Nutrition

Why Eggs Have Become the Latest Heart-Healthy Food

By now, most people are aware that the cholesterol in eggs does not negatively impact blood cholesterol levels. Eggs have done a complete turnaround over the past 50 years, from a food on the “Do Not Eat” list to one of the best healthy food choices.1 Here is a look at the latest research on eggs and why your patients may want to incorporate more of them into their diet.

Unscrambling Their Health History

In the 1960s, researchers identified an association between high blood cholesterol levels and increased risk of cardiovascular disease (CVD). Studies appeared to show that dietary cholesterol could increase blood cholesterol.1

In 1968, the American Heart Association recommended that eggs should be limited to no more than 3 whole eggs per week.1 This was incorporated into various dietary guidelines and other national recommendations, including the National Cholesterol Education program. For decades, Americans were advised to limit dietary cholesterol to less than 300 mg per day to help lower their cholesterol and reduce their risk of heart disease.1

Post-1990s, most nutrition experts admit that eggs were incorrectly vilified and did not increase CVD risk. The limit on dietary cholesterol was removed from most dietary recommendations, and scientists agree that the association between diet and CVD risk is far more complex than how much cholesterol and fat individuals consume.1

Consumers are slowly adding eggs back into their diets. According to statistics from the American Egg Board, the annual per capita consumption in 2017 was 276.3 eggs, which was up from 239.7 eggs per year in 1998.2 Given their history, consumers still have questions regarding the safety of eggs.

Eggs, Cholesterol, and CVD

The impact of egg consumption on lipid levels and CVD risk has been examined for decades. Most research has found that they have no or very little impact on serum cholesterol levels.1,3

In 1999, researchers with Harvard School of Medicine reviewed prospective data from the Nurse’s Health Study and the Health Professional’s Follow-up Study for their impact on heart disease risk.4 Their data showed no significant association between eating 1 egg per day and increased risk of coronary heart disease or stroke over short- and long-term periods.

Two studies published in 2017 showed favorable effects of eggs on lipoprotein high- and low- density cholesterol (HDL and LDL, respectively) among healthy young adults.5,6 Data from a study conducted by DiMacro et al5 showed that eating 1 to 3 whole eggs per day compared to eating no eggs increased the concentration of large size HDL and LDL particles, suggesting eggs may be cardioprotective or at least have a neutral effect. Those who ate more eggs also had higher levels of protective antioxidants in their blood. In a second study lead by DiMacro,6 the researchers found no changes in LDL-cholesterol or trimethylamine-N-oxide but increased HDL-cholesterol in those who ate 3 eggs per day.

Eggs and Weight Management

Due to the fact that eggs are low in calories, high in protein, and have moderate fat content, they can be an important tool for improving satiety and promoting weight loss or healthy weight management. Several recent studies are showing that adding more protein to a calorie-restricted diet helps to preserve lean body mass during weight loss.7-9

One study, conducted by Missimer et al, showed that substituting eggs for breads or cereals at breakfast improved satiety and enhanced weight loss without any negative impact on lipids.7 In addition, they noted lower levels of plasma ghrelin after participants consumed eggs at breakfast, but no change in biomarkers of CVD risk.7 Similarly, Leidy et al found that participants felt less hungry and more satisfied after eating eggs for breakfast than after eating oatmeal.8

Vander Wal et al investigated the impact of eggs versus a carbohydrate-rich breakfast on weight loss in overweight and obese adults.9 Participants consumed either 2 eggs or a bagel at breakfast. All Participants were placed on a calorie-restricted diet matched for total calories and energy density consumed throughout the day. Compared with those who ate a bagel at breakfast, those who ate eggs experienced a 61% greater reduction in body mass index, 65% greater weight loss, 34% greater reduction in waist circumference, and 16% greater reduction in body fat.9

Next Page: The Bottom Line

Eggs and Metabolic Syndrome

Metabolic syndrome, characterized by insulin resistance, elevated glucose, A1C, triglycerides, and blood pressure, as well as visceral obesity, affects more than 33% of Americans.10 It is a major risk factor for CVD, which can be reduced with dietary and lifestyle changes.

