Introduction
Getting enough dietary iron is important for all athletes (see Iron & Athletes Part I for more information). To see general daily iron requirements, which vary by sex, gender and age, click here. In addition, keep in mind that vegetarians need 1.8 times the Recommended Daily Allowance (RDA) of iron shown in this table due to the lower absorption rate of plant-based or non-heme iron. Thus, if you are a 36-year-old female vegetarian, you need to consume 33mg of iron as opposed to the 18mg recommended for a female meat eater of the same age (NIH). While individuals without a deficiency simply need to focus on meeting the Recommended Daily Allowance for iron, athletes with depletion or deficiency will benefit from being more cognizant of iron inhibitors and enhancers.
Getting enough dietary iron is important for all athletes (see Iron & Athletes Part I for more information). To see general daily iron requirements, which vary by sex, gender and age, click here. In addition, keep in mind that vegetarians need 1.8 times the Recommended Daily Allowance (RDA) of iron shown in this table due to the lower absorption rate of plant-based or non-heme iron. Thus, if you are a 36-year-old female vegetarian, you need to consume 33mg of iron as opposed to the 18mg recommended for a female meat eater of the same age (NIH). While individuals without a deficiency simply need to focus on meeting the Recommended Daily Allowance for iron, athletes with depletion or deficiency will benefit from being more cognizant of iron inhibitors and enhancers.
Food Sources and Types of Iron
Food sources of iron include the following: meat, seafood, poultry; iron-fortified breakfast cereals, breads and bars; white beans, lentils, spinach, kidney beans, peas, nuts, seeds (i.e. pumpkin and sesame seeds), soy protein and some dried fruits such as raisins and apricots. There are two forms of iron: heme iron and non-heme iron. Heme iron is the organic form of iron found in meat, seafood and poultry; approximately 15% of heme iron is absorbed. Non-heme iron is found in plant foods and iron-fortified products. The absorption rate of non-heme iron ranges from 3-8% depending on the presence of absorption enhancing factors (Mahan). The RDA for iron takes into account absorption rates, so don’t worry that you now need to start doing advanced math to calculate iron intake and absorption. As we mentioned above, vegetarians have a higher RDA for iron due to lower absorption rates of plant-based iron. As you look at % Daily Value on nutrition labels, know that this is based on the RDA’s value of 18mg/day (the RDA for women 19-50 years of age).
Food sources of iron include the following: meat, seafood, poultry; iron-fortified breakfast cereals, breads and bars; white beans, lentils, spinach, kidney beans, peas, nuts, seeds (i.e. pumpkin and sesame seeds), soy protein and some dried fruits such as raisins and apricots. There are two forms of iron: heme iron and non-heme iron. Heme iron is the organic form of iron found in meat, seafood and poultry; approximately 15% of heme iron is absorbed. Non-heme iron is found in plant foods and iron-fortified products. The absorption rate of non-heme iron ranges from 3-8% depending on the presence of absorption enhancing factors (Mahan). The RDA for iron takes into account absorption rates, so don’t worry that you now need to start doing advanced math to calculate iron intake and absorption. As we mentioned above, vegetarians have a higher RDA for iron due to lower absorption rates of plant-based iron. As you look at % Daily Value on nutrition labels, know that this is based on the RDA’s value of 18mg/day (the RDA for women 19-50 years of age).
Food Substances that Enhance Iron Absorption
If you are in an iron-depleted or -deficient state and wanting to enhance iron absorption, vitamin C rich foods, such as citrus fruits, strawberries, sweet peppers, tomatoes, and broccoli can increase non-heme iron absorption rates. In addition, eating sources of heme iron such as meat, fish and poultry along side non-heme iron food sources, can increase absorption (NIH).
If you are in an iron-depleted or -deficient state and wanting to enhance iron absorption, vitamin C rich foods, such as citrus fruits, strawberries, sweet peppers, tomatoes, and broccoli can increase non-heme iron absorption rates. In addition, eating sources of heme iron such as meat, fish and poultry along side non-heme iron food sources, can increase absorption (NIH).
Inhibitors of Iron Absorption
It is also important to understand that certain foods and food ingredients inhibit iron absorption. Tannins in commercial black and pekoe teas as well as polyphenols in coffee can reduce iron absorption by as much as 50%. Therefore, athletes in a depleted or deficient state should make sure there is at least one hour between coffee/tea consumption and iron-rich meals (Mahan). In addition, all athletes should be sure that they are not over-doing it on coffee and tea. Oxalic acid found in foods such as spinach and chocolate as well as phytic acid found in wheat bran and legumes (beans) can also decrease the absorption of non-heme iron. Of course, this is a bit confusing as spinach and legumes are listed as good iron sources—remember the absorption rates for non-heme iron mentioned above, which take into account iron inhibitors found in plant sources of iron. Finally, calcium carbonate supplements and dairy products decrease the absorption of iron. Therefore, if you are experiencing iron depletion or deficiency, make sure there is at least one hour between consumption of dairy products and consumption of iron-rich meals and snacks.
It is also important to understand that certain foods and food ingredients inhibit iron absorption. Tannins in commercial black and pekoe teas as well as polyphenols in coffee can reduce iron absorption by as much as 50%. Therefore, athletes in a depleted or deficient state should make sure there is at least one hour between coffee/tea consumption and iron-rich meals (Mahan). In addition, all athletes should be sure that they are not over-doing it on coffee and tea. Oxalic acid found in foods such as spinach and chocolate as well as phytic acid found in wheat bran and legumes (beans) can also decrease the absorption of non-heme iron. Of course, this is a bit confusing as spinach and legumes are listed as good iron sources—remember the absorption rates for non-heme iron mentioned above, which take into account iron inhibitors found in plant sources of iron. Finally, calcium carbonate supplements and dairy products decrease the absorption of iron. Therefore, if you are experiencing iron depletion or deficiency, make sure there is at least one hour between consumption of dairy products and consumption of iron-rich meals and snacks.
