E173 (aluminum)

E173 is aluminium used as a food colour to create a silver-grey metallic effect. Unlike plant pigments, it does not imitate fruit, berries or vegetables; it provides decorative shine. It may appear in some confectionery decorations, coatings and products where a metallic visual accent is desired. This is a narrow technological additive, not an ingredient that improves nutrition.

Metallic shine is easily perceived as premium, festive or carefully decorative. Aluminium colour does not add flavour, protein, minerals, useful fats or satiety. The word aluminium in food also deserves caution because aluminium exposure can come from different sources: foods, additives, cookware, antacids, some medicines and technological ingredients.

Where E173 is used

E173 is not used for ordinary colouring of the whole product mass, but for decorative metallic effects. It may be present in thin coatings, edible decorations, shiny confectionery elements and rare decorative products. It is usually not part of basic food, but part of festive or visually unusual categories.

This decorative role makes assessment simpler: a normal diet does not need aluminium shine. If a product is bought for silver coating, it is almost always a sweet, dessert, icing or decoration. In that case the nutritional role is determined by sugar, flour, starch, syrups, fats and serving size, not by the shine itself.

Safety and aluminium exposure

EFSA has assessed aluminium in the food context with attention to tolerable weekly intake from different sources. For E173 as a colourant, specifications, purity, particle size and actual use levels matter. Consumers, however, rarely receive aluminium from only one decorated product. Total exposure may come from several sources, especially when aluminium-containing medicines or multiple aluminium-containing additives are used.

This does not mean that one piece of decorated dessert is automatically dangerous. It means aluminium should not be treated as a neutral food element. Unlike iron or zinc, it is not a required nutrient. There is therefore no reason to seek products with E173 or consider metallic shine a beneficial feature.

Relevance for LCHF

E173 is not a carbohydrate, but products containing it almost always belong to decorative sweets or festive foods. For low-carbohydrate eating, the main issue is usually sugar, flour, starch, syrups, fillings and serving size. Aluminium shine can distract from the fact that the product is still a dessert.

Even if a dessert is made without sugar, metallic colour does not make it more suitable. Sweeteners, polyols, flour, nut bases, energy density, tolerance and frequency of use still matter. LCHF does not require panic over every decoration, but regular food should not be based on decorative products with low nutrient density.

How to read the label

On labels, E173 may appear as aluminium, aluminum or E173. For foods in the EU, current authorised categories and specifications need to be considered. If the product is imported, decorative or sold as confectionery decoration, it is useful to check whether it is actually intended to be eaten, not only for food contact or visual decoration.

The practical conclusion is simple: E173 is best treated as a rare decorative detail, not a normal part of eating. If the product containing it is sweet, flour-based or ultra-processed, the whole formula needs assessment. Metallic shine may look impressive, but it does not add benefit and should not hide a weak nutritional base.

Another practical point is the combination of aluminium sources. If a person regularly uses antacids, certain phosphate binders or other aluminium-containing products, decorative food sources become less irrelevant. E173 is usually rare, but when total exposure is high it is sensible to remove unnecessary sources, especially those that provide no nutritional value.