Iron Improves Women's Exercise Performance

A new study(1) about iron supplementation and female athletic performance has been making the rounds – it shows that athletic women, who are iron deficient, but not anemic, benefit greatly from iron supplementation.

Iron deficiency occurs when the body’s stores of iron are low, but not so low that it leads to decreased red blood cell size and numbers (anemia). Anemia results in poor oxygen delivery, as iron is necessary to build the protein hemoglobin that carries oxygen on the red cells.

This newer study is interesting, because the standard line in conventional medicine is that despite symptoms of anemia, women who present this way (fatigue, shortness of breath, pale skin, poor performance, etc) are rarely treated, if at all. Usually they’re told to go home, rest and quit exercising so much. !!

Why is this? Part of the reason lies in test-centered and “evidence-based” medicine which leaves no room for functional medical interventions and dictates that patients are treated only if they have a strictly defined diagnosis.

However, this new study (and a few others)(2,3) shows that even if athletic women aren’t frankly anemic, they will feel better if their iron stores are increased.

This makes sense because iron is necessary for our red blood cells to make hemoglobin, the protein that carries oxygen on the red cells. The more able we are to carry oxygen and deliver it to working cells, the better we can function.

Non-anemic iron deficiency occurs when iron stores get too low – not so low that the red blood cells become affected, but low enough to start causing symptoms of apparent anemia. And this is the problem – a person may complain of anemia symptoms, but their blood tests don’t show it – so they aren’t treated. Here's more information about the causes of anemia and diagnosis.

These new studies are great for a few reasons. First, it demonstrates that iron deficiency in female athletes should be treated and has good benefits. Second, it lends further credence to functional medicine, where more emphasis is focused on treating the individual patient, rather than lab results alone.

But before you go supplementing with iron, there’s a few things you should know:

1. These studies looked at women only. Generally, it is much more rare for men to be iron deficient. Women have a higher risk of iron deficiency due to monthly menstrual blood loss.

2. Iron is dangerous stuff. Taking too much, you can easily become toxic. And iron overdose is a leading cause of death in toddlers. So if you have iron supplements at home, keep them away from toddlers!

3.Testing for iron-deficiency is different than testing for anemia. If you’re suspicious that you may be iron deficient, you need a full iron panel AND a ferritin. It’s the ferritin test, in combination with the iron panel that will show if you’re iron-deficient, rather than anemic. Don’t let your doctor blow you off; this is how we can catch small things on labs that make a world of difference in performance!

4. If you are iron deficient and or anemic, the cause needs to be ruled out. Sometimes it’s a combination of diet and heavy menses. Other times bleeding in the GI tract may cause it. So be prepared to undergo more testing if you are found to be anemic.

5. Again, careful with iron supplementation. Too much can prolong infections (bacteria like to feed on it) and cause a ton of other problems. So don’t supplement unless you have a demonstrated need for it!

And if you aren't iron deficient, make sure you do eat some iron-rich foods to keep some on board. The iron found in animal products (referred to as heme iron) is better absorbed than the iron found in plants (non-heme iron).  

Good plant sources of iron include dark green leafys, olives, beans, nuts and seeds.

Vitamin C improves absorption of iron, so keep that in mind if you supplement or eat iron-rich foods.

1. Pasricha, SR, et al. Journal of Nutrition, 2014 Apr 9.  Iron Supplementation Benefits Physical Performance in Women of Reproductive Age: A Systematic Review and Meta-Analysis.

2. Reinke S, et al. Int J Cardiol. 2012 Apr 19;156(2):186-91.  Absolute and functional iron deficiency in professional athletes during training and recovery.

3. Dellavalle DM, et al.  Med Sci Sports Exerc. 2012 Aug;44(8):1552-9. Iron status is associated with endurance performance and training in female rowers.