Diet affects brain health, study finds Oregon researchers say those who eat a lot of fruits and vegetables fare better as they age

A new study by Oregon researchers suggests that all those holiday treats, backed up by year-round junk food, might be going to your head, and not in a good way.

Research by scientists at Oregon State University and Oregon Health & Science University has found that older people whose diets are big on unhealthy, fatty foods do worse on mental acuity tests and have more brain shrinkage than those with healthy diets. Older people who eat lots of fruits and vegetables and the healthy oils found in fish were sharper and had less brain shrinkage.

The study is getting attention because it’s the first to measure the effect of diet on brain size and function by directly measuring nutrient levels in the blood and by imaging brains using an MRI. Previous studies relied on people filling out food questionnaires that are subject to memory lapse and inaccuracies.

“This is the first time that we’ve actually been able to show that the brain is protected by a good diet,” said Maret Traber, a nutritionist at OSU’s Linus Pauling Institute and a co-author of the study. “I think that’s outstanding.”

A paper describing the research was published this week in the journal Neurology, published by the American Academy of Neurology. The lead author is OHSU’s Gene Bowman, a naturopathic doctor, neurology professor and brain researcher.

The human brain normally shrinks with age as mental agility also drops. But the new study suggests that what you eat could either accelerate or slow that process.

What the researchers found is that people with high levels of vitamins B, C, D and E and the omega-3 fatty acids found in fish had better cognitive ability than others, especially those with high levels of transfats.

Transfats are often found in baked and fried foods, margarine and fast foods, although many snack food manufacturers have recently begun to eliminate transfat from their products.

Traber said one of the findings that was most disturbing was that older people with high levels of transfats in their blood actually had measurably smaller brains than those with healthy diets.

“That’s the scary part,” she said. “What you eat actually does matter.”

The study looked at a group of 104 Oregonians with an average age of 87 with no special risk factors for problems with memory or mental acuity. They were tested for 30 different nutrient biomarkers in their blood, and 42 of the participants also had MRI brain scans.

The participants were taken from a larger group of almost 300 people participating in the Oregon Brain Aging Study, which was begun in 1989 using men and women age 65 and older at that time.

In some ways the results aren’t surprising, given that the same kind of diet that seems to protect the brain has long been known to benefit the heart and prevent other diseases.

But knowing that a good diet also helps the brain is important as more people in developed countries are living longer.

“There a phenomenal number of epidemiological studies that say people who eat a diet rich in fruits and vegetables have less chronic disease,” Traber said. “I like to say it’s exactly what your mother told you to do.”

But even people who get their vitamins and fish oil in pill form will benefit, Traber said. The study just looked at what was in people’s blood, not how it got there, and Traber said taking vitamins orally has the advantage of telling you just how much you are getting.

In a commentary published in the same issue of the journal, two other researchers said the use of blood assays to determine dietary effect on the brain holds promise. If results are confirmed in a larger and more ethnically diverse group of older adults, the value of other nutrients could be investigated, said Christy Tangney of Rush University Medical Center and Nikolaos Scarmeas of Columbia University.

“Moreover, additional biomarkers for food group and food subgroups might be explored,” they said, including beneficial nutrients found in red wine, olive oil and citrus fruits.

The study is being published just as many people are looking back at a holiday season where they might not have seen the healthiest food on their plates.

For those folks, Traber said the results provide yet another incentive to turning over a new leaf, especially if that leaf is attached to a vegetable.

“It comes out at such a good time,” she said. “Right now is when everybody is worrying about the sweets and treats they ate during the holidays, and here’s what they can do to get healthier.”