Getting Forgetful? Then Blueberries May Hold The Key

ScienceDaily (Apr. 12, 2008)  If you are getting forgetful as you get  
older, then a research team from the University of Reading and the  
Peninsula Medical School in the Southwest of England may have good  
news for you

They have found that phytochemical-rich foods, such as blueberries,  
are effective at reversing age-related deficits in memory, according  
to a study soon to be published in the science journal Free Radical  
Biology and Medicine. The researchers working at the Schools of Food  
Biosciences and Psychology in Reading and the Institute of Biomedical  
and Clinical Sciences at the Peninsula Medical School in Exeter  
supplemented a regular diet with blueberries over a 12-week period,  
and found that improvements in spatial working memory tasks emerged  
within three weeks and continued throughout the period of the study.

Blueberries are a major source of flavonoids, in particular  
anthocyanins and flavanols. Although the precise mechanisms by which  
these plant-derived molecules affect the brain are unknown, they have  
been shown to cross the blood brain barrier after dietary intake. It  
is believed that they exert their effects on learning and memory by  
enhancing existing neuronal (brain cell) connections, improving  
cellular communications and stimulating neuronal regeneration.

The enhancement of both short-term and long-term memory is controlled  
at the molecular level in neurons. The research team was able to show  
that the ability of flavonoids to induce memory improvements are  
mediated by the activation of signalling proteins via a specific  
pathway in the hippocampus, the part of the brain that controls  
learning and memory.

This innovative research was conducted by a multidisciplinary research  
team led by Dr. Jeremy Spencer, a lecturer in Molecular Nutrition at  
the University of Reading and included Dr. Claire Williams, a  
Psychologist also from Reading and Dr. Matt Whiteman, a Principal  
Investigator at the Institute of Biomedical and Clinical Science,  
Peninsula Medical School. Dr Spencer commented: "Impaired or failing  
memory as we get older is one of life's major inconveniences.  
Scientists have known of the potential health benefits of diets rich  
in fresh fruits for a long time. Our previous work had suggested that  
flavonoid compounds had some kind of effect on memory, but until now  
we had not known the potential mechanisms to account for this".

Dr. Whiteman added "This study not only adds science to the claim that  
eating blueberries are good for you, it also provides support to a  
diet-based approach that could potentially be used to increase memory  
capacity and performance in the future. Indeed, Dr. Spencer's research  
team plan on extending these findings further by investigating the  
effects of diets rich in flavonoids on individuals suffering from  
cognitive impairment and Alzheimer's disease."

Adapted from materials provided by The Peninsula College of Medicine  
and Dentistry


Natural Purple Pigments In Fruits, Vegetables And Berries, Such As  
Blueberries, May Help Prevent Obesity

Here's to purple power: Colorful pigments found in the skin of  
blueberries, strawberries and other fruits and vegetables may help  
prevent obesity, according to recent animal studies. (Courtesy of USDA  
Agricultural Research Service)

ScienceDaily (Feb. 14, 2008)  Scientists in Arkansas are reporting  
new evidence that natural pigments responsible for the beautiful blue/ 
purple/reddish color of certain fruits and vegetables may help prevent  
obesity. Their animal study however, reports that eating the whole  
fruit containing these pigments seems to be less effective than eating  
an extract of the berry.

Ronald L. Prior and colleagues, who did the new study, note that past  
research has shown that the pigments -- called anthocyanins -- prevent  
obesity in laboratory mice fed a high-fat diet. Anthocyanins are found  
in grape skins, blueberries, blackberries, purple corn, and other  
foods. The mice also had other healthful changes in disease-related  
substances found in the blood.

In the new study, researchers found that mice fed a high-fat diet for  
8 weeks plus drinking water with purified anthocyanins from  
blueberries and strawberries gained less weight and had lower body fat  
levels than a control group. "Anthocyanins fed as the whole blueberry  
did not prevent and may have actually increased obesity," the study  
reported. "However, feeding purified anthocyanins from blueberries or  
strawberries reduced obesity."

The article "Whole Berries versus Berry Anthocyanins: Interactions  
with Dietary Fat Levels in the C57BL/6J Mouse Model of Obesity" is  
scheduled for the Feb. 13 issue of ACS' Journal of Agricultural and  
Food Chemistry.

Adapted from materials provided by American Chemical Society, via  
EurekAlert!, a service of AAAS.


Wild Blueberries May Help Protect Arteries, Reduce Risks From  
Cardiovascular Disease

ScienceDaily (Nov. 3, 2003)  ORONO, Maine -- A University of Maine  
nutritionist has found evidence that consumption of wild blueberries  
can help arteries relax and reduce risks associated with  
cardiovascular disease. The project is the first using rats fed  
blueberry diets to demonstrate a relationship between consumption of  
whole wild blueberries and processes that can lead to high blood  

The study was published earlier this year in the FASEB Journal,  
published by the American Societies for Experimental Biology.

