Low iron levels are detrimental for your health, and possibly even for cognitive and mental well-being. As these tests are invasive and expensive, large and high quality data on how iron may impact your well-being is lacking. Furthermore, small studies show that the colour of your nails may also be used to analyse iron levels. In this project, we will assess hemoglobin values, nail images, cognitive functioning, and depressive symptoms data from a large, heterogeneous and healthy sample and 2) develop a prototype of an artificial intelligence driven app able to assess iron levels through photographs taken with your smartphone.