Could eating eggs prevent dementia?

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

Study: Association between egg consumption and dementia in Chinese adults. Image credits: MasAnyanka / Shutterstock

This is evident from a recent study published in the journal Nutrientsresearchers examined the association between egg consumption and dementia among Chinese adults through a population-based case-control study. Their results indicate that consuming eggs daily can reduce the risk of dementia, but excessive consumption of eggs (more than twice daily) or non-consumption showed no significant effects. More evidence is needed to guide dietary recommendations.

Background

Dementia is a major public health problem, affecting more than 55 million people worldwide. This number is expected to rise to 152 million cases by 2050 as approximately 10 million people develop the condition each year. Prevention is crucial because dementia cannot be cured.

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

Eggs are rich in nutrients and other beneficial substances, including vitamin D, folic acid and choline. They are also an essential and affordable source of protein. However, they can 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 is also some evidence that egg consumption might reduce the risk of cognitive impairment, but findings are mixed. In China, which suffers 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 the age of 50.

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

Participants provided information about 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 status, lifestyle, socio-economic status, gender and age.

Findings

The 466 people had an average age of 73.6 years. 63.5% of participants were female, while 57.7% reported having less than a high school education.

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

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

Researchers found that higher income and higher education levels were associated with 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 with chronic kidney disease reported lower consumption.

Significant differences were found in dietary intake (pork, beef, poultry, fish, fruits and vegetables) among egg intake levels. 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 the risk of dementia between individuals who ate eggs twice a day and those who did not eat eggs at all. This pattern persisted after researchers adjusted for health behavior, income, education, gender, and age.

Conclusions

Overall, increasing egg consumption from monthly to weekly to daily was associated with a reduced risk of dementia, and those who ate eggs daily had the lowest risk of dementia. The results suggested that non-consumption or excessive egg consumption did not significantly change 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 warned that consuming more than two eggs a day could increase cholesterol levels, which could increase the risk of dementia.

The study adds to a growing body of evidence on the links between egg consumption and cognitive function in different populations, although previous research has shown mixed results.

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