Blueberries, salmon, walnuts and other well-known brain-healthy foods are the go-to foods for people who want to keep their minds sharp.

But there’s another food that should be added to that list, according to a study published in Journal of Alzheimer’s Disease.

“It seems that a commonly available single ingredient could have a dramatic effect on cognitive decline,” said Lei Feng, MD, PhD, lead author of the study and assistant professor in the department of psychological medicine at the National University of Singapore.

What is this brain-friendly fare? It’s mushrooms!

Here’s how the research unfolded…

In the first phase of the six-year study, scientists gave 663 adults, age 60 and older, neuropsychological tests to assess whether they showed any mild cognitive impairment (MCI), a form of cognitive decline—beyond normal aging—that often progresses to Alzheimer’s disease.

The study participants were also interviewed to find out about their medical history, lifestyle and dietary habits. When the testing was complete, the researchers collated the data to determine whether there were any associations between MCI and consumption of mushrooms.

The researchers were particularly interested in the study participants’ intake of mushrooms because an earlier study had found that people with MCI have significantly lower levels of an amino acid known as ergothioneine (ET), whose mainly dietary source is—you guessed it!—mushrooms.

Study findings: The participants who ate more than two servings (a total of one-and-a-half cups) of cooked mushrooms each week were half as likely to have MCI as those who ate them less than once a week. This association was independent of age, gender, physical and social activities, and other medical conditions. The mushrooms identified in the study were golden, oyster, shiitake and white button mushrooms, as well as dried and canned mushrooms.

Good news: Even one ¾-cup portion of mushrooms per week contributed to better brain health in this study.

ET is a specific compound found in almost every type of mushroom. It has anti-inflammatory and antioxidant properties that seem to promote brain health. In addition, there are other phytonutrients in mushrooms that may play a role in preventing cognitive decline, so the authors plan to test additional compounds found in mushrooms to determine which ones have a positive effect. That way, they may be able to identify other foods that have the same benefits as mushrooms on the aging brain.

Bottom line: Because MCI has been shown to increase risk for Alzheimer’s disease, a simple dietary habit, such as consuming mushrooms, is a smart move. They are low-calorie, low-fat and delicious. To help your brain age like a champ’s, consider adding button mushrooms to a pizza…shiitakes to a stir-fry…or whatever mushroom dish strikes your fancy.

Bonus: For some delicious ways to add mushrooms to your meals, try these recipes.

Caution: Do not eat wild mushrooms unless they have been approved by a mushroom-identification expert, warns the National Capital Poison Center. Mushroom poisoning is common—and can be fatal.