Diet and Fitness Expert Dr. Melina Jampolis Physician Nutrition Specialist

Expert answer

Hi Tessa. This question is a good example of why it is probably best to speak with your doctor before taking most supplements.

Iron deficiency anemia (this is the condition you are actually talking about when you describe running-induced anemia) is one of the most common nutritional deficiencies worldwide.

Causes include inadequate dietary iron intake (often found with a vegan diet or in infants and children), iron absorption problems often seen in older adults, and physiologic losses caused by menstruation, pregnancy or lactation. It can also be caused by chronic blood loss which could be caused by a gastrointestinal problem such as an ulcer, cancer or in your case (most likely), through serious athletic training leading to microscopic blood loss.

Weakness and fatigue are common symptoms (I'm assuming that these are probably what you suffered from) as iron is an essential component of the oxygen carrying protein in your blood called hemoglobin. When your hemoglobin levels are low, you carry less energy generating oxygen, which can lead to fatigue. It is also an important component of myoglobin, which delivers oxygen to your muscles, so athletes in particular may feel the effects of iron deficiency even if they are not anemic. Other symptoms include decreased attention span, irritability, decreased immune function leading to more frequent illness, swollen and red tongue, poor performance at work or school, and delayed or impaired cognitive development in infants and young children.

Assuming that your anemia is due to athletic training, I generally recommend that people start with food to replace iron stores. The best sources of iron are red meat, dark meat chicken and turkey, beans, lentils, peas, iron-fortified cereals, dark leafy green vegetables and dried fruit. Meat-derived iron, known as heme iron, is more easily absorbed by the body.

Plant-derived iron, known as non-heme iron, is not as well absorbed and requires vitamin C (or meat) to improve absorption. In addition, absorption is diminished by calcium (dairy products), fiber, tea, and coffee. So if you are a vegetarian or vegan, be sure to consume iron-rich foods with vitamin C rich foods such as citrus fruits and juices, tomatoes, strawberries, broccoli, kiwi, melons, red and green sweet peppers, and dark green vegetables whenever possible.

This is also important when taking supplements, which are also better absorbed with vitamin C and whose absorption is diminished by calcium. Avoid taking iron supplements with milk or within several hours of your daily calcium supplement if you take one or antacids containing calcium.

The concern with an adult taking an iron supplement indefinitely (there is more of a concern for overdose associated toxicity in children), is that there is some evidence, albeit speculative, of an association between excess iron and heart disease risk and diabetes. In addition, while iron deficiency may negatively affect immune function, too much may impair immunity, too. So while you do not need to limit iron containing foods in your diet, especially plant based foods, you should take a supplement only if medically necessary under the supervision of a physician.

At this point, I would see your doctor and have your blood count and iron level checked (your doctor will probably also check something called ferritin, which is the storage form of iron and a more accurate reflection of total iron stores).

Assuming that your levels are normal, and assuming that you continue running, I would take a multivitamin with the Dietary Reference Intake of iron (18 mg per day for women 19-50 and 8 mg per day for women 51 and older) to keep up with training (or menstrual) associated blood loss. Make sure to eat plenty of a variety of iron rich foods to maintain adequate iron stores in general.