​Heart, veins, brains: cholesterol everything, everywhere, all at once

By Eli Liverani

Cholesterol is probably one of the first molecules I have ever heard of in my childhood. Most of the relatives on my mother's side had high cholesterol in their blood, and apparently, levels above a certain range are a risk of cardiovascular diseases. The treatment focused on their diet; limit dairy and egg consumption and lose weight. Some of them were successful just by changing their diet, but in some cases, they had to take some pills. Although they were able to get their cholesterol back in a healthy range, they still had to stick to their treatments all the time. On my father's side, cholesterol levels were always in range, despite their diet and lifestyle.

My humble family seems to represent the whole population (worldwide) then and today.

What is cholesterol? And why is it so relevant?

Cholesterol is a molecule that keeps our cells healthy, every cell in every organ in our body. Our brain, for instance, is made of a large amount of cholesterol. Our bodies can make cholesterol from other molecules and/or recycle it, so an external source is not required.

To reach the various cells, cholesterol travels in the blood, packed into spheres, which are called lipoproteins. They can be low or high density, called LDL and HDL, respectively. The LDL delivers the cholesterol to the cells, while the HDL clears the excessive LDL in the circulation. When LDL increases in the blood and is not properly cleared by HDL, it may stick to the wall of a vessel. Multiple LDLs sticking together can create a plaque — and if the plaque grows, it can obstruct your vessel and block the flow. That is what can develop thrombosis, heart disease and stroke.

Do people with high cholesterol necessarily develop heart disease?

No, but you increase your chances. Think of a ladder, with heart diseases on top. If you have high cholesterol, you are one step closer to the top. If you have high cholesterol and high blood pressure, you are two steps closer and so on. In the end, you want to be as far away from the top as possible, but one single step won’t bring you there. Plants do have a different molecule (phytosterol), which is why an external source of cholesterol in our diet has to come from animal products (dairy, milk, and egg yolk).

So, should you become vegan? Not fully vegan, but drastically decreasing egg (yolk) consumption and switching from butter to vegetable oil was recommended to my family when I was younger. A nutritionist is the best person to ask, but it does not seem to be the sole solution anymore. In fact, some vegans still have high cholesterol! If you keep fat intake around 10% (as recommended in the new dietary guidelines), and you have a healthy lifestyle, it may not matter if you introduce new cholesterol through animal products.

For your palate and soul, it may be a different story.

High cholesterol levels (LDL) can be detected in people with metabolic diseases, such as obesity and diabetes, but not necessarily. Indeed, some people can change their diet and restore a healthy level of “traveling cholesterol,” but unfortunately, it is not one-size-fits-all.

Other factors that contribute are stress, smoking, lack of exercise and an unhealthy diet. So, lifestyle changes can be the next steps. Again, in some cases, the levels stay high. Skinny, active people with a healthy diet can have high cholesterol, too. Excessive exercise can contribute to high cholesterol.

The overall metabolism of cholesterol is complex and, therefore, difficult to restore when a problem occurs. Genetics play a big role, too, and we cannot change our genetics — at least, not yet.

Lately, cholesterol levels (LDL) have been questioned as a reliable predictor of heart disease. In fairness, some studies show that the correlation between high cholesterol and cardiovascular disease incidence is not always strong. Should we find another (or more) appropriate predictor(s) for heart diseases? Yes! That is science, always reaching for better. However, having a high amount of LDL in your blood can increase the chances of sticking to your vessels. Therefore, it is always wise to restore a healthy range.

The evaluation on which action to take should come from your doctor, who will evaluate your overall health: other parameters, such as HDL or triglyceride, for example, your glucose levels, other diseases, and so on. You may have to try various strategies until you find your own, but it will be worth it.