Cholesterol is so vital to our body that we make it ourselves. We do not rely on our diet to provide it. If we were to never eat any cholesterol our body would make all it needs. When we do eat food with cholesterol in it, our body reduces the amount it makes, thereby keeping the correct balance that we need for our body to function well. It operates the same way a thermostat works to keep the room at the right temperature.
What is it?
Cholesterol is a fat. It is also a sterol from which steroid hormones are made. It looks a bit like fine candle wax. It flows through the blood stream carried in small protein-covered particles called lipoproteins, that mix easily with blood. The fat in these particles are a combination of cholesterol, triglycerides and phospholipids which hold the whole thing together.
Why we need it and what it does?
Cholesterol is vital to our body's survival. We would literally die without it.
Its four main functions are:
1. It helps to make the outer coating of every cell in our body
2. It makes up the bile acids that digest our food in the intestines
3 It helps the body make vitamin D and transport other fat soluble vitamins
4. It is involved in the production of our hormones, like testosterone and oestrogen
What is the difference between LDL and HDL?
There is no such thing as good or bad cholesterol - just cholesterol.
Because cholesterol is not water soluble it needs to be transported around the blood stream in a carrier. The carriers are called lipoproteins. The lipoproteins carry cholesterol, triglycerides, phospholipids and protein. All lipoproteins carry all of these substances, just in different proportions. HDL (high density lipoprotein) could be called the carrier of recycled cholesterol and LDL (low density lipoprotein - called so because they take up a lot more space compared to their weight) could be called the carrier of fresh cholesterol.
Why LDL is thought to be bad?
LDL is often called the "bad" cholesterol. Measurements above the "ideal" range of 2.6 - 3.3 mmol/L are classed as high and if it gets above 6.5mmol/L then the Doctor will want to put you on a low cholesterol diet and/or give you a prescription to lower your cholesterol. This might work, but it won't change your risk factors for heart disease. It does not explain the whole story.
There are two types of LDL. Pattern A are people who have mostly large fluffy particles with more cholesterol, and Pattern B have smaller, less fluffy particles. Pattern B LDL particles have less cholesterol. A low fat, low cholesterol diet is likely to result in more Pattern B LDL. This pattern has been repeatedly observed in research. If you put a pattern A person on extremely low fat diets they change to a pattern B person. So high cholesterol is OK if you are a pattern A person.
A recent study in Queensland in 2010 confirmed this. The 16 year study followed the dairy consumption of 1529 participants aged 25 - 78. The people who consumed full fat dairy had 69% lower risk of death by heart attack than the low fat group. Yes I have that the right way around - the higher the cholesterol in the diet, the less likely to die of heart attack.
An interesting addition to the research show that a diet high in fructose (sugar) also results in a pattern B, as fructose turns to fat easily but without the accompanying cholesterol.
Therefore which cholesterol pattern you are matters, not your overall LDL level. If you are a pattern B you have a three times the heart attack risk of pattern A people
Why?
The why involves more chemistry. The more cholesterol there is in LDL particle the less likely it is to oxidise. Oxidation turns fats rancid. The higher the temperature the quicker the oxidation process. Inside our body we are 37 degrees centigrade, much higher than our average room temperature. Oxidation is not good in your body. It is similar to rust on iron. Oxidation damages' all the cells in your body as if they are rusting, so, in fact the high cholesterol has a protective action.
So do we need to worry about cholesterol at all?
Your blood cholesterol level is determined by the sum of how much cholesterol your body makes and how much you take in from food, minus how much your body uses or excretes. High cholesterol reading can result from a problem in any of the variables in that equation - your body might produce more cholesterol than it needs due to a genetic predisposition, or you might not be using or excreting the excess cholesterol. Lifestyle factors affect cholesterol reading. Exercise can increase the amount HDL, while obesity and smoking lower HDL. So well before any medication is even thought about, change the lifestyle factors and your body will thank you in every way.
Ancel Keys was one of the early researchers on fat and cholesterol and he stated "Cholesterol in food has no impact on cholesterol in the blood and we've know that all along."
Cholesterol is vital for our body and every living thing. It is found in animal products, so enjoy your meat, fish, eggs, full fat dairy products and know that you are doing something good for prevention of heart attacks.