Public opinion has continued to swing back and forth on eggs in recent years. Experts have occasionally cast them as the hero of the breakfast plate, recommending frequent consumption to take advantage of their high protein and amino acid content.
But more often than not, we’ve been told to eat them sparingly. Above all, we’re typically advised to cut down on our consumption of the evil yolk — home to a whopping 185 milligrams of cholesterol, more than half of the 300 mg daily allowance long recommended by experts.
If we look at the facts, it’s understandable that eggs were villainized for their cholesterol contents. After all, for decades, nutrition science has posited a link between dietary cholesterol and elevated blood cholesterol, the latter of which has been linked to an increased risk of heart disease (which is the leading cause of death worldwide1).
But the egg may now be shedding its undeserved reputation, thanks to a recent study that shows that our derision of these little protein powerhouses stemmed from a massive misunderstanding. According to the new research published in July in the American Journal of Clinical Nutrition, eating two eggs a day could actually lower your levels of LDL cholesterol2. Perhaps even more surprising, eating more cholesterol has no effect on how much ends up in our blood.
The History of the Demonization of Eggs
To understand how we got here, we need to go back to the ‘70s. It was in 1972 that researchers posited that a high-cholesterol diet could increase cholesterol levels in the blood. To prove their hypothesis, researchers enlisted 56 adult male participants to first eat a cholesterol-free diet for three weeks before a six-week, high cholesterol regime. Following the second diet, participants’ blood cholesterol was elevated, leading the researchers to draw the most logical conclusion: that eating more cholesterol increased levels of the substance in the blood.
It’s no surprise that in their analysis published in The American Journal of Clinical Nutrition, researchers concluded with a proposal “that relatively greater importance should be given to dietary cholesterol as a determinant of the serum cholesterol level in the United States population2.” For years, we’ve believed that the causes for high cholesterol were largely influenced by eating foods with cholesterol, and that anyone hoping to lower LDL cholesterol levels should steer clear.
That recommendation has been widespread in nutrition circles ever since, clouding the reputation of the versatile and delicious egg. But based on the latest research, do eggs raise cholesterol? Are eggs bad for you?
New Research Adds Subtlety to the Research on Cholesterol
Experts have long been dubious of these conclusions, with many noting that dietary cholesterol didn’t seem to have as direct an impact on blood cholesterol as this initial study seemed to prove. And moreover, the demonization of cholesterol in general is more complex than it seems at first glance.
Some LDL cholesterol, after all, is essential for healthy cell function and endocrine function. And while the liver does produce all the LDL cholesterol we need, it curbs its own production when cholesterol is consumed in dietary form, creating a natural symbiosis between dietary and naturally occurring LDL cholesterol in our blood. In other words, consuming more cholesterol shouldn’t have an effect on blood cholesterol.
A Long-Standing Misunderstanding
The initial researchers weren’t completely off-base with their initial experiment; they just — quite understandably — drew the wrong conclusions. Their misunderstanding stemmed from the fact that nutrients do not exist in isolation, and many foods that are high in cholesterol are also high in another substance: saturated fat.
Seeing as a diet high in saturated fat has already been linked to elevated LDL cholesterol3, the team of Australian researchers behind the new study authored by Professor Jon Buckley posited that perhaps the authors of the 1972 study had overlooked the true culprit. And they designed an experiment tailor-made to prove it.
Over the course of five weeks, the researchers assigned each of 61 healthy volunteers a different diet: one high in both saturated fat and cholesterol, another high in saturated fat but low in cholesterol, and a third high in cholesterol but low in saturated fat. The results? Only those who consumed the third diet saw their LDL cholesterol levels fall.
“There was emerging evidence that it was saturated fat rather than cholesterol that was the ‘bad guy’ in terms of pushing cholesterol up, but ours was the first study to conclusively demonstrate that,” said Buckley. “This was the first study that had really been designed in a way that we could tease out those effects so convincingly.”
And the icing on the cake that was perhaps most convincing? The third diet included two eggs per day. The link between eggs and cholesterol had all been based on an incorrect assumption.
How to Decrease Your LDL Cholesterol Through Diet
If high cholesterol is a worry for you, the best course of action is to pay attention not to dietary cholesterol, but saturated fat — a substance found in high amounts in the red meat and full-fat dairy highlighted in the new federal dietary guidelines. Instead, focus on getting this macronutrient from sources of polyunsaturated fat like salmon, nuts, and seeds. Unlike saturated fat, polyunsaturated fat has been proven to reduce blood cholesterol levels4.
Above all, it’s time we invited foods high in cholesterol but low in saturated fat back to the table. So dig into shrimp and squid, and have an egg or two for breakfast: Your heart will thank you for it.
Sources:
- https://world-heart-federation.org/resource/cardiovascular-diseases-cvds-global-facts-figures/
- https://www.sciencedirect.com/science/article/abs/pii/S0002916525002539?via%3Dihub
- https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/saturated-fats
- https://www.sciencedirect.com/science/article/pii/S2161831325001383
