🟠 Moderate Evidence
A new observational study from Loma Linda University tracking nearly 40,000 adults over 15 years found that those consuming five or more eggs per week had a 27% lower incidence of Alzheimer’s disease compared to those eating fewer eggs. Four additional long-running cohort studies across three countries, involving over 170,000 adults total, showed consistent associations between higher egg consumption and reduced Alzheimer’s risk.
Key takeaways
- Adults eating 5+ eggs weekly showed 27% lower Alzheimer’s incidence in the Loma Linda cohort (15-year follow-up, ~40,000 participants)
- Four independent cohorts with 170,000+ adults across three countries report similar findings, suggesting a robust signal
- Egg yolks are rich in choline, a precursor for acetylcholine, the neurotransmitter depleted in Alzheimer’s disease; approximately 90% of Americans fall short of recommended choline intake
- Associations are strong within studied populations but causality remains unproven; generalisability to typical American diets requires further investigation
Study at a Glance
| Source | Journal of Nutrition |
| Study type | Prospective observational cohort |
| Sample size | N ≈ 40,000 (primary cohort); 170,000+ across four additional cohorts |
| Population | Adults followed over 15 years; primary cohort: Seventh-day Adventists |
| Country | United States and international (three countries total across all cohorts) |
Choline status in the United States population
Percentage of Americans meeting recommended daily choline intake, by age group and sex
Source: Wallace TC, Fulgoni VL, Nutrients (2017); adapted for GMJ News
The choline-acetylcholine pathway in cognitive health
Egg yolks represent one of the most bioavailable dietary sources of choline, an essential nutrient that the brain converts into acetylcholine, the primary neurotransmitter governing memory formation and cognitive processing. According to research published in Science (1982), post-mortem analysis of Alzheimer’s disease brains reveals that more than 75% of cholinergic neurons in the basal forebrain are lost in affected individuals—a finding that has persisted as a cornerstone of Alzheimer’s neuropathology.
Data from the Nutrients journal (2017) indicate that approximately 90% of Americans consume less than the National Institutes of Health’s recommended daily intake of choline (550 mg for adult women, 550 mg for adult men). This widespread deficiency occurs despite choline’s essential role in cell membrane integrity, methyl donation, and neurotransmitter synthesis. A single large egg contains approximately 147 mg of choline, primarily concentrated in the yolk, making eggs a practical whole-food source for populations seeking to optimise intake. More recent evidence from FASEB Journal (2018) suggests that individual genetic variation in choline metabolism may influence cognitive resilience.
Read more on research findings and nutritional science in our explainers section.
Consistency across multiple independent cohorts
The strength of the Loma Linda finding gains credibility from corroboration across four additional prospective cohort studies tracking a combined 170,000+ adults across three countries. These parallel investigations, published in peer-reviewed journals including the American Journal of Clinical Nutrition (2019), AJCN (2022), and AJCN (2025), report consistent associations between higher egg consumption and reduced Alzheimer’s risk. This pattern of replication across diverse populations strengthens confidence that the relationship is not merely a statistical artefact or confounding factor unique to a single cohort.
Earlier biomarker research published in Nature Medicine (2014) and Journal of Nutrition (2024) demonstrates that choline levels correlate with cognitive performance trajectories in ageing adults, providing mechanistic plausibility for the observational associations.
Important caveats: population specificity and causality
The primary Loma Linda cohort comprises Seventh-day Adventists, a population with distinctive health behaviours: lower smoking rates, minimal alcohol consumption, higher vegetable intake, and generally healthier lifestyle patterns compared to the general United States population. While the 27% risk reduction signal is robust within this group, whether this protective association generalises to adults following typical American diets—characterised by higher processed food consumption and lower overall micronutrient density—remains an open question requiring targeted investigation.
Furthermore, these are observational studies that establish association, not causation. People who eat more eggs may differ systematically from those eating fewer eggs in unmeasured ways (dietary quality, exercise, cognitive engagement, socioeconomic status) that could independently influence Alzheimer’s risk. Recent lipid research from Lipids in Health and Disease (2023) and cognitive reserve analyses from Alzheimer’s & Dementia (2021) suggest that multiple dietary and lifestyle factors interact in cognitive ageing, making it difficult to isolate egg consumption as an independent protective factor.
Adults consuming five or more eggs per week demonstrated a 27% lower incidence of Alzheimer’s disease over 15 years of follow-up, with corroborating evidence from four additional cohorts totalling 170,000+ participants across three countries, although causality cannot be established from observational data alone.
— Published data from Oh J, et al. (Journal of Nutrition, 2026) and supporting cohort studies
What this means
Frequently asked questions
How much choline do I need, and can eggs provide it?
The National Institutes of Health recommends 550 mg daily for adult women and 550 mg for adult men. One large egg yolk contains approximately 147 mg of choline. To meet the recommended intake through eggs alone would require consuming 4–5 eggs daily, supplemented by other choline-rich foods including fish, poultry, dairy, broccoli, and brussels sprouts. According to Nutrients (2017), eggs remain among the highest bioavailable food sources of choline available to most populations.
Does eating eggs increase cardiovascular risk or cholesterol concerns?
Systematic reviews have found that moderate egg consumption (up to one egg daily) is not associated with increased cardiovascular risk in populations without familial hypercholesterolaemia. The saturated fat content of eggs is modest compared to other animal proteins. However, preparation method matters: boiled or poached eggs pose less cardiovascular risk than fried eggs prepared in trans fats. Individuals with diagnosed cardiovascular disease or elevated low-density lipoprotein cholesterol should consult their clinician regarding appropriate egg intake.
If eggs are protective, should I take choline supplements instead?
The evidence supporting isolated choline supplementation for cognitive health remains limited compared to observational evidence for whole-food choline sources like eggs. Whole foods contain additional micronutrients (vitamins, minerals, phospholipids) that may contribute synergistically to cognitive health. Supplementation strategies should be discussed with a healthcare provider, particularly for individuals unable to meet dietary recommendations through food alone. Randomised controlled trials of choline supplementation specifically targeting cognitive outcomes are urgently needed.
These observational findings provide a timely reminder that micronutrient adequacy across the lifespan may influence cognitive resilience in ageing. However, the leap from associational evidence to clinical recommendation requires prospective intervention trials in diverse populations. In the interim, incorporation of eggs into a broader Mediterranean-style dietary pattern—emphasising vegetables, whole grains, fish, and olive oil—remains the most evidence-supported approach to dementia risk reduction. Future research should prioritise randomised trials evaluating choline supplementation and egg consumption across diverse populations and ethnic groups, with particular attention to interactions with genetic and lifestyle factors that modify Alzheimer’s risk.
Source: Loma Linda egg consumption and Alzheimer’s study with supporting cohort evidence
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