To fortify, in food use, is to add extra ingredients to a food or drink to improve its nutritional value — and sometimes its flavour. Classic examples include adding vitamins and minerals to flour, iodine to salt, vitamin D to milk and margarine, and folic acid to bread-making flour: public health measures that have sharply reduced deficiency diseases. Manufacturers also fortify products voluntarily, from calcium-enriched orange juice to protein-boosted yoghurts, as a selling point. Fortification differs from enrichment mainly in intent — enrichment replaces nutrients lost in processing, while fortification adds nutrients beyond natural levels — though the terms overlap in practice. Levels are regulated to ensure meaningful benefit without risking excessive intakes.