Writing in The Journal of Nutrition, Health and Aging, a team of Australian university researchers evaluated existing evidence on the association between egg intake and cognitive function in healthy adults, noting cognitive decline as increasing global concern and the need to overcome heterogeneity in study methods.
“Eggs are a widely consumed, nutrient-dense food containing choline, phospholipids, tryptophan and omega-3 fatty acids, which individually support cognitive processes such as memory, attention and neurogenesis,” they wrote. “While these individual nutrients have demonstrated benefits in supplementation studies, the cognitive effects of whole egg consumption are not well established.”
The review drew on 11 studies with a total of over 38,000 participants identified through a systematic search of Medline, Embase, CINAHL Plus, SCOPUS and PsychInfo online databases from inception through February 2025. It follows an initial review and meta-analysis by the same group on the impact of whole egg consumption on gastrointestinal health.
Eggs in isolation
Although interest in the cognitive effects of individual dietary components has grown, the specific role of nutrient-dense yet cholesterol-high whole eggs remains unclear.
“A comparison with broader dietary pattern literature reveals that eggs are not commonly studied in isolation,” the researchers noted. “Most cognitive nutrition studies focus on whole-diet approaches such as the Mediterranean or MIND diets, which emphasize nutrient-dense plant-based foods and typically limit cholesterol intake.”
Though studies on the cognition-boosting properties of whole eggs are limited, supplement science has investigated the potential influence of its compounds including protein, choline, phospholipids and unsaturated fatty acids on neurotransmission, neurogenesis and brain function.
“Protein (6.29 g per medium sized egg) has been linked to improved memory and reaction time in healthy young adults and reduced risk of cognitive impairment in older cohorts,” the researchers wrote. “The essential amino acid tryptophan (77 mg per egg) crosses the blood brain barrier for conversion to the neurotransmitter serotonin, which is involved in decision-making and memory.”
For choline—a precursor to acetylcholine, a neurotransmitter involved in memory and learning—they noted that intake between 187 mg and 399 mg per day has consistently been associated with improved cognitive performance across healthy younger and older adults. However, intakes exceeding 400 mg per day have been associated with non-significant effects.
Phospholipids, which modulate neurotransmitter receptors, have been linked to enhanced reaction time, and DHA omega-3 fatty acid has been associated with a lower risk of dementia. Some studies, however have linked the linoleic acid in eggs to an increased risk of dementia in older adults and reduced mathematics test scores in school children.
Eggs in moderation
The database search generated one pre-post intervention study, six prospective cohort studies, three cross-sectional studies and one case-control study, conducted predominantly in older adults.
Cognitive outcomes were categorized into domains including global cognitive function, memory, executive function, language, processing speed and dementia risk, with cognitive impairment and dementia risk the most consistently investigated outcomes.
Two of the prospective cohort studies reported that moderate egg consumption—about .5 to one egg a day—was associated with a reduced risk of dementia or cognitive impairment compared to lower intake.
“In both cases, the protective effect was observed in moderate but not high intake categories, suggesting a possible threshold beyond which benefits may either be not observed, or may even be detrimental,” the researchers wrote.
One study found increased risk at higher intake levels among participants consuming one egg or more a day, and several studies also found that moderate, but not high, egg intake was linked to improvements in memory, verbal fluency or processing speed. The pre-post study showed that consuming two eggs a day for eight weeks improve reaction time.
“This systematic review identified preliminary observational evidence that moderate habitual egg consumption may be associated with better cognitive performance, particularly in memory and verbal fluency domains, and reduced risk of cognitive impairment in adults without chronic disease,” the researchers wrote. “However, findings were inconsistent, and the overall evidence base remains limited in both quantity and quality.”
Noting that heterogeneity in exposure measurement and cognitive testing methods limited direct comparisons across studies, they called for further well-controlled intervention studies to determine optimal intake levels, explore mechanisms and assess whether eggs can be integrated meaningfully into dietary strategies to support cognitive aging.
Source: The Journal of Nutrition, Health and Aging. doi: 10.1016/j.jnha.2025.100696. “Egg intake and cognitive function in healthy adults: A systematic review of the literature”. Authors: Nessman Sultan
