Eating eggs five times a week was linked to a 27% lower Alzheimer’s risk in a study of nearly 40,000 adults

Alzheimer’s disease affects more than 55 million people worldwide, and that number is projected to nearly triple by 2050. Despite decades of research and billions of dollars in pharmaceutical investment, no drug has yet been proven to prevent or reverse the disease. Against that backdrop, a new study from Loma Linda University in California has produced a finding that is both surprising and accessible: eating eggs regularly may reduce the risk of developing Alzheimer’s by as much as 27 percent.

The study, published in the Journal of Nutrition, analyzed data from nearly 40,000 American adults aged 65 and older over 15 years. It is one of the largest investigations of its kind, drawing on Medicare records to identify Alzheimer’s diagnoses and using dietary questionnaires to assess eating patterns. The findings suggest that something as simple and inexpensive as adding eggs to a weekly routine could offer meaningful protection against one of the most feared diseases of aging.

The Loma Linda research team divided participants according to how frequently they consumed eggs, ranging from never to more than five times per week. Over the 15-year follow-up period, 2,858 participants developed Alzheimer’s disease. When researchers controlled for other variables, a clear pattern emerged.

Participants who ate eggs five or more times per week had a 27 percent lower risk of Alzheimer’s compared to those who ate no eggs at all. Even those who ate eggs only one to three times per month showed a 17 percent reduced risk. The researchers concluded that any egg intake was associated with a lower Alzheimer’s risk, suggesting a dose-response relationship where more frequent consumption conferred greater protection.

The study distinguished between two types of egg consumption. Visible eggs are boiled, scrambled, or fried and eaten on their own, and hidden eggs are used as ingredients in baked goods and packaged products. Both types were captured in the dietary assessment, providing a more complete picture of actual egg consumption than many previous studies.

Why Eggs and Not Something Else

The researchers were careful to note that they were measuring association, not causation. People who eat more eggs may differ from those who eat fewer in other ways that influence their Alzheimer’s risk. The study controlled for a range of potential confounders, but residual confounding can never be fully eliminated in observational research.

That said, there are credible biological mechanisms through which eggs could support brain health mechanisms that help explain why the association has appeared consistently across multiple independent studies. The researchers pointed to the nutrient profile of eggs as the most likely explanatory factor. As they wrote in the study, these nutrients may act synergistically to support cognitive resilience and mitigate neurodegenerative processes.

Of all the nutrients in eggs, choline has attracted the most attention in Alzheimer’s research. Choline is a water-soluble compound that plays a critical role in the production of acetylcholine, a neurotransmitter essential for memory, attention, and cognitive function. Acetylcholine deficiency is one of the most consistent neurological features of Alzheimer’s disease, and many of the drugs currently approved for Alzheimer’s treatment work by preventing the breakdown of acetylcholine rather than increasing its production.

Eggs are one of the richest dietary sources of choline available. A single large egg contains approximately 147 milligrams of choline, predominantly in the yolk. The adequate intake level for choline is 425 milligrams per day for adult women and 550 milligrams for adult men, meaning that two to three eggs per day could satisfy a significant portion of the recommended intake.

Despite its importance, choline is chronically underconsumed in Western diets. Surveys indicate that fewer than 10 percent of Americans meet the adequate intake for choline, making eggs one of the simplest ways to address a nutritional gap that may have direct implications for long-term brain health. Research into the role of nutrition in cognitive decline, including the emerging science around choline and brain health, is detailed in Thefirmo’s examination of why Alzheimer’s research may be entering a more hopeful era.

Choline is not the only nutrient in eggs that researchers believe contributes to the protective effect. The Loma Linda team specifically identified three additional compounds as likely contributors.

Lutein, a carotenoid found primarily in egg yolks, has been linked to cognitive preservation in several independent studies. Unlike many carotenoids, lutein accumulates in brain tissue and has been found at measurable concentrations in areas of the brain associated with memory and learning. Research from the University of Illinois found that higher lutein levels in the brain were associated with preserved neural efficiency, the brain’s ability to allocate cognitive resources effectively.

Tryptophan, an amino acid found in eggs, is a precursor to serotonin, a neurotransmitter that regulates mood, sleep, and appetite. Disruptions to serotonin signaling are increasingly linked to Alzheimer’s pathology, and adequate tryptophan intake supports the serotonergic systems that help maintain cognitive function.

