Iron Deficiency: An Under-Recognized Condition in Female Athletes

Up to 35% of female athletes (and up to 52% of adolescent female athletes) have iron deficiency. While iron deficiency doesn’t necessarily mean iron-deficiency anemia (a low concentration of red blood cells or hemoglobin), it’s still a concern for endurance athletes — or anyone who exercises, says Caitlin Lewis, MD, of Cleveland Clinic Sports Medicine Center.

“Iron deficiency in women athletes is not discussed enough,” she says. “It’s definitely under recognized in both adults and teens, including anyone who has menses.”

Female athletes are at high risk for iron deficiency not only due to blood loss with menstruation, but due to food restrictions that are common when training for athletic competition.

“Even if they’re eating iron sources such as legumes and fortified foods, females often are not consuming enough iron, especially if avoiding red meat,” says Dr. Lewis. “The body absorbs iron from animal sources at a much higher rate than iron from nonanimal sources.”

When to suspect iron deficiency

Iron is important for the formation of red blood cells, but also for energy production (metabolism) and brain performance, including concentration and cognition. Patients with low iron commonly present with complaints of low energy, fatigue, decreased endurance or generally reduced athletic performance.

As part of a complete workup, Dr. Lewis assesses:

• Complete blood count with differential (including hemoglobin concentration)
• Reticulocyte count (the number of immature red blood cells in bone marrow)
• Serum ferritin
• Serum iron
• Iron panel (including transferrin saturation and total iron-binding capacity [TIBC])

Low serum ferritin and low serum iron can indicate iron deficiency. Low hemoglobin and high TIBC can indicate iron-deficiency anemia.

“There’s been a trend in cross country coaches and other endurance coaches asking physicians to assess ferritin levels in all their athletes,” says Dr. Lewis. “But determining iron deficiency requires more than that. Ferritin levels can be falsely normal, and normal ferritin levels can be masked as deficient or elevated.”

In addition, Dr. Lewis does not advise checking levels in asymptomatic patients.

“You don’t check it just to check it,” she says. “We don’t want to unnecessarily supplement our athletes. I may check iron levels in professional or elite athletes, but not across the board, not even for my college athletes.”

Treating iron deficiency

If iron deficiency or iron-deficiency anemia is diagnosed, the next step is identifying the cause. Dr. Lewis evaluates possible causes including:

• Low dietary intake
• Poor absorption
• Heavy menstrual periods
• Foot-strike hemolysis
• Acute inflammation with activity (which can stimulate hormone changes that decrease iron stores)

In addition to addressing the cause, iron supplementation usually is advised.

“I prefer whole-food supplementation, but it’s often difficult to consume enough iron through food, given dietary preferences,” says Dr. Lewis. “Most female athletes should be consuming 18 mg of iron per day. Considering that a 120 g hamburger patty provides only 3.5 mg of iron, it’s no wonder that iron deficiency is so common — and that so many female athletes take iron supplements.”

Basic supplementation is 100 mg of iron per day, she says. If gastrointestinal side effects like upset stomach and constipation are troublesome, every-other-day supplementation may be just as effective.

Dr. Lewis advises her patients to take oral iron supplements with orange juice since vitamin C assists with iron absorption. If oral supplementation isn’t tolerated or if iron isn’t being absorbed sufficiently through the gut, iron infusions can be provided intravenously.

A caution about supplementation

Patients should be cautioned about banned-substance contamination in over-the-counter supplements, especially if they anticipate drug testing, she notes.

“Athletes must ensure that the supplements they are taking are pure,” says Dr. Lewis. “Encourage them to check third-party verifiers, even for supplements purchased from chain pharmacies or supplement stores. Manufacturers sometimes add substances to boost the perceived effectiveness of their products. Even some electrolyte packets have been found to contain banned substances.”