Why Cholesterol is Important For Your Hormones

All hormones are made from cholesterol. Cholesterol is essential for body function, it is a nutrient, some argue it is a hormone, and others even refer to it as an antioxidant. Cholesterol is needed to maintain the integrity of cell membranes, without cholesterol there would not be life, and it is the backbone of your hormone structure. 

You may have heard of “good and bad cholesterol” which is referring to High Density Lipoprotein (HDL) and Low Density Lipoprotein (LDL). Lipoproteins are what carries cholesterol in the blood. HDL is responsible for removing old cholesterol and other fat substances from the cells and taking it to the liver to be broken down, which is why it is known as “good” cholesterol. LDL carries cholesterol to the cells, which is why it’s known as “bad” cholesterol.

Categorising these liporoteins into “good” and “bad” is a complete misunderstanding of this physiological function, we absolutely need both. The problem is the structure and particle size of these lipoproteins and how they can impact the integrity of your cell membranes. 

This is where our diet comes into play. Firstly, cholesterol from your diet is not the same as the cholesterol that your body makes. Because cholesterol is essential for life, your liver will synthesise (make) cholesterol from the proteins, carbohydrates and fatty acids that you eat, regardless of whether you are on a low-cholesterol diet or not. How much cholesterol your liver makes is dependent on your body's needs for it, and this process is tightly regulated.

The structure of the cholesterol that your liver makes is dependent on the quality of the materials (nutrients) it has to work with. In this article I explain the problems with polyunsaturated fatty acids such as sunflower and rapeseed oil, and how overconsumption of these unsaturated fatty acids lead to oxidation and free radical damage. 

Cholesterol made from a diet of bioavailable protein, quality carbs and healthy saturated fatty acids is shown to create a healthy and fluid cholesterol particle that moves smoothly through the bloodstream, and functions optimally as part of the cell membrane where it works with saturated fatty acids to allow things such as nutrients, oxygen, water, hormones etc. in and out of the cells. I use the below diagram to explain this in my 6-week group coaching program.

As you can see, cholesterol molecules made from oxidised fatty acids, probably due to overconsumption of PUFA, can create a hardened, rigid particle which is usually quite small. Not only do these particles create a rigid cell membrane which can inhibit optimal cellular function, it can also contribute to the hardening of arterial walls as the cell membrane does make up this structure. 

This rigid cell membrane can prevent hormones passing in and out of the cell, which determines whether that hormone binds to its receptor to conduct its physiological action. It can also determine whether hormones such as oestrogen are efficiently removed from the cell and eliminated from the body. 

It is also shown that the smaller, rigid cholesterol molecules do not travel as smoothly through the bloodstream and can get stuck in the arterial walls, which can cause the arterial plaques commonly associated with heart disease and high cholesterol. 

This is why the structure and size of the cholesterol and lipoprotein particles is so important when it comes to understanding the function of cholesterol, and it is the quality and source of the food we eat that determines this.

One of cholesterol's key roles in our physiology is that it is the backbone to hormone synthesis. Without cholesterol, your body would struggle to make hormones - this is one of the reasons why the liver synthesises cholesterol and does not rely on dietary sources. 

Thyroid hormone is responsible for converting cholesterol into progesterone, testosterone, estrogen and our stress hormones cortisol and adrenaline. In fact, low thyroid function is often a hidden cause of high cholesterol, in the absence of active thyroid hormone T3 your body won’t convert cholesterol into hormones which essentially results in hormone dysregulation and the conditions and symptoms associated, as well as high circulating cholesterol levels.  

This is why thyroid function should always be explored when optimizing hormone function, but also when cholesterol levels are raised in bloods. Conventional thyroid testing is limited and does not take into account personal symptoms, and whilst I do use a full thyroid blood panel when necessary, I also use my health checklist alongside temperature and pulse readings to get a more therapeutic insight into individual thyroid function. You can find the temps and pulse guide under additional resources, and complete your health check below! This data can be a really valuable insight into your thyroid function and overall hormone physiology.