|
|
© BlueberrySupplements.co.uk 2004-2005. All Rights Reserved |
This new finding from ARS chemist Agnes Rimando at the Natural Products Utilization Research Unit, Oxford, Miss., adds to previous research by other scientists who found that dark-skinned bunch grapes contain resveratrol. Rimando is working with scientists at Agriculture and Agri-Food Canada, Kentville, Nova Scotia, and the ARS Small Fruit Research Station in Poplarville, Miss.
Using chemical identification procedures, the team of scientists measured the resveratrol content of 30 whole fruit samples of blueberry, cranberry, huckleberry and related plants. The samples represented five families and 10 species of Vaccinium fruit. They also measured resveratrol in skin, juice/pulp and seed samples of muscadine grape.
Because of its important biological properties, resveratrol (3,5,4-trihydroxystilbene) has been examined extensively in grapes. Studies showed the compound protects the grapes from fungal diseases. It also provides health benefits for consumers by reducing the risk of cardiovascular disease. The compound's anticancer potential warranted its examination in other fruits.
The teams studies showed that several fruit samples of Vaccinium contain varying amounts of the compound. Analysis of the extracts of the skin, juice/pulp and seed of muscadine grapes showed that concentration of resveratrol in the skin was highest. Levels in the juice/pulp were much lower than in the skin and seeds. Analysis of more Vaccinium and muscadine samples is continuing.
The new data could help build a foundation for increasing resveratrol in those berry and grape crops that are important to many small farmers. Future research goals will include enhancing production of resveratrol in selected species.
ARS is the lead scientific research agency of the U.S. Department of Agriculture.
![]()
Although the results are preliminary, the Department of Agriculture team thinks the antioxidant ingredient could be developed as a treatment.
They presented their findings to an American Chemical Society meeting.
Antioxidant
Dr Agnes Rimando and her team studied the effect of the chemical and three other blueberry compounds on rat liver cells.
Pterostilbene showed the most potent effect in stimulating a receptor protein in the cells which plays an important role in lowering cholesterol and other blood fats.
This is similar to the way the commercial cholesterol-lowering drug ciprofibrate works.
Ciprofibrate is effective but can cause muscle pain and nausea in some people.
But because the blueberry compound targets the liver cell receptor more accurately, Dr Rimando believes it is likely to have fewer side effects.
There were no signs of side effects in the study.
Similar antioxidants have already been identified in grapes and red wine.
We will be interested to see if similar results emerge from long-term studies involving people.
Belinda Linden,
British Heart Foundation
Other research suggests pterostilbene may help fight cancer and ward off diabetes.
Dr Rimando said: "We are excited to learn that blueberries, which are already known to be rich in healthy compounds, may also be a potent weapon in the battle against obesity and heart disease."
But she said until studies were conducted in humans, it would be impossible to know how many blueberries a person would need to eat to lower their cholesterol.
Belinda Linden from the British Heart Foundation said: "Research has suggested that natural chemicals found in fruit, including blueberries, have potent antioxidant properties which may reduce the harmful type of cholesterol, low density lipoprotein (LDL).
"This study claims that blueberries are particularly efficient at reducing cholesterol in a laboratory - we will be interested to see if similar results emerge from long-term studies involving people."
She said it was also important to remember that regular physical activity combined
with a diet high in fruit and vegetables and low in saturated fat was still
the best way to combat high cholesterol and reduce the risk of heart disease.
Antioxidants:
Researchers at the USDA Human Nutrition Center (HNRCA) have found that blueberries
rank #1 in antioxidant activity when compared to 40 other fresh fruits and
vegetables. Antioxidants help neutralize harmful by-products of metabolism
called "free radicals" that can lead to cancer and other age related
diseases.
Anthocyanin -- the pigment that makes the blueberries blue -- is thought to
be responsible for this major health benefit. (reference) More on antioxidants:
(antioxidants)
Top
Anti-Aging.
