Why all athletes should get their iron checked routinely
Running and Iron
Are you feeling fatigued, exhausted and disappointed in your results? Not surprising, given the events of the past year, but fatigue and poor performance could also be pointing to iron deficiency. Red blood cells carry oxygen around the body, and those cells require iron to bind oxygen. That’s why iron is particularly important for athletes, who may lose it through their sweat and urine, as well as from the pounding of their feet. Women also lose iron thanks to menstruation. And if you’ve been diagnosed with red-s (relative energy deficiency in sport) or lea (low energy availability), that can also cause lower iron status and poor absorption.
All athletes should get routine bloodwork done, preferably before they start training. Iron is one of those important minerals that may need to be supplemented if you don’t get enough from your diet, since it can’t be made in the body. In athletes, low iron reportedly affects between three and 11 per cent of males and between 15 and 35 per cent of females.
Iron comes in two forms: heme, from animal sources, like beef, tuna, chicken and pork, and non-heme, from plant sources, like spinach, dried fruit, legumes and almonds. Our bodies can only absorb around 12 per cent of the dietary iron we consume, so when athletes are deficient, it’s very important to supplement. Because non-heme iron is even less well absorbed than heme iron, vegan and vegetarian athletes need even more.
Nutrition can be tricky: citrus fruits, broccoli and tomatoes and carotenoids from foods such as pumpkin and carrots help maximize non-heme iron absorption, but certain compounds in healthy foods actually interfere with iron absorption: examples are calcium, phytates (found in whole-grain cereals, nuts, legumes and seeds) and polyphenols (found in tea, coffee, red wine and chocolate). Zinc, high in many healthy foods, also competes for absorption. If your bloodwork shows low iron, the answer is not to avoid these foods, but to start supplementing.
Serum ferritin is the storage form of iron in the body and is the most widely used marker when testing. Iron deficiency is defined as anything below 35 μg/l ferritin, with normal hemoglobin levels. (Hemoglobin is a protein in red blood cells that carries oxygen from the lungs to the body’s organs and tissues and transports carbon dioxide back to the lungs.) Both ferritin and a complete blood count ( cbc) should be assessed with bloodwork.
The best iron supplements are ferrous salts (ferrous sulphate, gluconate or fumarate), because they are absorbed well and are widely available and cost-effective. 100 mg of oral iron (ferrous salts) taken daily is ideal. Ferrous sulphate is considered the gold standard, but may cause an upset stomach. If this is an issue, new research shows taking the supplement on alternate days may be just as effective (or try switching to ferrous gluconate, which may be easier on your stomach). It’s best to take your supplement in the morning or within 30 minutes of exercising. If your iron status has not improved three or four months after you begin oral supplementation, parenteral (intravenous) iron supplementation may be necessary. (Consult your doctor.)
All athletes can benefit from a consultation with a sports dietitian for nutritional analysis and counselling. Finding the right combination of iron can sometimes require some experimentation with timing and with different types, in consultation with your healthcare professional.