Long debated for their cholesterol content, eggs are now vindicated by recent research showing saturated fat—not dietary cholesterol—is the main driver of elevated LDL ("bad" cholesterol). A randomized study found that a low-saturated-fat diet including 2 eggs daily reduced LDL and related markers, while a prospective cohort study linked 1–6 eggs/week to lower all-cause and cardiovascular mortality in older adults. These findings indicate moderate egg intake (1–2 daily) as part of a balanced, low-saturated-fat diet is safe and may benefit heart health.
Picture this: It’s a sunny morning in a cozy kitchen. A parent cracks open an egg into a sizzling pan, while their teenager argues, “Aren’t eggs bad for your heart? I read they’re loaded with cholesterol!” The parent pauses, confused—after all, they grew up hearing eggs were a “superfood,” packed with protein and nutrients. Sound familiar? For decades, eggs have been caught in a nutritional crossfire, with conflicting advice leaving many of us wondering: Are they friends or foes to our cardiovascular system?
Today, we’re diving into the science to settle the score. Recent groundbreaking research is turning old beliefs on their head, revealing that the real villain in heart health might not be the egg itself—but what we often eat alongside it. Let’s crack open the facts.
The Age-Old Controversy: Eggs, Cholesterol, and the Heart
Eggs are nutritional powerhouses, brimming with high-quality protein, vitamins, and minerals. Yet, when it comes to their impact on heart health, opinions have long been divided. On one side, critics warn that eggs—especially their yolks—are high in cholesterol, claiming excess consumption raises the risk of heart disease. On the other, proponents emphasize that the egg’s most valuable nutrients, like vitamin B12, choline, and lutein, are concentrated in the yolk, making it a nutrient-dense staple.
This debate stems from decades of dietary guidelines that urged limiting cholesterol intake. For years, eggs were singled out as a primary source of dietary cholesterol, thought to drive up levels of low-density lipoprotein (LDL), often called “bad cholesterol.” Elevated LDL was, in turn, linked to atherosclerosis—the buildup of plaque in arteries, a key precursor to heart attacks and strokes.
But new research is rewriting the rulebook. It turns out, the real culprit harming our blood vessels might be saturated fat, not dietary cholesterol from eggs. In fact, studies suggest that eating eggs in moderation could even lower the risk of cardiovascular disease.
A New Study: Saturated Fat vs. Egg Cholesterol
A pivotal study published in The American Journal of Clinical Nutrition by researchers from the University of South Australia has shed new light on this issue. Using a randomized controlled crossover design, the study evaluated how three different dietary patterns affect blood lipid levels in healthy adults—providing strong evidence to support the revised understanding of eggs and heart health.
DOI: 10.1016/j.ajcnut.2025.05.001
The key takeaway? Saturated fat, not dietary cholesterol, is the main driver of elevated LDL cholesterol. What’s more, when part of a low-saturated-fat diet, eating two eggs a day may actually reduce LDL levels, thereby lowering the risk of cardiovascular disease.
The Study Design
The researchers carefully selected 61 healthy adults with an average age of 39 and an average body mass index (BMI) of 25.8 kg/m². All participants had baseline LDL cholesterol levels below 3.5 mmol/L (135.3 μg/dL). Following the study’s design, each participant was randomly assigned to one of three isocaloric (equal in calories) diets, each lasting 5 weeks. This setup allowed the team to analyze how dietary saturated fat and cholesterol independently influence LDL levels.
The three dietary interventions were:
- High-cholesterol, low-saturated-fat diet (egg group): 2 eggs per day (providing 600 mg of cholesterol daily), with saturated fat making up just 6% of total calories.
- Low-cholesterol, high-saturated-fat diet (no-egg group): No eggs (300 mg of cholesterol daily), with saturated fat accounting for 12% of total calories.
- High-cholesterol, high-saturated-fat control diet: Only 1 egg per week (600 mg of cholesterol daily), with saturated fat comprising 12% of total calories.
Surprising Results: Two Eggs a Day Linked to Lower “Bad Cholesterol”
The findings challenged long-held assumptions. Compared to the control group, both the egg group and the no-egg group consumed less total fat overall. The egg group, in particular, had significantly lower saturated fat intake—just 8% of total calories, nearly 50% less than the other groups. The no-egg group, by contrast, had significantly lower intake of unsaturated fats.
