Heart disease is one of the biggest threats to our health and longevity. It is in the top four most common causes of death in our modern world.
In the coming three post series, I will be discussing cholesterol and saturated fats relationship (or lack thereof) to heart disease (HD).
Within this two part series, I hope to clear up some myths and misunderstanding that are very common around this topic. I think that the misunderstanding is largely driven by the media and also health professionals alike. Health professionals are not correctly educated on this topic, which is not ideal, because of how prevalent heart disease is.
Now before we dive in, I just want to give you some background information and explain to you how it came to be that there is an association between saturated fat and cholesterol intake in the diet and HD. I will also explain how this wrongful association changed our dietary patterns that ended up increasing our risk of HD, rather than decreasing it.
The lipid hypothesis myth
It all started with a researcher by the name of Ancel Keys. He is the father of what we call the lipid hypothesis, which is basically the idea that dietary cholesterol and saturated fat is one of the main causes of heart disease.
The lipid hypothesis came about as a result of a now infamous study that was run by Ancel Keys. Basically, he wanted to investigate if there was a connection between HD and dietary cholesterol and saturated fat.
So he looked at HD rates in 22 countries and then examined the amount of dietary cholesterol and saturated fat intake within these countries. His initial results were pretty unremarkable and showed no association.
However, he knew he couldn’t make a big splash in the scientific community with results like these, so he decided to eliminate countries from the study and only included 7 of them. Once he did this, the results showed a strong association.
Now not only did he falsify his research, but these studies were purely correlational. Meaning they were only drawing associations between two variables, which was HD and dietary fat intake.
As some of you may know, correlation does not mean causation. For example, in Florida, when ice cream sales go up, so do shark attacks. Does this mean ice cream sales causes shark attacks? Unlikely. However, in summer, more people are likely to buy ice creams and are more likely to be in the water, therefore increasing the risk of shark attacks.
As you can see, correlational research can’t take into account any confounding variables that may be contributing to the association made between two variables. Based on this, it should have cast even more doubt on Ancel Keys results as there may have been other reasons as to why there was a correlation with the 7 countries.
However, it didn’t. His research took off like wildfire, he was put on the cover of TIME magazine and as a result, government health agencies in the U.S, which then made it’s way to other developed nations, started to change dietary policies, ushering health professionals to tell people to replace our once traditional fats from things like dairy, meat and eggs, with vegetable oils from grains (soy oil, canola oil, sunflower and safflower oil – used in cooking and packaged food) that are low in saturated fat, as well as replacing fats with carbohydrates from things like grains (breads, pasta, rice, wholegrain cereals for breakfast).
This was supposed to decrease HD, but instead it lead to an increase in not only HD but other chronic diseases as well. Ancel even tried to justify his research with animal studies using rabbits where he fed them diets high in fat and they developed HD. However, rabbits diet is not naturally high in fat, so of course this was going to cause issues. Plus, human physiology is very different to humans.
Over the last few decades, recent research has practically debunked the connection between dietary saturated fat and cholesterol with HD. And in this three part blog series, I will explain to you what the real drivers of heart disease are.
But first, lets talk about cholesterol as a molecule.
What is cholesterol? As a molecule
I think people don’t really know how important this molecule is to our overall health. Its importance is a reason as to why statin/cholesterol lowering drugs can be so harmful, however I will talk more about this in the next post.
Cholesterol is mainly produced in the liver. If we eat a diet high in cholesterol and saturated fat, our liver produces less cholesterol. If our diet is low in cholesterol and saturated fat, our liver produces more cholesterol. So basically, our liver tightly regulates the production of cholesterol, which means that an “overproduction” of cholesterol in the blood by the liver is not a cause of HD.
As mentioned above, cholesterol and saturated fat are found in high amounts within eggs, meat and dairy products like milk and butter.
Cholesterol within the body plays some very important roles:
- It is involved in the production of vitamin D
- It is needed to produce sex hormones like Testosterone, estrogen and progesterone
- It is needed to produce bile salts in the liver, which helps us digest and absorb our fats
- It is also needed for brain and nervous system function as cholesterol is a major part of brain and nervous tissue.
As you can see, cholesterols function in producing sex hormones, vitamin D and bile salts are actually protective against HD. Vitamin D is needed to protect us from diabetes and HD, as well as testosterone, estrogen and progesterone. As well, without bile salts, we can’t absorb healthy fat-soluble nutrients from our foods (e.g. vitamin A, D, E and K) that may protect us from HD.
The vital roles of cholesterol shows you how cholesterol is not the enemy and decreasing its levels too low via drugs may actually be harmful and cause side effects.
Now that you have a basic understanding of how the lipid hypothesis came to be and what cholesterol actually is as a molecule, in the next post, I will be writing about dietary cholesterol and saturated fats lack of connection with HD.