Grapes and Age-Related and Other Illnesses
Emerging research suggests that grapes may help defend against a variety of age-related and other illnesses. For example:
A grape-enriched diet prevented blindness by protecting the retina from oxidative damage, and offered greater protection than lutein.1
This study looked at the effects of grapes on vision in mice prone to developing retinal damage in old age, similar to macular degeneration in humans. Mice were fed a grape diet, a lutein diet or a control diet. A grape-enriched diet protected against oxidative damage to the retina by protecting the function of its retinal epithelium pigment cells. Grapes were significantly more protective than lutein. Additionally, this study showed that consuming grapes at an early age protected vision into old age.
Grape consumption helped protect brain neurons from oxidative damage and cell death, and decreased inflammation.2
In this study, gerbils were fed a control diet, or a grape-enriched diet at one of two levels: low and high amounts of grapes. Both grape diets helped protect against neuronal damage caused by loss of oxygen in the brain. Animals not receiving a grape-enriched diet had extensive damage. Grapes also reduced inflammation in the support cells to the neurons.
A grape-enriched diet helped increase the expression of critical target genes that block the Alzheimer’s pathway and decrease inflammation in the brain.3
A study of aging mice that were either consuming a diet with or without grapes, found that the grape-enriched diet was able to increase the expression of critical target genes that block the Alzheimer's pathway and decrease inflammation in the brain.
A grape-enriched diet helped protect bladder function against oxidative damage caused by obstruction to the bladder.4 5 6
Obstructive bladder dysfunction, such as that observed with prostate enlargement, is linked to oxidative damage of the nerves, synapses and smooth muscle cells within the bladder wall.
- A series of animal studies investigated the impact of adding grapes to the diet on bladder function. The studies showed that grapes provided an antioxidant effect that helped to prevent and delay the damaging effects of oxygen deprivation (ischemia) and free radicals to cells that result from a partial obstruction to the bladder. Grapes helped maintain membrane and mitochondrial function in the cells, and reduce and reverse bladder damage caused by a partial outlet obstruction. The beneficial effects were attributed to the combination of multiple active components in grapes — not just one.
Grape extract helped promote the healthy functioning of liver cells, and protected liver cells from oxidative stress and cell death.7
Preventing liver cell death (apoptosis) may lead to the prevention of various liver diseases, and cell mitochondria are pivotal in controlling cell life and death.
- In this cell study, grape extract helped promote liver cell viability, growth, and metabolic activity. Specifically, grapes positively influenced a critical cell communication pathway that regulates liver cell health. Additionally, grapes helped protect the cells against oxidative stress and mitochondrial injury.
Grape extract helped to reduce inflammation and insulin resistance mediated by both immune cells and fat cells, and preserved cell function.8
In a cell study of immune and fat cells, grapes were shown to reduce inflammation and insulin resistance (improved glucose uptake) by fat cells, thus helping to protect important cell functions. Obesity and type 2 diabetes are both linked to chronic inflammation in fat tissue.
Grape consumption helped reduce the onset of autoimmune diabetes in mice.9
In this study, a grape-enriched diet protected against the destruction of insulin-producing cells in the pancreas, reduced levels of inflammation in the spleen, and increased antioxidant capacity in non-obese, diabetic mice.
Grapes helped decrease pain associated with arthritis and enhanced the impact of anti-inflammatory medicine.10
In this study, using an animal model of arthritis, four different treatments in rats were studied: sugar water (control); grapes (in powder form); the commonly used non-steroidal anti-inflammatory drug meloxicam; and a combined treatment with grapes and meloxicam. The grape-enriched diet reduced the amount of pain related to the arthritis, while the drug showed no impact on pain. However, the combination treatment of grapes and meloxicam gave greater pain relief than either did on its own.
