Sales of the fruit have been booming, going from £10.3m (€14.9m) in 2003 to almost £40m (€58m) in 2005, according to UK supplier BerryWorld, driven by dieticians and scientists hailing the fruit as one of nature's superfoods.
The results of the new study, published in the Journal of Nutritional Biochemistry (Vol 17, pp 109-116), add to the other reports in the literature linking the berry to lowering cholesterol, and protecting against cancer and neurodegenerative diseases like Alzheimer's.
The scientists, led by Dorothy Klimis-Zacas from the University of Maine, investigated the effects of blueberries on functional and structural molecules in the walls of the rats' aortas.
Over a 13-week period a control group was fed a standard diet, while an intervention group received the standard diet supplemented with eight per cent powdered wild blueberry.
The scientists focused on glycosaminoglycans (GAGs), carbohydrate molecules in the blood vessel walls that are directly or indirectly involved in a variety of functions, including lipoprotein metabolism, blood coagulation, and organization of the extracellular matrix.
"In this study we document for the first time that diets enriched with wild blueberries significantly alter the composition and structure of rat aorta at the glycosaminoglycan level," wrote lead author Anastasia Kalea.
Klimis-Zacas and her research team also found an increased level of a specific GAG called galactosaminoglycans (GalAGs).
"It seems that the increased GalAG content in the blueberry-fed group (plus 67 per cent compared to control) may well be a protective factor," they said.
By maintaining higher levels of GalAGs the blood vessel walls are more resistant to oxidative stress that could lead to cardiovascular disease.
"Our investigation of the potential of natural antioxidants like those found in wild blueberries to combat the precursors to cardiovascular disease is part of a broader research movement to gain a better understanding of the role of diet in disease prevention," said Klimis-Zacas.
The researchers said that identification of the bioactive compounds in the fruit that cause the structural GAG changes is needed to elucidate the specific mechanism of action.
The study has been welcomed by the blueberry industry. Susan Davis, nutrition advisor to the Wild Blueberry Association of North America said that the work expands on the importance of wild blueberries in helping fend off diseases of aging, like cardiovascular disease.
"Dr Klimis-Zacas' work helps build the case for including phytonutrient-rich foods in the diet for good nutrition and disease prevention. Colorful foods like Wild Blueberries should be the cornerstone of a healthy diet," she said.
An estimated 19m people are affected by diabetes in the EU 25, projected to increase to 26mn by 2030. CVD causes almost 50 per cent of deaths in Europe, and is reported to cost the EU economy an estimated €169 billion ($202bn) per year.
According to the American Heart Association, 34.2 percent of Americans (70.1 million people) suffered from some form of CVD in 2002. The direct (from hospitalization, medication, care and so on) and indirect costs (from lost productivity) are estimated to cost the US$403.1bn in 2006.