Berry berry good

Nutrition Action Healthletter, June, 2005 by David Schardt

Shoestring Blueberries

The little research on blueberries in humans isn't what you'd call rigorous. Several amateur investigators in the Danbury, Connecticut, area have been testing blueberries on the reaction speed and memory of older volunteers since 2000 (see www.blueberrystudy.com).

"We've found slight improvements in those who eat a cup of blueberries every day," says Roll Martin. But on a shoe-string budget, Martin can't afford to recruit enough people or develop a look alike but blueberry-free placebo. So it's impossible to know whether the results mean anything.

"The limitations of these studies prevents us from concluding that blueberries are having any effect," says Bruce Kristal of the Weill Medical College of Cornell University in New York City, who nonetheless says that the Connecticut research is "worth pursuing."

"There may be some small benefit if you eat a lot of blueberries during your adult life," says the National Institute on Aging's Mark Mattson. "But that's based on animal studies. In humans we just don't know."

What about blueberries and Alzheimer's? Here again, the evidence is in animals. Tufts researchers Joseph and Shukitt-Hale found that mice bred to develop an

Alzheimer's-like disease could negotiate a maze better in their old age if they had been fed blueberries every day through adulthood. (2) But it's not clear what that means for people.

"I've been in the neurodegenerative disorder field for quite a while, says Mattson. In no case has something that's worked with dramatic effects in animals had a similar beneficial effect in people with Alzheimer's or Parkinson's or in those who have suffered a stroke."

"If someone has Alzheimer's, blueberries are not going to cure them. There's no evidence that there would be any benefit."

How Blue?

Joseph and Shukitt-Hale fed their rats and mice the equivalent of one-half to one cup of blueberries a day. "We used frozen berries, but our studies show that fresh or frozen, wild or domesticated all have the same benefits," says Joseph.

If you want to eat more blueberries, just skip the blueberry pie and the big blueberry muffins in the gourmet coffee shop. Heating blueberries speeds up the degradation of their anthocyanins.

"I don't think there's much left in a muffin or a pie by the time you eat it," Joseph says.

(1) Journal of Neuroscience 19: 8114, 1999.

(2) Nutritional Neurosciences 6: 153, 2003.