Eggs are a rich source of high-quality protein, bioactive compounds (such as lutein and zeaxanthin), as well as minerals, folate, B vitamins, fat-soluble vitamins, and omega-3 fatty acids. However, they are also rich in cholesterol and some dietary recommendations have suggested limiting egg consumption to less than 3 eggs per week. Data published over the years has been inconsistent and the debate in the medical community continues.
Two new studies published in 2020 from USA and China involving nearly 200,000 people shed some new light on the issue.
The first study, published in the American Journal of Clinical Nutrition, examined the association between egg consumption and blood lipid profile, cardiovascular disease (CVD) and mortality in populations from low-, middle-, or high-income countries.
The study analysis included 177,555 participants from 50 countries based on 3 separate studies (PURE, ONTARGET, TRANSCEND). Overall 12,701 deaths and 13,658 CVD events occurred.
Results showed that higher intake of egg (up to 7 eggs per week) compared with low (1 egg per week) was not associated with levels of LDL ("bad" cholesterol), HDL ("good" cholesterol), triglycerides, risk of morality or risk of CVD. Furthermore, higher intake of egg was associated with lower, but not significant, systolic and diastolic blood pressure. Findings did not differ among those with or without a history of CVD or diabetes.
The second study, published in Clinical Nutrition, followed 18,914 adults aged 20 year or more from China Health and Nutrition Survey (CHNS) between 1991 and 2015. Overall 1,429 deaths were reported the period.
Higher consumption of eggs was associated with a reduced risk of mortality. When compared to consumption of up to 1 egg per week the risk was 31% lower for consumption of 1-3 eggs per week, 32% for consumption of 3-7 eggs per week and even 36% for consumption of more than 2 eggs per day.
Higher consumption of cholesterol derived from eggs was associated with a reduced risk of mortality while higher consumption of cholesterol not derived from eggs was associated with an increased risk of mortality, especially from red meat.
Bottom line:
An egg a day, free-range & organic is likely beneficial and provides a good source of cholesterol
References:
Dehghan M 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. doi: 10.1093/ajcn/nqz348.
Zhuang P et al. Egg and egg-sourced cholesterol consumption in relation to mortality: Findings from population-based nationwide cohort. Clinical Nutrition. 2020 39 (11): 3520-27 doi: 10.1016/j.clnu.2020.03.019.