Eggs and Heart Health: A Review of the Latest Research and Reports

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Articles / Eggs and Heart Health: A Review of the Latest Research and Reports

Eggs and Heart Health: A Review of the Latest Research and Reports

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Nutrient-rich eggs are part of heart-healthy diet patterns, according to findings from leading researchers and health authorities

By: Mickey Rubin, PhD

In 2015, the Dietary Guidelines Advisory Committee (DGAC) removeddietary cholesterol from the list of nutrients of public health concern1,and this conclusion remained unchanged in the 2020 DGAC report.2 Historically,there has been a limit of 300 milligrams per day for dietary cholesterol, eventhough eggs were listed as a nutrient-rich food and part of healthy dietarypatterns in previous guidelines.3

In making this decision, the 2015 DGA committee referenced,among other sources, a 2013 systematic review that examined the relationshipbetween egg consumption and cardiovascular disease in almost 350,000participants across 16 studies.4 The review and meta-analysis foundno relationship between egg intake and cardiovascular disease, ischemic heartdisease, or stroke.

Since 2015, the science evaluating the relationship betweendietary cholesterol, eggs, and cardiovascular health has continued to grow,with several new research studies and authoritative reports building on ourexisting knowledge.

LATEST RESEARCH FINDINGS FROM OBSERVATIONAL COHORTS

There are often competing headlines in nutrition science,with one study showing one thing, and another study showing the opposite. Thisis often true with a nutrient like cholesterol – or a food like eggs – in whichour knowledge has evolved considerably over the years. Rather than gettingcaught with nutrition science whiplash, it is important to not focus too muchon any one study, but rather view the research in totality.

For example, one observational study of U.S. cohortspublished early in 2019 found a small but statistically significant increase incardiovascular risk with egg consumption.5 However, another observationalstudy published just a few weeks later and analyzing data from over 400,000 menand women in Europe for over an average of 12 years, found a small butstatistically significant decrease inrisk for ischemic heart disease with egg intake.6 While these twoexamples appear similar in design and provide conflicting results, additionalstudies published later in the year had design aspects that provided uniqueinsights.

PURE Cohort ResultsReinforce Earlier Findings and Identify New Insights

A study published in the AmericanJournal of Clinical Nutrition assessed the association of egg consumptionwith blood lipids, cardiovascular disease, and mortality in three largeinternational cohorts. [6] In onecohort, the Prospective Urban Rural Epidemiology (PURE) study, egg consumptionwas assessed in 146,011 individuals from 21 countries. The researchers alsostudied 31,544 patients with vascular disease in 2 multinational studies:ONTARGET and TRANSCEND, both of which were originally designed to testtreatments for hypertension.

The findings from thePURE cohort found no link between egg consumption and cardiovascular diseaseoutcomes. In fact, in the PURE cohort, researchers found that higher egg intake was associated with a lower risk of myocardial infarction,a finding that is consistent with other recent studies of cohorts outside theU.S.6 In the ONTARGET and TRANSCEND cohorts of individuals withvascular disease, the researchers also reported no link between egg consumptionand cardiovascular events.

Thus, these findings from the PURE investigators reinforceprevious research regarding egg consumption in otherwise healthy individuals,but took a big step forward in our understanding of this relationship inindividuals with vascular disease.

Harvard School of Public Health FindingsReveal Decades of Strong Evidence

Yetanother study was published in 2020 that was a follow-up to a landmarkinvestigation first published in 1999. The original study, led by Hu andcolleagues from the Harvard School of Public Health, reported no relationshipbetween egg intake and coronary heart disease or stroke in women from theNurses’ Health Study (NHS) cohort and men from the Health ProfessionalsFollow-Up Study (HPFS) cohort.8  At that time the researchers concluded that an egg a day did not impact heart disease orstroke risk.

