HEALTH MATTERS

Exploring “The Great Cholesterol Myth”

Posted January 28, 2013, by Axel F. Sigurdsson MD. Last modified September 4, 2017

Exploring "The Great Cholesterol Myth"I have a strong interest in the prevention of heart disease. I believe healthy nutrition and lifestyle are the keys to our health and well-being. In my early career as a cardiologist, working in the hospital setting, I was fascinated by the diagnosis and treatment of heart disease. Don’t misunderstand me, I still am. However, as the years have passed I have become more and more interested in disease prevention.

Helping people stay healthy and avoid disease is very different from diagnosing and treating. Nonetheless, although prevention is important, it is not always easy to practice. It’s time-consuming, results are hard to measure and it deserves both patience and persistence. Therefore, it’s not surprising that doctors are often less interested in prevention than treating and curing. Let me quote Dr. Bernard Lown from his blog, The Lown Conversation: “Diligent prevention, unfortunately, plays second fiddle to heroic cures.”

I believe the most powerful tool to cut the burden of heart disease in our community is education. The remarkable Maya Angelou said: “When you know better you do better”. One of the most important roles for doctors and other medical professionals is educating people about healthy lifestyle, nutrition, exercise and other measures to prevent disease.

All things considered, education is a double-edged sword. Bad education is often worse than no education. A huge number of books and articles have been written on lifestyle, exercise, diet, and nutrition, and there is an overflow of information on the internet. Obviously, some of it is good and some of it is bad. In many cases, education and information is driven by a product line designed to enrich the bank account of the author. Obviously, such information may be misleading.

Much has been said and written about the role of cholesterol in heart disease. Elevated cholesterol is considered a risk factor for cardiovascular disease. Lowering cholesterol, low-density lipoprotein (LDL) cholesterol, in particular, is of key importance. Recently, however, the role of cholesterol in heart disease has been debated.

A few weeks ago a ran into a new book on the subject, called “The Great Cholesterol Myth written by nutritionist Jonny Bowden, PhD, and cardiologist Stephen Sinatra, MD. At first sight, I wasn’t interested in the book. There are so many similar books I thought: The Cholesterol Myths by Uffe Ravnskog, The Great Cholesterol Con by Malcolm Kendrick, The Great Cholesterol Con by Antonio Colpo and The Great Cholesterol Lie by Dwight Lundell. Sounds pretty boring. However, I decided to give Bowden’s and Sinatra’s book a chance.
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Cholesterol and Heart Disease – Can We Ignore Contradictory Evidence?

The role of cholesterol in atherosclerosis and cardiovascular disease is often debated. In my opinion, the so-called lipid hypothesis is an oversimplification of a complex disorder. Sometimes we debate because we disagree on how to simplify complex mechanisms. Cholesterol is just one of many players in the atherosclerotic process. The main reason it has become such a popular player is that it is easy to measure, not because it plays the main role. However, medical debates are often quite interesting, and they may actually have some positives. They often provoke lively discussions, and they may stimulate scientific research. The downside is that if you have already chosen a side, you run the risk of neglecting, or not choosing to accept scientific results or arguments that don’t support your own opinion.

There are different ways for authors to present a hypothesis they believe is true. You can choose to present all available data, and then make an argument for the data you believe support your hypothesis. Such a balanced, informative approach is honest, and it gives the reader a chance to make up his own mind. However, it doesn’t necessarily catch the attention of the news media or make the headlines.

If you believe you’ve found the truth, you may prefer to select data that reinforce your own beliefs. We could call this the preacher’s approach. There is no reason to discuss any contradictory evidence. That’s just confusing.

In my opinion, the recent book by Bowden and Sinatra is a good example oft he preachers approach. Somehow the authors believe they’ve managed to unlock the hidden truth. In fact, you may admire how fearlessly they expose, what they call the misinformation fed by the scientific community. Let me quote the first sentence of the first chapter: “The two of us came together to write this book because we believe that you have been completely misled, misinformed, and in some cases directly lied to about cholesterol”. Interesting and provoking.

Conspiracy theories are likely to get media attention. I presume that’s a part of the procedure. Somehow, we like to read about how we have been cheated and mislead. Consequently, if you manage to convince people they’ve been cheated, they’re more likely to listen to your theories and arguments.

While reading “The Great Cholesterol Myth”, I had this strong urge that I had to play the devil’s advocate. It’s not necessarily because I dislike the book or disagree with everything the authors write. On the contrary, I think they have some great tips on healthy lifestyle and diet. It’s just because I believe people have the right to hear both sides of the story, and then make up their own mind. I’m not a book critique, so whether I liked the book or not is irrelevant. However, taking on the role of the devil’s advocate I want to bring forward some of my thoughts while reading the book.
“Cholesterol Does Not Cause Heart Disease” – The Main Arguments

In the first two chapters, the role of cholesterol in heart disease is discussed. The authors believe that cholesterol numbers are a poor predictor of heart disease. They point out that more than half of the people hospitalized with heart attacks have what they call “perfectly normal cholesterol levels”. The importance of cholesterol for different bodily functions is underlined. The message is; because cholesterol is essential for life it can’t be bad. Let me quote the book: “Both of us became skeptical of the cholesterol theory at different points in our careers, traveling different pathways to arrive at the same conclusion: Cholesterol does not cause heart disease.”

