Could eating eggs prevent dementia?

By Priyanjana Pramanik, MSc.Reviewed by Susha Cheriyedath, M.Sc.Oct 3 2024

A new study finds that eating one egg daily could lower the odds of developing dementia, while consuming too few or too many eggs might not be as beneficial. Learn more about how this affordable, nutrient-rich food may protect your brain health.

Study: Association between Egg Consumption and Dementia in Chinese Adults. Image Credit: MasAnyanka / Shutterstock

In a recent study published in the journal Nutrients, researchers investigated the association between egg consumption and dementia among Chinese adults through a population-based case-control study. Their results indicate that consuming eggs daily may reduce the risk of dementia, but excessive egg consumption (more than twice daily) or non-consumption did not show significant effects. More evidence is needed to guide dietary recommendations.

Background

Dementia is a significant public health issue, affecting more than 55 million people around the world. This number is expected to rise to 152 million cases by 2050, as about 10 million people develop the condition each year. Prevention is critical as dementia cannot be cured.

The role of diet in reducing dementia risk has been studied, with research suggesting that eating seafood and following a Mediterranean diet (including eggs) can be protective against the condition.

Eggs are rich in nutrients and other beneficial compounds, including vitamin D, folate, and choline. They are also an essential and affordable source of protein. However, they may also raise cholesterol levels and have been implicated in a higher risk of heart disease, diabetes, and mortality in the United States but not in Asian or European populations.

There are also some indications that egg consumption could reduce the risk of cognitive impairment, but findings are mixed. In China, which faces the highest burden of dementia in the world and is also the largest producer and consumer of eggs, understanding the relationship between the two is critical to guiding prevention strategies.

About the study

Researchers recruited 233 individuals who had been diagnosed with dementia and 233 ‘control’ individuals who were confirmed not to have dementia, all of whom were over 50.

The former were recruited through a hospital’s dementia management system, while the latter were recruited from community health clinics during health checks for older residents.

Participants provided information on their medical history, lifestyle, and demographics. Their egg intake was categorized as more than twice daily, weekly, monthly, and less than monthly.

Statistical modeling was then used to assess the relationship between dementia and egg intake and calculate odds ratios after adjusting for other dietary characteristics, health conditions, lifestyle, socioeconomic status, gender, and age.

Findings

The 466 people were 73.6 years old on average. 63.5% of the participants were women, while 57.7% reported having less than a junior high school education.

Individuals in the group who had dementia were older and tended to have lower incomes and education. They also showed a higher prevalence of smoking, no or low alcohol use, Parkinson’s, head injuries, stroke, and heart disease. They reported higher red meat consumption and lower intake of fruits, vegetables, poultry, and fish.

Regarding egg intake frequency, less than 3% of participants ate eggs twice a day, while 35% ate them daily, 36.7% weekly, 12% monthly, and 13.5% either consumed them less than once a month or avoided egg consumption altogether. On average, people who consumed eggs twice daily were older, and those who consumed them monthly represented the youngest group.

Researchers found that higher income and educational attainment were linked to higher egg consumption. However, more frequent consumption was also associated with higher smoking rates, and individuals with chronic kidney disease reported lower egg consumption. While people with depression ate more eggs, those who had chronic kidney disease reported lower consumption.

Significant differences in dietary intakes (pork, beef, poultry, fish, fruits, and vegetables) were found across the levels of egg intake. Lamb consumption was the only dietary intake that did not show a positive relationship with egg intake.

The study found that weekly and monthly egg consumption was associated with a higher risk of dementia than daily consumption. However, there was no significant difference in dementia risk between individuals who consumed eggs twice daily and those who did not eat eggs at all. This pattern remained after researchers adjusted for health behaviors, income, education, gender, and age.

Conclusions

Overall, increasing egg consumption from monthly to weekly to daily was associated with a decreased risk of dementia, and those who ate eggs daily had the lowest odds of dementia. The results suggested that non-consumption or excessive egg consumption did not significantly alter the risk. These results were independent of health conditions, diet, smoking, education, and age.

The underlying mechanism could be that eggs are rich in omega-3 fatty acids, choline, antioxidants, and proteins. However, researchers cautioned that consuming more than two eggs daily might increase cholesterol levels, which could raise the risk of dementia.

The study adds to a growing body of evidence regarding links between egg consumption and cognitive function across different populations, though previous research has shown mixed results.

Study limitations include the fact that the exact quantity of eggs consumed was not measured, and participants with dementia were significantly older than those without, which may affect the findings. Further research is needed to strengthen the understanding of this relationship.