The Caco-2 cell bioassay is a method used to measure how well our bodies absorb iron from food. By using a human intestinal cell line called Caco-2, researchers can mimic the process of iron absorption in the gut. This bioassay involves simulating digestion and measuring the production of a protein called ferritin, which stores iron. The amount of ferritin produced reflects how much iron is taken up by the cells. Studies have shown that this bioassay accurately predicts how much iron we can absorb from different foods and diets. It is a cost-effective and efficient way to assess the nutritional quality of iron in our food.