Cardiovascular disease is the leading cause of death in the United  
States. Previous studies with cell cultures have shown that  
antioxidants such as anthocyanines contained in wild blueberries may  
help protect cells. Wild blueberry consumption in laboratory rats has  
also been linked to improvements in memory and motor skills.

At UMaine, Dorothy Klimis-Zacas, professor in the Dept. of Food  
Science and Human Nutrition, led a team of graduate and undergraduate  
students in a two-year research project that was supported by the  
Maine Agriculture and Forestry Experiment Station, the Maine Wild  
Blueberry Commission, the U.S. Dept. of Agriculture and the Wild  
Blueberry Association of North America. "Our experiments focused on  
the effect of whole wild blueberries on the biomechanical properties  
of arteries as related to cardiovascular disease," says Klimis-Zacas.  
"This is the first in-vivo study to examine this relationship."

Students working on the project included Cynthia Norton and Anastasia  
Kalea, master's and Ph.D. candidates respectively in the department.

Researchers found that arteries of Sprague-Dawley laboratory rats fed  
a diet enriched with wild blueberries generated less force in response  
to phenylephrine, a stress hormone, than did arteries in rats fed the  
same diet without blueberries. "Those arteries (in rats fed the  
blueberry enriched diet) were more relaxed. When they were challenged  
with the stress hormone, they didn't develop as much force. We know  
now that blueberries affect the contractile machinery of the artery,"  
says Klimis-Zacas.

The finding is important because the force with which an artery  
responds to stress can directly affect blood pressure. Norton and  
Klimis-Zacas presented the results of the study at the 2003 annual  
conference of the Federation of American Societies for Experimental  
Biology in San Diego, California and to the Wild Blueberry Association  
of North America in Bar Harbor, Maine.

The apparent benefit of the blueberry enriched diet carried over to  
older rats which received blueberries later in the study. The  
implication is that the addition of wild blueberries to the diet later  
in life may still have a protective effect on arteries.

The study has not been replicated in humans, and the researchers did  
not identify the compounds in wild blueberries that affect arteries.  
However, it is likely that high concentrations of antioxidants and  
trace minerals such as manganese which are high in blueberries could  
explain the beneficial effect, says Klimis-Zacas.

During the project, three groups of rats containing ten animals per  
group were fed the same diets with the exception of ground, whole wild  
blueberries. One group received the blueberry addition for the entire  
time, while another group had the same diet without blueberries. To  
test the addition of blueberries to the diet later in life, the third  
group received a diet without blueberries for 14 weeks followed by a  
blueberry enriched diet for eight weeks.

The amount of blueberries given to the rats per day corresponds to  
between one and two cups of blueberries per day for humans.

Researchers then surgically removed the aortas from each rat. They cut  
four ring sections from each aorta and tested the force generated by  
each section in response to the presence of hormones that stimulate  
arteries to relax or contract. During the tests, the arterial ring  
sections were hung in a tissue bath under conditions that mimicked the  
body's internal chemical environment.

In a second round of experiments, researchers wanted to find out what  
layers in the artery are affected by blueberries. They focused on the  
inside surface of the artery, a layer of cells known as the endothelium.

"Increasing vascular resistance may lead to an elevation of blood  
pressure which may in turn damage the delicate endothelial layer,"  
says Klimis-Zacas. "This layer is affected by many things in the  
blood. By removing the endothelium, we are left with the smooth muscle  
layer of the artery, and we can localize the effect of wild  
blueberries in response to stress hormones. "

In these tests, researchers purposely damaged a portion of the  
endothelium and then exposed the arteries to the hormones. "We found  
that when we remove the endothelium, the artery cannot relax. And the  
contractile force it exerts in response to the stress hormone is about  
three times what it was with the intact arterial rings," says Klimis- 

The endothelial layer is known to be an important source of nitric  
oxide that helps to relax the arteries. "You can imagine what happens  
with atherosclerosis. Your endothelium gets damaged. There are many  
different relaxation factors in the endothelium, but nitric oxide is a  
major one. We think that blueberries may function by preserving the  
bioavailability of nitric oxide," says Klimis-Zacas.

"We know that nitric oxide concentration decreases at the onset of  
cardiovascular disease. By preserving nitric oxide bioavailabilty,  
blueberries may aid in maintaining arterial relaxation and thus  
prevent elevation of blood pressure that damages the endothelium and  
contributes to cardiovascular disease," says Klimis-Zacas.

Future research is planned with rats that have high blood pressure,  
she says, to see if blueberries will lower blood pressure. A key will  
be the role of antioxidants in endothelium function.

Adapted from materials provided by University Of Maine.