A new study shows that leafy greens stand out over other foods, making their connection to brain health practically undeniable. (Andre Chung/for The Washington Post)

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

Researchers at Rush University Medical School in Chicago found that eating as little as 1⅓ cups of lettuce daily — or a bit more than half a 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, ages 58 to 99, were part of an ongoing study called the Rush Memory and Aging Project. The researchers tracked the study volunteers’ consumption of 144 foods for about five years, on average, measuring their 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, 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, 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. Morris helped develop the MIND diet, which identifies eight 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.

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.

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, such as 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.

Despite the strong link, Morris cautions that the study results do not definitively prove that leafy greens alone are responsible for slowing brain aging. Still, there’s no downside to ramping up your leafy-greens consumption. 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 raw lettuce and cooked collard greens, kale and spinach. But there are other types of greens that have a similar nutritional makeup. If leafy greens aren’t already staples of your diet, it’s not that hard to boost your intake. Try these suggestions from CR nutritionist Ellen Klosz.

Start your day right. Spinach and kale go great in omelets and other egg dishes. You can also puree them and add that to pancake or muffin batters and fruit smoothies.

Garnish sandwiches and wraps. Consider using a liberal amount of kale, spinach or other dark greens to add extra nutrition to your lunch.

Sneak them in. If leafy greens are a tough sell for you or your family members, chop them up finely and add to foods such as chili, soups and casseroles.

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.

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