(13)In particular, the Commission should be empowered to adopt certain specific Directives, a list of substances with specific nutritional purposes and of other substances intended to be added to foodstuffs intended for particular nutritional uses, together with the purity criteria applicable to them, and, where appropriate, the conditions under which they should be used, provisions rendering it possible to indicate on foodstuffs for normal consumption that they are suitable for a particular nutritional use, special provisions for foods for persons suffering from carbohydrate metabolism disorders (diabetes), rules for the use of terms concerning the reduction or absence of sodium or salt content or the absence of gluten, which may be used to describe the products, as well as conditions under which reference may be made in labelling, presentation and advertising to a diet or to a category of persons. Since those measures are of general scope and are designed to amend non-essential elements of this Directive, inter alia, by supplementing it with new non-essential elements, they must be adopted in accordance with the regulatory procedure with scrutiny provided for in Article 5a of Decision 1999/468/EC.