fortify

linnoittaa

terästää

rakentaa linnakkeita

vitaminoida

vahvistaa To increase the defenses of; to strengthen and secure by military works; to render defensible against an attack by hostile forces.
To impart strength or vigor to.
Sir Walter Scott

Pride came to the aid of fancy, and both combined to fortify his resolution.

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.