Walter Mertz first discovered that chromium was a trace nutrient in 1955. Chromium was determined to be essential for animals in 1959 by Schwarz and Mertz.
Absorption comes from active transport.
Amino acids keep chromium from precipitating in the small intestine where the pH is alkaline. The more acidic the milieu, the more soluble chromium becomes. Amino acids, oxalates and Niacin may enhance absorption. Chromium is actively transported from the small intestine. Then it is transported via transferrin to the liver.