An Egg a Day Wasn’t Linked to Heart Disease in 1.7 Million People

Few foods have flipped between villain and hero as often as the egg.

For decades, people were told to limit them because of the cholesterol in the yolk.

Then the advice softened. Then a big study revived the worry.

So where does the evidence stand now?

The short version: eggs can raise LDL cholesterol a little. But for most people, an egg a day doesn’t appear to raise heart disease risk.

Are eggs bad for cholesterol?

Eggs do contain cholesterol. As the US National Library of Medicine notes, cholesterol in food comes from animal sources such as egg yolks, meat and cheese.

Eating more eggs can raise your blood LDL cholesterol a little. A 2020 meta-analysis of 17 randomised trials found LDL was higher in people eating more eggs, by about 8 points on the usual scale.

But blood cholesterol is only part of the story. What matters most is heart disease.

And there, the large studies are mostly reassuring for moderate intake, up to about one egg a day.

The American Heart Association now advises focusing on healthy overall eating patterns that are naturally low in cholesterol.

What the research shows

Trials: a modest rise in LDL

The 2020 trial review in Nutrients pooled 17 randomised controlled trials in healthy people.

Compared with control groups, people eating more eggs had higher LDL cholesterol and a higher ratio of LDL to HDL (“good”) cholesterol.

The effect seemed larger in trials lasting more than two months. The authors suggest longer periods of eating more eggs may lead to a bigger rise, so the duration matters.

Huge cohorts: no link to heart disease

A 2020 study in The BMJ combined three large US cohorts followed for up to 32 years. Then it pooled them with other studies in an updated meta-analysis.

That meta-analysis covered 1,720,108 people and 139,195 cases of heart disease. An extra egg a day was not linked to heart disease risk.

The results were similar for coronary heart disease, and also for stroke.

For context, most people in the three US cohorts ate between one and four eggs a week. People eating at least one egg a day had no higher heart disease risk than those eating less than one a month.

A separate 2020 study, PURE, followed about 177,000 people in 50 countries on six continents. It found no significant link between egg intake and blood lipids, death or major heart disease.

That’s not a small sample of events, either. PURE recorded 12,701 deaths and 13,658 heart disease events across its cohorts.

The study that revived the worry

In 2019, a pooled analysis in JAMA followed 29,615 US adults for a median of 17.5 years. It reached a different conclusion.

Each extra half an egg a day was linked to a 6% higher risk of heart disease and an 8% higher risk of death.

But there was a twist. Once the researchers accounted for total dietary cholesterol, the egg link disappeared.

That suggests the issue, if any, is overall cholesterol intake, not eggs specifically.

The same study put a number on that.

Each extra 300 mg of dietary cholesterol a day was linked to 17% higher heart disease risk. The risk of death was 18% higher.

Over the follow-up, the study recorded 5,400 cases of heart disease and 6,132 deaths.

Why do the studies disagree?

Several reasons are likely, and the researchers themselves point to some.

• What else people eat. In the BMJ cohorts, people who ate more eggs also ate more red meat and had higher body weight.
• Statins. Higher egg eaters were less likely to be on cholesterol-lowering drugs.
• Total cholesterol vs eggs. In the JAMA study, eggs stopped mattering once total dietary cholesterol was counted.
• Location. The BMJ analysis found no link in US or European cohorts.

Food studies rely on people recalling what they eat, which adds noise.

What about people with diabetes?

People with type 2 diabetes are often told to be extra careful with eggs.

A 2017 systematic review looked at six randomised trials in people with or at risk of type 2 diabetes. Eating 6 to 12 eggs a week within a heart-healthy diet didn’t harm major heart risk factors.

The BMJ analysis also reported that egg intake was not associated with heart disease risk among participants with type 2 diabetes.

What earlier research found

Guidance now focuses on eating patterns

The American Heart Association’s 2020 science advisory recommends healthy eating patterns such as Mediterranean-style and DASH diets. These are naturally fairly low in cholesterol.

Patterns over single foods

That shift reflects a broader idea in nutrition: the whole diet matters more than any one food.

How it fits together

Eggs raise LDL a little in trials.

Yet across millions of people, moderate egg eating isn’t clearly linked to heart disease. One possible explanation is that the small LDL effect gets diluted by everything else in the diet.

How much should you trust this?

Promising. The large studies broadly agree, but not completely, and most are observational.

What makes it convincing

• Randomised trials measured the effect on LDL directly.
• Cohort data covered over 1.7 million people across many countries.
• The PURE study spanned 50 countries with different diets.
• The JAMA study helps explain where earlier worries came from.

What makes me cautious

• One major analysis did find a link, before adjusting for total cholesterol.
• Most heart evidence is observational and relies on recalled diets.
• People with very high cholesterol or genetic conditions may respond differently.
• What eggs are eaten with, like bacon and butter, is hard to separate.

What this means for you

• For most people, an egg a day looks fine. Large studies find no clear heart risk at that level.
• Watch what comes with them. Fried bacon, sausages and buttered toast change the picture.
• Think pattern, not single food. Mediterranean-style eating has strong evidence.
• If your LDL is high, ask your doctor whether to moderate eggs and other cholesterol-rich foods.
• Diabetes? Trials suggest moderate eggs within a healthy diet are fine, but check with your care team.

The NHS explains how to lower your cholesterol through diet and lifestyle.

In this short video from Mayo Clinic Health System, a clinician answers whether it’s okay to eat eggs every day:

What we still don’t know

1. Do eggs cause any heart harm at higher intakes? Few people in studies ate several a day.
2. Who is sensitive? Some people’s LDL rises more than others’.
3. What about long-term LDL effects? Trials were short.
4. Does cooking method matter? Studies rarely separate boiled from fried.
5. Why did one big study differ? Total cholesterol is the leading explanation, but not proven.

My take: the egg isn’t the villain

What I like about this research is how it untangles a confusing headline war. The JAMA study looked scary, until you read the part where the egg effect disappeared.

I’m less convinced by headlines declaring eggs “good for your heart”. The evidence shows no clear harm at moderate intake, not a benefit.

So an egg a day looks fine for most people. Pay more attention to what’s next to it on the plate.