Exploring "The Great Cholesterol Myth"

The second chapter is called “Cholesterol is harmless“. In this chapter the people who write the special reports and guidelines, meant to help doctors make treatment decisions get a fierce amount of critique. A quote from the book: “When the National Cholesterol Education Program lowered the optimal cholesterol levels in 2004, eight of the nine people on the panel had financial ties to the pharmaceutical industry, most of them to the manufacturers of cholesterol-lowering drugs who would subsequently reap immediate benefits from these same recommendations”.

Atherosclerosis is the underlying cause of cardiovascular disease. It leads to the building of plaques within the walls of our arteries. These plaques are composed of several substances, among them is cholesterol.

Atherosclerosis typically affects the coronary arteries, the vessels supplying blood to the heart muscle. In medical school, I was taught that the exact cause of atherosclerosis was unknown. However, there were certain risk factors, which if present increased the likelihood of developing atherosclerosis and coronary artery disease. The main risk factors were family history of heart disease, smoking, high blood cholesterol, high blood pressure, diabetes, and obesity. None of these risk factors was considered to be the cause of heart disease. However, by modifying the risk factors, the likelihood of developing heart disease could be reduced.

I have never believed that cholesterol is the sole cause of heart disease. However, it is certainly involved, and it is quite clear that cardiovascular disease as we know it would not exist if cholesterol was not present. Is a tsunami caused by water? No, but it won’t happen without it. Is heart disease caused by cholesterol? No, but it won’t occur without it.

The fact that cholesterol is a very important biologic substance and essential to life, does not prove that high levels may not promote a disease process. There are many examples of this phenomenon. Iron, for example, has important biologic functions. However high levels of iron in the body can cause a disease called hemochromatosis. Although insulin is essential for our metabolism, research indicates that high levels are undesirable and may promote obesity. A certain level of blood glucose is essential for life. If we don’t get glucose through our diet, the body produces it. However, high blood levels of glucose are undesirable and associated with the disease we call diabetes. So, although cholesterol is an important biologic substance, high levels could certainly be associated with disease.

In animal models, atherosclerosis does not occur in the absence of greatly elevated blood cholesterol. Furthermore, heart attacks have been shown to be uncommon in humans with very low plasma levels of LDL cholesterol due to a sequence variation in the PCSK9 gene. In cell cultures, according to Nobel prize winners Brown and Goldstein, cellular needs for cholesterol can be met with an LDL cholesterol level of 25 mg/dl (0.65 mmol/L). Human newborns have an LDL cholesterol in the range of 40-50 mg/dl (1.1-1.3 mmol/L). Healthy adult levels are 3-4 times higher. The normal LDL cholesterol range is 50 to 70 mg/dl (1.3-1.5 mmol/L) for native hunter-gatherers, healthy human newborns, free-living primates, and other wild mammals, all of whom do not develop atherosclerosis. Randomized trial data suggest atherosclerosis progression and coronary heart disease events are minimized when LDL is lowered to <70 mg/dl (1.8 mmol/L). No major safety concerns have surfaced in studies that lowered LDL to the range of 50 to 70 mg/dl.

Familial hypercholesterolemia (FH) is a disorder characterized by high cholesterol levels, specifically levels of LDL-cholesterol. Many individuals with this disorder die prematurely of atherosclerotic cardiovascular disease. I have found no mention of this disorder in Bowden’s and Sinatra’s book. The most common problem in FH is the development of coronary artery disease at a much younger age than would be expected in the general population. So, try telling a thirty-year-old woman with FH, and an acute heart attack that cholesterol is harmless. Statin drugs have improved prognosis and quality of life in patients with FH.

It is important to emphasize, that it is lipoproteins that interact with the arterial wall and initiate the cascade of events that leads to atherosclerosis. Cholesterol is only one of many components of lipoproteins. LDL, the major carrier of cholesterol in the circulation, is the most atherogenic lipoprotein. High levels of LDL in the blood may lead to increased transport of this substance into the vessel wall. When inside the arterial wall, LDL can undergo a variety of modifications including oxidation, uptake by white blood cells called macrophages, formation of so-called foam cells and the initiation of inflammation. This cascade of events may ultimately result in an atherosclerotic plaque within the vessel wall.

Obviously, cholesterol is not the cause of all this, but it is always involved. So, could it be that atherosclerosis is more likely to occur if plasma concentration of LDL-cholesterol is high than if it is low? The answer is yes. A number of scientific studies indicate that this is definitively the case. However, this does not mean that cholesterol causes heart disease. That’s an oversimplification.