Grapes are small round or oval berries that feature semi-translucent flesh encased by a smooth skin. Some contain edible seeds while others are seedless. Like blueberries, grapes are often covered by a protective, whitish bloom. Grapes that are eaten as is or used in a recipe are called table grapes and as opposed to wine grapes (used in viniculture) or raisin grapes (used to make dried fruit).
The portability, texture, flavor and variety of grapes have made them a popular finger food in countries all over the world. The potential health benefits of consuming grapes are numerous, with past studies associating them with prevention of cancer, heart disease, high blood pressure and constipation among others.
One cup of red or green grapes contains 104 calories, 1.09 grams of protein, 0.24 grams of fat, 1.4 grams of fiber, 4.8 milligrams of vitamin C, 10 micrograms of vitamin A, 288 milligrams of potassium, 0.54 milligrams of iron and 3 micrograms of folate.
Organized according to science-based categories, the list below will give you a general idea of the phytonutrient richness of grapes. While a single grape variety is unlikely to contain all of the phytonutrients listed below, grapes as a group have been shown to provide us with the following health-supportive nutrients:
o resveratrol, piceatannol, pterostilbene
o catechins, epicatechins, procyanidins, proanthocyanidins, viniferones
o quercetin, kaempferol, myricetin, isorhamnetin
• Phenolic Acids
o caffeic acid, coumaric acid, ferulic acid, gallic acid
o beta-carotene, lutein, zeaxanthin
In addition to the above-listed nutrients, grapes have also been shown to contain the hormone and antioxidant melatonin as well as unique oligopeptides (small protein-like molecules) that have anti-bacterial and other properties.
Grapes are high in water content and good for hydration. High water-content fruits and vegetables are nutrient dense, meaning they provide a large amount of essential nutrients while containing few calories. Grapes contain 70 milliliters of fluid per cup.
Grapes are high in antioxidants important for eye health such as lutein and zeaxanthin, and red grapes contain the phytochemical resveratrol in their skins, the antioxidant synonymous with wine known to lend protection from several chronic diseases and conditions. Grapes also boast the power of the flavonoids myricetin and quercetin which help the body to counter-act harmful free radical formation.
Research on antioxidant benefits provided by grapes or grape components includes the following findings. Grapes and grape components can:
• 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.
• 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
Grapes increase the nitric oxide levels in the blood, which prevents blood clots. Therefore, grapes are an effective way to reduce the chances of heart attacks. Additionally, the antioxidants present in grapes prevent the oxidation of LDL cholesterol, which blocks the blood vessels and is a main contributor to various coronary conditions. Grapes also have high numbers of flavonoids, which are what give grapes their color, but flavonoids are also very powerful antioxidants. The two main types in grapes are resveratrol and quercetin, and these two compounds negate the effects of free radicals that threaten the body and stimulate LDL cholesterol’s harmful effects on arteries. Also, these two antioxidant flavonoids act as a clean-up crew to reduce platelet clumping and filter toxins out of the blood.