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Low Iron

By Dr. Christine Rosenbloom

Athletes may sometimes feel as if their body is working against them when it comes to nutrition. The effects of deficiencies, allergies, and aging can be great. A diet that was once helping to optimize performance may now be causing performance to suffer.

But athletes should not fear. Once recognized, anything the body throws at an athlete can be handled with careful changes to their dietary regimen. It may not be easy at first, and the athlete may need to relearn how to fuel their body, but if their diet is tweaked correctly, performance will improve.

In the following case studies, three sports dietitians share how they each helped an athlete conquer a dietary issue. In all three cases, the athletes got back on track to athletic success.

Running Low on Iron

By Dr. Christine Rosenbloom

(Christine Rosenbloom, PhD, RD, CSSD, is the Sports Dietitian at Georgia State University and Owner of Chris Rosenbloom Food & Nutrition Services. She is also Professor Emerita at Georgia State and was the Editor in Chief of Sports Nutrition: A Practice Manual for Professionals, 5th edition. She can be reached through her Web site

A high school cross country and track and field athlete, Miranda became a vegetarian because she read about the health benefits associated with a plant-based diet. She also hoped it would help her lose five pounds and get her to her self-determined “ideal” body weight.

However, after successful sophomore and junior seasons, Miranda was struggling in her senior year of high school. The 5,000- and 10,000-meter specialist complained of fatigue, shortness of breath during exercise, cold intolerance, and an inability to fully recover between training runs.

Miranda’s physician diagnosed her with an iron deficiency (her hemoglobin was 10.3 g/dL, hematocrit 34 percent, transferrin 371 mg/dL, and ferritin 8 ng/mL) and suggested she see a Registered Dietitian for a nutrition consultation. When I initially met with Miranda, I reviewed her complete blood count and asked her to write down everything she ate for three days.

Along with revealing a lack of iron from food choices, her food record showed she was not eating enough carbohydrate and protein to sustain her training. She did have normal menses and was taking calcium carbonate gummies (500 mg/day). I explained to her that because she was not getting enough iron, her body was not able to carry enough oxygen to her muscles (hemoglobin) or make enough oxygen reserve in muscles (myoglobin), resulting in early fatigue and lack of energy.

Iron depletion in tissues can also cause cold intolerance and reduced exercise endurance. By not eating enough carbohydrate and protein, her body was not able to provide the building blocks to make the iron-carrying proteins or replenish glycogen stores in her muscles after a workout. I recommended she do the following:

Increase calorie intake. Miranda was consuming just 1,600 calories per day, but based on her age, training volume, and frequency of competitions, a calorie range of 2,600 to 2,800 per day was much more appropriate. We started by increasing her intake to 2,100 calories a day by adding snacks between meals. After two weeks, we bumped it up to 2,350 calories by increasing the portion sizes of her meals.

Increase carbohydrate intake. Miranda was consuming 192 grams of carbohydrate per day, which equaled 3.9 grams per kilogram of her body weight. The goal was to up that to 5 g/kg, and possibly to 6 or 7 g/kg as her training increased. We added carbohydrate-rich snacks between meals to help her accomplish this goal. Her favorites were dried fruit, granola bars, yogurt, and whole grain fruit muffins.

Increase protein intake. Miranda was taking in 56 grams of protein per day, which translates to 1.1 grams per kilogram of her body weight. She needed 1.5 g/kg to provide adequate protein for endurance exercise and for hemoglobin synthesis. She added yogurt smoothies after workouts, snacked on nuts, and we identified vegetarian protein-rich options like beans, lentils, soy nuts, and veggie burgers that would fit her dietary restrictions.

Increase iron intake. This was the main area of concern for Miranda, and probably the most difficult. Her average dietary iron intake was 8.2 milligrams per day and it needed to be 15 mg/day to reach the Recommended Dietary Allowance. She was prescribed 325 milligrams of ferrous sulfate once daily for three months. But she also needed to learn how to increase iron in a vegetarian diet. One strategy was to simply eat more iron-rich plant foods. I gave her this list for ideas:

  • Instant oatmeal

  • Fortified breakfast cereals

  • Long-grain enriched rice

  • Vegetarian baked beans

  • Lentils

  • Soy crumbles and soy burgers

  • Trail mix with raisins

  • Bean burrito

  • Chili with beans

  • Chick peas

  • Hummus

  • Black beans

  • Fat-free refried beans

  • Clam chowder

  • Lima beans.

A second strategy was to add more vitamin C (ascorbic acid) to her diet since it is a potent enhancer of iron absorption. It can change iron to a more absorbable form, giving the body up to three times more iron than when taken without vitamin C. Easy ways to add vitamin C include drinking orange juice with breakfast, adding peppers and salsa to a bean burrito, slicing strawberries into cereal, and eating a citrus fruit salad with a bowl of vegetarian bean chili.

We also talked about foods that can block iron absorption. Tea, coffee, and cocoa contain polyphenolic compounds that have some health benefits, but can block non-heme iron absorption. To get the most iron from her meals, I advised Miranda to choose beverages that don’t fight iron absorption such as water, citrus-based sparkling waters, and fruit juices. I told her to enjoy her coffee, tea, or cocoa only between meals.

Another discussion was about an “ideal” weight for a runner. Miranda was 5-foot-3 and 108 pounds, which is at the low end of the body mass index but still a healthy weight for her height and sport. We discussed that there is no “ideal” weight for an athlete and that performance is not tied to a specific body weight or body fat level. What was most important was how she was performing. She acknowledged that she was eating too little to maintain 108 pounds and that she ran better when she weighed 112 pounds.

Miranda reversed her iron deficiency anemia through supplementation and changes to her diet. She began to feel better and reported having more energy as the weeks progressed. She remained a vegetarian, but occasionally included fish in her diet and stuck with five to six small meals a day to boost calorie and nutrient intakes. Miranda was able to regain her endurance and energy and was a valuable part of the cross country and track and field teams. She is currently a college freshman and running on her university’s team.

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