Boiled eggs are often praised for being the ideal on-the-go snack — full of protein, easy to digest, and loaded with nutrients like vitamin D, B12, and choline.
But experts warn that how you eat them — particularly the yolk — could make a big difference when it comes to your heart health.
Why Egg Yolks May Be Harmful
The egg white is mostly protein and poses no cardiovascular concerns. The issue lies in the yolk, which contains cholesterol and phosphatidylcholine. When this compound is digested, gut bacteria convert it into trimethylamine (TMA), which the liver turns into TMAO — a chemical that has been strongly linked to arterial plaque and heart disease.
“TMAO is now recognized as a major contributor to cardiovascular disease,” says Dr. Karen Liu from Johns Hopkins University. “And egg yolks are one of the top dietary sources.”
A BMJ study found that eating just 10 grams of egg per day — about one-sixth of a large egg — could raise the risk of coronary artery disease by up to 54%, especially in people with metabolic health issues.
A Real-World Warning
One case in China raised red flags: a 30-year-old man who ate multiple whole boiled eggs daily was hospitalized after a mild stroke. His cholesterol had spiked from 5.1 mmol/L to 11 mmol/L. While other factors likely played a role, doctors believed his egg-heavy diet contributed.
Who Should Be Most Careful?
Egg yolks may not be dangerous for everyone, but certain individuals are more vulnerable:
• People with existing heart disease
• Those with high cholesterol
• Individuals with high blood pressure
• Diabetics, due to altered lipid metabolism
Even healthy individuals should consider moderation if they eat eggs frequently.
How to Enjoy Eggs Without the Risks
You don’t have to stop eating eggs — just be mindful of how you prepare and consume them. Some heart-smart strategies include:
• Stick to egg whites, which are high in protein and free of cholesterol
• Limit whole eggs to 2–3 per week, especially if you have a family history of heart disease
• Combine eggs with high-fiber foods like oats or vegetables
• Avoid cooking eggs in butter or oils
• Don’t eat eggs on an empty stomach, which can increase cholesterol absorption
For added protein without the cholesterol risk, consider other sources:
• Greek yogurt
• Tofu
• Lentils or beans
• Skinless chicken
• Fish like salmon or tilapia
How Eggs Stack Up Against Other Foods
Here’s how one egg yolk compares to other protein-rich foods:
• Egg yolk: ~185 mg cholesterol, TMAO risk high
• 3 oz salmon: ~50 mg cholesterol, TMAO risk low
• Oatmeal (½ cup cooked): 0 mg cholesterol, TMAO risk very low
• Almonds (1 oz): 0 mg cholesterol, TMAO risk heart-protective
• Chicken breast (3 oz): ~75 mg cholesterol, TMAO risk moderate
Eggs may not be the highest in cholesterol, but they pose a unique threat due to their impact on TMAO levels.
Metabolism and Genetic Factors Matter
Not everyone processes cholesterol the same. Some people — due to genetic or metabolic differences — are more sensitive to dietary cholesterol. If your blood cholesterol is high despite an otherwise healthy lifestyle, your egg habit could be part of the issue.
Final Thoughts
Boiled eggs are nutritious, affordable, and convenient. But when eaten in excess — especially with the yolk — they could quietly contribute to heart disease.
Professor David Spence sums it up this way:
“Egg yolks are the enemy of arteries, much like cigarette smoke is to lungs.”
So next time you reach for an extra boiled egg, ask yourself:
• Do I need the yolk?
• Could I get protein from another source?
• Am I nourishing my body — or unknowingly risking my heart?
Because even the smallest daily choices can shape your long-term health — and your arteries are paying attention.