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materials have protective effects against many of these diseases. At the same time, it has become increasingly appreciated that certain constituents in plants have antioxidant properties. It is therefore not surprising that there is a widespread presumption that at least some of the protective effects of plants depend upon these antioxidant compounds. It may be speculated that plant materials that are rich in antioxidants are also beneficial to human health.

However, various pieces in this intriguing jigsaw will have to be put into place before we can be sure that foods of plant origin like cocoa have a measurable beneficial effect on human health. Despite all the optimism in the field of phytochemicals, there remain large and tantalizing gaps in our knowledge. Although effects can be seen in vitro, we need to know whether and how much of these active compounds are absorbed. In most cases our knowledge about the absorption of phytochemicals is fragmentary, and thus we know little about their target tissues or their effects in vivo. Where these compounds do show protective activity, we will need to understand the mechanism of action. Studies of cocoa in this field lag some way behind other plant materials, so that less is known about the effects of cocoa than some other plant materials. Even our knowledge of the constituents of the most commonly consumed form of cocoa, namely chocolate, is very limited. Yet we know already from early work on cocoa raw and fermented that it has a high content of antioxidants. Cocoa is conceivably a treasure chest of compounds with potentially beneficial effects on human health. It will be fascinating to watch the development of the field of phytochemicals, and to learn its implications for cocoa products.

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6. Witztum, J.L. (1994) The oxidation hypothesis of atherosclerosis. Lancet 344, 793795.
7. Leake, D.S. (1998) The effects of flavonoids on the oxidation of low-density lipoproteins. In Flavonoids in Health and Disease (Ed. by Rice-Evans, C.A. and Packer, L.), pp. 253276. Marcel Decker, New York.
8. Kondo, K., Hirano, R., Matsumoto, A., Igarashi, O. and Itakura, H. (1996) Inhibition of LDL oxidation by cocoa. Lancet 348, 1514.
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