High blood cholesterol levels are a known risk factor for heart
For decades, people have been told that the dietary
cholesterol in foods raises blood cholesterol and
causes heart disease.
This idea may have been a rational conclusion based on the
available science 50 years ago, but better, more recent
evidence doesn’t support it.
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.
Many people think of cholesterol as being harmful, but the
truth is that it’s essential for your body to function.
Cholesterol contributes to the membrane structure of every
single cell in your body.
Your body also needs it to make hormones and vitamin D, and
perform various other important functions. Simply put, you
could not survive without it.
Your body makes all the cholesterol it needs, but it also
absorbs a relatively small amount of cholesterol from certain
foods, such as
eggs, meat and full-fat dairy products.
Bottom Line: Cholesterol is a waxy, fat-like
substance that humans need to survive. Your body makes
cholesterol and absorbs it from the foods you eat.
Cholesterol and Lipoproteins
When people talk about cholesterol in relation to heart health,
they usually aren’t talking about cholesterol itself.
They are actually referring to the structures that carry
cholesterol in the bloodstream. These are called lipoproteins.
Lipoproteins are made of fat (lipid) on the inside
and protein on the outside.
There are several kinds of lipoproteins, but the two most
relevant to heart health are low-density lipoprotein (LDL) and
high-density lipoprotein (HDL).
Low-Density Lipoprotein (LDL)
LDL makes up 60–70% of total blood lipoproteins and is
responsible for carrying cholesterol particles throughout your
It is often referred to as “bad” cholesterol because it has
been linked with atherosclerosis, or the buildup of plaque in
There are different types of LDL, mainly broken down by size.
They are often classified as either small, dense LDL or large
Studies show that people who have mostly small particles are at
a greater risk of developing heart disease than those with
mostly large particles (3).
Still, the most important risk factor is not the size of LDL
particles. It’s the number. This measurement is called LDL
particle number, or LDL-P.
Generally speaking, the higher number of LDL particles you
have, the greater your risk of developing heart disease.
High-Density Lipoprotein (HDL)
HDL picks up excess cholesterol throughout your body and takes
it back to your liver, where it can be used or excreted.
Bottom Line: Lipoproteins are particles that
carry cholesterol around the body. A high level of LDL
lipoproteins is associated with a greater risk of heart
disease, whereas higher levels of HDL lipoproteins lower your
How Does Dietary Cholesterol Affect Blood Cholesterol?
The amount of cholesterol in your diet and the amount of
cholesterol in your blood are very different things.
Although it may seem logical that eating cholesterol would
raise blood cholesterol levels, it usually doesn’t work that
The body tightly regulates the amount of cholesterol in the
blood by controlling its production of cholesterol.
However, in some people, high-cholesterol foods do cause a rise
in blood cholesterol. These people make up about 25% of the
population and are often referred to as “hyperresponders.” This
tendency is considered to be genetic (13, 14).
This is because the general increase in LDL particles typically
reflects an increase in large LDL particles, not small, dense
LDL. People who have mainly large LDL particles actually have a
lower risk of heart disease (3).
Hyperresponders 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
So even though hyperresponders experience raised cholesterol
levels 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 go up.
Of course, there are always exceptions in nutrition, and it is
possible that some individuals see adverse effects from eating
more cholesterol-rich foods.
Bottom Line: Most people can effectively
adapt to a higher intake of cholesterol. Because of this,
dietary cholesterol has little effect on blood cholesterol
Dietary Cholesterol and Heart Disease
Contrary to popular belief, heart disease is not only caused by
Many factors are involved in the disease, including inflammation,
oxidative stress, high blood pressure and smoking.
While heart disease is often driven by the lipoproteins that
carry cholesterol around, dietary cholesterol has
little to no effect on this.
The Myths About Cholesterol Are Based on Bad 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 by nature.
Although these results are not relevant to human disease, the
study sparked an increase in clinical studies aiming to
demonstrate the same relationship in people.
Unfortunately, many of the studies that followed were also
poorly designed and researchers selectively excluded
information in order to sway results.
Higher-Quality Research Finds no Link With Heart Disease
A lot of research has been done on eggs specifically. Eggs are
a significant source of dietary cholesterol, but several
studies have shown that eating them is
not associated with an elevated risk of heart disease
(20, 21, 22, 23, 24).
What’s more, eggs may even help improve your
lipoprotein profiles, which could lower your risk.
One study in particular compared the effects of whole
eggs and yolk-free egg substitute on cholesterol levels.
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
However, it is important to note that eating eggs may pose a
risk to diabetics, at least in the context of a regular Western
diet. Some studies show an increased risk of heart disease in
diabetics who eat eggs (26).
Bottom Line: Dietary cholesterol has no link
with the risk of heart disease. High-cholesterol foods like
eggs have been shown to be safe and healthy.
Should You Avoid High-Cholesterol Foods?
For years, people have been told that
high-cholesterol foods can cause heart disease.
However, the studies mentioned above have made it clear that
this is not the case (9).
It just so happens that many foods high in cholesterol are also
among the healthiest foods on the planet.
These include grass-fed beef, whole eggs, full-fat dairy
oil, shellfish, sardines and liver.
These foods are incredibly nutritious, so don’t avoid them just
because of their cholesterol content.
Bottom Line: Most foods that are high in
cholesterol are also super healthy and nutritious. This
includes whole eggs, fish oil, sardines and liver.
Ways to Lower High Blood Cholesterol
If you have high cholesterol, you can often lower it through
simple lifestyle changes.
For example, losing extra weight may help reverse high
Adding these foods to your diet can help lower cholesterol and
reduce the risk of heart disease.
Bottom Line: High cholesterol can be lowered
in many cases through simple lifestyle changes. Losing extra
weight, increasing physical activity and eating a healthy
diet can all help lower cholesterol and improve heart health.
Take Home Message
High blood cholesterol levels are a risk factor for heart
However, dietary cholesterol has little to no effect on blood
cholesterol in most people.
More importantly, there is no significant link between the
cholesterol you eat and your risk of heart disease.