Why are eggs unhealthy for you? A critical look at the risks

October 11, 2025 •

3 min read

For decades, the high cholesterol content of eggs has fueled a public health debate and caused many to question their safety. While often lauded as a nutritional powerhouse, for some individuals and in certain contexts, there are legitimate reasons to understand why are eggs unhealthy for you.

Quick Summary

This article explores the potential downsides of eggs, including their high cholesterol content, links to cardiovascular disease and diabetes risk, and the formation of the harmful compound TMAO. It also examines the risk of foodborne illness from salmonella and discusses egg allergies.

Key Points

High Cholesterol: Egg yolks contain significant dietary cholesterol, potentially increasing cardiovascular risk, particularly for those with pre-existing conditions.
TMAO Production: Choline in eggs is converted into TMAO, a compound associated with higher cardiovascular disease risk.
Diabetes Risk: Some studies suggest frequent egg consumption is linked to a higher risk of developing type 2 diabetes.
Salmonella Contamination: Raw or undercooked eggs can carry Salmonella, posing a food poisoning risk, especially for vulnerable individuals.
Allergy and Intolerance: Egg allergy is common, especially in children, causing reactions from mild to severe.
Nutrient-Dense Alternatives: Healthier, egg-free protein sources like legumes, tofu, nuts, seeds, lean meats, and fish offer nutritional benefits with fewer associated risks.

The Longstanding Egg Controversy

Historically, eggs faced criticism from health bodies mainly due to the high cholesterol in the yolk. A large egg contains roughly 186 mg of cholesterol. This led to past dietary recommendations to limit eggs, especially for those prone to cardiovascular issues. While current science offers a more complex view, indicating dietary cholesterol affects blood cholesterol less than saturated and trans fats for many, recent studies from 2019 and 2022 still suggest egg consumption may pose health risks for specific groups.

Cholesterol and Cardiovascular Disease

The primary concern regarding eggs and health is their high dietary cholesterol, which is linked to a higher risk of heart disease and overall mortality with increased consumption. A significant analysis involving nearly 30,000 U.S. adults over many years found a clear association between higher dietary cholesterol intake and increased risk of cardiovascular disease and death. The study noted that each additional half egg daily correlated with elevated risk. While some research shows a weaker link in healthy individuals, the risk appears higher for those with conditions like diabetes.

TMAO and Heart Health

Eggs contain choline, which gut bacteria convert into trimethylamine (TMA). The liver then transforms TMA into trimethylamine N-oxide (TMAO). Elevated blood TMAO levels have been associated with increased cardiovascular disease risk.

TMAO production from choline varies considerably among individuals based on their gut bacteria. Some studies report increased TMAO after eating eggs, while others find no significant long-term impact on healthy adults consuming multiple eggs daily. However, this potential link remains a concern due to individual variations in response.

Diabetes Risk

Research indicates a possible link between higher egg intake and increased risk of developing type 2 diabetes. A U.S. study found adults eating seven or more eggs weekly had a higher risk of type 2 diabetes. Similarly, a study in China connected regular egg consumption to increased diabetes risk. Though some controlled trials show no negative effects on blood sugar from eggs, observational studies point to a potential risk, particularly for those with prediabetes or diabetes.

Foodborne Illness (Salmonella)

Eggs can carry Salmonella, a bacteria causing food poisoning. This can be on the shell or, rarely, inside. Eating raw or undercooked eggs increases the risk of Salmonella infection. Vulnerable groups, including pregnant women, young children, older adults, and those with weakened immune systems, face a higher risk of severe illness. Proper cooking until yolks and whites are firm is essential to reduce this risk.

Egg Allergies

Egg allergy is a common food allergy, especially in young children. The body's immune system overreacts to egg proteins, causing symptoms from mild hives to severe anaphylaxis. Many children outgrow this allergy, but those affected must avoid eggs strictly. Some people also experience egg intolerance, leading to digestive issues like bloating and diarrhea.

Protein Comparison: Eggs vs. Alternatives

For those seeking alternatives due to health concerns, several options provide high-quality protein and essential nutrients without the potential downsides of eggs.

High-Protein, Egg-Free Alternatives

Consider these protein sources, which also offer benefits like fiber:

Legumes: Lentils, chickpeas, and black beans provide plant-based protein and fiber, aiding fullness and gut health.
Soy-based products: Tofu and edamame are complete proteins containing all essential amino acids.
Nuts and Seeds: Almonds, walnuts, and pumpkin seeds are rich in protein, healthy fats, and fiber.
Lean Poultry and Fish: Chicken, turkey, salmon, and tuna are excellent sources of complete protein; fish also provides omega-3s.
Dairy: Cottage cheese and Greek yogurt offer high protein, calcium, and often probiotics.


Feature	Whole Egg (1 large)	Firm Tofu (1/2 cup)	Cooked Lentils (1/2 cup)
Protein	~6.3 grams	~22 grams	~9 grams
Saturated Fat	~1.6 grams	~0.7 grams	~0.1 grams
Dietary Cholesterol	~186 mg	0 mg	0 mg
Fiber	0 grams	~1.5 grams	~8 grams
Essential Fatty Acids	Present	Present (varied)	Present (varied)
Risk of Salmonella	Yes	No	No

Conclusion

While eggs are an affordable source of protein and nutrients for many, their universal health benefits are debatable. Concerns about high cholesterol, potential links to heart disease and diabetes (especially for those at risk), TMAO formation, and the risk of Salmonella from raw or undercooked eggs highlight the need for moderation and considering individual health factors. For those with genetic predispositions, existing health conditions, or who want to vary their protein intake, many healthy alternatives are available. Understanding both the benefits and risks of eggs allows for more informed dietary choices.

For more information on balancing a healthy diet, visit the U.S. Department of Agriculture's dietary guidelines at MyPlate.

Frequently Asked Questions

For most healthy people, dietary cholesterol from eggs impacts blood cholesterol less than saturated and trans fats. However, some individuals, known as 'hyper-responders,' may see a significant increase in blood cholesterol, including LDL, with higher egg intake. Studies also suggest a possible increase in LDL for lean, healthy egg consumers.

Yes, cholesterol is concentrated in the yolk, with one large egg having about 186 mg. Some research indicates that eating an extra half-egg daily is linked to increased cardiovascular risk and mortality.

TMAO (trimethylamine N-oxide) is linked to increased cardiovascular disease risk. Eggs contain choline, which gut bacteria turn into TMA, and the liver converts to TMAO. TMAO production from eggs varies greatly depending on an individual's gut microbiome.

Yes, individuals with diabetes, existing cardiovascular conditions, or certain genetic factors (like the ApoE4 gene or familial hypercholesterolemia) may face higher risks and might need to limit egg intake.

Raw or undercooked eggs can contain Salmonella, potentially causing severe food poisoning, especially for vulnerable groups like children, the elderly, pregnant women, and those with weakened immune systems.

Yes, many healthy alternatives exist. Plant-based options like legumes, tofu, edamame, nuts, and seeds offer protein without cholesterol. Lean poultry and fish are also good sources of complete protein and other nutrients.

Individuals with diagnosed egg allergies or certain severe pre-existing health conditions, such as familial hypercholesterolemia, should completely avoid eggs or consult a doctor about their consumption. For others, eating eggs in moderation as part of a balanced diet is key.