Wine vs. grape juice – differences in composition and health effects
Grape juice and wine are made from the same fruit, the Vitis vinifera grape. However, their composition and health effects differ significantly in some respects.
A recent review paper compiled the available information in detail to compare the processing, composition, and health effects of grape juice and red wine in particular. The first steps in making juice or wine from grapes are very similar: after harvesting, the fruits are crushed and separated from their stems. For grape juice, they are then pressed, filtered, and bottled. For the production of wine, however, after the crushing, the fermentation of the sugar contained in the fruits into alcohol follows. Wine is thus fermented grape juice (even though different grape varieties are used for juice production), and this has an impact on its composition and health effects. Grape juice retains its original ingredients better, as the sugar does not ferment, making it significantly higher in sugar than wine. This results in an energy-rich, sweet drink. For individuals with type 2 diabetes or insulin resistance, consuming grape juice can be counterproductive because the large amounts of sugar worsen their already high, ineffective insulin levels. However, grape juice does offer benefits, including a high content of organic acids and significant amounts of vitamin C.
Due to the fermentation process, wines also contain alcohol (i.e. a 12.5 vol% wine = 10 g of alcohol per 100 ml glass). Fermentation also changes the bioavailability of other ingredients: in red wine in particular, more resveratrol is extracted from the grape skins and the amount of effective bioactive components, such as polyphenols, increases. These wine compounds are best known for their antioxidant and anti-inflammatory properties, which are credited with a significant portion of the health benefits of moderate wine consumption. They can also exert a beneficial effect on the gut microbiota and thus promote cardiovascular health, for example.
The interaction of all ingredients determines not only the sensory properties of both beverages, but also their effects on metabolism and health. Both beverages promote a healthy gut microbiota by improving the ratio of Bacteroidetes to Firmicutes. This is important because an excess of Firmicutes bacteria can promote obesity. In addition, both beverages support the growth of beneficial lactobacilli and bifidobacteria, which use lactic acid to create an acidic environment in the gut that inhibits disease-causing germs. These beneficial bacteria also support the immune system, aid in the absorption of vitamins, and help strengthen the intestinal barrier.
Both grape juice and red wine are popular worldwide due to their bioactive ingredients. A new trend is the increasing demand for non-alcoholic wines. The advantage of grape juice is that it does not contain alcohol and is therefore also suitable for children, pregnant women, and individuals who do not want to or should not consume alcoholic beverages. It should be consumed in small portions of 100 to 150 ml daily and can replace a handful of fruit.
Wine scores points for its wide variety of types and tastes and its abundant bioactive compounds are better bioavailable. When consumed in moderation (up to a maximum of 200 ml for women and 300 ml for men) with a meal, it has been shown to have heart and vascular protective effects, among other things.
