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Iron Deficiency, Anemia and Performance

By Bob Seebohar

Iron is an extremely important mineral for good health and performance. The most important role iron plays is as a component of the protein hemoglobin, which carries oxygen from the lungs to the body’s cells. A higher level of iron can mean a higher aerobic capacity and better performance.

Maintaining iron balance can be difficult for some athletes because iron is lost through sweat, urine and the gastrointestinal tract. Iron stores are quite difficult to maintain in some athletes, especially endurance athletes (females more than males). And because the iron from foods and supplements is not fully absorbed, athletes must pay particular attention to the quality and timing of foods eaten to prevent iron deficiency anemia.

The easiest symptom to notice associated with iron deficiency anemia is fatigue that worsens with exertion. Fatigue is common and can have many different causes (such as other nutritional imbalances, illness or stress). If an athlete experiences normal fatigue throughout the day and is not worsened with exercise, the cause is likely not iron deficiency by itself. The following are also possible symptoms of iron deficiency anemia:

  • Decreased performance
  • Sleepiness and fatigue (outside of normal)
  • Poor concentration
  • Moodiness or irritability
  • Always feeling cold

Let’s Get Technical
A full laboratory blood iron panel is the best way to assess iron status. There a number of clinical markers that describe iron status including serum iron, red blood cell count, hemoglobin, hematocrit, total iron binding capacity and serum ferritin. Serum ferritin, a marker of stored iron, is not tapped into until levels of iron become too low to support demands. For example, if the body is using and excreting more iron than it is receiving from food, the ferritin level will slowly decline. If an iron deficiency is suspected, I recommend visiting a physician who specializes in working with endurance athletes and receive a complete blood count (CBC) and iron panel. 

Iron Periodization
Based on the lab and geographical region, normal ranges will differ so it is important to receive a baseline test. Ideally, this would be done during a transition cycle in their training program since there typically exists a linear relationship between iron stores and training status. Typically, high volume training can cause a decrease in iron stores; therefore, it is important to periodize iron intake from foods and possibly supplements based on training load changes. Normally, I recommend a 3-6 week iron focus including iron rich foods and possible supplementation prior to an increase in training load or extended stay at altitude. 

Improve the Ferritin Level
Training increases the demand placed on the body’s iron stores but depending on the athlete and current iron stores, it is possible to improve iron stores through a well structured eating program.  Heme iron (found in animal products) has the highest amount of iron and is absorbed in higher amounts in your body. Non-heme iron (found in non-animal products) is lower in iron and is absorbed in lesser amounts in your body.  Non-heme iron is regularly consumed by vegans or athletes not eating animal products. The following is a short list of heme and non-heme iron containing foods:

Heme Non-heme
Clams Enriched breakfast cereals and pasta
Oysters Beans
Sardines Dates and prunes
Shrimp Enriched pasta
Beef Green, leafy vegetables (spinach, kale)
Turkey Blackstrap molasses
Liver Pumpkin seeds
Kidney beans

As mentioned before, heme iron is absorbed better than non-heme iron. To increase the absorption of non-heme iron containing foods, have the athlete consume a source of vitamin C at the same time that a non-heme food source is eaten. For example, drink a glass of orange juice with spinach salad made with chickpeas and kidney beans or enriched pasta made with marinara sauce with crushed tofu added.

For athletes with diagnosed anemia, it may be important to not only focus on eating foods high in iron but also taking an iron supplement. Consult with a sports physician and a sports dietitian before doing so as there could be complications of iron overload. Taking iron supplements does not fall into the “more must be better” category and can have very dangerous side effects.  In addition, supplemental iron (found in multivitamins also) may cause constipation. There are many types of iron supplements and the type that is more absorbable with a lower dosage and has very few, if any, negative gastointestinal effects is ferrous bisglycinate, also called ferrochel. 

Replenishment of iron stores typically takes about 6-8 weeks and in most cases of low-grade iron deficiency, supplementation is not necessary. Emphasize the consumption of  iron rich foods with a good source of vitamin C accompanying it and be sure to have frequent blood tests performed if you are at risk for low iron stores and have these results interpreted by a qualified health professional.

Nutrition Periodization for Endurance AthletesBob Seebohar, MS, RD, CSSD, CSCS is a sport dietitian and elite triathlon coach.  He traveled to the 2008 Summer Olympics as the U.S. Olympic Committee Sport Dietitian and the personal Sport Dietitian for the 2008 Olympic Triathlon Team.  He is also Sarah Haskins' personal coach and was a performance team member (sport dietitian and strength coach) for Susan Williams, 2004 Olympic Triathlon Bronze Medalist.

Bob's book, Nutrition Periodization for Endurance Athletes: Taking Sports Nutrition to the Next Levelwill provide triathletes of all levels education on how to structure their nutrition program based on their exercise program. For more information, visit or contact Bob at