Spinach didn't just make Popeye strong — it gave him the mind of a much younger man. Spinach and other leafy greens are as good for the mind as they are for the muscles, a recent study suggests. People in the study who ate one or two servings a day of spinach, kale, mustard greens and collard greens had the mental abilities of people eleven years younger.

Popeye's beloved Olive Oyl appears to have been a factor as well, since olive oil heightens leafy greens’ effects.

Increasing consumption of green leafy vegetables could offer a very simple, affordable and non-invasive way of potentially protecting your brain from Alzheimer’s disease and dementia.

“Losing one’s memory or cognitive abilities is one of the biggest fears for people as they get older,” researcher Martha Clare Morris said in a statement. “Since declining cognitive ability is central to Alzheimer’s disease and dementias, increasing consumption of green leafy vegetables could offer a very simple, affordable and non-invasive way of potentially protecting your brain from Alzheimer’s disease and dementia.”

The study tracked 950 older adults, average age 81, for five years, assessing cognition annually with a battery of 19 tests.

Researchers adjusted their results for age, sex, education, smoking, genetic risk for Alzheimer’s disease and physical activity before estimating the effects of diet on cognitive decline.

When the people who ate one or two servings a day of leafy greens had their mental abilities compared to those who did not eat any leafy greens, the "leaf eaters" tested out as eleven years younger (better).

Since all these vegetables are rich in vitamin K, the researchers suspect that vitamin K may be responsible for the beneficial effects reported. Other nutrients found in these vegetables include lutein, folate and beta-carotene, making it difficult, however, to tease apart the specific association of vitamin K from other nutrients, according to Morris.

One way to ensure that you are getting all the important nutrients found in leafy greens is to just eat leafy greens and leave it to the experts to chew over what exactly is making you so healthy.

There are other studies suggesting that what's good for the body is also good for the mind. And this is hardly the first study linking leafy greens and good health. But if further research reproduces its results, it may be an important one. Once you reach a certain age, having the mind of someone over a decade younger is a dream come true.

The study was presented at the American Society for Nutrition (ASN) Annual Meeting.