Increasingly, consumers are making the link between food and health, and functional foods have been key beneficiaries of this trend. Cholesterol-lowering, fat-busting or probiotic foods have boomed in recent years, but many products are encountering serious obstacles in reaching a mass market. Consumers find them expensive and confusing, and general acceptance is a long way off. How can manufacturers communicate to consumers that functional foods are worth paying for? In the first of a two-part feature, Rajiv Desai reports