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Guest Columnist: Joe Schwarcz
Keep your cool over blueberry hype
Research suggests that blueberry juice could enhance memory and promote brain health. But no single food holds the secret to well-being.
Dr. Joe Schwarcz is Director of McGill University's Office for Science and Society, which is dedicated to demystifying science for the public, the media and students. He is a bestselling author of books such as An Apple a Day, Brain Fuel, and Science, Sense & Nonsense. Among his many honours are the Royal Society of Canada's McNeil Medal for the public awareness of science and the American Chemical Society's Grady-Stack Award for interpreting chemistry for the public.
Is blueberry juice a good investment in your health? If recent U.S. research is corroborated by bigger and better trials, we may be drinking it for breakfast instead of orange juice. And we may be having another glass of the stuff for a nightcap — if we can afford it.
So why would we drink blueberry juice? To improve memory, counter depression, improve coordination and perhaps even reduce the risk of dementia.
Blueberries first made the news big time back in 1999 when researchers at Tufts University in Boston determined that aging rats given a blueberry supplement performed better on memory and motor skills tests than their counterparts who were fed a standard laboratory diet.
So how do you test memory and motor skills in rodents? By seeing how long it takes them to learn to find an underwater platform in murky water and noting how long they can balance on a spinning rod. The blueberry-fed rats clearly performed better. In fact, they performed like more youthful animals. Young rats, for example, can stay on a spinning rod for about 14 seconds, while senior citizens tend to fall off after 6 seconds. But not the blueberry-supplemented seniors! They managed to stay on the rod for roughly 10 seconds.
Humans though, with possibly some exceptions, are not giant rats. Can blueberries do anything for us? Can they improve a failing memory? Can they have an effect on Alzheimer's disease?
Anthocyanins give many fruits and vegetables their intense colour (e.g. blueberries, cranberries, purple potatoes, red cabbage). They are a good source of antioxidants.
The enhanced memory and motor performance in aging animals is probably due to the presence of anthocyanins, the characteristic blue pigments in blueberries. These have antioxidant and anti-inflammatory properties, which could account for the benefits. More interestingly, after rodents have been fed blueberries, anthocyanins can be detected in the hippocampus and neocortex brain areas, which are essential for cognitive function.
Can something that works for rats work for humans? A logical question — and that's just what researchers at the University of Cincinnati aimed to find out. They chose to focus on elderly subjects who already had mild cognitive impairment, since this is known to be a significant risk factor for later development of Alzheimer's disease.
Nine people in their 70s who had been diagnosed with mild cognitive impairment (through standardized memory and comprehension tests) were recruited for the study. Their task was simple: drink two to two-and-a-half cups of wild blueberry juice a day. After adjusting for body weight, this was roughly the dose that had shown beneficial effects in test animals.
Did you know?
Canada is the world's second largest producer and exporter of blueberries after the United States. In 2008, we exported more than $300 million worth of blueberries to the world.
Twelve weeks later the subjects were tested again and showed a clear improvement in word recall tests. In addition, depressive symptoms were reduced, as were blood glucose levels.
Of course, any such scientific trial requires a placebo control. After all, it's possible that if subjects believe that a memory enhancing substance is being tested, they will try harder to memorize the test words.
To counter such a placebo effect, the experimenters tested another group of similar subjects who were also given "blueberry juice" to drink, but this time the juice was actually a grape beverage. Not a perfect placebo to be sure, but better than no placebo control. Word recall was clearly better with the real blueberry juice. It seems that the specific anthocyanins in blueberry juice may really have memory enhancing effects.
Did you know?
Oxford, Nova Scotia is known as the wild blueberry capital of Canada. Atlantic Canada is the world's largest supplier of frozen wild blueberries.
But blueberries may not be unique in this regard. A study of 3,774 subjects aged 65 and older found that strawberries had a significant effect on cognitive decline. Subjects who consumed more than one serving of strawberries per month had a slower decline than those who consumed less.
All of this sounds very alluring, but let's be realistic here. Drinking a couple of glasses of blueberry juice a day is not an option for most people. And it is scientifically unsound to look on individual foods or beverages as "healthy" or "unhealthy." It is the overall diet that matters. It is possible to guzzle blueberry juice every day and still have a terrible diet, just as it is possible to have a very healthy diet without ever drinking the stuff.
Of course, given what we know about the chemistry of berries, and looking at the accumulating experimental evidence of benefits, a blueberry-strawberry smoothie is a better choice than soda pop. 
The views expressed in this article are those of the author. Stay tuned for more guest columns in future issues of Dimensions.
Antioxidant powerhouse
Berries such as blueberries and cranberries have high concentrations of antioxidants. Antioxidants can prevent or slow the oxidation process that damages our cells. Health problems such as heart disease, macular degeneration, diabetes and cancer are all attributed to oxidative damage. Antioxidants can be found in brightly coloured vegetables and fruits, particularly within vitamins A, C and E. *Agriculture and Agri-Food Canada
