1. A plant-derived flavonol-containing dry composition suitable for human consumption obtained from grapes, wine or flavonol-containing by-products or waste-products of the wine-making process, wherein at least 25% comprises polyphenols, comprising at least 1% w/w flavonol and wherein the composition is effective in one or more of the following: inhibiting oxidation of plasma LDL; stimulating TGF-β production; inhibiting platelet aggregation; and stimulating fibrinolysis. 2. A composition according to claim 1, wherein the flavonol content comprises at least 2% of the total the plant-derived polyphenol content of the composition. 3. A composition according to claims 1 or 2, wherein obtained from red grape or red wine and comprising red wine polyphenols. 4. A composition according to any one of the preceding claims, comprising an excipient, diluent or carrier. 5. A composition according to any one of the preceding claims, comprising one or more substances selected from the group consisting of: nutrients, antioxidants. therapeutic substances (especially those having a therapeutic effect in relation to prevention and/or treatment of CHD), flavourings, and sweeteners. 6. A composition according to any one of the preceding claims, comprising one or more substances selected from the group consisting of: lutein, lycopene, α- or β-carotene, vitamin A, vitamin C, vitamin E (α-tocopherol and other active tocopherols), folic acid, selenium, copper, zinc, manganese, ubiquinone (coenzyme Q10), salicylic acid, 2,3-dihydroxy benzoic acid, 7,5-dihydroxy benzoic acid and aspirin. 7. A formed product, comprising a composition according to any one of the preceding claims. 8. A formed product according to claim 7, packaged in a unitary dose form. 9. A formed product according to claim 7 or 8, packaged in the form of a tablet, capsule, and pill. 10. A drink comprising a composition according to any of claims 1 to 6 and a physiologically acceptable liquid. 11. A drink according to claim 10, wherein the physiologically acceptable liquid comprises water, an aqueous solution, an alcoholic solution, fruit juice, milk, or yogurt. 12. A method of making a drink, comprising mixing a composition in accordance with any one of claims 1-9 with a physiologically acceptable liquid. 13. A method according to claim 12, wherein the physiologically acceptable liquid comprises water, an aqueous solution, an alcoholic solution, fruit juice, milk, or yogurt. 14. A method of inhibiting oxidation of plasma LDL in a human subject, the method comprising: preparing a composition or a product according to any one of claims 1-9, or a drink according to claim 10 or 11; and administering the composition or drink to the human subject. 15. A method of stimulating TGF-β production in a human subject, the method comprising: preparing a composition according to any one of claims 1-9, or a drink according to claim 10 or 11, and administering the composition or drink to the human subject. 16. A method of inhibiting platelet aggregation and/or stimulating fibrinolysis in a human subject, the method comprising: preparing a composition according to any one of claims 1-9 or a drink according to claim 10 or 11; and administering the composition or drink to the human subject. 17. Use of a composition according to any one of claims 1-6, for the manufacture of a medicament for inhibiting stimulating oxidation of plasma LDL in the human subject. 18. Use of a composition according to any one of claims 1-6, for the manufacture of a medicament for stimulating TGF-β production in a human subject. 19. Use of a composition according to any one of claims 1-6, for the manufacture of a medicament for inhibiting platelet aggregation and/or stimulating fibrinolysis in the human subject. 20. A method of making a medicament for oral consumption the method comprising preparing a composition or a product according to any one of claims 1-9 and preparing unitary doses of the composition. 21. A product, particularly a foodstuff, comprising a composition according to any one of claims 1 to 9.