Iron isn’t well absorbed from plant sources, so it’s important for vegan and vegetarian athletes to frequently include foods in their menu that are higher in iron to meet their high iron needs.
TL;DR: Vegan athletes are often low in iron, as it’s best absorbed from animal sources. Check out the list below for high(er) iron sources for vegans and vegetarians, as well as a link to the Lucky Iron Fish! Need more personalized assistance? Contact Dr. Schubert!
What does iron do, why do we need it?
Iron is a major component of hemoglobin, the molecule that transports oxygen through the bloodstream from lung to tissue.1 Without oxygen, the amount of energy available in a cell is limited. More iron –> more functional hemoglobin –> more oxygen delivery –> more energy in cells –> more cellular functions can occur. It’s also part of myoglobin (same idea as hemoglobin, except moves oxygen around within muscle cells) and a wide variety of other enzymes and functions within the body.2
For athletes, this is particularly important, since athletes often put their bodies to the test, pushing their bodies to get bigger, stronger, faster. This requires energy – and oxygen – above and beyond that needed by more sedentary people.
What are the major forms of iron in the diet?
Hemoglobin, found in animals, contains 4 heme molecules within the protein structure. Each heme molecule contains one iron molecule, which binds to one O2 molecule. Each O2 molecule is two oxygen atoms bound together with a double bond. Therefore, each hemoglobin molecule has 8 oxygen atoms to provide to cells.
Non-heme iron sources are iron molecules bound to salts, or organic chelates, like ferrous sulfate, ferrous bisgycinate chelate (Ferrochel), ferrous gluconate (Floradix), or ferrous fumarate.
Absorption differences
Heme iron is more easily absorbed than non-heme iron, although rates of absorption are low in general for minerals and iron specifically. Around 14-18% of heme iron is absorbed while 5-12% of non-heme iron is absorbed.
The Meat, Fish, Poultry Factor (MFP Factor) is a side effect of protein digestion. Small segments of muscle protein high in cystine and histidine, as well as glutathione, have all been shown to improve iron absorption.3
Vitamin C increases absorption, regardless of source. So pair your iron source with foods high in vitamin C, such as citrus/ citrus juices, bell peppers, particularly red bell peppers, kiwi, broccoli, strawberries, tomatoes/ tomato juice, cantaloupe, cooked cabbage, and even potatoes!
In plants, several compounds reduce iron absorption. Phytates from grains and legumes and some polyphenols can both have this effect.2 That said, many people eat a fairly mixed diet, so it’s unclear how great the effects of these foods are unless you’re a strict vegan.
Why vegan athletes should care
Vegan athletes get less iron from their food (below) and have less access to high-volume sources. So they’re more likely to have anemia and the consequences of anemia, including fatigue, shortness of breath, feeling cold all the time, and worst, poor performance and slower progression toward athletic goals.
Plant sources with high(er) iron
| Food | Iron Content, mg |
| Edamame | 3 mg/oz powder |
| Tofu, firm | 3.5 mg/cup |
| Tempeh | 4.48 mg/cup |
| Soy protein isolate | 3 mg/oz powder |
| White beans | 7.83 mg/cup |
| Lentils | 6.59 mg/cup |
| Chick peas/ garbanzo beans | 4.74 mg/cup |
| Kidney beans | 5.2 mg/cup |
| Green peas | 2.46 mg/cup |
| Pumpkin seeds | 11.4 mg/cup |
| Sesame seeds | 21 mg/cup |
| Hemp seeds | 2.38 mg/cup |
| Pecans | 2.76 mg/cup |
| Walnuts | 2.91 mg/cup |
| Pistachios | 4.82 mg/cup |
| Cashews | 9.45 mg/cup |
| Almonds | 5.3 mg/cup |
| Peanuts | 5.71 mg/cup |
| Romaine lettuce | 0.46 mg/cup |
| Raw spinach | 0.82 mg/cup |
| Raw kale | 0.34 mg/cup |
| Tomato, red, raw | 0.49 mg/cup |
| Tomato paste | 7.81 mg/cup |
| Potato, cooked | 0.48 mg/cup |
| Sweet potato, cooked | 1.38 mg/cup |
| Mushrooms, white, raw | 0.48 mg/cup |
| Carrots, raw | 0.38 mg/cup |
| Palm hearts, canned | 4.57 mg/cup |
| Oranges | 0.17 mg/cup |
| Apple | 0.07 mg/cup |
| Watermelon | 0.37 mg/cup |
| Grapes | 0.54 mg/cup |
| Plums | 0.28 mg/cup |
| Prunes (dried plums) | 1.62 mg/cup |
| Prune juice | 3.02 mg/cup |
| Olives | 0.86 mg/cup |
| Strawberries, halved | 0.62 mg/cup |
| Mulberries | 2.59 mg/cup |
| Amaranth, cooked | 5.17 mg/cup |
| Spelt, cooked | 3.14 mg/cup |
| Oats, cooked | 2.11 mg/cup |
| Corn, cooked | 0.67 mg/cup |
| Quinoa, cooked | 2.76 mg/cup |
| Brown rice, cooked | 1.13 mg/cup |
| Coconut milk (cooking) | 7.46 mg/cup |
| Coconut milk (drinking) | 0.72 mg/cup |
| Soy milk, Silk plain | 1.07 mg/cup |
| Dark chocolate chips | 5.26 mg/cup chips |
| Milk chocolate chips | 3.95 mg/cup chips |
| Molasses | 15.9 mg/cup |
| Honey | 1.42 mg/cup |
| Dried thyme | 1.25 mg/tsp leaves |
| Fresh thyme | 0.14 mg/tsp leaves |
Fortified and enriched foods
Enriched: Nutrients lost during processing were added back after processing.
