In a new study, a team of scientists found that people who consumed eggs had lower rates of being diagnosed with the disease over 15 years. In turn, completely avoiding its consumption is associated with a 22% greater risk of contracting it.
Alzheimer’s disease is a type of dementia that causes a global, progressive and irreversible deterioration of several cognitive functions.
In a new one, published last month in The Journal of Nutritionresearchers followed 40 thousand elderly people for more than 15 years and found that people who regularly consumed eggs were less likely to be diagnosed with the disease than those who never or rarely consumed them.
According to , the study was based on data from the Adventist Health Study-2a research project that involved more than 96 thousand members of the Seventh-day Adventist Church in all 50 US states between 2002 and 2007.
This population is useful for studying diet because Adventists have a wide variety of eating habits, from vegans who never touch an egg to omnivores who eat eggs daily.
By linking participants’ dietary records with health insurance claims data, researchers tracked who ended up receiving a clinical diagnosis of Alzheimer’s through the medical system rather than relying on self-reported memory problems.
Participants completed a dietary questionnaire at enrollment, which covered more than 200 foodsincluding the frequency with which they consumed eggs.
The researchers then classified the participants into five groups based on your frequency of consumption. A separate calculation also estimated total daily egg intake in grams, including eggs found in baked goods, mixed dishes and recipes.
After applying eligibility requirements, including being at least 65 years old, enrolled in Medicare, and not having a diagnosis of Alzheimer’s at baseline, the final sample included 39498 people.
The average age at the time of registration was 64 yearsapproximately 64% were women, approximately 74% were non-Hispanic white, and 19% were black. The average follow-up period was 15.3 years, covering more than 603 thousand people per year of observation.
During that period, 2,858 participants received a clinical diagnosis of Alzheimer’s through Medicare records.
The researchers created statistical models that progressively took into account a long list of factors that could distort the results. Even after adjusting all these variables, the pattern was clear.
Compared to people who never or rarely ate eggs, those who ate them just one to three times a month had a 17% lower risk of Alzheimer’s. Eating eggs once a week was also associated with a 17% reduction. Two to four times a week was associated with a 20% lower risk, and five or more times a week was associated with a 27% lower risk.
A separate analysis modeled egg consumption as a continuous daily measure rather than classifying people into groups. Using approximately one egg per week as a reference, the model found that people who did not consume eggs had a 22% increased risk of Alzheimer’s disease.
The results remained valid even after several checks designed to test their reliability. When the researchers excluded all vegans from the analysis, as they represented a large portion of the group that did not consume eggs and tended to differ from others in lifestyle, the conclusions practically did not change.
The large sample size, 15 years of follow-up, clinically confirmed Alzheimer’s diagnoses, and consistent results across multiple statistical approaches make this one of the largest and longest-running investigations into the issue of eggs and Alzheimer’s disease to date.
However, the study population presents both a strength and a limitation. Adventists tend to be healthier than the general population, with about 80% never smoking and very few reporting alcohol consumption.
Thus, this reduces the interference of known risk factors, but it also raises the question of whether the results would be the same in a more common population.
