1. The use of a mixture of oligomeric procyanidins (ORS) and ascorbic acid or vitamin C analogs for the preparation of a composition containing at least one catechin, to improve the bioavailability of said catechin. The use according to claim 1, where the catechin comes from green tea, wild fruits, in particular berries, cocoa, beans or other sources of fruits containing catechin. The use of claim 1, wherein the composition is a food product, a pet product, a nutritional composition, a nutraceutical, a dietary supplement, a cosmetic composition, or a medicine. The use according to claim 3, wherein the food product is selected from the group consisting of a complete nutritional mixture, a dairy product, a beverage cooled or stable in storage, a powdered beverage, mineral water, a liquid beverage, soup, a dietary supplement, a food substitute, a nutritional bar, and a confectionery a product, milk or dairy product, yogurt, milk-based powder, enteral nutrition product, infant formula, cereal product or fermented cereal product, ice cream, chocolate, coffee or culinary product. 5. The use according to claim 3, wherein the biologically active food supplement is provided in the form of capsules, gelatin capsules, soft capsules, tablets, sugar-coated tablets, pills, pastes or lozenges, chewing gums, drinking solutions or emulsions, syrups or gels. The use according to claim 1, wherein the composition further comprises at least one of a sweetener, stabilizer, flavoring agent and coloring agent. The use according to claim 3, where the cosmetics1. Применение смеси олигомерных процианидинов (ОРС) и аскорбиновой кислоты или аналогов витамина С для приготовления композиции, содержащей по меньшей мере один катехин, для улучшения биодоступности упомянутого катехина.2. Применение по п.1, где катехин происходит из зеленого чая, плодов диких растений, в частности ягод, какао, бобов или других источников плодов, содержащих катехин.3. Применение по п.1, где композиция является пищевым
