Micronutrients
Etymology
A modern scientific compound: Greek "mikros" (small) plus "nutrient," from Latin "nutrire" (to nourish). Coined to contrast with the bulk energy-providers the body consumes in large quantities.
noun · /MY-kroh-NOO-tree-uhnts/
Nutrients the body needs only in small amounts — vitamins and minerals — but cannot function without.
What it names
The trace essentials that carry no calories yet gate countless bodily processes, a category easy to overlook when counting energy.
Example
The diet had plenty of calories but was starved of micronutrients, leaving her low on iron and vitamin D.
Related idea
The counterpart is macronutrients, needed in large amounts for fuel; micronutrients are the catalysts and cofactors that let the body actually process that fuel.