- Blueberries could help slow the mental decline that often comes with old age.
- Their secret? Antioxidant molecules called anthocyanins.
- Animal studies have supported the brain-boosting power of blueberries for a while, but this is the first study of its kind in people.
There may be a simple way to ease the memory lapses and brain slips that typically accompany old age: Eat more blueberries.
In a small study, older adults who drank a couple cups of blueberry juice a day improved their scores on a learning and memory task by 20 percent. Studies in animals have linked blueberries with brain function, but this is one of the first such studies in people.
The results, while still preliminary, suggest that blueberries might just live up to their reputation as "superfoods."
Among other health benefits, adding the tasty little, blue marbles to your diet could help slow the march of memory decline and possibly even prevent memories from slipping in the first place.
"We're getting the first signal in humans that this might work," said Robert Krikorian, a neuropsychologist at the University of Cincinnati in Ohio. "There's so much research now suggesting that fruits and vegetables are beneficial. I don't have any qualms about recommending that people eat blueberries."
The case for blueberries has been building for more than a decade. In animal studies, older individuals that consume blueberry extract improve their performance on memory tasks, sometimes to the point of being just as sharp as their younger counterparts.
To explain how blueberries might bring about such impressive brain-boosting effects, other studies have zeroed in on a type of antioxidant called anthocyanins. These molecules belong to a larger group called polyphenols, which come in thousands of varieties.
Polyphenols appear in virtually all fruits and vegetables, and have been shown to reduce the risk of cancers and heart disease, among other benefits.
In animals that have consumed lots of blueberries, scientists have spotted anthocyanins in the brain structures that are known to be involved in memory. There, molecules appear to work their magic by helping neurons communicate with each other, facilitating memory processing.
Anthocyanins also make brain cells more resilient in the face of stress. The molecules might even act as a sort of mild toxin that prods the body to grow stronger.
The major question lingering from all of that work, Krikorian said, was whether any of it applied to people. To find out, he recruited nine adults who were, on average, in their mid-70s. All participants had experienced some mild memory decline.
At the beginning of the study, each participant took a series of learning and memory tests. In one task, they memorized pairs of unrelated words, such as "garden" and "note." Words in each pair had no obvious connection to each other, making them challenging to remember.
For the next 12 weeks, participants drank three glasses of blueberry juice a day, for a total of between two and two and a half cups. The exact amount they drank depended on body weight. During the last week of the study, participants took the memory tests again.
Out of a possible score of 20 on the paired-words task, the average score was about 9 before the juice drinking began. Three blueberry-filled months later, average scores rose to about 13, the researchers reported in the Journal of Agricultural and Food Chemistry. That's a 20 percent improvement.
Krikorian had previously conducted a similar study with anthocyanin-rich grape juice, which turned up similar results.
While the number of subjects in the blueberry study was small, the results were encouraging, said Mark Smith, a neuroscientist at Case Western Reserve University in Cleveland. The findings raise hopes, he added, that blueberries could help stave off Alzheimer's and other age-related neurodegenerative diseases.
"It's an early study, and I don't want to hype it, but you're getting the effects of a pharmaceutical here by using a food supplement," Smith said. "The data is all pointing in the right direction. I think it's brilliant. It's a major step into human beings."
Plenty of details have yet to be worked out. How many blueberries do you need to eat to see any benefits, for example? Does juice work better than whole fruit? When is the best time in life to stock up on the fruit?
For now, research suggests that blueberries will do more for older people whose brains are starting to fade than for younger people who are still sharp. Still, it can't hurt to get into the habit early of eating a variety of colorful fruits and vegetables.
"Blueberries in the context of a balanced diet is never a bad idea," Smith said. "They're not going to do any harm."