Being a fit female with normal iron levels can make a difference of 0.34 in your grade point average (GPA). That could be enough to bump you up one letter grade. The study conducted by Penn State University and the University of Nebraska-Lincoln was published in The Journal of Nutrition.
Researchers analyzed data on 105 female college students with an average GPA of 3.68. Subjects who were fit and had the highest levels of stored iron tended to have higher grades than unfit subjects with iron deficiency. Consider that iron helps transport oxygen in the blood. Iron deficiency has also been associated with fatigue and a reduced capacity for work.