An experimental protocol requires that a nutrient deficiency be induced to assess its effects on memory. What is the most appropriate study design to use to address this question?

The most appropriate study design to use to address this question would be of randomized controlled trial.

Explanation:

With an intention to induce a kind of deficiency, an individual can be fed with only the food that lacks the particular nutrient whose deficiency is to be created. After considerably enough of deprivation of that particular nutrient, the individual can be made to go through a memory test to check whether there is any apparent effect or not.