Eggs have had a complicated history when it comes to health and nutrition. First, they’re good, then they’re bad, then food scientists say they’re good again. Well, researchers are once again placing all their eggs in the “good” basket, finding that these controversial sources of cholesterol may be even better your our brains than we thought.
A team from the University of California-San Diego has discovered that older women who eat eggs each week may experience less memory loss and less decline in their executive brain functions over time. This is the latest research to suggest that eggs, a food often criticized for their high cholesterol content, could actually benefit cognitive health among certain groups.
The study, published in the journal Nutrients, examined a group of 890 adults over the age of 55 from the Rancho Bernardo study in California. The participants kept track of their egg consumption from 1988 to 1991. They also underwent a series of cognitive tests during that time and once again between 1992 and 1996, measuring their global cognition, executive function, and semantic memory.
When the researchers analyzed the data by sex, they found that among women, those who ate more eggs each week experienced less decline in category fluency — a test of verbal abilities and executive function — over the four-year period. This association remained even after accounting for factors like age, education, lifestyle behaviors, cholesterol levels, and each participant’s calorie and protein intake.
Overall, researchers found that the magic number for older women appears to be five eggs per week. In other words, an egg a day may keep cognitive decline away.
“Women in the highest category of egg intake would have a half-point less decline in category fluency score over 4 years compared to women who never consumed eggs. Although small, this association was still significant after further adjustment for behaviors, cholesterol, and calorie and protein intake, as well as after additional adjustment for diabetes and hypertension,” researchers Donna Kritz-Silverstein and Ricki Bettencourt write in their report.
In contrast, the researchers did not find any significant links between eating eggs and brain changes among men. Kritz-Silverstein notes that this difference among the sexes is intriguing and warrants further investigation.
The exact reason that causes eggs to benefit cognitive health is not fully clear, but the researchers point to some promising clues. Eggs are rich in nutrients like choline, lutein, and zeaxanthin, which have been linked to better brain health in prior research. The high-quality protein in eggs may also help preserve neuronal structure and function.
Additionally, while eggs do contain dietary cholesterol, unlike meat, they have relatively low levels of harmful saturated fat. This may allow them to provide cognitive benefits without the potential downsides associated with high-cholesterol foods. The team also notes that eggs are relatively affordable and accessible, making them a cheap way to get important nutrients for brain health.
“The lack of cognitive decline with egg consumption is reassuring and suggests that despite having high levels of dietary cholesterol, eggs do not have a detrimental effect and may even have a role in the maintenance of cognitive function over time,” the study authors conclude.
Of course, this was an observational study, so more research is necessary to confirm a causal relationship. However, the results add to a growing body of evidence challenging the notion that eggs should be strictly limited in the diet, especially for older adults focused on preserving their mental sharpness.
