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The leaves harvested from grapevines had astringent properties useful for treating diarrhea and for topical application to wounds where tightening of tissues was beneficial. The tea made from dried grape leaves was traditional remedy for digestive upset, the tannins providing the astringent effect that reduced intestinal inflammation. The external application used fresh leaves crushed into paste, the same astringent properties being beneficial for skin conditions.
The seeds pressed from grapes after crushing for wine yielded oil rich in compounds that modern analysis has confirmed have antioxidant and anti-inflammatory properties. The traditional use for cooking was simultaneously culinary practice and health measure, the regular consumption of grape seed oil providing benefits that were recognized through observation even without understanding the chemical basis. The external application to skin provided moisturizing effects and possibly some protection against sun damage.
The skins remaining after wine pressing—the pomace—contained concentrated amounts of the same compounds that gave red wine its color and some of its health benefits. The pomace could be dried and powdered for use in various preparations, or it could be fermented again to produce grappa or similar spirits that had even higher alcohol content and different therapeutic applications than wine itself.
The fresh grapes eaten directly provided hydration, sugars for quick energy, and various beneficial compounds in their natural state before fermentation. The traditional practice of consuming grapes during harvest season was simultaneously practical nourishment for laborers and seasonal health boost from the concentrated nutrients in fresh fruit. The dried grapes—raisins—preserved these benefits for consumption during seasons when fresh grapes were unavailable.
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