According to New Harvard Study: An Egg a Day Not Associated with Cardiovascular Disease Risk

By: Mickey Rubin, PhD
Mounting evidence continues to support the role of eggs in a heart-healthy diet. A new Harvard study updates findings first published over 20 years ago, and reinforces that eating eggs is not associated with cardiovascular disease.

The latest study is a follow-up to a landmark investigation first published in 1999. The original study, led by Hu and colleagues from the Harvard School of Public Health, reported no relationship between egg intake and coronary heart disease or stroke in women from the Nurses’ Health Study (NHS) cohort and men from the Health Professionals Follow-Up Study (HPFS) cohort. At that time the researchers concluded that an egg a day did not impact heart disease or stroke risk.

The current study is an updated analysis of the study published in 1999 and includes up to 24 additional years of follow-up and extends the analysis to the younger cohort of Nurses’ Health Study II. Thus, this latest analysis included 83,349 women 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 on the topic of egg intake and cardiovascular risk, the researchers performed a systematic review and meta-analysis of 27 other published studies from the U.S., Europe, and Asia.

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

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

An important strength of this study is the use of repeated dietary assessments over the course of several decades in contrast to some observational cohorts which utilize only a single dietary measure at enrollment. According to the authors, it is desirable to have repeated dietary assessments over time to account for variation of dietary intake and other factors that contribute to atherosclerosis.

This latest study makes a significant contribution to the scientific literature on egg intake and cardiovascular health. These results are also consistent with the 2015 Dietary Guidelines recommendation that cholesterol is no longer a nutrient of concern for Americans and guidelines published in a science advisory from the American Heart Association in 2019.

Eggs are a good or excellent source of eight essential nutrients including choline and lutein, nutrients important for brain and memory development along with long-term health. Eggs can be an important part of all healthy eating plans.