A diet supplemented with berries could help to protect brain functioning during aging, according to new animal data.
A diet supplemented with berries could help to protect brain functioning during aging, according to new animal data.
A higher intake of flavonoid rich berries may delay cognitive and memory decline in older women, according to a study published in Annals of Neurology. Strawberries and blueberries, which are high in flavonoids, appear to delay cognitive aging by up to 2.5 years in elderly women. Researchers at Brigham and Women’s Hospital, Harvard Medical School in Boston, and the German Center for Neurodegenerative Diseases in Bonn, Germany examined the association between long-term dietary intake of berries and flavonoids, including anthocyanidins, and cognitive decline in a large group of older women. The study analyzed 16,010 women, ages 70 and older, who participated in the Nurse’s Health Study between 1995 and 2001. Women who ate more than two servings of strawberries per week had less cognitive decline than those who ate less than one serving per week.
Berries are particularly high in a subclass of flavonoids called anthocyanidins, which affect areas of learning and memory (e.g., hippocampus) in the brain. Flavonoids have powerful antioxidant and anti-inflammatory properties. Both oxidative stress and inflammation are thought to be important contributors to cognitive impairment. Thus, increased flavonoid consumption from strawberries and other berries could be a strategy for reducing cognitive decline in older adults.
These findings are significant, as the study presents epidemiological evidence that berries may slow progression of cognitive decline in elderly women, and increasing berry intake is a fairly simple dietary modification. According to the 2010 U.S. Census, the number of elderly Americans aged 65 years and older increased by 15% between 2000 and 2010, faster than the total U.S. population during the same period.
From Annals of Neurology:
Dietary Intake of Berries and Flavonoids in Relation to Cognitive Decline
Devore, E. E., Kang, J. H., Breteler, M. M. B. and Grodstein, F. (2012), Dietary intakes of berries and flavonoids in relation to cognitive decline. Ann Neurol.. doi: 10.1002/ana.23594
Research has identified a number of bioactive substances in berries. One less well-known flavonoid, fisetin, is showing promise as an antioxidant and anti-inflammatory which has the potential to mitigate multiple complications of diabetes. Researchers at The Salk Institute for Biological Studies fed diabetic-like mice fisetin (in an amount equivalent to eating about 37 strawberries) and saw positive effects in kidney and brain function, and markers of inflammation . Fisetin is unique among natural substances previously tested for diabetic complications, because it impacts so many organ systems affected by the disease. The highest levels of fisetin are found naturally in strawberries. While this is emerging data in an animal model, it further
substantiates the health benefits of frequent consumption of fruit, like strawberries.
View the press release at: http://www.salk.edu/news/pressrelease_details.php?press_id=500
The full text of the article can be found at:
Dementia is the loss of cognitive function of sufficient severity to interfere with everyday tasks. Alzheimer’s disease is the most common form of dementia. It is estimated that 10-13 percent of the population over 65 years has Alzheimer’s, and 50 percent of those are 85 years and over. There is no cure for Alzheimer’s and treatments are ineffective. According to recently released census estimates, the world’s 65-and-older population will triple by 2050 to make up 1 in 6 people. The number of senior citizens has already increased 23 percent since 2000 to 516 million, more than double the growth rate for the general population. As a result, the incidence of dementia is likely to rise. The frequent consumption of berries is emerging as a potential simple dietary factor for prevention.
Data from the Chicago Healthy Aging Project (CHAP) presented by Martha Morris, Sc.D., of the Rush Institute for Healthy Aging showed that older adults who consume strawberries have less cognitive decline as they age than those who don’t consume strawberries. Women who consumed more than one serving of strawberries per month had a 16.2 percent slower rate of cognitive decline versus those who consumed less than one serving per month. CHAP is a study examining dietary patterns and effects on cognitive function in men and women over 65 years of age. Over 10,000 people have participated in this study since 1993, 60 percent of whom are African- American.
With increasing age, brain function diminishes. James Joseph, Ph.D., and Barbara Shukitt-Hale, Ph.D., of the Human Nutrition Research Center on Aging (HNRCA) at Tufts University also presented at the Symposium. They showed that aging results in deficits in learning, memory and motor function, such as balance and walking speed. Strawberries and other berries improved both memory and motor function in animal studies. These researchers have begun to investigate these same aspects of aging in humans who eat berries.
Several speakers at the conference described how berries may be contributing to the preservation of brain function. Most disease processes in the body are believed to begin through inflammation and oxidation which damage cells, particularly cell membranes. Healthy nerve cell membranes promote optimal communication within the brain and nervous system, so preventing membrane damage from inflammation and oxidation is essential. Berries contain numerous antioxidant substances and may be able to prevent membrane damage from inflammation and oxidation. Pterostilbene, a compound similar to reservatrol but more available for use by the body, is emerging as a plant nutrient found in berries correlated with improved cognitive performance. Also discussed at the Symposium was how various compounds in berries may be acting in ways other than as antioxidants to help prevent the cognitive decline of aging.
Consumer demand for natural foods with anti-aging properties is increasing. And science continues to show that berries may protect against aging’s deleterious effects like memory and coordination loss. Dr. James Joseph, lead scientist at the neuroscience lab of the Human Nutrition Research Center for Aging at Tufts University in Boston presented some of this research at the Institute of Food Technologists meeting in New Orleans in June.
Compounds in fruits and vegetables such as strawberries and spinach may help the brain to counteract stress and inflammation, which contribute to aging diseases like Alzheimer’s and arthritis. Eating the daily equivalent of a pint of strawberries or a large spinach salad reduces specific effects of brain aging in rats. Including these foods in the diets of rats protected against declines in nerve cell communications that are important for movement learning and control. In addition, the diets prevented a dip in memory performance seen in old-age, according to a water maze test.
