Blueberries may cut osteoporosis link, for rats at least
bones that occurs after the menopause, suggests a new study with
rats.
If the study can be translated to humans, it could see the berry's health benefits being extended beyond those already reported in the literature including lowering cholesterol, and protecting against cancer and neurodegenerative diseases like Alzheimer's.
Researchers from Florida State University and Oklahoma State University published their findings in The Journal of Nutritional Biochemistry .
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.
Lead author Latha Devareddy and co-workers looked at the effects of blueberries on bone loss in rats that had had their ovaries removed (ovariectomised).
This animal model is designed to represent senile osteoporosis, or the bone-wasting condition that affects the elderly, as it combines both hormone deficiency with chronic inflammation.
The researchers divided 30 female rats into three groups.
One group acted as the control and was not ovariectomised, while the other groups were ovariectomised.
The ovariectomised rats were further divided into two groups - one fed the control diet, the other supplemented with blueberries (five per cent) for 100 days.
As Devareddy expected, the ovariectomised rats that did not receive the berries showed bone mineral density decreases of about six per cent at the whole-body, tibial, femoral, and 4th lumbar level.
On the other hand, feeding the animals with blueberry was found to prevent the loss of whole-body BMD, as well as having an effect on prevention of the BMD loss at the tibial and femoral position, when compared to both the control and ovariectomised rats not fed blueberries.
"The findings of the present study indicate that blueberry protected against the ovariectomised -induced bone loss as it prevented the loss of whole-body BMD and had an intermediary effect on tibial and femoral BMD," wrote the researchers.
"This effect may be due to the components of blueberry which function as free radical scavengers.
This observation is supported by a report which ranks the blueberry extract to have the highest antioxidant capacity in comparison with other fruits and reference compounds such as vitamin C," they added.
According to the researchers, future studies should focus on identifying the bioactive component(s) of blueberry that may be responsible for the apparent benefits, while work must also establish the mechanism of action and the lowest effective dose of the compound.
The majority of research for bone health has focused on women since elderly females are four times as likely to develop osteoporosis as their male counterparts.
Osteoporosis is estimated to affect about 75m people in Europe, the USA and Japan.
According to the International Osteoporosis Foundation, the total direct cost of osteoporotic fractures is €31.7bn in Europe, and 17.5bn in the US (2002 figure).
Source: The Journal of Nutritional Biochemistry Published online ahead of print, doi:10.1016/j.jnutbio.2007.09.004 "Blueberry prevents bone loss in ovariectomized rat model of postmenopausal osteoporosis" Authors: L. Devareddy, S. Hooshmand, J.K. Collins, E.A. Lucas, S.C. Chai, B.H. Arjmandi