The currentstudy, an updated analysis of the study published in 1999, includes up to 24additional years of follow-up and extends the analysis to the younger cohort ofNurses’ Health Study II.9  Thus, this latest analysis included 83,349women from NHS; 90,214 women from NHS II; and 42,055 men from HPFS.Additionally, to compare these new findings to the extensive literature base onthe topic of egg intake and cardiovascular risk, the researchers performed asystematic review and meta-analysis of 27 other published studies from theU.S., Europe, and Asia.

Resultsfrom the updated analysis from NHS, NHS II, HPFS, as well as the updatedmeta-analysis of global cohorts are consistent:

  • Eggconsumption of one egg per day on average is not associated withcardiovascular disease risk overall
    • Results were similar for coronary heartdisease and stroke
  • Eggconsumption seems to be associated with a slightly lower cardiovascular diseaserisk among Asian cohorts

An important strength of this study is the use of repeateddietary assessments over the course of several decades in contrast to someobservational cohorts which utilize only a single dietary measure atenrollment. According to the authors, it is desirable to have repeated dietaryassessments over time to account for variation of dietary intake and otherfactors that contribute to atherosclerosis.

The studies from the PURE cohort and Harvard School ofPublic Health make significant contributions to the scientific literature onegg intake and cardiovascular health. These results are also consistent withthe recent dietary recommendations that cholesterol is not a nutrient of publichealth concern.2

NEW RECOMMENDATIONS FROM LEADING HEALTH AUTHORITIES

In the past year, we have also had multiple recommendationsfrom leading health authorities that have assessed the totality of evidence fordietary cholesterol and cardiovascular disease, as well as the role of eggs inheart healthy diet patterns across the lifespan. A common theme from theseauthoritative recommendations is that eggs can be a part of heart healthy dietpatterns, and in some cases nutrient dense eggs should be emphasized in dietpatterns due to their unique nutrient package.

In fact, the 2020 DGAC report highlights eggs and shellfishas animal-source foods, which are higher in dietary cholesterol, but not highin saturated fat as compared to other animal-source foods.  This report indicates that due to theco-occurrence of dietary cholesterol and saturated fat in animal-source foods,the independent effects of these dietary components can be difficult toseparate in observational studies.  Thisobservation is consistent with the most recent research and recommendationsrelated to eggs – that is, the entire foods is more than the sum ofsingle nutrients.2

There were no major changes to the three USDA Food Patternsrecommended by the 2020 DGAC, but the value of nutrient-rich eggs was emphasizedin the new dietary recommendations for infants, toddlers, and women who arepregnant and lactating.  The nutrients ineggs are essential across the lifespan to support health, and for early life,to support brain development.2

American Heart Association:Eggs Fit in Heart Healthy Diet Patterns

In late 2019, the American Heart Association (AHA) NutritionCommittee published a science advisory on Dietary Cholesterol andCardiovascular Risk.10  Accordingto the authors, “the elimination of specific dietary cholesterol targetrecommendations in recent guidelines has raised questions about its role withrespect to cardiovascular disease.” This review examined evidence fromobservational cohorts and randomized controlled trials and concluded that “a recommendation that gives a specificdietary cholesterol target within the context of food-based advice ischallenging for clinicians and consumers to implement; hence, guidance focusedon dietary patterns is more likely to improve diet quality and to promotecardiovascular health.” The science advisory recommends heart-healthyeating patterns such as the Mediterranean-style and DASH (Dietary Approaches toStop Hypertension)–style diets. Specifically, regarding eggs, the advisoryconcluded:

  • Healthyindividuals can include up to a whole egg daily in heart-healthy dietarypatterns.
  • For older healthy individuals, given thenutritional benefits and convenience of eggs, consumption of up to 2 eggs perday is acceptable within the context of a heart-healthy dietary pattern.
  • Vegetarians who do not consume meat-basedcholesterol-containing foods may include more eggs in their diets within thecontext of moderation.

