High blood cholesterol levels have been sighted as one of the main risk factors for heart disease. And for decades, people have been told that the dietary cholesterol in certain foods that we consume raise blood cholesterol and causes heart disease.
Although this idea may have been a rational conclusion based on the available science 50 years ago, more recent science now disputes its claim.
This article takes a close look at the current research on dietary cholesterol and the role it plays in blood cholesterol levels and heart disease.
What Is Cholesterol?
Cholesterol is a waxy, fat-like substance that occurs naturally in the human body. And although many people have been lead to believe that cholesterol is harmful, the truth is that it’s essential for proper body function.
Your body makes all the cholesterol it needs and this cholesterol then contributes to the membrane structure of every single cell in your body.
However, a small amount is also absorbed from certain foods, such as eggs, meat and full-fat dairy products.
This cholesterol then has a critical role in making hormones, vitamin D, and substances that help in the digestion of food as well as other important tasks. Simply put, you would literally be unable to survive without it.
Cholesterol and Lipoproteins
When people talk about cholesterol in relation to heart health, they usually aren’t talking about cholesterol itself. What they are actually referring to are the structures that carry cholesterol in the bloodstream. These structures are called lipoproteins.
Lipoproteins are made of droplets of fat (lipid) which is surrounded by protein. In other words, fat is the transport vehicle and protein is the passenger. (1)
There are several kinds of lipoproteins, but the two that are most noted and considered relevant to heart health are low-density lipoprotein (LDL) and high-density lipoprotein (HDL).
Low-Density Lipoprotein (LDL)
LDL makes up approximately 60 to 70 percent of our total blood lipoproteins and is responsible for carrying cholesterol particles throughout your body.
This type of cholesterol is often referred to as “bad cholesterol” because it has been linked with “Atherosclerosis” or what is known as the buildup of plaque in arteries.
However, even though all LDL is lumped into the same basket, there are different types of LDL, mainly broken down by size. They are often classified as either small, dense LDL or large LDL.
Studies show that people who have mostly small LDL particles are at a greater risk of developing heart disease than those with mostly large LDL particles. (4)
In other words, if the small LDL particles outnumber the large LDL particles, the risk of developing heart disease is higher. Therefore, it’s the type of particles most prominent in the blood that determines our risk factor. This measurement is called LDL particle number, or LDL-P.
So, generally speaking, the higher number of small LDL particles you have, the greater your risk of developing heart disease.
High-Density Lipoprotein (HDL)
Making up the other 30 to 40 percent of your body’s cholesterol is HDL or what is commonly referred to as “good cholesterol”. One of HDL’s main roles is to pick up excess cholesterol throughout the body and takes it back to your liver, where it can either be used or excreted.
Conclusion: A high level of “small LDL lipoproteins” is associated with a greater risk of heart disease, whereas higher levels of “HDL lipoproteins” lower your risk.
Dietary Cholesterol and Blood Cholesterol
The amount of cholesterol in your diet and the amount of cholesterol in your blood are two very different things.
Although it may seem logical that eating high cholesterol foods would raise ones blood cholesterol level, it doesn’t typically work that way. You see, the body “automatically” tightly regulates the amount of cholesterol in the blood by controlling its internal production.
Because of the body’s ability to control its own cholesterol output, foods high in dietary cholesterol have very little to no impact on blood cholesterol levels in most people, approximately 75 percent of the population. (11, 12)
Conversely, in some individuals, high cholesterol foods can cause a rise in blood cholesterol. These people are commonly referred to as cholesterol “hyper-responders” and tend to make up about 25 percent of the population. This hyper-responsive act is considered to be a genetic predisposition. (13, 14)
This is because the general increase in LDL particles typically reflects an increase in large LDL particles, not small, dense LDL. And people who have mainly large LDL particles actually have a lower risk of heart disease. (17)
Equally, is that hyper-responders also experience an increase in HDL particles, which offsets the increase in LDL by transporting excess cholesterol back to the liver for elimination from the body. (18)
So, even though hyper-responders may experience a rise in their cholesterol level when they increase their dietary cholesterol, the ratio of LDL to HDL cholesterol in these individuals stays the same and their risk of heart disease doesn’t seem to increase.
Conclusion: The majority of people can effectively adapt to a higher intake of cholesterol. Therefore, because of this, dietary cholesterol has little to no effect on blood cholesterol levels for the masses.
Dietary Cholesterol and Heart Disease
Contrary to popular belief, heart disease is not caused by just having high cholesterol but rather by a multitude of factors, including inflammation, oxidative stress, high blood pressure and smoking to name a few.
And while heart disease is often driven by the lipoproteins that carry cholesterol throughout the body, dietary cholesterol has little to no effect on this.
The myth about dietary cholesterol was based on biased research
The original studies that found a relationship between dietary cholesterol and heart disease were flawed.
One of the original experiments discovered this link after feeding cholesterol to rabbits, which are herbivores and do not consume cholesterol in their normal diet.
And although these results were completely irrelevant to human disease, the study sparked an increase in clinical studies aiming to demonstrate the same relationship in humans.
Unfortunately, many of the studies that followed were also designed around poorly chosen research which was selectively biased, excluding important information in order to sway results.
New research finds no link with dietary cholesterol and heart disease
A lot of research has been done on eggs specifically. Eggs are a significant source of dietary cholesterol, but many studies have proven that eating them is not associated with an elevated risk of heart disease. (21, 22)
What’s more, in many cases, eggs have even helped improve lipoprotein profiles, which could lower the risk for heart disease.
In fact, one study in particular compared the effects of whole eggs to yolk-free egg substitute on cholesterol levels.
What this study concluded was that the individuals who ate three whole eggs per day experienced a greater increase in HDL particles and a greater decrease in LDL particles than those who consumed an equivalent amount of egg substitute. (23)
Conclusion: Dietary cholesterol has no link with the risk of heart disease. High cholesterol foods like eggs have been shown to be safe and healthy.
So…should you avoid high cholesterol foods?
For years, people have been told to eliminate high cholesterol foods from their diet as a precautionary measure against heart disease. However, the studies outlined in this article have made it clear that this has been unsound advice. (24)
In fact, it just so happens that many foods high in cholesterol are also among the healthiest foods we can consume. These include grass-fed beef, liver, whole eggs, full-fat dairy products, shellfish, and fatty fishes like sardines.
These foods are incredibly nutritious, so avoiding them in fear of their cholesterol content is keeping you astray from some of healthiest foods you can feed your body.
Conclusion: Most foods that are high in cholesterol are also super healthy and nutritious and should NOT be avoided.
Ways to naturally lower high blood cholesterol
If you have high cholesterol, you can often lower it through some simple dietary and lifestyle changes.
For example, losing extra weight may help reverse high cholesterol.
There are also many foods that can help reduce cholesterol naturally. These include avocados, legumes, nuts and seeds, soy foods, fruits and vegetables. Adding these foods to your diet can help lower cholesterol and reduce the risk of heart disease. (28, 29, 30)
Conclusion: High cholesterol can be lowered in many cases through simple diet and lifestyle changes. Losing extra weight, increasing physical activity and eating a healthy diet can all help lower cholesterol and improve heart health.
Even though we’ve been repeatedly told for over five decades that eating foods high in cholesterol will increase the risk of heart disease, newer sciences firmly proves that there is no significant link between the cholesterol you eat and your risk of heart disease.