Table: Dietary Intake
All three groups met their target cholesterol intake: 594 mg/day in the egg group, 520 mg/day in the control group, and 300 mg/day in the no-egg group. Additionally, the no-egg group consumed about 7% fewer total calories than the other groups, with a higher proportion of calories coming from carbohydrates and more dietary fiber. However, there were no significant differences in micronutrient intake across the groups.
When it came to blood lipids, the results were striking:
- Compared to the control group, the egg group had significantly lower LDL cholesterol levels (103.6 μg/dL vs. 109.3 μg/dL). They also had lower total cholesterol and non-HDL cholesterol (non-HDL refers to “bad” cholesterol particles, excluding high-density lipoprotein, or “good” cholesterol).
- The no-egg group showed no significant difference in LDL cholesterol compared to the control group (107.7 μg/dL vs. 109.3 μg/dL).
Digging Deeper: The Role of ApoB
To understand why these changes occurred, the researchers looked at apolipoprotein B (ApoB), a protein that serves as the main structural component of LDL cholesterol. They found that:
- The egg group had significantly lower ApoB levels compared to the control group, while the no-egg group showed no significant change.
- Saturated fat intake was positively correlated with ApoB levels, meaning more saturated fat led to higher ApoB.
- Dietary cholesterol, on the other hand, had no significant association with ApoB levels.
These results confirm that saturated fat intake—not dietary cholesterol—is strongly linked to higher LDL cholesterol levels.
Figure: LDL Cholesterol Expression in the Three Dietary Groups
Why Early Studies Conflicted
This research also helps explain why earlier studies on eggs and heart health often produced conflicting results. In many cases, people who eat lots of eggs also consume high amounts of saturated fat—think bacon, butter, or sausage alongside their morning eggs. It’s likely that the saturated fat, not the eggs themselves, was driving the increased heart disease risk observed in some studies.
How Many Eggs Should You Eat? The Sweet Spot
If moderate egg consumption doesn’t harm the heart and may even help, the next question is: How many eggs are optimal?
A study published in Nutrients by researchers from Monash University in Australia offers reassuring guidance. The study found that compared to people who never or rarely ate eggs, those who ate eggs 1–6 times per week had a 15% lower risk of all-cause mortality and a 29% lower risk of cardiovascular disease (CVD) mortality.
DOI: 10.3390/nu17020323
The research tracked 8,756 older adults (average age 76.9, 54% female) for an average of 5.9 years. Participants were grouped by egg intake: never/rarely (1–2 times per month), weekly (1–6 times per week), or daily (multiple times per day).
Key findings included:
- Weekly egg eaters had a 15% lower all-cause mortality and a 29% lower CVD mortality than those who rarely ate eggs. There was no significant difference in cancer mortality.
- Among those with moderate to high-quality diets, weekly egg consumption was linked to a 33% and 44% lower CVD mortality, respectively.
- For individuals with dyslipidemia (abnormal lipid levels), weekly egg intake was associated with a 27% lower CVD mortality. For those without dyslipidemia, the risk dropped even further, by 43%.
Figure: All-cause and cause-specific mortality, total mortality, and frequency of egg consumption
These results suggest that for most older adults, 1–6 eggs per week strike the right balance between nutritional benefits and potential risks.
Conclusion: Eggs in Context
The relationship between eggs and health isn’t black and white—it depends on a mix of dietary context, age, and individual genetic factors.
For most people, enjoying 1–2 eggs per day as part of a balanced diet is safe and beneficial. For those with hypertension, high blood sugar, or high cholesterol, focusing on reducing saturated fat from sources like red meat, organ meats, butter, cheese, and cream is more critical than avoiding eggs altogether. As always, it’s wise to adjust egg intake based on your personal health status and overall dietary pattern.
So, whether you prefer your eggs boiled, fried, poached, or scrambled—paired with veggies, whole-grain toast, or a side of fruit—rest assured that this versatile food can be a delicious and nutritious part of your daily routine.