Research Outline

Egg Consumption - Nutrition Studies


To understand the number of eggs that can be safely eaten per day by identifying recent scientific studies that have analyzed this subject for personal health purposes.

Early Findings

Four Egg Consumption Studies

  • A 2009 study analyzed an elderly population that was undergoing anti-cholesterol treatment. The goal of the study was to determine if higher egg consumption could have an effect on macular pigment optical density and it also analyzed lipid profile changes.
  • This study found that there was no significant increase in low density lipoprotein (LDL) levels in individuals eating 4 egg yolks a day. Furthermore, high density lipoprotein (HDL) levels increased in both the group consuming 2 egg yolks a day and the group eating 4 egg yolks a day. High HDL levels have been reported as having a protective role regarding cardiovascular events.
  • In addition, macular health was benefited by the consumption of either 2 or 4 egg yolks a day according to this study.
  • A 2005 study evaluated if egg consumption could lead to an increased expression of inflammatory markers such as C-Reactive Protein (CRP) and serum reactive amyloid (SAA) as well as lipoprotein levels among healthy individuals with varying degrees of body mass and insulin sensitivity.
  • It was observed that lean individuals who were insulin sensitive had a higher reaction to ingesting 4 eggs a day for 4 weeks as part of their diets. The study reported that both CRP and SAA levels had increased as well as non-HDL cholesterol. It was hypothesized that the reason for this could be that insulin-sensitive patients have better cholesterol absorption than insulin-resistant and obese patients.
  • A 2003 study analyzed the lipid profile of healthy individuals, individuals with insulin resistance, and obese individuals with insulin resistance after administering no egg yolks, 2 egg yolks, or 4 yolks a day during different periods.
  • This study reported that the healthy population was more sensitive to increased levels of lipids such as total cholesterol, LDL, and HDL when eating 4 eggs a day. Elevated LDL has been associated with a higher risk of cardiovascular disease.
  • That said, increased risk for atherogenesis and cardiovascular disease was not analyzed in this study; however, it was hypothesized that considering that both HDL and LDL levels increase, it is unlikely that there is an increased risk for the formation of atheromatous plaques because the rate does not change.
  • In addition, the levels of LDL corresponded to a type of LDL molecule that has a low association with atherosclerosis, providing additional evidence for low atherogenic risk.

Clinical Trial

  • A clinical study is in preparation in Canada, in which the impact of including 4 eggs as part of the diet of elderly people in an exercise program will be examined. This study is performed with the goal of promoting higher protein intake among elderly adults.
  • According to the study design, "participants (healthy persons, age 60-75 years old) will consume their normal diet or their normal diet plus 4 eggs completing a structured exercise program (designed to meet Canada's Physical Activity Guidelines) for a total of 12 weeks. Participants will be randomly assigned to the Egg or Control (non-egg) group. Before and after the 12-week intervention, participants' undergo assessments of diet-quality, muscle health, fitness, bone health, and vascular health."

Summary of Findings

  • During our initial hour of research, we found scarce recent studies that studied egg daily intake superior to three eggs. Most studies found analyzed individuals consuming up to three eggs a day. While we initially searched for studies published after 2016 with no pertinent results, we expanded our search, which allowed us to provide information from three different studies published between 2003 and 2009 in which participants ate up to 4 eggs daily.
  • We also provided information about a current clinical trial that has been designed and is still to enter the recruiting phase, showing the existence of a continued interest in researching this subject.