- Some existing research has suggested that egg consumption could benefit brain Health as we age, with one recent study indicating that eating one egg per week was linked to lower Alzheimer’s risk.
- A new study now claims that eating eggs at least five times a week is linked to a lower likelihood of receiving an Alzheimer’s diagnosis.
- The study authors emphasize that moderate egg consumption is part of a balanced diet, which benefits Health overall.
- However, some questions remain in place about whether or nor the relationship between egg intake and brain Health is causal.
When it comes to Health benefits, eggs have had a fluctuating reputation over time. For years, a belief persisted that their high content of dietary cholesterol might negatively affect cholesterol levels in the human body.
More recent studies, however, argue that dietary cholesterol from moderate egg consumption does not contribute to higher levels of “bad” cholesterol in the human body and thus does not heighten heart disease risk.
In fact, there is evidence to suggest that the high nutritive content of chicken eggs could bring several health benefits, including better protein synthesis in muscles, and increased satiety (the sensation of being full) that can aid weight management.
A study published in in The Journal of Nutrition in July 2024 even found a link between egg consumption and a lower risk of Alzheimer’s disease.
According to this study of 1,024 older adults, eating one egg per week was linked with a 47% lower risk of Alzheimer’s compared with having eggs less than once a month.
Now, new research from scientists at Loma Linda University Health in California — which also appears in The Journal of Nutrition — has drawn similar conclusions, offering further support to the notion that regular moderate egg consumption may help protect brain Health and lower the risk of cognitive problems.
The research team acknowledges that “the analyses in this study were supported by an investigator-initiated grant from the American Egg Board.”
In the current study, the researchers analyzed data provided through the Adventist Health Study-2 (AHS-2), which was linked with Medicare claims data files.
AHS-2 totalled a cohort of more than 96,000 people; of these, a little over 39,400 met the selection criteria for the current study.
Looking at participants’ reported dietary habits and the Medicare claims linked to their health diagnoses, the researchers found that people who reported eating eggs at least five times a week had an up to 27% lower risk of receiving an Alzheimer’s diagnosis compared to those who reported no egg consumption.
Compared to no consumption, having eggs 1 to 3 times per month was linked to a 17% lower risk of Alzheimer’s, and having eggs 2 to 4 times per week was linked to a 20% lower Alzheimer’s risk.
Speaking to Medical News Today, first author Jisoo Oh, DrPH, MPH, Associate Professor of Epidemiology in the School of Public Health at Loma Linda University, said that she and her colleagues were keen to study this association because they wanted to gain a better, more granular understanding of the modifiable risk factors for Alzheimer’s disease.
“While there is substantial interest in how nutrition influences brain health, there is still a knowledge gap regarding specific foods, including eggs,” said Oh.
“Eggs are widely consumed and contain several nutrients relevant to brain function, yet the evidence linking egg intake to clinically diagnosed Alzheimer’s disease has been limited,” she added.
“Most prior studies relied on short-term cognitive outcomes or cross-sectional data. The Adventist Health Study-2 provided a unique opportunity to examine this question in a large, well-characterized cohort with long-term follow-up and linkage to Medicare data, allowing us to study incident Alzheimer’s disease more rigorously,” the researcher explained.
While this study hasn’t addressed causation, the researchers hypothesize that eggs may have a protective effect on brain health thanks to the specific nutrients they contain.
Oh mentioned:
- “choline, which is essential for producing acetylcholine, a neurotransmitter involved in memory
- lutein and zeaxanthin, which accumulate in the brain and may help reduce oxidative stress
- omega-3 fatty acids (including DHA), important for neuronal structure and function
- vitamin B12, which plays a role in reducing homocysteine levels and supporting neurological function
- high-quality protein and tryptophan, which are involved in neurotransmitter pathways.”
According to her, “these nutrients may contribute to maintaining synaptic integrity, reducing inflammation and oxidative stress, and supporting overall cognitive resilience.”
“While our study does not directly test mechanisms, the findings are consistent with these biologically plausible pathways,” she noted.
Speaking of whether or not people should up their egg intake in light of these study findings, Oh advised “moderation” and paying attention to context.
“Our findings suggest that including eggs as part of a balanced diet may be beneficial for brain Health, but they should not be viewed in isolation or as a ‘silver bullet’,” she cautioned.
“For most people, moderate [egg] consumption, such as a few times per week, appears reasonable and potentially beneficial, especially when part of an overall healthy dietary pattern that includes fruits, vegetables, whole grains, and other nutrient-dense foods.”
