Eggs have gotten a bad reputation among nutritionists and heart-healthy eaters, though many of those findings are being re-evaluated. The cholesterol in eggs is high, but according to cardiologist Thomas Behrenbeck at Mayoclinic.com, the amount of cholesterol from eggs and other foods that actually affects your blood cholesterol levels is different for everyone. Since cooking vegetables is known to have an effect on the nutrients that they contain, it’s reasonable to wonder what effect, if any, boiling eggs has on their cholesterol content.
The average chicken egg contains approximately 71 calories and 210 mg of cholesterol. According to the University of Michigan Health System, the protein in egg whites is the “gold standard,” meaning that all other sources of protein are evaluated in comparison to egg whites. Egg yolks also contain high levels of lutein and zeaxanthin. These two carotenoids have an antioxident effect on your eyes, and help protect them by filtering out high-energy blue light wavelengths. The American Optometric Association states that there are 600 carotenoids found in nature, but lutein and zeaxanthin are the only two which are deposited in the retina. Their presence in your eye helps prevent age-related macular degeneration, which can lead to blindness.
The American Heart Association recommends that people with healthy levels of LDL cholesterol should consume no more than 300 mg of cholesterol per day, while those with problematic LDL levels should stay below 200 mg of cholesterol. Since one whole egg contains about 210 mg of cholesterol, limiting consumption is a good idea for people with high cholesterol. Egg cholesterol is located in the yolk. Preliminary research suggest that there is a substance in egg whites that helps your body process that cholesterol, but if you are concerned, it’s best to avoid the yolks.
According to researcher J. Constant in a 2007 article in “The Keio Journal of Medicine,” boiling eggs oxidizes the cholesterol in them, intensifying their effect on the blood cholesterol in your arteries. The article recommends that eggs be consumed in a mostly liquid, soft-boiled state to be safe, though concerns about salmonella may contradict this advice. No other studies have confirmed this theory, however, so more research is needed.
Boiling eggs, especially hard boiling, makes it very easy to separate the yolk and discard it. Egg whites are packed with protein, contain no cholesterol, and can be used in a variety of ways, including grating them to sprinkle on salads or slicing them to add to sandwiches. If you hard boil an egg, you can also divide the yolk in half and cut the amount of cholesterol in egg salad without sacrificing flavor. The greatest concentration of lutein and zeaxanthin are in the egg yolks, but leafy green vegetables are an even better source of these carotenoids, and they have no cholesterol.
Boiling an egg does not lower the cholesterol levels in the egg, itself, and may actually raise the threat of clogged arteries, though more studies are needed to confirm this theory. Many popular methods of preparing eggs -- frying them in butter, scrambling them with cream or adding cheese to make omelettes -- do add cholesterol. But, there is not enough evidence to conclude that simply boiling eggs either lowers or raises the cholesterol levels they contain when raw.
- MayoClinic.com: High Cholesterol
- University of Michigan Health System: Eggs
- PubMed.gov: The Role of Eggs, Margarines and Fish Oils In the Nutritional Management of Coronary Artery Disease and Strokes.
- American Heart Association: Common Misconceptions About Cholesterol
- American Optometric Association: Lutein & Xeaxanthin