Australian Heart Foundation: No Evidence to LimitEgg Consumption

It wasn’tonly the American Heart Association that clarified the role of eggs in a hearthealthy diet, but the Australian Heart Foundation (AHF) made similarrecommendations with a new position statement on eggs and cardiovascularhealth.11  The AHF summary of evidence concluded thereis no evidence to suggest any limit on egg consumption for normal, healthyindividuals. The review does suggest a limit to fewer than 7 eggs per weekfor those with type 2 diabetes or cardiovascular disease that require LDL cholesterol-lowering interventions.

Both theAHA and AHF guidelines were clearly a step forward, building on the knowledgethat dietary cholesterol is not a nutrient of concern in healthy individuals.

SUMMARY

The science ondietary cholesterol and eggs continues to grow and demonstrates that eggs arean important part of healthy dietary patterns across the lifespan. Overall,these data support the value of eggs as a nutrient dense food within healthydietary patterns. As a good or excellent source of eight essential nutrientsincluding choline, six grams of high quality protein, 252 mcg of thecarotenoids lutein and zeaxanthin, the 70 calories of an egg can be viewed asso much more than just a source of dietary cholesterol.

See our recipes that fit into a heart-healthy diet or heart health toolkit for more information.

References

  1. Dietary Guidelines Advisory Committee. Scientific Report of the 2015 Dietary Guidelines Advisory Committee: Advisory Report to the Secretary of Health and Human Services and the Secretary of Agriculture,. 2015
  2. Dietary Guidelines Advisory Committee. Scientific Report of the 2020 Dietary Guidelines Advisory Committee: Advisory Report to the Secretary of Agriculture and the Secretary of Health and Human Services,. 2020; Available from: https://www.dietaryguidelines.gov/sites/default/files/2020-07/ScientificReport_of_the_2020DietaryGuidelinesAdvisoryCommittee_first-print.pdf
  3. Dietary Guidelines Advisory Committee. Scientific Report of the 2010 Dietary Guidelines Advisory Committee: Advisory Report to the Secretary of Health and Human Services and the Secretary of Agriculture,. 2010
  4. Shin, J.Y., et al., Egg consumption in relation to risk of cardiovascular disease and diabetes: a systematic review and meta-analysis. Am J Clin Nutr, 2013. 98(1): p. 146-59.
  5. Zhong, V.W., et al., Associations of Dietary Cholesterol or Egg Consumption with Incident Cardiovascular Disease and Mortality. JAMA, 2019. 321(11): p. 1081-1095.
  6. Key, T.J., et al., Consumption of Meat, Fish, Dairy Products, Eggs and Risk of Ischemic Heart Disease: A Prospective Study of 7198 Incident Cases Among 409,885 Participants in the Pan-European EPIC Cohort. Circulation, 2019. 18;139(25):2835-2845.
  7. Dehghan M, Mente A, Rangarajan S, et al. Association of egg intake with blood lipids, cardiovascular disease, and mortality in 177,000 people in 50 countries. Am J Clin Nutr. 2020;111(4):795-803.
  8. Drouin-Chartier JP, Chen S, Li Y, et al. Egg consumption and risk of cardiovascular disease: three large prospective US cohort studies, systematic review, and updated meta-analysis. BMJ. 2020;368:m513. Published online 2020 Mar 4.
  9. 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):1387-1394.
  10. Carson JAS, Lichtenstein AH, Anderson CAM, Appel LJ, Kris-Etherton PM, Meyer KA, Petersen K, Polonsky T, Van Horn L; on behalf of the American Heart Association Nutrition Committee of the Council on Lifestyle and Cardiometabolic Health; Council on Arteriosclerosis, Thrombosis and Vascular Biology; Council on Cardiovascular and Stroke Nursing; Council on Clinical Cardiology; Council on Peripheral Vascular Disease; and Stroke Council. Dietary cholesterol and cardiovascular risk: a science advisory from the American Heart Association. Circulation. 2019;140: e-pub ahead of print.
  11. Australian Heart Foundation; Eggs and Cardiovascular Health: Summary of Evidence. 2019.

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