In Sharon Johnson's mind, eating to improve mental function is a no-brainer.

In Sharon Johnson's mind, eating to improve mental function is a no-brainer.

"It's eating foods that make you feel better, and then you think better."

Much like diet plans to prevent cancer, heart disease, diabetes and other illnesses, the consumption of natural, unprocessed foods is shown to prevent memory loss. Whole grains, legumes, nuts, seafood, lean meats, eggs, dark-green leafy vegetables and citrus fruits all support a healthy brain and noticeably affected cognition in a study of older adults by Oregon State University, says Johnson, an associate professor.

"What's good for your heart is good for your head."

Along with medications, physical activity and depression, memory difficulties and diet are significant issues for many aging adults, says Johnson. She plans to bring both memory and diet to the table for two April classes, titled "Feed Your Brain," at OSU Extension in Jackson and Josephine counties.

While memory difficulties can start as early as age 30, half of people over age 50 experience lapses, and all adults over age 65 report episodes of forgetfulness, says Johnson. The problem is pronounced for anyone taking prescription drugs or eating and sleeping poorly, she adds. Not surprisingly, anxiety mounts in anyone with a family history of Alzheimer's disease.

"Some of this is reversible," says Johnson. "Everything counts."

Even small amounts of foods high in the right nutrients can have a big impact. So Johnson's class doesn't focus just on healthful meals but also on wholesome snacks. Participants likely will sample a smoothie with spinach, the chickpea spread known as hummus, as well as kale chips, says Johnson.

"They are largely plant-based foods or seafood."

Salmon is the main dish in a brain-foods menu that Mary Shaw, culinary educator for Ashland Food Co-op, developed for Johnson. Working in tandem at a Co-op class more than a year ago, Johnson and Shaw scheduled a February repeat of "Feed Your Brain," which included a full Co-op dinner and sold out more than a month in advance.

"It's a really, really big topic right now because we know more about the brain," says Shaw.

Some dietary wisdom, however, is centuries old. Shaw cites traditional Chinese medicine's "doctrine of signatures," which advocates eating foods to support organs that they most resemble. For example, shelled, crinkly walnuts mimic the various bulges and creases of the human brain. Bulbous, bumpy cauliflower also evokes gray matter.

"It's so cool how much it looks like a brain," says Shaw.

Although modern-day medicine hasn't validated the ancient "doctrine of signatures," there is plenty of scientific evidence that the aforementioned foods are good for the brain, says Shaw.

Cauliflower is high in folate and vitamin C, both critical nutrients, along with vitamins D and E. High in vitamin E, walnuts exceed their counterparts in omega-3 fatty acids, the primary compound touted in many fish for enhancing mental function and preventing neurological diseases. Ten nuts supply the body's daily requirement for omega-3, says Shaw.

"It keeps the brain elastic," she says, explaining that both adults' aging brains and children's growing brains need good-quality fats.

Preserving the nutrients in foods is as important as making healthful choices, says Shaw. Slower cooking with gentler heat keeps more beneficial properties intact, she says. Shaw bakes salmon in a medium-temperature oven after encasing each fish fillet in a packet of seaweed, which infuses subtle flavor and an extra dose of minerals.

"All of the juices are sealed inside of the nori," says Shaw.

The dish also is ideal for a single serving. Many who attend her lectures, says Johnson, are women who live alone and resort to eating tea and toast.

The process of planning a menu, following recipes and practicing cooking techniques are yet more ways to engage the aging mind, says Johnson. And she suggests reading Michael Pollen's "Food Rules: An Eater's Manual," a short, commonsense guide to a healthful diet.

When the context is brainpower, says Johnson, the concept of "mindful eating" gains new meaning.