When it comes to nutrition, eggs have been a tough nut — or shell — to crack.

The small, oval, protein-packed goodies were once declared a no-no because they are naturally high in cholesterol. More recently, eggs have swung back into the good foods category, thanks to their high levels of vitamins, minerals, protein, and good fats.

Now, a new study offers more evidence favoring the humble egg. Researchers found that women aged 55 and over who ate eggs on a regular basis saw notable improvements in their brain health. The women experienced less decline in executive brain functions and less memory loss over time.

The researchers accounted for a variety of factors, including age, education, cholesterol levels, and lifestyle factors — and the positive results remained.

So, eggs are good for women’s brain health, but how many eggs should women consume to see these positive benefits? Researchers found that five eggs per week seems to be the optimal number, so nearly an egg per day.

Interestingly, the study did not note any significant link between egg consumption and improved brain health for men.

Researchers said the reason for the healthy brain boost in women isn’t completely clear, but they suggest the lesser-known nutrients packed into eggs, like choline [ko-lean] and lutein [loo-teen], may have something to do with it. These nutrients are known to benefit brain health.

This study ultimately puts another point in the “good” category for eggs and adds to the ever-growing collection of evidence showing that the once-spurned egg may not be as bad as it’s cracked up to be.