– Jisoo Oh, DrPH, MPH
“It’s also important for individuals to consider their overall health profile and dietary needs, ideally in consultation with a healthcare provider,” the researcher added.
Other experts also emphasized that we would be remiss to believe that the answer to better brain health as we age is to be found primarily in egg consumption.
After reviewing the study findings, Michelle Routhenstein, MS, RD, CDCES, CDN, a preventive cardiology dietitian at EntirelyNourished, who was not involved in this research, told MNT: “My first reaction was, well what else are [the people in this cohort] eating? That question matters more than most people realize.”
For Routhenstein, it is important to acknowledge that the group this study focused on is already characterized by better overall health thanks to consistently healthy lifestyle habits.
“This was an observational study done in a very specific population, Seventh-day Adventists, who as a group smoke less, drink less, eat more plants, and have lower baseline rates of obesity, diabetes, and cardiovascular disease than the average American,” the dietitian pointed out.
“So when we see that moderate egg intake was associated with lower Alzheimer’s diagnoses in this cohort, we’re looking at what happens when people add eggs to an already protective dietary pattern, not to the typical Western diet,” she maintained.
“Eggs do contain nutrients with real brain health relevance, but we need to assess the full dietary pattern, cardiometabolic health, labs, and individual metabolic markers before drawing any conclusions about what eggs mean for any one person.”
– Michelle Routhenstein, MS, RD, CDCES, CDN
“It is also important to recognize that some of the funding came from the American Egg Board and the headlines need to be in check with the details of the study, what the actual study looked at and found,” the dietitian cautioned.
Routhenstein also outlined some potential health drawbacks to upping egg consumption, while stressing that overall it’s not a bad idea to include eggs in our diets.
Whether or not a person should start eating more eggs is always a matter of personal health context, said the dietitian.
“Eggs aren’t a ‘free’ food, but they’re not automatically off-limits either,” she told us. “They do contribute saturated fat and dietary cholesterol, so whether adding an egg makes sense really comes down to what the rest of your diet looks like and whether it keeps you within your daily saturated fat target.”
“It’s also important to recognize that some people are more sensitive to dietary cholesterol than others, they are called ‘cholesterol hyper-responders’,” Routhenstein pointed out.
“In those individuals, egg yolks can raise LDL more significantly, and may need to be limited more carefully, especially if cardiovascular risk is already elevated,” she explained.
There are also people who prefer a diet that mostly or completely excludes animal food products, including eggs. According to Routhenstein, there is no reason for them to worry, as long as they are making sure they’re following a nutritious diet overall.
Like Oh, Routhenstein explained that “eggs can support brain health because they contain several relevant brain protective nutrients —from choline [to] lutein, zeaxanthin, vitamin B12, selenium, [and] protein — all of which can play positive roles in memory, brain structure, and brain associated inflammation.”
“That said, the human data we have right now is mostly observational, which means we can see associations, but we can’t say eggs prevent Alzheimer’s disease,” she cautioned.
“And it’s worth knowing that most of these same nutrients can be found in other foods or through a well-planned plant-forward diet,” Routhenstein emphasized.
The dietitian advised that:
“Choline can come from foods like soy, kidney beans, quinoa, and Brussels sprouts. Omega-3s and B12 are worth supplementing, with dosing based on your labs, age, and individual needs. And lutein and zeaxanthin? Dark leafy greens have you covered.”
Concerning the current study, Oh outlined “several important” caveats, including that it was observational in nature, meaning that it cannot establish causation, and that “the study population is relatively health-conscious (Seventh-day Adventists), which may limit generalizability.”
She also noted that “diet was assessed at baseline only, and changes [to diet] over time were not captured” and there was “limited data on very high levels of egg consumption.”
“While the results are encouraging, they should be interpreted as part of a broader body of evidence,” Oh said.
Going forward, Oh noted she would like to see this research replicated in more diverse populations, as well as “studies examining egg consumption earlier in life and long-term cognitive outcomes, more detailed work on specific nutrients in eggs (e.g., choline, DHA) and their independent roles, research incorporating biomarkers and neuroimaging to better understand mechanisms,” and a rigorous exploration of potential causal relationships.
“Ultimately,” she shared, “we hope this work contributes to a more nuanced understanding of how specific foods fit into dietary patterns that support healthy brain aging.”