Grape consumption helped protect healthy colon tissue by inhibiting a key cell communication pathway that promotes colon cancer cell growth.11
In a human study of five colon cancer patients, researchers studied the effects of consuming grapes on colon tissue. After the subjects consumed grapes for two weeks, samples of healthy and cancerous tissue were taken from each subject's colon. The results showed a 47% reduction in the expression of the target genes responsible for promoting tumor growth in the colon, compared to baseline measurements before the study. The beneficial effects were observed in the healthy tissue of the cancer patients, but not the cancerous tissue, suggesting that regular consumption of grapes may help to maintain a healthy colon.
Grape extract demonstrated anti-cancer activity alone, but was more potent in combination with green tea.12
In mice, tumor growth was stimulated with a specific cancer-growth protein, and the impact of grapes and green tea was tested. In the mice, a whole grape extract had some effect, but a grape skin extract combined with green tea was more effective. Green tea on its own provided no impact.
Cell studies compared the ability of various grape extracts to inhibit the growth protein in human cervical cells and the growth of mouse mammary cells. Grapes and green tea combined were more effective than either alone. Grape skin extracts were more effective than whole grape extract or a grape juice extract. This study also observed that grape polyphenols (specifically flavonoids) inhibited the growth protein without impacting healthy cells.
The role of grapes in maintaining cell health to prevent the development of cancer is an area of ongoing scientific interest, with promising preliminary work in the areas of breast, prostate and colon cancers.11
1 Yu, C.-C, et al. Dietary antioxidants prevent age-related retinal pigment epithelium actin damage and blindness in mice lacking αvβ5 integrin, Free Radic. Biol. Med. (2011), doi: 10.1016/j.freeradbiomed.2011.11.21
2 Wang, Q. et al., Dietary grape supplement ameliorates cerebral ischemia-induced neuronal death in gerbils. Mol. Nutr. Food Res.
3 Klein, RM Presentation. “Grape-enriched diet upregulates transthyretin in aged mice.” Presented by Dr. Nancy Berman at the 2007 Society for Neuroscience annual meeting in San Diego, California.
4 Agartan, CA, et al. Protection of urinary bladder function by grape suspension. Phytother Res. 2004, 18;(12):1013-18.
5 Lin A, et al. Protective Effects of Grape Suspension on In Vivo Ischemia/Reperfusion of the Rabbit Bladder. BJU Intl. Dec 2005, 96(9)1397-402.
6 Venugopal V, Levin RM, et al. Effect of Hydrogen Peroxide on Rabbit Urinary Bladder Citrate Synthase Activity in the Presence and Absence of a Grape Suspension. International Braz J Urol. Nov/Dec 2010, Vol. 36(6):749 – 758.
7 Xu Y, Yoffe B, et al. Freeze-dried grape powder attenuates mitochondria- and oxidative stress-mediated apoptosis in liver cells. J Agric Food Chem. 2009, 57:9324-9331.
8 Overman A, McIntosh MK, et.al. Polyphenol-rich grape powder extract (GPE) attenuates inflammation in human macrophages and in human adipocytes exposed to macrophage-conditioned media. International J Obesity. January 2010:1-9.
9 Zunino, SJ. Diets rich in polyphenols and vitamin A inhibit the development of Type 1 autoimmune diabetes in non-obese diabetic mice. J Nutr. 2007,137:1216-1221.
10 Borzan, J. Findings presented at the Society for Neuroscience 2008 conference in Washington DC.
11 Nguyen AV, Holcombe RF, et al. Results of a phase I pilot clinical trial examining the effect of plant-derived resveratrol and grape powder on Wnt pathway target gene expression in colonic mucosa and colon cancer. Cancer Manag Res. 2009:I 1-9
12 Morre DM, Morre DJ. Anticancer activity of grape and grape skin extracts alone and in combination with green tea infusions. Cancer Letters. 2005.
13 Vislocky LM, Fernandez ML. Biomedical effects of grape products. Nutrition Reviews. 2010, Vol 68(11):656-670.