Gabriella Rao, RD

I’ve decided that I’m going to do a small micronutrient series over the next few weeks to talk about a few of the micronutrients which are particularly important for endurance sport. The first micronutrient we’re going to talk about, one with which I have a rocky relationship, is IRON!

Functions of Iron:

• Plays a huge role in red blood cell health
• A component of hemoglobin, a protein on red blood cells that transfers oxygen from the lungs to tissues
• A component of myoglobin, another protein that provides oxygen and helps support muscle metabolism
• Necessary for growth, neurological development, cell function, hormone synthesis

Heme vs Non-Heme Iron:

• Heme iron —> found only in animal products (e.g., meat, seafood, poultry)
  • More bioavailable
• Non-heme iron —> comes from plant sources (e.g., beans, seeds, fortified grains, dark leafy greens, tofu, dark chocolate)
  • Less bioavailable than heme iron
  • BUT its absorption can be enhanced when eaten in combination with vitamin C-containing foods (citrus fruits/juices, bell peppers, strawberries, broccoli, Brussels sprouts)

Ferritin: the storage form of iron

• Currently the most efficient and cost effective lab for diagnosing iron deficiency
• The “serum iron” lab only tells you how much iron is in your blood, which is very much dependent on your recent food/supplement intake, how recently you’ve exercised, etc. This is why ferritin is a much better indicator of iron status!
• Ferritin values <30 mcg/L indicate iron deficiency, whereas values <10 mcg/L indicate iron-deficiency anemia
  • HOWEVER, as an endurance athlete, optimal ferritin is >50 mcg/L. If your ferritin is lower than this, it’s possible the you might begin to experience symptoms of iron deficiency (which is much more noticeable as people who exercise frequently)

Symptoms of Iron Deficiency:

• Fatigue
• Feeling sluggish during endurance efforts
• Cold hands and feet
• Headaches
• Brittle nails or hair loss
• Abnormal paleness
• Irritability 

What to do if you think you may be iron deficient:

• Get some labs!!!
  • When you go to the doctor and tell them you think you have low iron, they will typically assess hemoglobin and hematocrit. These labs are often late to the game — by that I mean that by the time your hemoglobin or hematocrit levels are abnormal, you are likely very deep in the iron deficiency hole.
  • The best lab to assess for early signs of iron deficiency is ferritin — ask your doctor for this lab, as they sometimes will not order it
  • Request a full iron panel (serum iron, ferritin, total iron binding capacity (TIBC), transferrin saturation)
• Add more iron-rich foods into your diet 
  • Heme iron sources: lean red meat, liver, oysters, clams, sardines
  • Non-heme iron sources: lentils, beans, spinach, fortified cereals and grains, pumpkin seeds, molasses, cashews, dried fruits, tofu
• If you are very deficient based on your ferritin level, work with your RD or doctor to obtain an appropriate supplement — never supplement blindly!
  • Trying to improve your iron status through food first is ideal, though sometimes we need a short (6-8 week) stint on an iron supplement to get our bodies back from a deep iron deficiency hole
  • Always make sure any supplement you take is third-party approved (meaning that it has been tested in a lab to ensure that it contains the correct ingredients in the amounts advertised on the label)

Oh yes, I mentioned before that I have a rocky relationship with iron. Some of you may have been wondering about that — in my second year of running, I started experiencing extreme fatigue and my race times began to suffer. I got my ferritin assessed, and it was a 4! I had to get two IV iron infusions to get me back to normal. That experience is what initiated my interest in nutrition and led me on the path to becoming an RD!