Iron-Rich Snacks and Meals
As an athlete, snacking is important to fuel workouts, get sufficient nutrition (including iron) and stay energized throughout the day. Here are five ideas for iron-rich snacks:
As an athlete, snacking is important to fuel workouts, get sufficient nutrition (including iron) and stay energized throughout the day. Here are five ideas for iron-rich snacks:
1. (Great pre-workout snack) 1c Multi-grain Cheerios + 1/2c Strawberries + 1c almond milk
2. (Great recovery snack or meal) Turkey sandwich with 3-4oz turkey + tomato + spinach + whole wheat bread + avocado
3. (Great at work/school snack) 1/4c Walnuts + 1c Blueberries
4. (Great at work/school snack) 1/8c Pumpkin seeds + 2 clementine oranges
5. (In a pinch) Bars with 10% or more of the daily value (DV) for iron (18mg is the DV)
- Go Raw Bar, Dark Chocolate (240kcal, 2.7mg iron [15% DV], 12g protein, 24g Carb)
- Tigers Milk Peanut Butter (150kcal, 3.6mg iron [20% DV], 6g protein, 18g carb)
- Go Raw Pumpkin Seed Sprouted Bar (240kcal, 1.8mg iron [10% DV], 9g protein, 16g carb)
- Luna Protein, Chocolate Chip Cookie Dough (190kcal, 5.4mg iron [30% DV], 12g protein, 21g carb)
- Luna Protein, Chocolate Peanut Butter (190kcal, 5.4mg iron [30%], 12g protein, 19g carb)
- Rx Bar, Peanut Butter Chocolate (210kcal, 2mg iron [10% DV], 12g protein, 21g carb)
In addition visit our Pinterest page for iron-rich recipe ideas: https://www.pinterest.com/katiebrookselliott/iron-rich-recipes/.
Conclusion
Getting enough iron is not difficult so long as athletes understand requirements, develop a plan to take in adequate nutrition and get sufficient calories. If you are an athlete, who is experiencing iron deficiency or depletion, you can further optimize your efforts to restore iron levels by paying attention to both enhancers and inhibitors of iron absorption. If you are not struggling with iron issues, aim to get the RDA for iron each day and have your levels checked periodically to stay on top of things. One easy way to determine how much iron you are getting each day is to record your meals and snacks in My Fitness Pal and select iron as a nutrient you want to review. This will give you a baseline for how you are doing. Another option is to work with a Registered Dietitian (RD) to create a plan to meet all of your fueling and nutrient needs (click here to contact us if you are interested in such a plan).
Getting enough iron is not difficult so long as athletes understand requirements, develop a plan to take in adequate nutrition and get sufficient calories. If you are an athlete, who is experiencing iron deficiency or depletion, you can further optimize your efforts to restore iron levels by paying attention to both enhancers and inhibitors of iron absorption. If you are not struggling with iron issues, aim to get the RDA for iron each day and have your levels checked periodically to stay on top of things. One easy way to determine how much iron you are getting each day is to record your meals and snacks in My Fitness Pal and select iron as a nutrient you want to review. This will give you a baseline for how you are doing. Another option is to work with a Registered Dietitian (RD) to create a plan to meet all of your fueling and nutrient needs (click here to contact us if you are interested in such a plan).
Bio
Katie Elliott, MS, RD, is the founder of Elliott Performance and Nutrition, based in Aspen, Colorado, and also works with clients at Achieve Health and Performance in Basalt, Colorado. Katie’s knowledge areas and counseling specialties include sports nutrition, nutrition for prevention and treatment of disease, weight loss, and worksite wellness initiatives and programs. In addition, Katie attended IMG Academies as a junior tennis player, played Division I tennis at Davidson College, has competed on numerous amateur world triathlon teams and has coached athletes to several podium finishes as a USA Triathlon Coach.
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References
Coates, A., Mountjoy, M., & Burr, J. (2016). Incidence of iron deficiency and iron deficient anemia in elite runners and triathletes. Clin J Sport Med.
Coates, A., Mountjoy, M., & Burr, J. (2016). Incidence of iron deficiency and iron deficient anemia in elite runners and triathletes. Clin J Sport Med.
Eichner R. Anemia and female athletes. Sports Med. Dig. 2000; 22:57.
Mahan, L. Kathleen, Escott-Stump, Sylvia, Raymond, Janice L. (2012). Krause’s Food and the Nutrition Care Process, Edition 13. Elsevier Saunders.
Mayo Clinic. Ferritin Test. Feb.10, 2017. Retrieved from: http://www.mayoclinic.org/tests-procedures/ferritin-test/details/results/rsc-20271960.
NIH. Iron Dietary Supplements Factsheet for Health Professionals. (Feb. 11, 2016). Retrieved from: https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/.
NIH. Iron Fact Sheet For Consumers. (Feb 17, 2016). Retrieved from: https://ods.od.nih.gov/pdf/factsheets/Iron-Consumer.pdf.
Rosenbloom, C., & Coleman, E. (2012). Sports Nutrition: A Practice Manual for Professionals. (5th ed.). Chicago, Illinois: Academy of Nutrition and Dietetics.
