Grapes are the fruit of the grape vine, vitis vinifera, juicy, sweet and tasty, have been a part of human life for thousands of years. There are different types of grapes, sweeter or more sour, smaller or bigger and of different colors. Today we will talk about black grapes.
Black grapes, properties and benefits
Black grapes, more than other varieties, are an exceptional source of polyphenols, which are powerful antioxidants. Polyphenols are mainly found in grape skin and, in case of catechins, also in the seeds. Examples of polyphenols that can be found in black grapes are resveratrol, but also kaempferol, myricetin and quercetin, anthocyanins and catechins, to name but a few examples. These antioxidants are really beneficial for human health since they help fight free radical damages, are antibacterial, antifungal, antiviral, protect the heart, liver and brain and are also anti-cancer and anti-inflammatory (Yadav et al, Indian J Pharmacol, Nov 2015). In fact, grapes are able to counteract chronic inflammation, a condition that in the long run can lead to diseases such as diabetes, autoimmune diseases, arthritis, tumors and degenerative diseases. And there's more, according to scientific studies, extracts of wine made from a type of black grapes, called Jacquez, showed an even greater anti-inflammatory action than indomethacin, a non-steroidal anti-inflammatory drug (Georgiev et al , Nutrients, 2014). For what concerns brain health, the intake of grape juice in young adults has been shown to improve reaction times and attention and to have beneficial effects also on mood by promoting calm (Haskell-Ramsay et al, Eur J Nutr, 2017). Grape polyphenols and grape products such as juice help reduce obesity and type 2 diabetes by counteracting inflammation and improving glucose tolerance. These polyphenols are also protective on the liver especially in case of hepatic steatosis (Park et al, Mol Nutrition Food Res, Feb 2013). Finally, the grapes are also beneficial for the cardiovascular system as they counteract the oxidation of bad LDL cholesterol and improve cardiovascular function. These benefits were observed after the intake of 125 ml of commercially available grape juice for one week (Day et al, Ann Nutr Metab, 1997).
White grapes or black grapes, fruit or juice
It is often said that black grapes are healthier than white grapes, is that true? The two types of grapes actually differ in their antioxidant composition. In fact, in black grapes the percentage of catechins compared to the total amount of antioxidants reaches 30% while in white grapes it reaches almost 60%. However, anthocyanins, other very important antioxidants, are found almost exclusively in black grapes. Other antioxidants such as kaempferol and quercetin are found both in white and black grapes while myricetin, a substance with an anti-tumor action, is only found in black grapes. Therefore, both types of grapes are healthy and, thanks to their different antioxidant composition, complement one another (Georgiev et al, Nutrients, 2014). For what concerns instead the form in which grapes can be taken, the scientific studies that show the properties of the fruit always refer to both the whole fruit and its products, such as the juice. Even the wine contains antioxidants, however, the alcohol content reduces its beneficial effect. In any case, it has been observed that it is preferable to choose organic grapes and juices, as they show a higher antioxidant action than conventional agricultural products (Dani et al, J Med Food, Mar 2008).