I thought it would be interesting to lay out some of the known facts about this substance we know as cholesterol, which from a health perspective has acquired such a “bad reputation.” This information might just change your perceptions about cholesterol.
The first and most important point is that cholesterol is essential to life!
Its major biological value can be gauged by the fact that cholesterol is required for all of the following:
- Structure of all the cell membranes in our body (accounting for 90% of the body’s cholesterol) in new cell formation and cellular repair.
- Structure and functioning of our brains and nerve tissue, which contain 25% of the body’s cholesterol; the brain by weight is ⅕ cholesterol.
- Formation of all our steroid hormones including our sex hormones like testosterone and oestrogen.
- Formation of Vitamin D, which is essential for bone health, heart health, weight management, mental & immune function.
- Production of bile salts which we release from our gallbladder into the intestine to digest and absorb essential fats and vitamins.
- Normal immune system function.
So the bottom line is…no cholesterol…no sex! No cholesterol…no life!
If you thought that we get high cholesterol from our food, you are wrong.
The chief source of cholesterol in the body is from internal liver and cell production, which accounts for more than 85% of the body’s cholesterol. The cholesterol content in our diet from foods like eggs and meat makes little or no contribution to measured (blood) cholesterol levels.
Cholesterol and saturated fats are related but they are not the same thing.
Cholesterol is biochemically a sterol, which is not the same as a fat but both cholesterol and saturated fats share common dietary sources like eggs, meat, liver and dairy. Cholesterol is secreted in bile so that fat digestion can take place in the intestine. Both cholesterol and fats are “lipids,” which are substances that do not dissolve in water (or blood); they therefore require a special “lipoprotein” transport system in the body, which means they are both transported through the blood in the same “Taxis.” These are known as very low density lipoprotein VLDL, low density lipoprotein LDL and high density lipoprotein HDL.
When the liver manufactures a lot of fats (triglycerides) from excessive sugar and refined carbohydrates then it secretes these fats inside VLDL particles. LDL (so called “bad cholesterol”) is not actually cholesterol, but is a lipoprotein transport particle formed from VLDL and which transports cholesterol along with fats (triglycerides) from the liver to the body’s cells and in reverse. 70% of the body’s circulating cholesterol is carried in LDL. Cell receptors, especially in the liver, regulate LDL levels by taking up more or less LDL to maintain LDL levels. LDL particles vary in size from large (buoyant) to small (dense). People with Familial Hypercholesterolaemia (FH) have a deficiency of these LDL receptors resulting in very elevated LDL cholesterol levels up to 5x normal.
HDL (so called “good cholesterol”) transports cholesterol from the body tissues back to the liver and is also an antioxidant.
The modern understanding of cholesterol and heart disease risk:
- There is no such thing as “good” or “bad” cholesterol. Cholesterol is cholesterol!
- Total cholesterol as measured in a blood test is a weak predictor of future heart disease.
- More than half of all heart attacks occur in people with ‘normal’ cholesterol levels.
Increased heart attack risk is more closely associated with:
- An increase in the number of small dense LDL particles
- Low levels of HDL
- Elevated levels of blood triglycerides
- Elevated levels of oxidised (“damaged”) LDL particles
- High blood insulin levels
- High blood sugar levels
- Increased small dense LDL levels occur in diabetes, pre-diabetes (metabolic syndrome, insulin resistance syndrome) and in FH.
Dr Jeans is a specialist sport, exercise and lifestyle medicine physician in Harare, Zimbabwe, where he has practised medicine for 30 years. He graduated in medicine from the Godfrey Huggins School of Medicine in Harare. After initially pursuing a medical career in the military and emergency medicine, he completed a postgraduate degree in Sports Medicine at the University of Cape Town. He is currently the Medical Director of the Rolf Valley Sports Medicine Centre, the Innovate High Performance Centre and the Low-Carb Companion Lifestyle Program. He has written many public information media articles and has given numerous lectures on topics relating low-carb, higher healthy fat nutrition to weight-loss, improved health outcomes and sports performance.