Eating burnt eggs could increase the risk of heart problems and cancer, experts warn.
Prolonged temperatures above 350F can cause the release of chemicals linked to inflammation and the thickening of arteries.
These chemicals, called oxysterols, are created when dietary cholesterol is cooked at a high temperature for an extended period of time.
This means that eggs fried to a crisp, such as too hard, could be at risk of producing 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 omelets and other eggs that cook best at lower temperatures.
And reduce the oil, as excess amounts can cause eggs to burn more quickly.
In addition to heart disease, oxysterols have also been linked to some cancers, such as colorectal cancer and bladder cancer.
Overcooking eggs can lead to the release of harmful chemicals called oxysterols, which have been shown to increase the risk of heart disease and several forms of cancer (stock image)
The above graph shows the increase in colorectal cancer in Americans under the age of 50 over the past twenty years
However, eggs are nutritious foods that have been shown to help with weight loss, muscle strength and heart health due to their 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 fat and lowers the risk of heart disease.
Research on oxysterols in eggs is also limited compared to the evidence on the breakfast food’s benefits.
Mrs. Luk told me Health overview that when HDL cholesterol becomes overheated, compounds called oxysterols can be formed.
‘Some research shows that oxysterols have negative health effects, including an increase in the risk of heart disease and cancer.’
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According to 2019 research from the National Institutes of Health, oxysterols can 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.
Furthermore, a 2017 study shows Lipids in health and disease discovered that oxysterols bind to LDL, or “bad” cholesterol, causing harmful plaque to build up in the arteries.
This makes it harder for the blood to flow properly through the blood vessels, increasing the risk of heart disease.
Cooking eggs over high heat, such as 350 degrees Fahrenheit (176 degrees Celsius), most likely leads to the formation of oxysterols, research has shown.
Over-hardened eggs, which are typically fried longer than other types, such as over-easy, are considered over-cooked after about five minutes over high heat.
Processed meats such as sausages that are cooked at high temperatures have also been shown to release oxysterols.
To reduce the risk of oxysterol formation, Ms. Luk recommends choosing eggs that can be cooked at a lower temperature, such as scrambled eggs and omelettes.
She said: ‘I recommend making a vegetarian omelette 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 extra fiber and antioxidants.’
She also suggested using avocado oil as it is rich in monounsaturated fats which are linked to lower cholesterol levels, reducing the risk of heart disease.