These foods may help keep the brain young

Blueberries, olive oil, kefir, walnuts, leafy greens, oatmeal, bananas, and algal oil. These are some of the foods that could play a role in helping to keep the brain healthy throughout life, according to scientific experts interviewed by CBS News.

The brain is the "motherboard of reality," said Dr. Joel Salinas, a neurologist at Massachusetts General Hospital. "The better we can take care of this organ that is so deeply tied to who we are as a person, to this universe that we exist in, the more fulfilling of a life we'll be able to live."

"Brain health" encompasses a person's ability to remember things as well as avoidance of dementia and Alzheimer's disease, said Francine Grodstein, Sc.D., a professor of medicine at Harvard Medical School. Dementia is a broad term referring to a decline in mental ability, including problems with memory, communication, focus, and reasoning. Although dementia is more common in older adults, it is not part of the normal aging process. Alzheimer's disease, which affects about 5.5 million Americans, is the most common type of dementia, according to the Alzheimer's Association.

But doctors and scientists still have much to learn about how our eating habits may affect brain health.

"It's important to emphasize that research and understanding of the possible impact of diet on brain health is a relatively new field," Grodstein said.

Yet even as that work continues, a person is never too young to start caring for their brain health, said Salinas. "Much like we brush our teeth every day… and see a dentist regularly, we should place that same kind of value on our brains," he said. 

Keeping the bacteria happy

Oatmeal, pulpy orange juice, bran cereal, bananas, fruit smoothies from unpeeled fruits, and other fiber-containing foods are all prebiotics. 

"Prebiotics means fiber and roughage that's helping to promote the growth of the beneficial bacteria in your gut. It's making the existing bacteria in your gut happy," explained Rudy Tanzi, Ph.D., a professor of neurology at Massachusetts General Hospital and director of the Alzheimer's Genome Project.

Probiotic foods include yogurt, kefir (a liquid yogurt), and fermented foods like sauerkraut, pickles, and kimchi. Probiotic supplements also contain billions of live bacteria.

"Probiotics are actually adding bacteria to your gut that's beneficial, the types of bacteria you see on the back of your yogurt cup," according to Tanzi. "You want to add both prebiotics and probiotics to your diet."

Our intestines are filled with bacteria that are a normal part of the digestive process. The large intestine has the most bacteria and is where the "gut controls inflammation in the brain," Tanzi said.

Prebiotic and probiotic foods can reduce harmful inflammation in the brain, called neuroinflammation, said Tanzi. "First and foremost is keeping the bacteria in your gut happy."

Blueberries 

"There is exciting preliminary evidence of blueberries for brain health." said Grodstein. Blueberries have high levels of flavonoids, a compound in food that reduces oxidation in the body. Over time, oxidation can damage cells and contribute to aging. 

Blueberries help "fight inflammation," according to Tanzi.

Berries are also on the list of foods that Salinas recommends to his patients. "Overall, what I tell people who come to me in clinic is you want to eat a diet that's high in fish, berries, leafy greens, and whole grains."

And even the experts eat berries. "I have started eating lots of berries and more nuts in recent years," said Grodstein.

Green, leafy vegetables

Green, leafy vegetables such as romaine, arugula, kale, collard greens, broccoli, spinach, and Swiss chard are among the foods that support brain health.

"Across several studies there is fairly consistent findings that green, leafy vegetables do seem to be related to decreased risk of cognitive impairments or dementia," said Grodstein.

Vegetables are also a key component of the MIND Diet. Developed by researchers at Rush University Medical Center in Chicago, the MIND diet was shown to reduce the risk of developing Alzheimer's disease in one study.

MIND stands for "Mediterranean-DASH Intervention for Neurodegenerative Delay." It bases its healthy food choices on principles of the Mediterranean diet and the heart-healthy DASH diet, both of which are grounded in scientific research. 

Nuts, olive oil and other healthy fats

The experts recommended replacing saturated fats from red meat with fats from fish, tree nuts, and healthy oils. The better-for-your-brain options include salmon, tuna, walnuts, pistachios, almonds, olive oil, and algae oil.

"People whose diets have more fish in them do seem to be less likely to develop memory problems," said Grodstein.

Certain fish and nuts contain high levels of omega-3 fatty acids, a specific type of fat that has been shown to provide health benefits, including reducing neuroinflammation, according to Tanzi. 

"There's good evidence that these omega-3 fatty acids help to lower LDL, the 'bad cholesterol' that increases risk of stroke or heart attack," said Dean Hartley, Ph.D., director of science initiatives at the Alzheimer's Association. "With my diet, I do try to go more toward the Mediterranean diet, including things like olive oil and salmon."

A word of warning from Dr. Tanzi: Fish oil supplements are sometimes contaminated with heavy metals, which can actually end up killing cells in the brain.

"Fish oil comes from fatty fish, which live in the ocean. Our oceans are now unfortunately contaminated with heavy metals like mercury, cesium, cadmium, and lead," said Tanzi.

"You can gamble and hope you're buying the best possible fish oil, or you can buy a vegan, omega-3 supplement that comes from algae. And you aren't going to get the heavy metals, because it's not coming from fish."

Tanzi recommends an algal oil supplement high in DHA and EPA. "Those are the compounds you really need."

Fasting and eating less

Research on animals has shown that caloric restriction – eating fewer calories in a strategic way – helps prevent several diseases, but there isn't enough evidence to recommend fasting as a preventative measure for brain health, according to Hartley.

Salinas agrees. "I think the verdict is still out with regard to fasting."

"In fact, one of the problems that we often see is that people with Alzheimer's disease have a failure to thrive," said Hartley. "They are not necessarily able to take in the proper calories."

Although the effects of fasting and caloric restriction on brain health aren't fully understood in people, limiting food to a certain extent may improve other aspects of health, according to Josh Mitteldorf, Ph.D., an independent scientist who writes about aging and evolutionary biology. He's the author of "Cracking the Aging Code: The New Science of Growing Old – And What It Means for Staying Young."

"The body is trying to kill itself," said Mitteldorf. "Aging is programmed into our genes." He argues that, like the surge of growth hormones in our youth and sex hormones during puberty, there are genes that get "turned on" during the twilight of life that serve to age and ultimately kill us. "This is done with programmed cell death. It's done with inflammation. It's done by shutting down the immune system, which is so important to protecting us."

How does one slow down that aging process? "You've got to find some way convince the body not to kill itself," said Mitteldorf. "Natural approaches to anti-aging is an oxymoron…. You're going to have to trick the body."

Periodic fasting might be one way to "trick the body" into living longer, he suggested. But how much longer? "My guess is five years," said Mitteldorf.