fortification

vitaminointi, vahvistaminen

linnoitus

linnoittaminen The act of fortifying; the art or science of fortifying places to strengthen defence against an enemy.
That which fortifies; especially, a work or works erected to defend a place against attack; a fortified place; a fortress; a fort; a castle.
(RQ:EHough PrqsPrc)

“… We are engaged in a great work, a treatise on our river fortifications, perhaps? But since when did army officers afford the luxury of amanuenses in this simple republic?(..)”

Compare the nutrition information label of a regular ready-to-eat fortified cereal with that of a presweetened brand and you'll note that, although the sweetened one's sugar content is higher, the fortification is virtually identical.