High cholesterol is one risk factor for heart disease. So, as it is heart health month in the UK I want to discuss this important substance. Should we worry about it? Can we lower our levels without medications from the doctor?
Cholesterol in your body
Our body and the bodies of all animals are a collection of cells. The outside “skin” of these cells is the cell membrane. Cholesterol forms a large and important part of this cell membrane. In fact, without it, the cell could not exist.
It is also a building block for other chemical compounds. Several important hormones and vitamin D are made from it. And, the body needs it to make bile salts, which help us to digest fats. It also helps to repair damage to blood vessels.
Where does cholesterol come from?
When we eat a diet rich in animal foods we also consume lots of cholesterol. However, it is so important that if we don’t eat enough, our body makes it’s own. In fact, up to 80% of the cholesterol in your body may have been made by you. If you eat less cholesterol your body will compensate and make more of its own. If you eat more of it then most people would make less.
What’s more, we also reabsorb our own cholesterol from the bile salts used in the digestion of fats.
Cholesterol – the good, the bad and the ugly
So, if the body is so keen to have plenty of cholesterol why should we worry about it? In part, the problem lies in how it exists in the body.
Cholesterol is a fatty substance that is not soluble in water or blood. Soluble proteins called lipoproteins carry cholesterol and other fatty substances around the body. There are different types of lipoproteins. The two main types are high-density lipoproteins or HDL, and low-density lipoproteins or LDL.
HDL and LDL are often known as good and bad cholesterol respectively. Yet this is inaccurate as all cholesterol is identical. The difference is in the lipoproteins carrying the cholesterol.
People with better HDL levels generally have less heart disease. Whereas higher LDL may increase heart disease risk. But, that is not the whole story.
We know that there are different subtypes of LDL. Researchers found that there are small, dense LDL particles and large LDL particles. And, it takes many more small dense LDL particles to carry the same amount of cholesterol.
In studies, people with a higher number of small dense LDL particles have a greater risk of heart disease. It appears the small dense LDL is more likely to penetrate the artery walls. LDL is also easily oxidised, especially if antioxidants are low. Which means it is easily damaged by free radicals. And, oxidation makes LDL smaller and denser.
If LDL penetrates the artery walls, it provokes the immune system. This causes an inflammatory reaction that results in the formation of an arterial plaque. These plaques can build up and eventually block the artery. As can happen in the coronary arteries.
Even worse, oxidised LDL is even more inflammatory. This inflammation causes the liver to produce more cholesterol. Then, because cholesterol patches up damaged blood vessels, this creates more plaque. And so on…
So, what is the solution? We know that cholesterol production by the body can be reduced with statin drugs. The problem here is that it is crucial to the body. So, the statins have side effects in a large number of people that take them. For instance, statins can block energy production and slow cell renewal. This means people on statins often feel tired and in pain.
We know changing the amount we eat has little effect on our total cholesterol. However, studies show that eating saturated fats can increase our levels. But, this was only over the short term. In the longer term, researchers found a different result. Saturated fat intake is insignificant for LDL for most people.
As we might expect, there are a lot of research studies on LDL and especially small dense LDL. However, studies of statins show they do not consistently change the proportion of LDL particles sizes. In fact, it is the blood triglyceride levels that change the number of small dense LDL particles. This makes sense because the lipoproteins also carry triglycerides, which are fats. The body needs more lipoproteins to carry a greater amount of triglycerides.
So, lowering triglycerides may help to change the LDL profile. To do this, research shows we must avoid the low fat, high carbohydrate diet. In fact, this diet is now being blamed for the epidemic of metabolic syndrome, type 2 diabetes and obesity.
Inflammation and oxidation also have a role. So, we should also keep inflammation low and provide plenty of antioxidant micronutrients. Eating, for example, an anti-inflammatory diet high in vegetables and fruits, lean meat, fatty fish, full-fat dairy, eggs, nuts and seeds.
It is important to remember that not everyone responds to fat and cholesterol in the diet the same way. Have your levels checked in heart health month!