Hand Harvesting Blueberries
It was in the late ‘90s when the news that blueberries had high antioxidant levels started making its way into the public consciousness. This was at a time when many people didn’t even know what antioxidants were or why they would want them in their diet.
Leslie Wada, owner of LW Consulting in the San Francisco area (and a previous research administrator with the US Highbush Blueberry Council), explains that the research into blueberries has continued far past ORAC levels and antioxidants when she spoke to producers at the International Blueberry Organization summit earlier this year.
“In general, blueberries have one of the highest levels of antioxidants,” she says. “There has been an increase in the number of studies on the health (benefits) of blueberries [after this discovery.]”
Studies weren’t the only thing that increased due to the new revelations about antioxidants.
Wada says that as research into blueberries grew and benefits were discovered, there was a correlating increase in farm gate sales. Researchers were wondering what other properties existed in blueberries that could be beneficial to human health. While there have been many studies, she focused on three health areas where blueberries are proven to benefit humans; cognitive function, insulin resistance and cardiovascular health.
In a study of retired individuals, scientists were hoping to see similar results in humans as in tests where older mice, which were fed blueberries, had the ability to respond and react with improved memory as quickly as younger mice. In the human study, the retirees were given the equivalent of a cup of blueberries (in a dried powder form) for 90 days.
“Those who were given the blueberries had fewer errors in a verbal test,” explains Wada. “There is an enhanced neural response.”
In a similar task-based test, those receiving the blueberries had fewer wrong answers. Thus, it is believed that blueberries can improve cognitive function in adults to some degree. This assumption is supported by MRIs that were done on individuals who were eating more blueberries, as the MRI showed an increase of blood oxygen levels in the brain.
Other studies around blueberries and cognitive function are ongoing, including a $20 million study by the US Alzheimer’s Association on preventing cognitive decline that includes blueberries as part of a complete lifestyle diet.
In a recent diabetes and insulin study, fat was seen to create insulin resistance, but blueberries were seen as a food that can help reduce that unhealthy trend.
“If you feed those same mice a high fat diet, but add blueberries, they become less insulin resistant,” Wada says. “Researchers surmised that blueberries improved beta cell function.”
In a study of obese humans, the equivalent of two cups of blueberries were administered and the results were similar to that of the mice in that the amount of insulin required to keep glucose levels stable was reduced.
“There was improved insulin sensitivity in obese, insulin resistant humans,” she explains.
Blueberry studies are also showing that the fruit can help promote heart health; a positive discovery given that Wada says 31 per cent of all global deaths are linked to cardiovascular disease.
“We’ve done a couple of studies of blood pressure and blueberries,” she says, adding that one positive study involved post-menopausal women with a higher risk of cardiovascular disease. “When they were fed blueberries, they showed a significant drop in their blood pressure,” notes Wada.
In another study conducted in the UK with 115 overweight men and women for six months, participants were given a placebo, ½ cup of blueberries or one cup of the fruit. The Flow Mediated Dilation was measured in these subjects at the three month and six month marks. This is the rate or speed at which an artery can dilate in response to the bodies need for increased blood flow (a stressor).
The study found an improvement in the flow mediated dilation rate, which means there is the potential for a reduction in cardiovascular disease in those who ate one cup of blueberries daily. Additionally, there was also an increase in the healthy cholesterol levels of participants who consumed the one cup a day level.
Wada says the data continues to show blueberries are continuing to prove their worth in human health. As studies carry on and information is disseminated to the public, the berries are more likely to keep growing in popularity as a regular part of the daily North American diet. This will correlate to an increase in blueberry sales both at the farmgate and through retail channels.