What is the purpose of cholesterol? Are our livers betraying us? Maybe, but only if your liver overproduces. Cholesterol is a fundamentally important compound serving at least two important and different functions in our bodies.

In the first instance, it is one of the compounds responsible for cell membrane fluidity. Cells are a collection of liquid and other stuff surrounded by two layers of lipids. Simplistically, they are the molecular version of a tiny water balloon.

Lipids are long, skinny mol- ecules with polar head groups attracted to water and tails attracted to each other. These lipids line up with their heads facing out from the membrane into the extracellular aqueous media and into the cytoplasm of the cell.

As a result, lipids create a bilayer membrane or the skin of each cell.

If the lipids were left to themselves, this arrangement would be fairly rigid with no flex or give as the molecules would line up row upon row. But flexibility is essential for moving organisms, such as you or me. Indeed, all animals require soft cells for mobility.

It is fluidity of our cells that allows us to bend and move around. It allows muscles to flex and our digestive system to handle food. Cholesterol inserts into these lipid bilayer cell membranes and disrupts the structure.

In doing so, it prevents the lipids from getting too organized. Cholesterol is estimated to make up as much as 30 per cent of every cell membrane.

This is part of the reason cholesterol is only found in animals and not in plants. For a vegetable, such as broccoli, being able to bend or having fluid cells is not an asset. Indeed, plants and other organisms have generally evolved to have very stiff walls and little flexibility.

But cholesterol’s other role in our bodies is equally important. Cholesterol is a steroid and although steroids continue to receive a lot of bad press in the wake of their use by Olympic and professional athletes, they are very important compounds for Lipitor pills are seen at Medco Health Solutions Inc., in Willingboro, N.J. Lipitor is a statin drug, used to control high cholesterol levels. animal growth. Some of the most important hormones in our body are steroids and they are all built with cholesterol as the starting material.

The common feature of all steroids is they have four atomic rings – carbon atoms bound together in fused hexagons – structured like a very small piece of chicken wire. This ring system is synthesized in the body through a complex series of reactions from much simpler compounds. Working out the biochemical synthesis led to the 1964 Nobel Prize in Physiology or Medicine for Konrad Bloch and Feodor Lynen.

The synthesis of cholesterol occurs in every cell in the body but predominantly in the liver. Vitamin D is a by-product of this synthetic pathway and cholesterol is the primary building block for a number of important compounds including the sex hormones progesterone, testosterone and the estrogens. In essence, without cholesterol, there would be no sex or it would certainly be a lot different than it is presently.

Of course, this doesn’t mean cholesterol is always good.

Excessive amounts of cholesterol are carried in the blood plasma by a variety of lipoproteins and may eventually be deposited in arteries. Not all cholesterol forms deposits as it appears deposition requires oxidation of the cholesterol molecules. But the resulting plaques can eventually lead to chronic heart disease such as atherosclerosis or hardening of the arteries and ultimately to CHD.

Ironically, the compound our cells use to keep their membranes supple and pliable, when present in large quantities in the blood can lead to stiff, non-pliable arterial walls and the formation of plaques or blockages. But, as with all things, moderation is important.

Some is OK, but too much can kill you.