In another USDA Human Nutrition Center (HNRCA) lab, neuroscientists discovered
that feeding blueberries to laboratory rats slowed age-related loss in their
mental capacity, a finding that has important implications for humans. Again,
the high antioxidant activity of blueberries probably played a role. (reference)
Disease Prevention
Blueberries may reduce the build up of so called "bad" cholesterol
that contributes to cardiovascular disease and stroke, according to scientists
at the University of California at Davis. Antioxidants are believed to be
the active component. (reference)
Prevention of Urinary Tract Infections - Researchers at Rutgers University in New Jersey have identified a compound in blueberries that promotes urinary tract health and reduces the risk of infection. It appears to work by preventing bacteria from adhering to the cells that line the walls of the urinary tract. (reference)
Blueberries and Eyesight - A number of studies in Europe have documented the relationship between bilberries, the European cousin of blueberries and improved eyesight. This is thought to occur because of the anthocyanin in the blue pigment which is also available in the blueberry. One study in Japan documented that blueberries helped ease eye fatigue. (reference)
Top
New Research
Cholesterol Reducing Blueberries
At the recent American Chemical Society meeting it was reported that a compound found in blueberries called pterostilbene has "the potential to be developed into a nutraceutical for lowering cholesterol, particularly for those who do not respond well to conventional drugs," reports foodnavigator.com (8/24/04). Study authors from the USDA's Agricultural Research Service (ARS) indicate that the compound found in Vaccinium berries could be a "potent weapon in the battle against obesity and heart disease through its cholesterol-reducing potential." Head researcher, Agnes M. Rimando and her associates "earlier showed that this compound may help fight cancer." An abstract of the study is found on the Agricultural Research Service website which also studied the presence of resveratrol and piceatannol. According to the technical abstract, "These naturally occurring stilbenes, known to be strong antioxidants and to have cancer chemopreventive activity, will add to purported health benefits derived from consumption of these small fruits."
Eating blueberries may help you remember where you placed your car keysimportant
findings if youd like to keep Alzheimers and heart disease at
bay.
The research was presented Monday, August 19, at the ACS national meeting
in Boston.
In one study, Jim Joseph, director of the neuroscience laboratory in the USDA Human Nutrition Center (HNRCA), fed blueberry extractionsthe equivalent of a human eating one cup of blueberries a dayto mice and then ran them through a series of motor skills tests.
He found that the blueberry-fed mice performed better than their control group counterparts in motor behavioral learning and memory, and he noticed an increase in exploratory behavior. When he examined their brains, he found a marked decrease in oxidative stress in two regions of the brain and better retention of signal-transmitting neurons compared with the control mice.
The chemical that appears responsible for this neuron protection, anthocyanin also gives blueberries their color and might be the key component of the blueberrys antioxidant and anti-inflammatory properties. Blueberries, along with other colorful fruits and vegetables, test high in their ability to subdue oxygen free radicals. These oxygen radicals, which can damage cell membranes and DNA through a process known as oxidative stress, are blamed for many of the dysfunctions and diseases associated with aging.
These findings could become increasingly important as the U.S. population
ages. It is projected that by 2050, more than 30% of Americans will be over
65 and will have the decreased cognitive and motor function that accompanies
advanced age. Joseph is currently testing the effects of blueberries on humans.
Preliminary results show that people who ate a cup of blueberries a day have
performed 56% better on motor skills tests than the control group.
Top
Ethnobotany and Blueberries: Blueberries have been associated with positive physiological and cosmetic benefits for centuries. Here we list non scientific information which although not endorsed by the USHBC, may be of interest to researchers as a direction for further research.
Blueberry Health and Nutrition traditions in China. (under construction)
Native American and First Nations of Canada blueberry health and medicinal
traditions. (under construction)
Blueberry health and nutrition in Russia and Central European Traditions.
