Eating at least five eggs a week is associated with a 27 percent lower risk of Alzheimer’s

A new study published in The Journal of Nutrition provides evidence that eating eggs in moderation tends to reduce the risk of being diagnosed with Alzheimer’s disease in older adults. Consumption of eggs is associated with a lower risk of cognitive decline for those 65 years and older. These findings suggest that incorporating eggs into a balanced diet might offer protective benefits for brain health over time.

Alzheimer’s disease is a progressive brain disorder that slowly destroys memory and thinking skills. Without a known cure, medical professionals have increasingly focused on preventing the disease before it starts. The researchers wanted to explore how everyday lifestyle choices might influence brain health as people get older.

“We were motivated by the growing need to identify modifiable dietary factors that may influence Alzheimer’s disease risk, especially given the lack of curative treatments,” said Jisoo Oh, an associate professor of epidemiology at Loma Linda University School of Public Health. “While eggs are widely consumed and contain nutrients relevant to brain health, there has been relatively limited evidence linking egg intake to clinically diagnosed Alzheimer’s disease over long follow-up periods. The Adventist Health Study-2 provided a unique opportunity to examine this question in a large cohort with detailed dietary data and linkage to Medicare records.”

Previous research has hinted that certain nutrients found in eggs could support brain function. Eggs are known to be a source of key nutrients that support brain health, according to Joan Sabaté, a professor at Loma Linda University School of Public Health and the study’s principal investigator. They provide choline, a nutrient that helps nerve cells communicate and form memories.

Eggs also contain specific carotenoids like lutein and zeaxanthin that accumulate in brain tissue and are associated with improved cognitive performance and reduced oxidative stress. Additionally, eggs provide key omega-3 fatty acids that help maintain the physical structure of brain cells. The yolks are particularly rich in phospholipids, which make up nearly 30 percent of total egg lipids and are essential for proper brain signaling.

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To track these dietary factors, the researchers analyzed data from an ongoing project called the Adventist Health Study-2. The scientists focused on nearly 40,000 subjects based in the United States who were at least 65 years old. Eligibility was determined using the Medicare Master Beneficiary Summary Files. The participants were monitored for an average of 15.3 years.

At the beginning of the project, each person completed an extensive dietary questionnaire. The researchers studied the consumption of eggs in visible ways, such as eating eggs scrambled, fried, or boiled. They also measured hidden ways, such as eggs included in baked goods and packaged foods.

To track who developed Alzheimer’s disease over time, the researchers linked the dietary surveys to official Medicare health insurance claims. By using billing codes from hospital visits and doctor appointments, the scientists could accurately pinpoint when a participant received a formal medical diagnosis. The cases of Alzheimer’s disease in the Adventist Health Study-2 cohort were diagnosed by physicians, according to these Medicare records.

The researchers adjusted their statistical models to account for a wide range of factors that might influence brain health. These variables included age, sex, race, education, physical activity levels, and sleep habits. They also factored in whether the participants had other medical conditions like high blood pressure, diabetes, or heart disease.

Because overall diet plays a massive role in health, the researchers controlled for the consumption of other major food groups. To be as precise as possible, the scientists even ran separate analyses to see what happened when eggs were hypothetically swapped for other protein sources, like nuts, seeds, or legumes.

The scientists found that people who ate eggs experienced a noticeably lower risk of developing the condition compared to those who never or rarely ate them. This inverse relationship remained consistent even after adjusting for all the demographic, lifestyle, and medical variables.

“The main takeaway is that moderate egg consumption was associated with a lower risk of Alzheimer’s disease in this cohort,” Oh told PsyPost. “Individuals who consumed eggs regularly had lower risk compared to those who rarely or never ate eggs. However, this does not mean eggs prevent Alzheimer’s disease, but rather that they may be one component of a brain-healthy dietary pattern.”

The specific risk reductions varied based on how often participants consumed eggs. “Compared to never eating eggs, eating at least five eggs per week can decrease risk of Alzheimer’s,” Sabaté said. Eating one egg per day for at least five days a week reduces risk of Alzheimer’s by up to 27 percent.

Even less frequent consumption of eggs significantly reduced the risk of Alzheimer’s. Researchers found that eating eggs one to three times per month had a 17 percent decrease in risk, while eating eggs two to four times per week had a 20 percent decrease in risk, Sabaté said.

The authors also used a statistical tool to map the precise relationship between the daily weight of eggs consumed and disease risk. This continuous analysis showed that eating exactly zero eggs per day was associated with a higher risk of Alzheimer’s disease compared to eating 10 grams of eggs daily, which is roughly equivalent to one large egg per week.

“One notable finding was the consistent inverse association across multiple levels of adjustment, even after accounting for overall diet, lifestyle, and comorbidities,” Oh said. “We were also interested to observe that even relatively modest intake (such as 1-3 times per month) was associated with lower risk. The nonlinear pattern, where zero intake was associated with higher risk, was also an unexpected and intriguing observation.”

The researchers acknowledge a few limitations to their work. One potential issue is that dietary habits were only recorded at the very beginning of the long tracking period. A person might have changed their eating habits over the 15 years they were monitored.

“This is an observational study, so we cannot establish causation,” Oh said. “Although we adjusted for many confounders, residual confounding is always possible, and dietary intake was measured only at baseline. It is also important not to interpret the findings as eggs being a standalone preventive strategy, or that higher intake necessarily leads to greater benefit.”

The population studied also presents a specific context for the findings. The participants belong to a group known for being highly health-conscious.

“One important context is that this was a health-conscious cohort with relatively low rates of smoking and alcohol use, which strengthens internal validity but may limit generalizability,” Oh said. “Additionally, Alzheimer’s disease develops over decades, so identifying long-term dietary associations is particularly important. Overall, the findings add to a growing body of evidence suggesting that whole foods rich in brain-relevant nutrients, such as eggs, may play a role in healthy cognitive aging.”

Looking ahead, the authors plan to expand upon these findings to better understand the mechanisms at play.

“Future research should examine whether these associations hold in more diverse populations and whether dietary patterns earlier in life influence later Alzheimer’s risk,” Oh said. “We are also interested in exploring the role of specific egg-derived nutrients, such as choline and DHA, and their biological pathways. Ultimately, integrating biomarker and mechanistic studies would help strengthen causal inference.”

The study, “Egg Intake and the Incidence of Alzheimer’s Disease in the Adventist Health Study-2 Cohort Linked with Medicare Data,” was authored by Jisoo Oh, Keiji Oda, Gabriela Chiriac, Gary E Fraser, Rawiwan Sirirat, and Joan Sabaté.

The authors provided the following statement regarding conflicts of interest and funding: “Initial support for the cohort was provided by the National Cancer Institute (grant 1U01CA152939). The analyses in this study were supported by an investigator-initiated grant from the American Egg Board. The funding sources had no role in the study design, execution, data analysis, interpretation, manuscript preparation, or publication.”