A high-cholesterol animal product eaten by billions of people worldwide is not as bad for your health as it's often cracked up to be. It might even be good for you.
Researchers at the University of California San Diego have now analyzed the health data of 890 men and women and found that eating two to four eggs a week is linked to lower blood cholesterol levels.
Their analysis is based on data from a healthy aging study that began in 1988, and which tested three aspects of cognitive function in middle-aged or older adults over the course of four years.
Of all 531 women considered, those who reported eating more eggs showed less of a decline in short- and long-term memory.
No such association was found among men who ate more eggs. That said, another data analysis using the same database but a cohort from a different decade did find that men who ate more eggs scored better on cognitive tests, whereas no association was found for women.
This suggests there's other factors at play too, that need to be cleared up by further research.
Public health researchers Donna Kritz-Silverstein and Ricki Bettencourt from UCSD argue that "despite having high levels of dietary cholesterol", their results show "eggs do not have a detrimental effect and may even have a role in the maintenance of cognitive function over time."
For nearly half a century, people were advised to avoid animal products high in cholesterol, like eggs, butter, or cream, because these foods were thought to raise cholesterol levels in the blood, increasing the risk of cardiovascular disease.
While that advice may still stand for some people with certain health conditions, like diabetes, emerging evidence suggests it's really saturated fats, sugar, and sodium that are the main contributors to plaque buildup in the arteries, not dietary cholesterol.
The trouble is, many foods rich in cholesterol also deliver a hearty dose of saturated fats. Eggs and shellfish are two key exceptions, depending on how they are cooked.
In fact, eggs are low-fat, high-protein, nutrient-dense foods that could actually lower your body's cholesterol levels, an effect that seems to help protect against cognitive decline.
Perhaps that is one reason why eating eggs was linked to slightly improved cognitive test scores among women in the recent analysis, but further research is needed to explore that association.
Kritz-Silverstein and Bettencourt point out in their paper that eggs are rich in proteins, amino acids, and cholesterol, and these factors could possibly work to preserve neuron structure and function in the brain.
Eggs also contain carotenoids, which are linked to improved cognitive performance, and they are packed with choline, which is a precursor to a crucial neurotransmitter.
"Cross-sectional studies have shown that those with greater choline intake and those with higher plasma concentrations of choline had better scores on several measures of cognitive function," note Kritz-Silverstein and Bettencourt.
There's still lots of questions left to be answered about the nutritional benefits of eggs, but these recent findings provide additional evidence that if a food is high in cholesterol, that doesn't always mean it's bad for your body or your brain.
The study was published in Nutrients.