Strawberries contain powerful antioxidants that may help neutralize free radicals. Free radicals are unstable oxygen molecules which are always looking for other molecules to combine with because they have one or more unpaired electrons in their outer orbits. If antioxidants do not intercept the free radicals, then their rush for a mate can sometimes damage or kill the cells they attach to. As we age, we lose the ability to neutralize the effects of free radicals. The brain may be particularly vulnerable to the damaging effects of free radicals because it is relatively deficient in antioxidants to begin with. Free radical destruction is thought to be a contributing factor to the decline in memory and motor performance seen in aging.
Dr. Joseph emphasized that the key is to eat nutritious foods, not take supplements. The evidence is overwhelming that it’s better to get these substances in real food, like strawberries.
Researchers at the University of Alberta, Canada, reported that children who ate the most fruits and vegetables and ate less fat scored higher on academic tests compared to children who ate the least amount of produce. While breakfast eating has been shown to improve children’s academic performance, this is one of the first studies to show that diets rich in fruits and vegetables and improved diet quality were correlated with better academic performance.
Since children like the great taste of strawberries, they make a wonderful option to help improve children’s diets. A serving of strawberries-just 8 medium- contains more vitamin C than an orange, as well as folic acid, fiber, potassium and antioxidant phytonutrients.
Florence MD, Asbridge M, Veugelers PJ. Diet quality and academic performance. J Sch Health. 2008 Apr;78(4):209-15.
At the USDA Human Nutrition Research Center on Aging, the neuroscience laboratory is trying to answer those questions.
Several studies have suggested that oxidative stress or the production of excess reactive oxygen species (ROS) is associated with a loss of neuronal functioning, and may, in part, be associated with declines in memory and cognitive function that occur with aging. Diets rich in antioxidants and anti- inflammatory compounds are thought to be a promising approach to help reduce the deleterious effects of brain aging from ROS.
Tufts neuroscientists reported their preliminary findings when they supplemented aged rodents diets with 1-2% strawberry extract, then evaluated them on several memory and behavioral tests to compare before and after results to a control group of animals of the same age that consumed a normal chow diet. With 1-2% strawberry supplementation in the diet, the aged rodents performed better on all tests to measure memory and cognitive function compared to the control rodents. The studies found that strawberry supplementation was equally beneficial as the same percentage of blueberry extract added to the diet.
Currently in the second year of a three-year project, the researchers are further studying the mechanisms by which strawberry anthocyanins, the flavonoid pigments, are neuro-protective. Anthocyanins may help protect the neuronal cells from reactive oxygen species (ROS), inhibiting inflammation and impacting neuronal cell signaling that are linked to declines in cognitive function. Through additional studies that are able to evaluate the regional localization of the strawberry compounds on the animals’ brain, the researchers are assessing the mechanisms involved in the motor and cognitive benefits found with strawberries to gain more insight into exactly how strawberry bioactives influence the brain.
Joseph JA. The USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA.
Two new studies from the USDA Human Nutrition Research Center on Aging at Tufts University have shown that strawberry extract protected the performance capabilities of rats exposed to cosmic radiation, a model of accelerated aging. The studies extended the findings of earlier work by the same scientists, who are trying to identify dietary components that can help protect astronauts on lengthy space missions. Once they leave the earth’s atmosphere, space travelers are exposed to intense cosmic rays that have been shown to damage brain cells and cause deficits in motor behavior (upper body strength), spatial learning and operant responding (performance based on memory).
Current theories of aging emphasize the role of oxidative stress in the process. Radiation also increases oxidative stress. There are similarities in the neurobehavioral changes observed in aged rats and in young rats exposed to low doses of 56Fe particles, suggesting that exposure to these particles produces accelerated aging. Strawberries and blueberries were tested because they contain antioxidant phytochemicals that might be protective against such oxidative neural damage.
One experiment found that a diet containing strawberry extract protected the ability of irradiated animals to perform a variety of tasks as well as the non-irradiated group. A diet containing blueberry extract did not have the same protective effect. When the animals were tested again 12 months later, the irradiated groups that had been on the control diet and the blueberry extract diet still had significantly poorer performance than the non- irradiated control group and the irradiated strawberry group. The animals that had been given the strawberry extract performed equally as well as the animals that had not been irradiated.
A second experiment explored whether these differences would be seen at a higher level of radiation, and whether performance deficits are related to age. In this study there were five groups of animals: control diet, irradiated; control diet, non- irradiated; strawberry plus blueberry diet, non- irradiated; blueberry diet, irradiated; strawberry diet, irradiated. The rats were irradiated at 3.5-4.0 months of age, then tested for operant response at 5, 8, 13 and 18 months. As before, the strawberry extract diet provided protection comparable to the non-irradiated animals at 5 and 8 months. However, as the animals aged, their performance began to deteriorate in the final two tests.
Comparing the experiments in this series, the authors noted that at the lower dose of radiation, the strawberry diet prevented disruption of performance, but at the higher dose, the effect of aging in these rats was to eliminate the beneficial effects of the strawberry diet on operant performance. Thus, the effectiveness of the strawberry diet varies as a function of both dose and age.
Rabin BM, Carrihill-Knoll KL, Carey A, Shukitt-Hale B, Joseph JA. Effect of diet on the disruption of operant responding at different ages following exposure to 56Fe particles. Age 2005;27:69-73.
Rabin BM, Joseph JA, Shukitt-Hale B. Effects of age and diet on the heavy particle-induced disruption of operant responding produced by a ground-based model for exposure to cosmic rays. Brain Research 2005;1036:122-129.