Friday, October 12, 2012

Science Friday: Diagnosis and Discoveries about Iron

This week I finally got the results of a blood test to determine if low iron was the culprit of my running funk. At first glance it seemed like everything was fine. My doctor told me I had normal iron and hemoglobin levels, but could be maybe, possibly, considered borderline anemic because of low ferritin. She suggested an iron supplement but then proceeded to tell me she thinks I am just running too much. Ah yes, well if I wasn't running, I wouldn't be in here complaining about how my running is going poorly. True, but irrelevant for a die hard runner.

After leaving her office I immediately Googled ferritin (ahh, Google, every doctor’s nightmare.) I remembered an article I had read a while ago about Stephanie Rothstein having iron issues. I discovered that her issue (eventually attributed to celiac disease) had been low ferritin as well. According to the article, normal levels are 20 nanograms/milliliter, but runners actually need more, in the range of 30-40. Rothstein’s was 4 ng/mL. Mine was 6 ng/mL.

Why did Rothstein's doctor suspect that was an issue while mine seemed doubtful? More Googling (and some more sophisticated scientific "Googling") ensued. Why do runners have iron issues? What the heck is ferritin? Could low ferritin be my problem?

Runners need iron to produce hemoglobin, which is the molecule that carries oxygen to your muscles. Without it, your muscles can’t function as well, so you can’t run as fast, you feel more tired, etc. The problem is runners lose a lot of iron. To start with, iron is hard to absorb.We only absorb 15% of the iron we eat; the best (and most easily absorbed iron) is from animal sources like red meat. If you choose not to eat a lot of red meat, like me, that can start the problem. (Good plant sources of iron include beans, nuts, bran, and spinach.) Absorption is inhibited by calcium, coffee, tea, and anti-inflammatories, all of which runners, as a whole, consume a lot. We lose iron through sweat (which can be worse in hot, humid conditions) and through GI stress. We also lose iron through foot strike hemolysis, when blood cells burst from the force of impact with the ground. Women are more likely to have iron deficiency anemia because of blood lost through menstruation.

Ferritin stores iron; most of the iron in our body is bound to ferritin. Less ferritin in your blood means less stored iron. According to some data, low ferritin levels is the best indicator of iron deficiency. However, by definition, anemia is diagnosed by low hemoglobin levels, which is why I am technically not anemic and why my doctor is less than concerned. But then I found this from an article by Coach Jeff Hess in Track and Field News:

Anemia, clinical iron deficiency, is not rare among runners, but even more common than iron deficiency is "iron depletion" due to low ferritin stores... It is common among distance runners to have acceptable hemoglobin and hematocrit counts even when ferritin levels are severely depleted. For less active people, low ferritin levels are much less significant and don't often draw the attention of medical professionals.

So your average doctor might not think anything of it, while a sports medicine specialist might notice the red flag. The symptoms of iron depletion are similar to iron deficiency and include abnormal exhaustion, slow recovery, declining performances, heavy legs, loss of motivation, etc. This was sounding all too familiar and the statistics gave me some validation: one doctor suggested that if ferritin dips below 20 ng/mL, performance begins to suffer. Worse yet, injury rates double when ferritin is less than 20 ng/mL and triple when less than 12 ng/mL.

One study had some good news. Iron deficient female runners were split into two groups: one given an iron supplement and the other a placebo. While the placebo runners continued to experience a drop in their performance, the iron supplemented runners improved. But the catch is it usually takes 2-3 months for iron to right itself; you can’t pop a pill or eat a big steak and feel better in the morning.

Warning: Excess iron is also not a good thing and can have far worse consequences. Before taking a supplement based on suspicions, get a blood test (make sure you specify ferritin to be checked as it isn't always reported) and discuss it with your doctor. A study found that among male marathoners, <2% had iron depletion, but 15%  had signs of excess iron. (On the other hand, 28% of female marathoners had iron depletion, <5% had signs of excess.) In addition, iron supplements are notoriously hard on your digestive system so ask your doctor for suggestions that may work for you. (My doctor suggested Vitron-C.) 

At first I thought I was grasping at straws but, as the evidence piled up, this seems like a common issue, especially among women runners. I had been thinking it was all in my head, that I just needed to stop being a wuss and toughen up. It may be a placebo effect (except I haven't even taken the pill yet!) but having a possible explanation and a plan of attack makes me feel better already.

Special Announcement: Do you enjoy Science Fridays? Do you live in the DC area? If so, come hear me talk about exercise and the brain on Tuesday, October 23 at 7:00 pm at the MLK Library. I’ll be discussing how running cures diseases, slows the aging process, and makes you feel all around spectacular—things you surely already know, but I can give you the hard facts for the next time your coworker says running is bad for your knees. More information about the series Hot Topics In Health Science here.

Dream big,

P.S. Shout out to the Flexatarian Filly for suggesting this months ago. It planted a seed, and I finally listened. Thanks!


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