Grapes grow wild on vines or are cultivated. They are believed to be native to northwest Asia although they have been grown throughout Europe and the United States for centuries. The seeds, skin, leaves, stems, and grape itself are used in herbal remedies. At times in the past, diets consisting solely of grapes have been touted as an alternative means of treating cancer. Some chemicals found in grape extract (called proanthocyanidins) and in grape skins (called resveratrol) are currently being studied for possible uses in the prevention and treatment of cancer and other illnesses.
Other common name(s): grape diet, grape cure, grape seed extract (GSE), grape seed proanthocyanidin extract (GSPE), grape seed oil, grape skins, proanthocyanidins, oligomeric proanthocyanidins (OPCs), resveratrol
Scientific/medical name(s): Vitis vinifera, Vitis coignetiae
Grapes are extremely high in antioxidants. In fact the number of different antioxidant nutrients are well into the hundreds ranging from common carotenoids like beta-carotene to unusual stilbenes like resveratrol. It is the resveratrol content in red wine that makes a glass a day so beneficial to one’s longevity. The seed and the skin contain the richest concentration of these antioxidants.
Research on antioxidant benefits provided by grapes includes the following findings:
- help prevent certain oxygen-related enzymes from becoming overactive. These enzymes include xanthine oxidase and catalase.
- increase our blood levels of glutathione (a critical antioxidant nutrient) and also increase the ratio of reduced-to-oxidized glutathione (one important measure of antioxidant capacity).
- help protect cell membranes from free radical damage.
- lower levels of oxygen reactive molecules in our blood.
- reduce oxidation of fat (lipid peroxidation).
- lower biomarkers of oxidative stress.
Grapes provide us with strong anti-inflammatory benefits.
The cells in our blood need protection from potential oxygen damage. This is especially true for our arteries where oxygen concentration in our blood is especially high. Our blood vessel linings also need strong antioxidant support. Chronic inflammation in our cardiovascular system is also a primary concern for many types of cardiovascular disease, and optimal regulation of inflammatory system activity is especially important in lowering our risk of atherosclerosis and other conditions.
It’s also one of the reasons that consumption of grapes in the form of red wine has been regarded by some researchers as a key for understanding “the French Paradox.” The French Paradox refers to research observations about heart health in the French population in relationship to their saturated fat intake. Despite eating fairly large amounts of saturated fat in their overall diet, the French population as a whole has been observed to have much lower levels of heart disease than would be expected with high saturated fat intake.
All of the following cardio benefits have been demonstrated in research studies on grapes and grape components:
- better blood pressure regulation, including blood pressure reduction if high
- better total cholesterol regulation, including total cholesterol reduction if high
- reduced LDL cholesterol levels
- reduced LDL oxidation
- reduced levels of reactive oxygen molecules in the blood
- reduced likelihood of cell adhesion to the blood vessel walls
- less clumping together of platelet cells, when inappropriate
- enhanced release of nitric oxide from endothelial cells lining the blood vessel walls in situations where vasodilation is needed
- better inflammatory regulation in the blood
- increase levels of glutathione in the blood
Blood Sugar Benefits
Studies now show that grapes improve blood sugar balance, create better insulin regulation, and increased insulin sensitivity. Strong phytonutrient content of grapes plays a key role in providing these blood sugar-related benefits.
Anti-Aging and Longevity Benefits
Several grape phytonutrients may play a role in longevity and may provide us with anti-aging benefits. Resveratrol has recently been shown to increase expression of three genes all related to longevity. (These three genes are SirT1s, Fox0s, and PBEFs.) Some researchers have shown a connection between activation of these longevity genes by resveratrol and activation by calorie-restricted diets.
Daily consumption of Concord grape juice in a 1-2 cup amount over a period of several months has been shown to improve the scores of study participants on the California Verbal Learning Test.
Recent studies have determined that grapes may also contain unique sets of oligopeptides which are short protein-like molecules that have anti-microbial properties. Research in this area is in early stages. It will be interesting to see whether diets that are rich in grapes (or grape products like red wine) turn out to be associated with reduced risk of microbe-related problems like food-borne illness.
Resveratrol found in grape skins, has been reported to convert into a cancer fighting agent that can target and attack cancer cells. When juicing grapes you should include the skins and the seeds but thoroughly rinse them if they are not organic to remove any possible traces of herbicides or pesticides that are often sprayed on the crops.
Grapes contain high levels of natural sugars and so people with sugar sensitive conditions such as Diabetes or Candida should take care not to consume too much grape juice.
The antioxidant and anti-inflammatory properties of grapes make them a natural for protection against cancer because chronic oxidative stress and chronic inflammation can be key factors in the development of cancer. If our cells get overwhelmed by oxidative stress (damage to cell structure and cell function by overly reactive oxygen-containing molecules) and chronic excessive inflammation, our risk of cell cancer is increased. By providing us with rich supplies of antioxidant and anti-inflammatory nutrients, grapes can help us avoid this dangerous combination of chronic oxidative stress and chronic inflammation.
One interesting development in the research on grapes and colon cancer prevention has involved studies on GADF, or grape antioxidant dietary fiber. Fiber is greatly needed for a healthy colon, and grapes provide us with approximately 1 gram of fiber in every 60 calories. Antioxidants are also needed, and grapes come through strong in the antioxidant category. This antioxidant-plus-fiber combination may be one of the reasons that colon cancer prevention has jumped out in health research on grapes. In the area of prostate cancer, it is the stilbenes (including resveratrol) have been the major focus in research on the anti-cancer properties of grapes.
Several epidemiological studies have shown that populations that consume diets rich in fruits and vegetables have an overall lower cancer incidence. Based on these encouraging observations, research efforts from across the globe have focused on identifying, characterizing, and providing scientific basis to the efficacy of various phytonutrients in an effort to develop effective strategy to control various human malignancies.
Nutritional benefits of Grapes
Vitamins and Minerals
Rich in C, E small amounts of B1, B2, B3
Rich in calcium, magnesium, phosphorus, potassium, sodium, sulfur, small amounts of copper, iron and zinc.
- caffeic acid
- coumaric acid
- ferulic acid
- gallic acid