There is perhaps no other wholesome food that has caused such a scramble among health experts as the egg. Are they healthy? Of course. But how many eggs can one consume to not interfere with heart health. Harvard says one per does not appear to be associated with cardiovascular disease (CVD) risk, according to a new study and meta-analysis led by researchers at Harvard T.H. Chan School of Public Health. There is one caveat, Asian populations may be at greater heart disease risk with egg consumption.
“Recent studies reignited the debate on this controversial topic, but our study provides compelling evidence supporting the lack of an appreciable association between moderate egg consumption and cardiovascular disease,” said first author Jean-Philippe Drouin-Chartier, visiting scientist in the Department of Nutrition and assistant professor at Laval University in Québec, Canada. The study will be published online March 4, 2020 in the BMJ.
The relationship between egg consumption and CVD risk has been a topic of intense debate in the scientific community in recent decades. Just in the past 12 months, three published studies have reported conflicting results.
Egg Study Results and Cardiovascular Disease Risk
The new findings update a 1999 study–the first major analysis of eggs and cardiovascular disease–that found no association between eggs and CVD risk. That study was led by Frank Hu, Fredrick J. Stare Professor of Nutrition and Epidemiology, chair of the Department of Nutrition, and a co-author of the current study.
- Scientists used repeated measures of diet during up to 32 years of follow-up to gain a detailed picture of potentially confounding lifestyle factors such as high body mass index and red meat consumption.
- The researchers also conducted the largest meta-analysis of this topic, including 28 prospective cohort studies with up to 1.7 million participants.
The analysis of NHS and HPFS participants found no association between moderate egg consumption and risk of CVD. Results from the meta-analysis supported this finding in U.S. and European populations; however, some evidence suggested that moderate egg consumption may be associated with lower CVD risk in Asian populations although this may be confounded by the overall dietary pattern.
- Participants with a higher egg intake had a higher body mass index, were less likely to be treated with statins, and consumed more red meats.
- Most people consumed between one and less than five eggs per week. In the pooled multivariable analysis, consumption of at least one egg per day was not associated with incident cardiovascular disease risk after adjustment for updated lifestyle and dietary factors associated with egg intake (hazard ratio for at least one egg per day v less than one egg per month 0.93, 95% confidence interval 0.82 to 1.05).
- In the updated meta-analysis of prospective cohort studies (33 risk estimates, 1,720,108 participants, 139,195 cardiovascular disease events), an increase of one egg per day was not associated with cardiovascular disease risk.
- In analyses stratified by geographical location (P for interaction=0.07), no association was found between egg consumption and cardiovascular disease risk among US cohorts (1.01, 0.96 to 1.06, I =30.8%) or European cohorts (1.05, 0.92 to 1.19, I2=64.7%).
- An inverse association was seen in Asian cohorts (0.92, 0.85 to 0.99, I2=44.8%).
Conclusion/ Egg consumption and risk of cardiovascular disease: three large prospective US cohort studies, systematic review, and updated meta-analysis. Results from the three cohorts and from the updated meta-analysis show that moderate egg consumption (up to one egg per day) is not associated with cardiovascular disease risk overall, and is associated with potentially lower cardiovascular disease risk in Asian populations.