The research on egg consumption and metabolic syndrome indicates that incorporating eggs into a healthy diet could help improve all the above metabolic markers and reduce cardiometabolic risk.11-14 This appears to be specific to whole eggs only, as a study by Blesso et al showed that the consumption of 3 whole eggs more effectively reduced insulin resistance and improved fasting lipid profiles compared with yolk-free egg substitutes.13 In participants with diabetes and obesity (defined using body mass index), eating 2 whole eggs per day as part of a high-protein, energy restricted diet was more effective at reducing fasting glucose, fasting insulin, and blood pressure than other forms of low-cholesterol animal protein.14

The Bottom Line

Eggs are back on the “Eat This” list, and that is good news for consumers. It gives them a green light to enjoy a familiar food that is inexpensive, versatile, quick and easy to prepare, and convenient for meals or snacks. When included as part of a meal plan, eggs enrich the diet with high-quality protein, healthy fat, and numerous vitamins, minerals, and antioxidants.

Those who are looking for a satiating food that can still promote weight loss can be assured that eating up to 2, or even 3, whole eggs per day is safe and can be beneficial. For patients who are at risk for CVD or diabetes, eggs are also a convenient way to reduce glycemic load of a meal or snack and improve cardiometabolic markers. For recipes and ways to incorporate eggs into your patient’s diets, encourage them to visit IncredibleEgg.org.

Contributed by Anne Danahy MS RDN

References and Recommended Reading

  1. McNamara DJ. The fifty year rehabilitation of the egg. Nutrients. 2015;7(10):8716-22. doi:10.3390/nu7105429.
  2. Egg industry overview. American Egg Board website. https://www.aeb.org/farmers-and-marketers/industry-overview. Updated May 1, 2018. Accessed December 17, 2018.
  3. Natoli S, Markovic T, Lim D, Noakes M, Kostner K. Unscrambling the research: Eggs, serum cholesterol and coronary heart disease. Nutr Diet. 2007;64(2):105-11.
  4. Hu FB, Stampfer MJ, Rimm EB, et al. A prospective study of egg consumption and risk of cardiovascular disease in men and women. JAMA. 1999;281(15):1387-94. doi:10.1001/jama.281.15.1387
  5. DiMarco DM, Norris GH, Millar CL, Blesso CN, Fernandez ML. Intake of up to 3 eggs per day is associated with changes in HDL function and increased plasma antioxidants in healthy, young adults. J Nutr. 2017;147(3):323-29.
  6. DiMarco DM, Missimer A, Murillo AG, et al. Intake of up to 3 eggs/day increases HDL cholesterol and plasma choline while plasma trimethylamine‐N‐oxide is unchanged in a healthy population. Lipids. 2017;52(3):255-63.
  7. Missimer A, DiMarco DM, Andersen CJ, et al. Consuming two eggs per day, as compared to an oatmeal breakfast, decreases plasma ghrelin while maintaining the LDL/HDL ratio. Nutrients. 2017;9(2):89. doi:10.3390/nu9020089
  8. Leidy HJ, Carnell NS, Mattes RD, Campbell WW. Higher protein intake preserves lean mass and satiety with weight loss in pre‐obese and obese women. Obesity. 2007;15(2):421-29.
  9. Vander Wal J, Gupta A, Khosla P, Dhurandhar N. Egg breakfast enhances weight loss. Int J Obes. 2008;32(10):1545-51. doi:10.1038/ijo.2008.130.
  10. Aguilar M, Bhuket T, Torres S, Liu B, Wong RJ. Prevalence of the metabolic syndrome in the United States, 2003-2012. Jama. 2015;313(19):1973-74.
  11. Woo HW, Choi BY, Kim MK. Cross-sectional and longitudinal associations between egg consumption and metabolic syndrome in adults≥ 40 years old: The Yangpyeong Cohort of the Korean Genome and Epidemiology Study. PloS One. 2016;11(1):e0147729.
  12. Becerra-Tomás N, Babio N, Martínez-González MÁ, et al. Replacing red meat and processed red meat for white meat, fish, legumes or eggs is associated with lower risk of incidence of metabolic syndrome. Clin Nutr. 2016;35(6):1442-49.
  13. Blesso CN, Andersen CJ, Barona J, Volek JS, Fernandez ML. Whole egg consumption improves lipoprotein profiles and insulin sensitivity to a greater extent than yolk-free egg substitute in individuals with metabolic syndrome. Metabolism. 2013;62(3):400-10.
  14. Pearce KL, Clifton PM, Noakes M. Egg consumption as part of an energy-restricted high-protein diet improves blood lipid and blood glucose profiles in individuals with type 2 diabetes. Br J Nutr. 2011;105(4):584-92.