has presented an even broader definition of functional food, specifying four categories of its production: (a) upgrading;
i.e. enhancement by adding a substance which is already present in the product; (b) substitution; i.e. substituting a component with a similar, but healthier substance; (c) enrichment; i.e. adding a substance not present in the basic product; and (d) elimination; i.e. removing an unhealthy component.