The complete guide to cholesterol
Introduction
We still get more questions about cholesterol than virtually any other topic. I have done many blogs on this topic and there have been many club threads, but let's pull everything together in one article and present the information as clearly as possible. There will be some parts with which you feel familiar, but there is new information for everyone and some great, significant studies for you to have to hand to quote as evidence when faced with challenges from health professionals.
What is cholesterol?
The word Cholesterol comes from the Greek words "chole" meaning bile and "stereos" meaning solid followed by the standard chemical suffix (bit that goes at the end of a word) for an alcohol, which is "ol". Cholesterol is a waxy substance - it would look a bit like candle wax from a creamy coloured candle. It is an essential structural part of the cells of all mammals. Its chemical (molecular) formula is C
27H
46O, which means that it is made up of Carbon, Hydrogen and Oxygen atoms.
What does cholesterol do?
The simple answer is - it keeps us alive. We would die instantly without cholesterol. Every single cell in the human body depends upon cholesterol for its structure and existence. In more detail, there are the most critical functions of cholesterol:
- Cholesterol builds and maintains the integrity of the cell walls. Every cell in our body is covered by a membrane made largely of cholesterol, fat and protein. Membranes are porous structures, not solid walls, letting nutrients and hormones in while keeping waste and toxins out. If cholesterol were removed from cell membranes they would literally explode from their internal water pressure. Human beings are simply not viable without cholesterol.
- Cholesterol plays a vital role in hormone production. Steroid hormones can be grouped into five categories by the receptors to which they bind: glucocorticoids; mineral corticoids; androgens; estrogens; and progestagens. (Vitamin D derivatives are seen as a sixth hormone system, but we will cover vitamin D separately below). Glucocorticoids help to regulate blood glucose levels and without cortisone, for example, the body could not cope with stress. Mineral corticoids regulate minerals, such as calcium, and they help to regulate blood pressure (the mineral corticoid, aldosterone, regulates sodium and water levels). The sex hormones and therefore the entire human reproductive system are totally dependent on cholesterol. Hence, not only would humans die without cholesterol, the human race would die out.
- Cholesterol is vital for digestion. The human body uses cholesterol to synthesise bile acids. Without cholesterol-rich, bile salts, the human body could not absorb essential fatty acids or the fat soluble vitamins (A, D, E and K) and serious, even life threatening, deficiencies could develop. (It is interesting, therefore, that nature puts cholesterol in virtually every food that contains fat – providing a digestion mechanism in tandem).
- Cholesterol is abundant in the tissue of the brain and nervous system and is critical for the brain and memory functions. Even though the brain is only 2% of the body’s weight, it contains approximately 25% of the body’s cholesterol[i]. Myelin is a substance that we can view as the insulation around nerves. Myelin covers nerve axons (nerve endings, for simplicity) to help conduct the electrical impulses that make movement, sensation, thinking, learning, and remembering possible. Myelin is over one fifth cholesterol by weight. One of the key reasons that we need to spend approximately one third of our lives sleeping is to give the body time to produce cholesterol, repair cells and perform other essential maintenance.
- Cholesterol is also critical for bones and for all the roles performed by vitamin D. Vitamin D is best known for its role in calcium and phosphorus metabolism, and thus bone health, but we are continually learning more about potential additional health benefits of vitamin D from mental health to immune health. Vitamin D can be ingested (and is, interestingly again, found in foods high in cholesterol) and it can be made from skin cholesterol. As we noted in our latitude observation in the Seven Countries Study, sunlight hitting cholesterol in skin cell membranes turns the cholesterol into vitamin D. Modern ‘health’ advice to avoid the sun, take cholesterol-lowering drugs, eat a low cholesterol diet – combined with there not even being a recommended dietary allowance for vitamin D – is undoubtedly contributing to avoidable modern illness.
How much cholesterol do we need?
