DEAR DR. ROACH: I’m a 62-year-old woman in fairly good health. I’m currently on Wellbutrin, carvedilol, Farxiga, Entresto and spironolactone, and my blood pressure is very well-controlled. I also recently started Zoloft. About eight months ago, I started feeling bad and spoke to my doctor about it. She wasn’t concerned at the time and said that it might be due to my recent weight loss. I’ve lost about 25 pounds.

I went to my cardiologist and had an echocardiogram and stress test done, and both were normal. Recently, I read about ferritin levels and the symptoms of a low ferritin level, which matched all of my symptoms — fatigue, breathlessness, dizziness and brain fog. I asked my doctor to check my iron levels, which all came back normal except for the ferritin level. It came back at 39.1 ng/mL, which I’ve read is on the low end and could be causing my symptoms.

I am a frequent blood donor and have given blood four times during the past eight months. My hemoglobin level was normal at 13.4 g/dL, while my iron was low and my total iron-binding capacity (TIBC) was high. Could the frequent blood donations be leading to my lower levels of ferritin?

Other than limiting the number of times I give blood in a year, is there anything else I can do to bring my ferritin levels back up to a more normal range? Or do you think there is something else that is causing my symptoms?

• K.B.

ANSWER: Ferritin is an iron storage protein, so your ferritin level is a pretty good indication of the iron levels in your body, although it isn’t perfect. In your case, your low iron and high TIBC essentially make the diagnosis of low iron a certainty. (Definitive proof of iron deficiency comes from a bone marrow biopsy, which is almost never done for the purpose of iron evaluation.)

You don’t have anemia, but it’s become clear that low iron can cause significant symptoms even without anemia. Fatigue is the most common symptom, but decreased exercise ability, cognitive problems (“brain fog”), and depression and anxiety are also well-documented.

Restless legs syndrome, which many people aren’t aware that they have, is also associated with low iron. Cravings for unusual foods, called “pica,” is also associated with iron deficiency. (Ice is classic, but I’ve seen many different cravings, including a person who ate two boxes of Triscuit crackers a day.)