THE CHOLESTEROL CONTROVERSY PART 2

Discover the new facts about your cholesterol

Cholesterol has received more media attention than most other biological molecules. This controversial lipid has appeared not once but twice on the cover of Time magazine. The first article in Time condemned cholesterol as a harbinger of heart attack. A few years later, cholesterol was exonerated with the exhortation to bring back the bacon. It’s time to reveal the private life of this public diva. For decades cholesterol has been implicated as a major risk factor for heart disease and most people try to keep their blood cholesterol as low as possible. But is this the best way to lower your risk of heart attack and stroke? And are drugs or diet the way to go about it? Older people with higher cholesterol levels actually tend to live longer and have a lower risk of Alzheimer’s disease than do people with low levels of cholesterol. This is not what we have believed for decades.

What do we now understand about cholesterol?

1. Cholesterol is essential to life and each cell in the body can make it through a 37-step process. It’s a component of cell membranes and a precursor for making oestrogen, progesterone, adrenal hormones, Vitamin D and bile acids.

2. Cholesterol is also a vital part of the myelin sheath that enables signaling between brain and nerve cells.

3. It plays many and varied roles in the body and is carried around in the blood by lipoproteins of varying size, weight and density.

4. The cholesterol within each lipoprotein is the same - it is the carrier molecule that differs. The higher the protein to fat ratio, the denser the lipoprotein. Hence the terms HDL (High Density Lipoprotein) and LDL (Low Density Lipoprotein).

However, the picture is far more nuanced than that.

HDL and LDL are only two of many lipoproteins involved in cholesterol transport.

In decreasing order of density there are also:

• intermediate Density Lipoproteins (ILD),

• very Low-Density Lipoproteins (VLDL)

• chylomicrons.

• each lipoprotein is designed to carry its cholesterol to a different location in the body to be used for a different purpose.

And here is where the controversies start.

Traditional methods of measuring blood cholesterol were not able to differentiate between the different lipoproteins that transport cholesterol. We now understand that this is of critical importance.

• In the 1980s, we believed that the only thing that mattered was your total blood cholesterol level. This was a big mistake.

• In the 1990s, we believed that HDL-C (High Density Lipoprotein-Cholesterol) was good (prevented heart disease) and LDL-C (Low Density Lipoprotein-