Saturday, 23 February 2013

Cholesterol, Part 1

Are you scared of Cholesterol? 

 

Why do we hear so much about trying to lower our cholesterol levels?  The story told by most doctors and drug companies is that  eating animal products that contain saturated fat and cholesterol clog your arteries and cause heart disease.  Saturated fats are solid at room temperature and will clog up your kitchen sink if you try and pour them down the drain so they will do the same thing in your blood vessels.  ( Even though you blood vessels are 15 C warmer than your kitchen pipes)  The scientists who believed cholesterol caused heart disease knew that analogy was ridiculous.  Their theory was that when there is too much cholesterol in the blood it gets stuck in the arterial wall which leads to the build up of plaque and atherosclerosis.


This Means War!


There is a  group of doctors and scientist who are waging a war on cholesterol.  They are trying to get your cholesterol levels as low as possible.The seem to believe that any amount of cholesterol is dangerous and their views can be summed up in the following quote:  "Eating foods that contain any cholesterol above 0 mg. is unhealthy"   T. Colin Campbell, PhD, author of The China Study

There is another group of "Cholesterol Skeptics" who say that cholesterol has nothing to do with heart disease.  They claim that measuring cholesterol at all is a waste of time.  I was confused so I started looking for the truth.  What I found that was there was some truth to both sides.  High cholesterol does not cause heart disease but the metabolism of cholesterol does play a role in heart disease.  I will expand on the latest theories of heart disease in this blog post series.  I found two websites that had a lot of well referenced material run by two incredibly smart people.   Chris Masterjohn, PhD  at his website "Cholesterol and Health" and Peter Attia, MD at his website "The Eating Academy" 


So what is cholesterol??  Is it really a dangerous substance?


Cholesterol is one of the most important molecules in the human body.  Every cell in your body has the ability to make cholesterol since every cell in your body needs cholesterol.  It is a critical part of cell membranes and is essential to cell membrane permeability.(1)

Cholesterol is needed for brain function.  It is involved in the development of synapses,(2) which enables brain cells to communicate with one another.  It is essential for myelin membrane growth which insulates neurons. (3)  The brain represents 2% of the mass of the  human body but it uses 25% of the cholesterol.  Cholesterol is vital to brain health.

Cholesterol is a precursor to all steroid hormones, which include sex hormones and adrenal hormones.(4)

Cholesterol is a precursor to Vitamin D.(5)

Cholesterol is essential to bile acid production which is used to digest and absorb fats and fat soluble vitamins.(6)



What happens to us if we don't have enough cholesterol?


Smith-Lemli-Opitz Syndrome (SLOS) is a metabolic disorder in which sufferers can not make enough cholesterol to support normal growth and development.  Symptoms of SLOS include mental retardation, poor growth, cleft palate, malformed genitals, extra fingers and toes, heart defects, hearing or sight loss and autism.  The most serious cases (produce almost no cholesterol) are spontaneously aborted during pregnancy or die a few months after birth. (8)


Low Cholesterol levels have also been linked to cancer (9), Depression and suicide (10), stroke (11), Infectious disease (12), autoimmunity (13), inflammation (14), and premature birth (15).


What about high cholesterol.


So we know cholesterol is an essential molecule but is too much cholesterol dangerous. Familial Hypercholesterolemia (FH)  is a genetic defect in which cholesterol levels are extremely high.  People with FH have an increased risk of heart disease.  This would suggest that high cholesterol is involved in heart disease.

But we also know that people with low cholesterol also get heart disease.  If high cholesterol causes heart disease how could you get heart disease if you had low cholesterol.  A 2008 study found that 73% of patients admitted to hospital with coronary heart disease had normal or low cholesterol levels. (16)  


Will eating eggs kill me


Many people do not eat eggs because they are trying to keep their cholesterol low.  Does eating cholesterol raise your cholesterol?  It turns out that cholesterol consumption has no effect on blood cholesterol for 70% of people.  Since about 75% of the cholesterol we need is made by our body if we eat more cholesterol our bodies respond by making and absorbing  less.  There is a slight increase in blood cholesterol in 30 % of people, but their HDL (the so called good cholesterol) goes up as much as their LDL  (so called bad cholesterol) so their cholesterol ratios actually get better.  

Even Ancel Keys, the father of the "lipid hypothesis", knew that eating cholesterol does not cause heart disease.  In 1997 he stated:

“There’s no connection whatsoever between the cholesterol in food and cholesterol in the blood. And we’ve known that all along. Cholesterol in the diet doesn’t matter at all unless you happen to be a chicken or a rabbit.”

Dr. William Castelli, the director of the Framingham Heart Study, stated in a 1992 editorial that:

 "... in Framingham Mass., the more saturated fat one ate, the more cholesterol one ate, the more calories one ate, the lower the person's serum cholesterol ... we found that the people who ate the most cholesterol, ate the most saturated fat, ate the most calories, weighed the least and were the most physically active."



So as you can see cholesterol in not an evil toxin.  It is a vital molecule that is needed for life.  In the next post we will examine how it came to be regarded as a dangerous substance.


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