Iron has an unequivocally positive reputation among the general public. After all, pregnant women use it to construct tiny humans, tiny humans use it to become slightly larger, more functional humans, and our cells require it to grow. And in many developing countries, iron deficiency is a real issue. Too little iron can have disastrous effects on cognition, growth, and overall physical robustness. Even adult women who aren’t building tiny humans inside their wombs may run low on iron due to menstrual cycle blood loss. Ask the average person and you’ll hear “the more iron, the better.” Consequently, many countries mandate iron fortification of wheat flour; in the US, we fortify pretty much everything with the stuff because it’s just so, so good for us. Is it true, though?