Q. What are the signs of iron deficiency, and which foods prevent it?

A. Iron deficiency is the most common nutritional deficiency, and can lead to anemia (a lack of red blood cells). The most prominent sign is fatigue, says Jean Connors, a hematologist at Brigham and Women’s Hospital. “It’s harder to do the same amount of exercise you used to do,” she says, and symptoms include shortness of breath, rapid heart rate, lightheadedness, and pallor. More rarely, iron deficiency can cause pica, a condition characterized by cravings to eat ice, chalk, or corn starch. It has also been linked to restless leg syndrome.