‘Bad’ LDL cholesterol and ‘good’ HDL cholesterol – the former kills while the latter is beneficial to health. Some people are extremely fit and lead healthy lifestyles, yet have high levels of LDL and very low HDL levels. What is going on?
The truth is that no one knows everything about the workings of cholesterol in the body.
Cholesterol is an insoluble lipid – a fat. That means this compound must travel in the blood by binding to and being carried by protein molecules.
Combinations of fat and protein are unsurprisingly called lipoproteins. There are two types: low density lipoproteins (LDL) and high density lipoproteins (HDL). The former is ‘bad’ because it is a risk factor for atherosclerosis – furring up of the arteries, which can cause heart attack or stroke.
However, there are many other factors involved with atherosclerosis that add to the confusion, such as immune responses and inflammation.
Cholesterol levels are affected by how much dietary fat is absorbed into the bloodstream from the gut, and how the liver makes ‘bad’ LDL cholesterol.
There are also genetic factors involved with an individual’s cholesterol levels. These are linked to levels in parents and siblings. They might be perfectly healthy, but have elevated levels of ‘bad’ cholesterol.
While high levels of ‘good’ HDL cholesterol are known to be protective, there is no evidence that low levels of HDL are in any way harmful. All the blame for atherosclerosis therefore appears to lie with ‘bad’ LDL cholesterol.
The advice from medical practitioners is to do all we can to reduce ‘bad’ LDL cholesterol levels to below 3 mmol per litre, and for total cholesterol levels to 5 mmol per litre or less.
In order to do this they suggest having a diet based on plants, fruit and vegetables. They suggest minimizing animal fat intake, and obtaining proteins and fats as much as possible from oily fish. In addition they suggest to lose weight if overweight, and not to smoke.
However, in the light of the new health idea to reverse obesity and heart disease by severely cutting down on sugar, and increasing healthy saturated fats in the diet, these recommendations now seem rather simplistic.
Could it be that today’s widespread sugar-filled, carbohydrate-rich diets that are clearly the root cause of obesity might have something to do with high levels of bad cholesterol?
Perhaps excessive sugar consumption interferes with cholesterol metabolism?
That there is a global obesity crisis, and concern over the levels of ‘bad’ LDL cholesterol in many people, it seems that there may be a link between these two diseases.
Or perhaps is it because too much polyunsaturated man-made vegetable oils are consumed? The current recommendations are to ‘avoid’ natural fats in foods such as butter, whole fat milk, and cheese. Perhaps this ‘abnormal’ way of being told what to eat is actually causing high levels of ‘bad’ LDL cholesterol?
The results of studies on these ideas should be rather interesting.