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Fruit vegetables

More support for heart-healthy benefits of Mediterranean diet

Submitted by Fiona McPherson on

A very large Italian study provides more evidence that the Mediterranean diet reduces inflammation, with their finding that those with a greater adherence to such a diet had significantly lower levels of platelets and white blood cells. These are both inflammatory markers: high platelet counts are associated with both vascular disease and non-vascular conditions such as cancer, and a high white blood cell count is a predictor of ischemic vascular disease.

Tart cherry juice improves sleep for insomniacs

Submitted by Fiona McPherson on

A small trial involving seven older adults with insomnia has found that when they consumed 8 ounces of tart cherry juice twice daily for two weeks, they were able to sleep more than an hour longer each night (averaging 84 minutes) compared to when they took the placebo, and their sleep tended to be more efficient.

Montmorency tart cherries are a natural source of melatonin, a hormone that helps regulate the sleep-wake cycle. The juice also helped to increase the availability of tryptophan, an essential amino acid and a precursor to serotonin that helps with sleep.

Berries protect the aging brain

Over the years, I have reported on several studies that have found evidence that colorful berries — blueberries in particular (but I think that’s more of an artifact, due to the relative cheapness of these berries in North America) — benefit older brains. Indeed, I myself consume these every day (in my lunch smoothie) for this very reason (of course, the fact that they taste so good doesn’t hurt!).

Fruit & vegetables

A number of studies have pointed to the benefits of a diet rich in fruit and vegetables for memory and cognition in older adults. These benefits are thought to accrue from the antioxidants present in these foods, of which some are more important than others.

The anthocyanins appear to be the best — these are responsible for the reds, purples, and blues in some plants. Several studies have affirmed the cognitive benefits of blueberries and Concord grape juice (Concord grapes are particularly purple). Cell studies have also found the compounds in blackcurrants protect neurons from stress, such as that caused by the Alzheimer's peptide amyloid-beta. The darker the fruit, the more anthocyanins, and presumably the more powerful it will be. Another compound in blueberries called pterostilbene apparently, like resveratrol, which is found in grapes and red wine, lowers cholesterol. Yet another compound, called quercetin, has been found to protect against cell damage. This compound is also found in blueberries, and also cranberries. A particularly good source is apples, and red ones are best.

All of this perhaps explains why it is so much better to eat well rather than hope to receive what you need from dietary supplements! And do note that in most cases, most of the 'good' compounds are in the skin. That's why juices (and wines!) are often better ways of consuming these foods.

Of the vegetables, green leafy vegetables, especially spinach, have been found to be especially beneficial. Onions are also a good source of quercetin. Spirulina (not really a vegetable, I know) also appears to be of benefit.

Older news items (pre-2010) brought over from the old website

Drinking Concord grape juice may improve memory in older adults

A small pilot study, involving only 12 older adults with early memory decline, has found that those who drank Concord grape juice daily for a 12-week period showed significant improvement in list learning compared to those taking a placebo, and trends suggested improved short-term retention and spatial memory.

The results were presented at the 38th annual scientific meeting of the American Aging Society in Boulder, Colo., May 30-June 2, 2008.

http://www.eurekalert.org/pub_releases/2008-06/w-dpc060208.php

How blueberries help the aging brain

An animal study has found that supplementing the regular diet of older animal with blueberries over a 12-week period, produced improvements in spatial working memory tasks emerged within three weeks. This improvement was associated with the activation of the protein CREB and increases in the level of BDNF in the hippocampus. Blueberries are a major source of flavonoids, in particular anthocyanins and flavanols.

