Eggs and Cholesterol: Are They Good or Bad for Heart Health?

To the well-intentioned consumer, the seemingly back-and-forth nature of egg recommendations can be frustrating. For years the American Heart Association recommended limiting egg intake due to their high cholesterol content, yet in 2015 the Dietary Guidelines ultimately dropped these restrictions saying eggs are part of a healthy diet. Recently, an article published by the New York Times put eggs back on the naughty list. What gives? We are here to put the science to bed once and for all.

Do eggs raise cholesterol and increase the risk for heart disease?

Most of the studies, that concluded that eggs are damaging to our health were observational studies, meaning the researchers did not control the participants’ diet. [1] To “control” a participants diet requires that all participants would consume the same diet with the exception of their egg intake. In this format, changes in blood biomarkers, like LDL cholesterol, could be correlated with higher or lower intake of eggs. [2] In observational studies, however, the researchers simply ask questions about food consumption and disease risk. They seek out statistically significant (usually p<0.05) relationships between a wide range of variables. Then conclude that one thing is correlated with another. Like intake of eggs is correlated with cardiovascular disease.

One problem with the findings in observational studies and the NYT report is that they don’t often control for other factors. For egg studies, other dietary components like intake of refined carbohydrates and high saturated fat foods, and low intake of dietary fiber are also very important factors that can contribute to health. It is difficult to evaluate someone’s overall diet as opposed to their intake of a singular food using observational studies.

When people consume eggs it’s typically in conjunction with saturated fat and carbohydrate-heavy foods like bacon, cheese, potatoes, and white bread. [3] These types of foods will contribute to increased risk for cardiovascular disease, yet if egg intake is what’s being measured, it makes eggs look like the culprit. This is why it is critical to examine the diet as a whole and not each food individually.

Can you eat eggs daily? 

The short answer is, yes. Significant amounts of scientific research indicate that the cholesterol you consume is only weakly related to changes in your blood cholesterol levels. [4]Your body’s cholesterol levels are tightly maintained by feedback loops: if your diet is high in cholesterol, your liver will respond by producing less cholesterol and you will excrete more cholesterol out. [4] A healthy individual can safely eat 1-3 eggs per day at no consequence to HDL, LDL, or total cholesterol levels.

This means that even though eggs are high in dietary cholesterol, they don’t have much of an impact on cholesterol levels in our body when we eat them, especially if you have healthy cholesterol levels to start with. Another food that often falls into this trap is shellfish, but the same mechanism holds true. Eating shrimp won’t lead to increased cholesterol levels. [5]

Eggs aren't the problem: it's often the food they're paired with

Since one food in isolation does not contribute to overall health, we emphasize the importance of all aspects of diet. The other foods on your plate are just as important as the eggs themselves. For maximized nutritional benefits of eating eggs, consider pairing them with foods such as spinach, tomatoes, mushrooms, avocados, and whole grain bread. 



Are egg whites healthier than eating the whole egg? 

Nutritionally speaking, no. Most of the vitamins and nutrients in an egg are stored within the yolk. Egg whites are great if you want a low-calorie substitute, but they’re nutritionally sub-par as they are 90% water and a mere 10% protein. 

Should you be eating brown eggs over white eggs?

Not unless you have a color preference! The difference in egg color doesn’t correlate to its nutritional value, it simply is indicative of the mother hen’s color. The same goes for the intensity of the yolk color, which is related to the type of hen feed.

Which is best? Cage-free, free-range, or organic?

When shopping for whole eggs, we’re bombarded with labels and phrases without any indication of what they actually mean. Cage-free means that the hens are able to roam around a room, either a building or cage, but it does not actually indicate they have access to the outdoors. Free-range means the hens do have access to the outdoors, but it could be as limited as a small door connected to an outdoor area. Organic eggs mean the hens were either cage-free or free-range with outdoor access and were raised on organic feed. Because of this, free-range eggs tend to be superior to cage-free, and organic eggs are a great option as well.

What's the final verdict?

The moral of the egg story is that whole eggs are a great source of protein, nutrients, and antioxidants. They’re packed with vitamins and minerals in a small, easy-to-prepare and easy-to-transport package. Despite being a cholesterol-dense food, consumed cholesterol does not have a significant impact on blood cholesterol levels. Consistent egg consumption, when paired with foods such as vegetables, avocados, and whole grains, can optimize lipid profiles and are a part of a healthy diet.

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References

[1] Bakalar, Nicholas. “Are Eggs Bad for Your Heart Health? Maybe.” The New York Times, 19 Mar. 2019. NYTimes.com, https://www.nytimes.com/2019/03/15/well/eat/eggs-cholesterol-heart-health.html.

[2] DiMarco, Diana M., et al. "Intake of up to 3 eggs per day is associated with changes in HDL function and increased plasma antioxidants in healthy, young adults." The Journal of nutrition 147.3 (2017): 323-329.

[3] McNamara, Donald J. "Eggs and heart disease risk: perpetuating the misperception." The American journal of clinical nutrition 75.2 (2002): 333-334.

[4] Kim, Jung, and Wayne Campbell. "Dietary Cholesterol Contained in Whole Eggs Is Not Well Absorbed and Does Not Acutely Affect Plasma Total Cholesterol Concentration in Men and Women: Results from 2 Randomized Controlled Crossover Studies." Nutrients 10.9 (2018): 1272.

[5] Matheson, Eric M., et al. "Shellfish consumption and risk of coronary heart disease." Journal of the American Dietetic Association 109.8 (2009): 1422-1426.