Eating burnt eggs may raise the risk of heart problems and cancer, experts warn.
Prolonged temperatures of over 350F can cause the release of chemicals that are linked to inflammation and the thickening of arteries.
These chemicals, called oxysterols, form when dietary cholesterol is cooked at high heats over a sustained period of time.
This means that crispy fried eggs like over hard could be at risk of creating these chemicals, which have been linked to heart disease and cancer, according to Angel Luk, a registered dietitian in Canada.
Instead, she suggests opting for omelettes and other eggs that cook best on lower heats.
And cut down on the oil, as excess amounts can cause eggs to burn faster.
In addition to heart disease, oxysterols have also been linked to some forms of cancer like colorectal and bladder cancer.
Overcooking eggs could lead to the release of harmful chemicals called oxysterols, which have been shown to increase the risk of heart disease and several cancers (stock image)
The above graph shows the rise of colorectal cancer in Americans under 50 over the last two decades
However, eggs are nutrient-dense foods that have been shown to help with weight loss, muscle strength, and heart health due to high amounts of protein, amino acids, and brain-healthy nutrients like choline.
They are also rich in HDL cholesterol, a ‘good’ cholesterol that helps rid the body of excess fats and lower the risk of heart disease.
The research on oxysterols in eggs has also been limited compared to evidence on the benefits of the breakfast staple.
Ms Luk told Health Digest that when HDL cholesterol is overheated, ‘compounds called oxysterols can be created.
‘Some studies show that oxysterols have negative health effects, including increasing the risk of heart disease and cancer.’
According to 2019 research from the National Institutes of Health, oxysterols can increase increase oxidative stress, which occurs when unstable molecules called free radicals damage cells and tissues and lead to inflammation.
This oxidative stress damages disease-fighting antioxidants, leaving the body unprotected against cancer cells.
A 2018 review suggested that oxysterols increased the risk of breast, prostate, colon, and bile duct cancer.
And a study published last month in the journal Cancer Prevention Research found that high oxysterols increased the risk of colon cancer by 22 percent.
Additionally, a 2017 study in Lipids in Health and Disease found that oxysterols bind to LDL, or ‘bad,’ cholesterol, causing harmful plaque to build up in the arteries.
This makes it more difficult for blood to properly flow through the arteries, increasing the risk of heart disease.
Cooking eggs on high heat, such as 350 degrees Fahrenheit (176 degrees Celsius), is most likely to result in oxysterols forming, research has shown.
Over hard eggs, which are typically fried longer than other types like over easy, are considered overcooked after about five minutes on high heat.
Processed meats like sausages cooked at high heats have also been shown to release oxysterols.
To reduce the risk of oxysterols forming, Ms Luk recommended opting for eggs that can be cooked at lower heats, such as scrambled eggs and omelets.
She said: ‘I recommend making a veggie omelet with minimal oil that is heat stable, without overcooking the eggs.
‘This way, the protein in the egg is more easily digested while the vegetables provide additional fiber and antioxidant compounds.’
She also suggested using avocado oil, as it is rich in monounsaturated fats linked to lower cholesterol, reducing the risk of heart disease.