Williams, C. M., Mohsen, M. A. E., Vauzour, D., Rendeiro, C., Butler, L. T., Ellis, J. A., … Spencer, J. P. E. (2008). Blueberry-induced changes in spatial working memory correlate with changes in hippocampal CREB phosphorylation and brain-derived neurotrophic factor (BDNF) levels. Free Radical Biology & Medicine, 45(3), 295-305. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/18457678

http://www.eurekalert.org/pub_releases/2008-04/tpco-gft041008.php

Blackcurrants may protect against Alzheimer's

A cultured cell study has found that compounds in blackcurrants strongly protect neuronal cells against the types of stress caused by dopamine and amyloid-b, a peptide associated with Alzheimer's disease. Blackcurrants and boysenberries also contain anthocyanins and polyphenolics. Those that are darker (like British blackcurrants) have more anthocyanins and are likely to be more potent. Compounds from these berries are already known to act as antioxidants, but a role in neuroprotection has not been demonstrated previously.

Ghosh, D., McGhie, T. K., Zhang, J., Adaim, A., & Skinner, M. (2006). Effects of anthocyanins and other phenolics of boysenberry and blackcurrant as inhibitors of oxidative stress and damage to cellular DNA in SH‐SY5Y and HL‐60 cells. Journal of the Science of Food and Agriculture, 86(5), 678-686. Retrieved from http://onlinelibrary.wiley.com/doi/10.1002/jsfa.2409/abstract

http://www.eurekalert.org/pub_releases/2006-01/jws-bbb011906.php

Antioxidant-rich diets reduce brain damage from stroke in rats

A new rat study suggests antioxidant-rich fruits and vegetables may limit brain damage from stroke and other neurological disorders. The study built upon previous research showing that diets enriched with blueberries, spinach or spirulina reversed normal age-related declines in memory and learning in old rats, and found that the same diet significantly reduced brain cell loss and improved recovery of movement in rats who had an ischemic stroke induced. The size of the stroke in the rats fed blueberry or spinach supplements was half that seen in the brains of untreated rats. Rats fed spirulina-enriched diets had stroke lesions 75% smaller than their untreated counterparts.

Wang, Y., Chang, C.-F., Chou, J., Chen, H.-L., Deng, X., Harvey, B. K., … Bickford, P. C. (2005). Dietary supplementation with blueberries, spinach, or spirulina reduces ischemic brain damage. Experimental Neurology, 193(1), 75-84. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/15817266

http://www.eurekalert.org/pub_releases/2005-04/uosf-adr041205.php

Diet, exercise, stimulating environment helps old dogs learn

A new study of beagles provides more evidence that diet and mental stimulation are important in reducing or preventing age-related cognitive decline. The study, involving 48 older beagles (aged 7 to 11), compared four combinations of behavioral enrichment (regular exercise and lots of mental stimulation) and supplementation of diet with antioxidants had on a beagle's ability to learn: regular diet and regular experience; regular diet and enriched experience; regular experience and an enriched diet; and enriched diet and an enriched experience. The study followed the beagles over two years. Those in the groups with either an enriched diet or enriched environment did better than those without either, but those who had both the enriched diet and an enriched environment did noticeably better than all the rest.

Milgram, N. W., Head, E., Zicker, S. C., Ikeda-Douglas, C. J., Murphey, H., Muggenburg, B., … Cotman, C. W. (2005). Learning ability in aged beagle dogs is preserved by behavioral enrichment and dietary fortification: a two-year longitudinal study. Neurobiology of Aging, 26(1), 77-90. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/15585348

http://www.eurekalert.org/pub_releases/2005-01/uot-mtc011705.php
http://www.eurekalert.org/pub_releases/2005-01/nioa-des011805.php

More support for the benefits of blueberries

Several recent studies have provided evidence for the benefits of blueberries in preventing age-related cognitive decline. Consistent with this, and with the linking of cholesterol levels and age-related cognitive decline, is a new study suggesting a compound in blueberries may lower cholesterol as effectively as a commercial drug, with the potential for fewer side effects. The compound pterostilbene is an antioxidant that is similar to resveratrol, an antioxidant identified in grapes and red wine that is also believed to lower cholesterol. Pterostilbene has also been implicated in helping fight cancer, as well as having anti-diabetic properties.

