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Is Cholesterol Bad? 3 Essential Roles of Cholesterol

For many years we have seen news reports and articles that have told us how bad saturated fat and cholesterol are for our health. Anyone who is my age or older remembers the TIME magazine cover from March 26, 1984 that shows a frowny face that was made with two eggs and piece of bacon. We were told, and are still told, that saturated fat and cholesterol will lead to heart disease and surely kill us. But is this true? It does not appear so according to this quote.

“The low-fat “diet–heart hypothesis” has been controversial for nearly 100 years. The low-fat–high-carbohydrate diet, promulgated vigorously by the National Cholesterol Education Program, National Institutes of Health, and American Heart Association since the Lipid Research Clinics-Primary Prevention Program in 1984, and earlier by the U.S. Department of Agriculture food pyramid, may well have played an unintended role in the current epidemics of obesity, lipid abnormalities, type II diabetes, and metabolic syndromes. This diet can no longer be defended by appeal to the authority of prestigious medical organizations or by rejecting clinical experience and a growing medical literature suggesting that the much-maligned low-carbohydrate–high-protein diet may have a salutary effect on the epidemics in question.” [1]

Cholesterol...What Is It Good For?

Cholesterol is essential for life. Several studies have shown that increased cholesterol levels, even increased LDL-C levels, are inversely associated with all-cause mortality in people over 60 years of age. This means that people with higher levels of cholesterol and LDL-C were less likely to die from any cause than those with lower levels. [2] Cholesterol also plays a role in cell membranes and neurons, production of sex hormones and digestion.

Cells and Neurons

Our bodies are made up of many different cells. All cells have a lipid bilayer that makes the cell membrane. Cholesterol is a key component of this membrane. Cholesterol can strengthen this membrane and plays a role in membrane permeability. This means that cholesterol helps to control what gets into and out of the cell. Another key factor is the regulation of certain proteins in the membrane that have critical roles in intracellular, inside the cell, and intercellular, between cells, signaling. [3]

Depiction of lipid bilayer. Photo from wikipedia [3]

The brain has about 20–25% of the body’s total cholesterol. It has been found that cholesterol plays a role in how neurons communicate with each other. It appears that cholesterol plays a

Photo by ColiN00B from

role in learning and memory. [4] Neurons in the brain provide cholesterol so that they can survive and grow but additional cholesterol is needed to form new synapses between neurons. The glial cells are capable of providing this extra cholesterol. [5]


The photo below shows the pathway for the formation of different sex hormones. The first component of the pathway is cholesterol. You can see the similarity in structure of each hormone with that of cholesterol. Without cholesterol, we would not have cortisol which would have a profound influence on our ability to respond to stress and we would have a hard time waking up each morning. Without cholesterol, we would not be able to produce testosterone which would also hamper our ability to grow muscle. Without cholesterol, we would not be able to produce estrogen which would affect menstrual health and fertility in women. This list is not exhaustive by any means but does provide a glimpse into the importance of cholesterol.

Depiction of hormones derived from cholesterol. Photo from wikipedia [6]

Digestion Requires Cholesterol

Cholesterol is used in our bodies to synthesize bile acids. Bile acids play a critical role in the digestion of fat in the intestine. If you still believe that eating fat makes you fat, then you are probably thinking that it would be a great idea to avoid cholesterol and bile. Unfortunately, you would be entirely wrong. Many vitamins, like Vitamin A, D, E and K, are only soluble in fat. This means that our body cannot absorb these vitamins and use them without fat. These vitamins are important for bone health, immune function, eye health and can help in reducing inflammation.

Photo by Terje Sollie from

Foods that are rich in cholesterol include eggs, liver and shrimp. Are the foods only useful due to their cholesterol content? No. They also are rich in many other nutrients that our body needs. Eggs, i.e. the yolks, are rich in choline which has beneficial effects on brain function, mood and can boost mental and physical function. Liver is rich in iron and B vitamins. Both play a role in energy production and have other essential roles in our bodies. Shrimp are rich in iron, selenium and astaxanthin. Astaxanthin is an antioxidant and plays a role in decreasing inflammation. It is also the compound that is responsible for the pinkish color of shrimp and salmon.

Turn The Frown Into A Smile

Photo by CreativeMagic from

It seems that we never should have seen that Time cover vilifying cholesterol given the important role it has in our body. It is essential for life and is found in every cell in our body. It is time to stop fearing cholesterol and eating egg white omelets! Eat the yolks and enjoy the flavor while knowing that you are providing your body with many key vitamins and nutrients.


This article is for educational use only. Nothing contained in this article should be considered, or used as a substitute for, medical advice, diagnosis or treatment. This article does not constitute the practice of any medical, nursing or other professional health care advice, diagnosis or treatment. Always seek the advice of a physician or other qualified health care provider with any questions regarding personal health or medical conditions. Never disregard, avoid or delay in obtaining medical advice from your doctor or other qualified health care provider because of something you have read in this article. If you have or suspect that you have a medical problem or condition, you should contact a qualified health care professional immediately. If you are in the United States and are experiencing a medical emergency, you should dial 911 or call for emergency medical help on the nearest telephone.


1. Sylvan Lee Weinberg. The diet–heart hypothesis: a critique. Journal of the American College of Cardiology Mar 2004, 43 (5) 731–733; DOI: 10.1016/j.jacc.2003.10.034

2. Ravnskov U, Diamond DM, Hama R, et al. Lack of an association or an inverse association between low-density-lipoprotein cholesterol and mortality in the elderly: a systematic review. BMJ Open 2016;6:e010401. doi: 10.1136/bmjopen-2015–010401

5. Mauch DH, Nägler K, Schumacher S, Göritz C, Müller EC, Otto A, Pfrieger FW. CNS synaptogenesis promoted by glia-derived cholesterol. Science. 2001 Nov 9;294(5545):1354–7.

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