Moderate egg consumption (up to one egg per day) is not associated with cardiovascular disease (CVD) risk, a study* published by The BMJ shows.
Eggs are a high-quality protein which are rich in iron and unsaturated fatty acids, but they also contain cholesterol so there has been concern that a diet including lots of eggs could increase CVD.
Studies have reported conflicting findings, and not even previous meta-analyses have provided consistent results. To clarify the association between egg intake and CVD, including non-fatal heart attack, fatal coronary heart disease and stroke, repeated measures of diet and lifestyle factors over a long period of time are needed and then the effect of eggs on CVD risk compared with those of other animal and plant-based foods.
In this study, US used repeated measures of diet over a period of up to 32 years, starting from 1980. They accessed data from three large US cohort studies: The Nurses' Health Study (NHS), the NHS II, and the Health Professionals' Follow-Up Study (HPFS); these included 83,349 female nurses aged 30-55, 90,214 female nurses aged 25-44, and 42,055 male health professionals aged 40-75, respectively, who were free of CVD, type 2 diabetes, and cancer at the start of the study.
During the follow up period, there were 14,806 cases of CVD, including 9,010 cases of coronary heart disease and 5,903 cases of stroke. Most people ate between one to five eggs per week, and those with a higher egg intake had a higher BMI, were less likely to be treated with statins, and ate more red meat.
After adjusting for age, lifestyle, and dietary factors, no association was found between egg intake and risk of CVD.
There was an estimated higher risk of CVD when the researchers statistically replaced one whole egg a day with one serving of processed red meat (15%), unprocessed meat (10%) or full fat milk (11%), but foods such as fish, poultry, legumes, cheese and nuts in place of eggs were not linked to CVD risk.
Results from an updated meta-analysis of 28 observational studies further support the overall lack of an association between egg intake and CVD risk, but evidence varied between studies conducted in the US, Europe and Asia.
There was no overall association between egg intake and CVD risk among US and European studies, but moderate egg consumption was associated with a slightly lower CVD risk in Asian populations.
This is potentially explained by the fact that in Asian cultures, eggs are typically included in a variety of different dishes, while in Western populations, eggs tend to be eaten with red and processed meats and refined grains.
The authors pointed out that the participants were made up of health professionals, therefore the findings may not be reflective of the general population, and that people with higher egg intake were generally less healthy.
In a linked editorial**, Professor Andrew Odegaard at the University of California, Irvine, said that the results of the study are convincing, but "we should not put all our eggs in this observational basket for formal guidance on eating eggs.
"If frequent egg consumption is occurring in the context of an overall dietary pattern known to be cardioprotective, or eggs are being consumed for essential nutritional needs, then it is probably nothing to worry about.”
He added: "Single foods could have contextual relevance for health, but a complex and extensive body of nutrition and dietary research really does support the current focus on overall dietary patterns in recommendations and guidelines."
*Jean-Philippe D-C, Siyu C, Yanping L, 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
**Odegaard Andrew O. Egg consumption and cardiovascular disease BMJ 2020; 368:m744