The findings were presented on August 23 at the 228th national meeting of the American Chemical Society.

http://www.eurekalert.org/pub_releases/2004-08/acs-cs_1081604.php

Grape juice may help memory in older adults

A study of older rats has found that Concord grape juice significantly improved their short-term memory in a water maze test as well as their neuro-motor skills in some coordination, balance and strength tests. The results are similar to those found with blueberries. Concord grape juice has the highest total antioxidants of any fruits, vegetables or juices tested (I assume the point of using “Concord” grape juice is the concentration of grape juice, not that this effect is specific to Concord grapes – although the fact that it is a “purple” grape juice is probably significant).

The preliminary report was presented at the 1st International Conference on Polyphenols and Health recently held in Vichy, France.

http://www.eurekalert.org/pub_releases/2003-12/jai-cgj121803.php

More support for value of antioxidants in protecting against age-related cognitive decline

Several studies have come out supporting the value of a diet rich in antioxidants to help stave off cognitive impairment in old age. A recent study has found that old dogs on an antioxidant-rich diet performed as well as young animals on a variety of cognitive tests. Young dogs did not benefit from the diet. Two years ago, researchers reported that a blueberry-enriched antioxidant diet may prevent age-related deterioration of object recognition memory in aged rats. A new report, from a study of the same rats, reveals that the diet also prevented an age-related increase in a protein (NF-kappaB) that responds to oxidative stress, a probable cause of brain aging. This adds to growing evidence that a buildup of oxidative damage is an important factor in brain aging. Another rat study has found that blueberries can help lessen some of the damage caused by a brain injury.

The research was presented at the 2003 annual meeting of the Society for Neuroscience.

http://www.eurekalert.org/pub_releases/2003-11/sfn-dmi110603.php

Apples fight memory loss

The study involved adult and old mice (some engineered to develop Alzheimer's-like symptoms) being fed either a standard diet, a nutrient-deficient diet, or a nutrient-deficient diet supplemented with apple juice concentrate. The mice on the apple juice-supplemented diet showed an increased production of acetylcholine in their brains and performed significantly better on maze tests. The amount of consumption was comparable to humans drinking approximately two 8 oz. glasses of apple juice or eating 2-3 apples a day. The findings also suggest that the apple-supplemented diet was most helpful in the framework of an overall healthy diet. Acetylcholine levels declined in both adult and old mice on the nutrient-deficient diet.

Chan, A., Graves, V. & Shea, T.B. 2006. Apple juice concentrate maintains acetylcholine levels following dietary compromise. Journal of Alzheimer's Disease, 9(3), 287-291.

http://www.sciencedaily.com/releases/2006/08/060801225922.htm

Apple consumption protects against age-related cognitive decline

Previous research has found apple juice concentrate alleviated cognitive decline in genetically engineered mice compromised by a deficient diet. A study in normal, aging mice has now found that regular consumption of apple juice (in the context of a balanced diet) protected against the oxidative damage to brain cells that occurs in normal aging. Further, stronger mental acuity resulted when the mice consumed the human equivalent of 2-3 cups of apple juice or 2-4 apples a day. Apples are high in antioxidants.

Tchantchou, F., Chan, A., Kifle, L., Ortiz, D., & Shea, T. B. (2005). Apple juice concentrate prevents oxidative damage and impaired maze performance in aged mice. Journal of Alzheimer’s Disease: JAD, 8(3), 283-287. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/16340085

http://www.eurekalert.org/pub_releases/2006-01/uaa-ami012306.php

Compound in apples may help fight Alzheimer's disease

Researchers are recommending that apples may be a particularly beneficial food to protect against Alzheimer’s. A study that exposed groups of isolated rat brain cells to varying concentrations of either quercetin or vitamin C supports the theory that quercetin protects against cellular damage. A particularly good source of quercetin is apples — mainly in the skin. In general, red apples tend to have more of the antioxidant than green or yellow ones. Other foods containing high levels of quercetin include onions, which have some of the highest levels of quercetin among vegetables, as well as berries, particularly blueberries and cranberries.

