Here are six things that we need to know about cholesterol:
i) It is virtually impossible to explain how vital cholesterol is to the human body. If you had no cholesterol in your body you would be dead. No cells, no bone structure, no muscles, no hormones, no sex, no reproductive system, no digestion, no brain function, no memory, no nerve endings, no movement, no human life – nothing without cholesterol. It is utterly vital and we die instantly without it.
ii) Cholesterol is so vital to the body that our bodies make it. The body cannot risk leaving it to chance that we would get it externally from food or some other external factor – that’s how critical it is.
iii) There is no such thing as good cholesterol and bad cholesterol. Cholesterol is cholesterol. The chemical formula for cholesterol is C27H46O. There is no good version or bad version of this formula.HDL is not even cholesterol, let alone good. LDL is not even cholesterol, let alone bad. HDL stands for High Density Lipoprotein. LDL stands for Low Density Lipoprotein. (There are three other lipoproteins, by the way, chylomicrons, VLDL and IDL).
Fat and cholesterol are not water soluble so they need to be carried around the body in something to do their vital work. The carriers of such substances are called lipoproteins. We can think of lipoproteins as tiny ‘taxi cabs’ travelling round the blood stream acting as transporters. So, lipoproteins are carriers of cholesterol – oh – and triglyceride and phospholipids and protein. All lipoproteins carry all of these substances – just in different proportions. LDL would more accurately be called the carrier of fresh cholesterol and HDL would more accurately be called the carrier of recycled cholesterol.
iv) The standard blood cholesterol test does not measure LDL – it estimates it. The fasting blood cholesterol test can only measure total cholesterol and HDL. There are two other unknowns in a four variable equation – LDL and VLDL. The estimation is refined further using the Friedewald equation (named after William Friedewald, who developed it).
Total cholesterol = LDL + HDL + Triglycerides/5 (Ref 1) (More detail here.)
As any mathematician will tell you, one equation, with four variables, only two of which can be measured, is a fat lot of good. We need at least one more equation or known variable, to avoid circular references. This also means that:
– All other things being equal, LDL will rise if a) total cholesterol rises and/or b) if HDL falls and/or if c) triglycerides fall.
– All other things being equal, LDL will fall if a) total cholesterol falls and/or b) if HDL rises and/or if c) triglycerides rise.
No wonder an inverse association is observed between LDL and HDL – it is by definition. More surprising is that a fall in triglycerides, which would be welcomed by doctors, would be accompanied by an automatic increase in LDL, all other things being equal, which would not be welcomed by doctors. And you thought that this was scientific.
v) Statins stop the body from producing the cholesterol that it is designed to produce. They literally stop one of our fundamental body processes from being able to function. The intelligent view on statins is that in the very limited arena where they appear to have some ‘benefit’ (men over 50 who have already had a heart attack), they ‘work’ by having anti-inflammatory properties and that the fact that they lower cholesterol (by stopping the body from being able to produce this vital substance) is a very unfortunate side effect. (Drug companies should work on developing something that has the anti-inflammatory benefit without this huge and damaging side effect – it’s called aspirin).
One in 500 people have familial hypercholesterolemia and may have a problem clearing cholesterol in their body (rather like type 1 diabetics who can’t return their blood glucose levels to normal). For anyone else to be actively trying to lower their vital and life affirming cholesterol levels is deeply troubling.
vi) “Cholesterol in food has no impact on cholesterol in the blood and we’ve known that all along.” Ancel Keys.
Ancel Keys, the same man who did the brilliant Minnesota starvation experiment, spent the 1950’s trying to show that cholesterol in food was associated with cholesterol in the blood. He concluded unequivocally that there was not even an association, let alone a causation. He never deviated from this view.
Cholesterol is only found in animal foods (it is a vital substance for every living creature). Hence the only foods that Keys could add to human diets, to test the impact of cholesterol, were animal foods. Given that he concluded that eating animal foods had no impact on blood cholesterol levels, it follows that animal foods per se have no impact on blood cholesterol levels (not that high cholesterol is a problem – quite the contrary – but that’s another story).
There is no need, whatsoever, to avoid liver, red meat, other meat, fish, eggs, dairy products etc for any cholesterol that they may contain.
The body makes cholesterol. I worry about a number of things, but I don’t worry that my body is trying to kill me.
UPDATE: Following numerous blog comments from people “worried about cholesterol”, I’ve written this post.
Ref 1: EH Mangiapane, AM Salter, Diet, Lipoproteins and Coronary Heart Disease: A Biochemical Perspective, Nottingham University Press, (1999). (See reference 159 The Obesity Epidemic)