Fortified: Additional nutrients added that weren’t originally in the food.
| Food | Iron Content, mg |
| Cheerios, Original | 8.4 mg/cup |
| Flour, white | 5.8 mg/cup |
Cast iron pans and the Lucky iron fish
Does cooking in a cast iron pan help? It might, but results are inconsistent. It seems to vary with use of cast iron pan (the more you use one, the more iron exposure you have, not surprisingly), the age and size of the pan, and how familiar a study participant is with using cast iron as cookware.
Ingots, such as the Lucky Iron Fish or Leaf, are also popular. These are molded ferrous iron that is added to acidic cooking liquid so that the ferrous iron leaches out into the liquid. The liquid is consumed as soup or a decaf beverage, and iron is absorbed. Regular and frequent use is recommended, plus, in the case of the Lucky Iron Fish, you’re doing a good deed and fighting global anemia levels as well as your own!
Next Steps
Check your diet for iron sources. Are you getting enough? How about supplements? Is it actually included in any reasonable amount in any supplements you consume? And do you consume them daily, before your workouts?
Think about symptoms: fatigue, shortness of breath, feeling cold, poor training response (you’re putting a LOT of effort for little return). If you have any of these, see your doctor!
Add these things to your days: Vegan foods high in iron. Blackstrap molasses is your friend, as is coconut milk, tempeh, white beans and lentils, almonds and peanuts, tomato paste, prune juice and amaranth.
If you don’t want to have nightmares trying to figure out how to fit molasses, prune juice, amaranth and tempeh into a meal, reach out! You can contact me here. I can help you craft tasty, quick meals that meet your nutrient needs and fit around a training schedule.
If you’re thinking about becoming a vegetarian or vegan, read about the Pros and Cons of a Vegetarian Diet for Athletes! Or check out this blog on iron absorption! What you eat with iron and when you supplement make a difference!
References
- Gilman AD, Volpe SL. Vitamins, Minerals and Exercise. Karpinski C, Rosenbloom, CA, eds. In: Sports Nutrition: A Handbook for Professionals, 6th Ed. Academy of Nutrition and Dietetics; 2017: 95-96.
- Iron: Fact Sheet for Health Professionals. Updated March 30, 2021. https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/ Accessed on March 16, 2022.
- Hurrell RF, Reddy MB, Juillerat M, Cook JD. Meat Protein Fractions Enhance Nonheme Iron Absorption in Humans. J Nutr, 136(11):2006; 2808-2812.
- Geerligs PD, Brabin BJ, Omari AA. Food prepared in iron cooking pots as an intervention for reducing iron deficiency anaemia in developing countries: a systematic review. J Hum Nutr Diet. 2003;16(4):275-281. doi:10.1046/j.1365-277x.2003.00447.x
- Alves C, Saleh A, Alaofè H. Iron-containing cookware for the reduction of iron deficiency anemia among children and females of reproductive age in low- and middle-income countries: A systematic review. PLoS One. 2019;14(9):e0221094. Published 2019 Sep 3. doi:10.1371/journal.pone.0221094
- Sharma S, Khandelwal R, Yadav K, Ramaswamy G, Vohra K. Effect of cooking food in iron-containing cookware on increase in blood hemoglobin level and iron content of the food: A systematic review. Nepal J Epidemiol. 2021;11(2):994-1005. Published 2021 Jun 30. doi:10.3126/nje.v11i2.36682