Cholesterol and eggs have been unfairly villainised.
Research has shown high levels of cholesterol in your bloodstream increases risk for heart disease and stroke. However, the source of blood cholesterol, and function of cholesterol itself is often forgotten.
Cholesterol is vital to your health, and is in fact, found in every cell in your body. It plays a crucial role in forming cell membranes, oestrogen, testosterone and vitamin D.
Key point: Cholesterol is necessary for your health.
The Myth Behind Cholesterol
Last century, research first showed that blood cholesterol levels increased the risk for heart disease. This triggered health warnings to avoid foods that contains high levels of cholesterol. However, numerous scientific studies have shown that there is only a weak link between dietary and blood cholesterol levels.
A boiled egg contains about 200 mg of cholesterol, with the majority contained in the yolk.
In comparison, your liver produces an additional 800 mg of cholesterol per day.
Dietary cholesterol only has a small impact on the levels of cholesterol in your blood. The majority
Key Point: The majority of cholesterol in your blood does not come from food. It is produced by your liver.
The Carriers of Cholesterol
Fat molecules do not naturally float through your blood alone. They need to be transported by lipoproteins which transport the fat molecules to their target cells and organs.
There are 5 classes of lipoprotein that differ in their density, and have creative names:
- High-density lipoprotein (HDL)
- Low-density lipoprotein (LDL)
- Intermediate-density lipoprotein (IDL)
- Very-low-density lipoprotein (VLDL)
In terms of cholesterol, these 5 classes can be split based on their direction of movement as they carry cholesterol.
HDL carries cholesterol from all other cells of your body back to your liver. Your liver processes cholesterol, which is then excreted in the faeces. So HDL earns its name as the “Good Cholesterol” as it helps remove cholesterol.
On the other hand, the other lipoproteins transport cholesterol from your liver to the rest of your body, including your arteries. These lipoproteins, with LDL most commonly singled out, are known as “Bad Cholesterol”. High levels of LDL, IDL, VLDL, chylomicrons will increase the risk of excess cholesterol accumulating in the arteries. This contributes to an increased risk of heart disease and stroke.
Key Point: Consuming eggs decreases LDL, the “Bad Cholesterol”, which deposits excess cholesterol in your arteries.
What You Should Actually Avoid
What you eat with your egg has a much greater effect on your cholesterol. Saturated fatty acids in butter, and refined carbohydrates in white bread.
The liver is stimulated to make cholesterol primarily by saturated fat and trans fat in our diet, not dietary cholesterol.
- Anthony Komaroff, MD
Key Point: Minimise saturated fats and carbohydrates, which have a greater impact on your blood cholesterol levels than any cholesterol you consume.
For most people, one egg a day will not raise blood cholesterol. It is more important to limit the amount of saturated fat and refined carbohydrates - these have a greater impact on your cholesterol level and health risks than the eggs you eat.
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Dawber, T. R., Nickerson, R. J., Brand, F. N., & Pool, J. (1982). Eggs, serum cholesterol, and coronary heart disease. The American journal of clinical nutrition, 36(4), 617-625.
Harvard School of Public Health (2020). Cholesterol. Nutrition Source. Sourced from: https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-and-cholesterol/cholesterol/
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