Docosahexaenoic acid, or DHA, is an omega-3 fatty acid present in eggs, particularly in eggs from hens fed omega-3-enriched diets. DHA is a structural component of brain cell membranes and has been associated with reduced Alzheimer’s risk in multiple longitudinal studies. Its anti-inflammatory properties may help protect against the neuroinflammation that drives Alzheimer’s progression.

The Loma Linda study does not stand alone. Its findings are consistent with a growing body of research from independent institutions that have examined the relationship between egg consumption and cognitive outcomes.

A 2024 study from the University of California, San Diego found that egg consumption among middle-aged participants was associated with better cognitive performance in later life. A 2025 study from researchers at Tufts University in Massachusetts and the Rush Alzheimer’s Disease Center in Chicago, one of the leading Alzheimer’s research institutions in the United States, found that participants who ate more than one egg per week could see as much as a 47 percent decline in Alzheimer’s risk.

According to ScienceDaily’s coverage of the Loma Linda findings, researchers found that people aged 65 and older who eat eggs regularly have a significantly lower risk of developing Alzheimer’s disease, with daily or near-daily consumption linked to up to a 27 percent reduction. The convergence of findings across multiple research groups using different populations and methodologies strengthens the case that the association is real rather than an artifact of any single study’s design.

Eggs have a complicated public health history. For decades, dietary guidelines discouraged frequent egg consumption because of its cholesterol content, with concerns that dietary cholesterol would raise blood cholesterol and increase cardiovascular risk. The scientific consensus on this question has shifted considerably.

Current evidence indicates that for most people, dietary cholesterol has a limited effect on blood cholesterol levels compared to saturated and trans fats. The 2020 Dietary Guidelines for Americans removed the previous recommendation to limit dietary cholesterol to 300 milligrams per day, reflecting the updated evidence base. More recently, the FDA formally classified eggs as a healthy food.

For individuals with specific health conditions, familial hypercholesterolemia or certain forms of diabetes, the picture may be more nuanced, and consultation with a physician remains appropriate. But for the general population of healthy older adults, the weight of evidence no longer supports the blanket restriction of egg consumption that characterized dietary advice for several decades.

How This Fits the Broader Picture

The egg study adds a new dimension to an increasingly well-characterized field of dietary Alzheimer’s research. Scientists have found that legumes, whole grains, and plant-based dietary patterns are also associated with meaningful reductions in Alzheimer’s risk, with the MIND diet, which incorporates both eggs and plant-based foods, showing some of the strongest protective associations in the literature.

What the emerging dietary evidence collectively suggests is that Alzheimer’s risk is not fixed at birth by genetics or inevitable with aging. It is influenced by choices made across decades of adult life, choices about food, physical activity, sleep, and social engagement that individually produce modest effects but in combination may substantially alter the trajectory of cognitive aging.

According to the EurekAlert announcement of the Loma Linda study, the research underlines that eggs are a source of key nutrients that support brain health, a characterization that applies not just to choline but to the full complement of brain-active compounds that eggs provide in a single, inexpensive food.

For most adults, the practical implication of this research is straightforward. Eating eggs several times per week as part of a broader diet that includes vegetables, whole grains, and other brain-healthy foods is consistent with the current evidence on Alzheimer’s prevention. It does not require expensive supplements, specialized diets, or significant lifestyle disruption.

The cost dimension matters. A dozen eggs costs between two and four dollars in most U.S. markets, making daily egg consumption one of the most affordable nutritional interventions available. For older adults on fixed incomes, who face elevated Alzheimer’s risk and often have limited resources for health interventions, eggs represent a rare convergence of accessibility, affordability, and scientific support.

Alzheimer’s research has produced important pharmaceutical advances in recent years, including the approval of new drugs that can slow cognitive decline in early-stage patients. But drugs that slow an existing disease are not the same as habits that reduce the probability of developing it in the first place.

That distinction is where dietary research matters most. The evidence on eggs is not definitive. No single food prevents Alzheimer’s. But the pattern across multiple independent studies pointing consistently toward a protective association between egg consumption and reduced Alzheimer’s risk is strong enough to take seriously, and accessible enough to act on.