(under construction)
Bibliography:
Prior, RL, et. al. J of Agric. Food Chem. 1998, 46:2686-2693 Bickford, P.C. et. al. Society for Neuroscience Abs. 1998, 24: 2157 Heinenen, L.M. et al. J. Agric. Food Chem. 1998, 46:4107-4112 Howell, A.B. and V. Nicholi. New Engl. J. Med 1998, 339: 1085-1086
Top
Nutrition Summary
The following summarizes some of the published research in the area of nutraceuticals and health.
The belief that food products have medicinal properties has been celebrated
in folk medicine for centuries. Today food properties are being explored by
the medical and scientific fields. Some cultures have long valued many naturally
occurring substances believed to have preventative and therapeutic value.
In the United States, nutraceuticals are part of a rapidly expanding area
of biomedical research, generating considerable interest among consumers,
manufacturers, and regulators alike. This is a progressive area; the field
is continually conducting studies and discovering possible benefits.
Though blueberries themselves are not a cure-all, they contain a number of substances which are thought to have health benefits. These substances include, but are not limited to fructose, fiber, vitamins and antioxidants. Antioxidants thus far, seem to have the most conclusive role in the prevention/ delaying of such diseases as cancer, heart disease and the aging process however, a limited number of studies, especially long term and on human beings, are not available at this time.
What is a Nutraceutical?
Nutraceutical- Any substance that may be considered a food or part of a food that provides health benefits, including the prevention or treatment of disease. They range from isolated nutrients to genetically engineered "designer foods".
The term "nutraceutical" was coined by The Foundation for Innovation in Medicine in 1989 to provide a name for this area of biomedical research, and has since become part of the standard lexicon in both the medical - scientific community and in the food and drug industries (The Foundation for Innovation in Medicine, 1991). The wide acceptance of this term itself provides ample testimony that a new product category is ready to be born. Largely based on their cultural and historical beliefs, Japan and many European countries hold established places in the international marketplace for nutraceuticals. They have long valued many natural substances that hold preventative and therapeutic values, and have a rapidly expanding body of research to back them up. The United States, however, is at the beginning of this process. Nutraceuticals have become a focal point for updating the U.S. economic and regulatory system in response to worldwide medical and scientific trends.
Top
Free Radicals - Antioxidants:
Antioxidants are thought to help protect the body against the damaging effects of free radicals and the chronic diseases associated with the aging process (Ames, 1993). Fresh fruits (blueberries) and vegetables contain many of these naturally occurring antioxidants such as vitamins A, C and E.
Blueberries contain 0.04 mg of beta-carotene, 13 mg of vitamin C and 1 mg vitamin E per 100 g of blueberries. Blueberries contain 10 RE (Retinol Equivalents, a unit of vitamin A) of vitamin A per 100 grams of blueberries. The RDA for vitamin A is 1000 RE for men and 800 RE for women. In addition, blueberries contain anthocyanins and phenolics that can also act as antioxidants.
Ellagic and Folic Acid:
Although their modes of action is still poorly understood, it appears that these acids may inhibit cancer initiation. Ellagic acid (in its most biologically active form, ellagitannin) is found in blueberries and some other berries. (Stoner, 1989).
Folic acid may help guard against cervical cancer (Toufexis, 1992), and may
benefit the fetus during pregnancy. Blueberries contain 6 ug./ 100g of folic
acid. The RDA for women is 180 ug.
Other Substances: Antibacterial Agents
In Sweden, dried blueberries are used to treat childhood diarrhea (Kowalchuk,
1976). This use is attributed to anthocyanosides, a natural substance found
in blueberries which is believed to be "lethal" to E. Coli (a bacteria
sometimes linked to the infection).
Fiber: Multiple Health Benefits
Considerable evidence collected over the last 20 years has proven the numerous advantages of high fiber diets (Potter, 1986). Blueberries are a source of dietary fibers: 2.7g/100g. A diet containing 25g. of dietary fiber per day is generally recommended.
Blueberries contain a variety of compounds. These include: antioxidants,
anthocyanosides, bacterial inhibitors, folic acid, vitamins A and C, carotenoids,
ellagic acid, folic acid, and dietary fibers. The significance of their presence
and modes of action remain largely unexplored