Heo, H. J., & Lee, C. Y. (2004). Protective Effects of Quercetin and Vitamin C against Oxidative Stress-Induced Neurodegeneration. Journal of Agricultural and Food Chemistry, 52(25), 7514-7517. Retrieved from http://dx.doi.org/10.1021/jf049243r

http://www.eurekalert.org/pub_releases/2004-11/acs-ia111604.php

Plant flavonoid reduces inflammatory response in the brain

Cell and mouse studies have found that luteolin, a plant flavonoid available in abundance in celery and green peppers, has a dramatic effect on a key component of the inflammatory response in the brain. The findings have implications for research on aging and diseases such as Alzheimer’s and multiple sclerosis.

Choi, I.-G., Hwang, D.-Y., Song, H., Jang, Y., Chung, N., Kim, S.-H., … Huh, Y. J. (2008). Chemicals that modulate stem cell differentiation. Proceedings of the National Academy of Sciences, 105(21), 7467-7471. Retrieved from http://www.pnas.org/content/105/21/7467.abstract

http://www.eurekalert.org/pub_releases/2008-05/uoia-pff051908.php

Vegetables, not fruit, help fight memory problems in old age

A study of 3,718 Chicago residents aged 65 and older found that people who ate at least 2.8 servings of vegetables a day had a 40% slower rate of cognitive decline compared to people who consumed less than one serving of vegetables a day — equivalent to about five years of younger age. Green leafy vegetables had the strongest association to slowing the rate of cognitive decline. The benefit was greater the older the person. However, unexpectedly, fruit consumption was not associated with cognitive change.

Morris, M. C., Evans, D. A., Tangney, C. C., Bienias, J. L., & Wilson, R. S. (2006). Associations of vegetable and fruit consumption with age-related cognitive change. Neurology, 67(8), 1370-1376. Retrieved from http://www.neurology.org/cgi/content/abstract/67/8/1370

http://www.eurekalert.org/pub_releases/2006-10/aaon-vnf101706.php

A natural chemical found in strawberries boosts memory in healthy mice

The search for a safe, orally active drug that activates memory-associated pathways and enhances memory has uncovered fisetin, a naturally occurring flavonoid commonly found in strawberries and other fruits and vegetables. Fisetin was one of several flavonoids (substances with anti-oxidant activities found in many plants) found to induce differentiation or maturation of neural cells. The signaling pathway activated by fisetin in neural differentiation also turned out to play a role in memory formation, specifically in the process called "long-term potentiation". When tested on mice, fisetin was found — after a single dose — to improve recall of familiar objects. Besides strawberries, fisetin is found in tomatoes, onions, oranges, apples, peaches, grapes, kiwifruit and persimmons (but not gingko biloba, although it is rich in other flavonoids). However, you would need to eat about 10 pounds of strawberries a day to achieve a beneficial effect.

Maher, P., Akaishi, T., & Abe, K. (2006). Flavonoid fisetin promotes ERK-dependent long-term potentiation and enhances memory. Proceedings of the National Academy of Sciences, 103(44), 16568-16573. Retrieved from http://www.pnas.org/content/103/44/16568.abstract

http://www.eurekalert.org/pub_releases/2006-10/si-anc101706.php

Juices may reduce Alzheimer's disease risk

In a large epidemiological study, that followed 1836 Seattle residents for up to 10 years, it was found that those who drank three or more servings of fruit and vegetable juices per week had a 76% lower risk of developing Alzheimer’s disease than those who drank juice less than once a week. The benefit seemed greatest for those who carried the so-called “Alzheimer’s gene”. Previously, researchers suspected that antioxidant vitamins (vitamins C, E and -carotene) might help protect against Alzheimer's disease, but this has not been supported in recent clinical studies. Another class of antioxidant chemicals, polyphenols, are now suspected. Polyphenols generally exist primarily in the skins of fruits and vegetables and are particularly abundant in teas, juices and wines.

