If you’re looking for another reason to swap fries for a salad, a new study offers some inspiration.

Researchers at Rush University Medical School in Chicago found that eating as little as 1 1⁄3 cups of lettuce daily—or a bit more than ½ cup of cooked dark leafy greens—may delay the decline in memory and thinking skills that can occur with age. Eaters of leafy greens had brains that functioned as well as people 11 years younger, the researchers determined.

The 960 participants, aged 58 to 99, were part of a larger ongoing study called the Rush Memory and Aging Project. For the current analysis, the researchers tracked the study volunteer's consumption of 144 different foods for about five years on average, measuring cognitive function periodically.

Even after controlling for other aspects that can affect memory—such as age, activity level, alcohol consumption, and smoking—leafy-greens intake emerged as the most significant factor in protecting the brain.

“This study is promising,” says Orly Avitzur, M.D., a neurologist and Consumer Reports’ medical director. “While cognitive disease can stem from multiple factors—some of them genetic—there is evidence that modifying your diet can have a positive impact.”  

What’s So Special About Leafy Greens?

According to lead researcher Martha Clare Morris, Sc.D., a nutritional epidemiologist at Rush who has studied diet and dementia for decades, leafy greens aren’t the only food linked to better brain health. Along with colleagues from Rush, Morris developed the MIND diet, which identifies 8 foods—beans, berries, fish, nuts, olive oil, whole grains, wine, and leafy greens—that, when made a regular part of a diet low in saturated fat and sugars, have been shown to potentially lower the risk of Alzheimer’s disease.

More About Salads

But the results of the current study, published in the journal Neurology, show that leafy greens stand out, making their connection to brain health practically undeniable. “When it comes to slowing cognitive decline, [eating leafy vegetables] appears to be one of the most significant behaviors you can adopt,” Morris says.

The power of leafy greens may lie in their combination of nutrients. For example, Vitamin E has been shown to reduce inflammation in the brain and the accumulation of amyloid plaques on nerve cells in the brain (a hallmark of Alzheimer’s disease). And Morris points to the B vitamin folate, which assists with the DNA-building process and has positive effects on the vascular system. The researchers also considered other nutrients in leafy greens, like the antioxidant lutein and phylloquinone (a type of vitamin K).

“There aren’t many foods that contain all of these nutrients in the same package,” says Morris, adding, “if any.”

Despite the strong link, however, Morris cautions that the study results do not definitively prove that leafy greens alone are responsible for slowing brain aging. There may be other factors at play, and the study’s demographic makeup (older, mostly white greens eaters) raises the possibility these results would be different among younger subjects, or people of color.

Still, there’s no downside to ramping up your leafy-greens consumption. Not only may adding a serving to a daily diet be a simple way to foster brain health, leafy greens are among the most nutrient-dense foods you can eat, and other research has shown they help cut the risk of cancer, type 2 diabetes, and more.

Easy Ways to Get More Greens

The study participants were asked about their intake of specific leafy greens—raw lettuce and cooked collard greens, kale, and spinach. But there are other types of greens that have a similar nutritional makeup. If you aren’t already getting adequate leafy greens in your diet, it’s not that hard to boost your intake. Try these simple suggestions from Ellen Klosz, a CR nutritionist.

Start your day right. Spinach and kale go great in omelettes and other egg dishes, but you can also puree them and add that to pancake or muffin batters.

Garnish sandwiches and wraps. Consider using a liberal amount of kale, spinach, or other dark greens to add extra nutrition to your lunch. A few leaves here and there throughout the day can add up.

Sneak them in. If leafy greens are a tough sell for your palate, chop them up finely and add to foods like chili, soups, and casseroles. Or throw a handful of spinach or kale into a fruit smoothie, where the fruit will mask the somewhat bitter taste of the greens.

Toss a salad. Eating a salad a day may be the easiest way to get your greens. But if a bowlful of lettuce seems too boring, add beans, nuts, whole grains, and other foods identified in the MIND diet to make your salad tastier and more beneficial to the brain.