Their findings join mounting evidence that highlights the antioxidant power of vegetables and fruit to help the human body fight a raft of diseases.
Benefiting from ongoing research into these common foods, the food industry is enjoying strong growth for food formulations that absorb health-fighting compounds, with a dynamic fruit and vegetable extracts market.
The €819.9 million European and US fruit and vegetable extracts and powders market is on course to grow 4.5 per cent annually, reaching €1.07 billion by 2009, estimate market analysts Frost & Sullivan.
For this latest study researchers at the University of South Florida College of Medicine, James A. Haley Veterans' Hospital and the National Institute on Drug Abuse, found that rats fed diets preventatively enriched with blueberries, spinach or an algae known as spirulina experienced less brain cell loss and improved recovery of movement following a stroke.
"The size of the stroke was 50 to 75 per cent less in rats treated with diets supplemented with blueberries, spinach or spirulina before the stroke," says Dr. Bickford, a lead researcher involved in the study.
They suggest antioxidant and anti-inflammatory substances in the fruits and vegetables may somehow reduce the nerve cell injury and death triggered by a stroke.
The researchers studied four groups of rats, all fed equal amounts of food for one month. One group was fed rat chow supplemented with blueberries, a second group chow with spinach, and the third chow with spirulina. The control (untreated) group ate chow only.
After four weeks, an ischemic stroke with reperfusion was induced in the rats. An ischemic stroke occurs when a blood clot cuts off the oxygen supply to the brain like the kink in a hose cuts off water flow. Then, later, the clot is released and blood flow returns, known as reperfusion.
The size of the stroke in the rats fed blueberry or spinach supplements was half that seen in the brains of untreated rats.
Rats fed spirulina-enriched diets had stroke lesions 75 per cent smaller than their untreated counterparts. In addition, rats pretreated with the blueberry, spinach or spirulina diets showed greater increases in post-stroke movement than the control group.
All the supplemented diets were rich in antioxidants, which scientists say may counteract the burst of free radicals involved in the cascade of brain cell death triggered by an ischemic stroke. An excess of free radicals can damage cellular lipids, proteins and DNA.
Their study builds upon previous USF/VA research that revealed diets enriched with blueberries, spinach or spirulina reversed normal age-related declines in memory and learning in old rats.
Full findings are available posted online and will be published in the May issue of the journal Experimental Neurology.