Dai, Q. et al. 2006. Fruit and Vegetable Juices and Alzheimer's Disease: The Kame Project. The American Journal of Medicine, 119 (9), 751-759.

http://www.eurekalert.org/pub_releases/2006-08/vumc-jmr082806.php
http://www.eurekalert.org/pub_releases/2006-08/ehs-ssf082806.php

Antioxidant-rich diets improve age-related cognitive decline in rats

Two new animal studies add to the growing body of evidence that certain fruits and vegetables may slow down or reverse age-related cognitive decline. In the first study, older rats fed a diet rich in spinach for six weeks learned a simple association faster than those fed regular rat food. The second study compared three different foods - one group of older rats ate a diet supplemented by spirulina (high in antioxidants), another was fed a daily ration of apple (moderate in antioxidant activity),and the third was given a cucumber-enriched diet (low in antioxidants). Those fed either spirulina-or apple-enriched diets for two weeks demonstrated improved neuron function, and a suppression of inflammatory substances in the brain. Indeed, spirulina reversed the impairment in adrenergic neural function normally associated with aging. There was no improvement in rats fed a diet supplemented with cucumber. The best fruits and vegetables for antioxidant activity are generally the most colorful.

Cartford, C., Gemma, C., & Bickford, P. C. (2002). Eighteen-Month-Old Fischer 344 Rats Fed a Spinach-Enriched Diet Show Improved Delay Classical Eyeblink Conditioning and Reduced Expression of Tumor Necrosis Factor alpha (TNFalpha ) and TNFbeta in the Cerebellum. J. Neurosci., 22(14), 5813-5816. Retrieved from http://www.jneurosci.org/cgi/content/abstract/22/14/5813

Gemma, C., Mesches, M. H., Sepesi, B., Choo, K., Holmes, D. B., & Bickford, P. C. (2002). Diets Enriched in Foods with High Antioxidant Activity Reverse Age-Induced Decreases in Cerebellar beta -Adrenergic Function and Increases in Proinflammatory Cytokines. J. Neurosci., 22(14), 6114-6120. Retrieved from http://www.jneurosci.org/cgi/content/abstract/22/14/6114

http://www.eurekalert.org/pub_releases/2002-07/uosf-adi071002.php

Benefits and dangers of iron

A study involving 676 children (7-9) in rural Nepal has found that those whose mothers received iron, folic acid and vitamin A supplementation during their pregnancies and for three months after the birth performed better on some measures of intellectual and motor functioning compared to offspring of mothers who received vitamin A alone. However, there was no significant benefit for those whose mothers received iron, folic acid and zinc (plus vitamin A), or multiple micronutrients.

Beet juice promotes brain health in older adults

Following on from previous studies showing that drinking beet juice can lower blood pressure, a study involving 14 older adults (average age 75) has found that after two days of eating a high-nitrate breakfast, which included 16 ounces of beet juice, blood flow to the white matter of the frontal lobes (especially between the dorsolateral prefrontal cortex and anterior cingulate cortex) had increased. This area is critical for executive functioning.

Poor blood flow in the brain is thought to be a factor in age-related cognitive decline and dementia.

Compound in celery, peppers reduces age-related memory deficits

Inflammation in the brain appears to be a key contributor to age-related memory problems, and it may be that this has to do with the dysregulation of microglia that, previous research has shown, occurs with age. As these specialized support cells in the brain do normally when there’s an infection, with age microglia start to produce excessive cytokines, some of which result in the typical behaviors that accompany illness (sleepiness, appetite loss, cognitive deficits and depression).