From the prefix
micro and
nutrient. Micronutrients are
chemicals which
animals need to consume to sustain life and health, but which are required in very small quantities -- typically several
micrograms to <10
grams per
day. The primary human micronutrients are the
vitamins and certain
minerals.
The micronutrients are contrasted to the
macronutrients, which must be consumed in larger quantities.