Tired – as in extremely, consistently fatigued. Run down. Washed out. Pale. Diminished appetite. Performances spiralling downward. Reduced endurance. Cold hands and feet. Headaches. Light-headedness. Irritability. Repeated infections.
Any of these sound like you? If so, you may be low on iron. Iron is a trace mineral required for energy and endurance. At any one time, there should be 3-5 grams of circulating in our bodies. The majority of iron in our body is found as hemoglobin, in our blood, vital for the transportation of oxygen. It is also found as myoglobin, in our muscles, for oxygen management, and as ferritin, the storage form of iron.
It is a fact that many runners struggle with low iron stores. The Journal of Internal Medicine published a study showing systemic iron deficiency was found in 56% of the runners they tested. And why might that be?
Maybe their diet wasn’t supplying enough. Louise Burke in Clinical Sports Nutrition outlines vegetarians (no red meat, aka heme iron), natural food eaters (no iron-fortified foods), fad dieters and calorie restricted dieters all at risk for iron-deficiency. Just to be clear, that doesn’t mean the first two are ‘bad’, you just need to pay a bit of extra attention to your diet. For the record, I don’t recommend fad diets or calorie restriction.
Runners are also known to lose iron in sweat, through gastrointestinal bleeding, and through breakdown of red blood cells caused by the ‘trauma’ of repeated foot strikes on hard surfaces.
And then there’s the hormone hepcidin which is produced by the liver. Its role is to reduce iron levels and hinder the body’s efforts to store iron. The problem is that a study published in the International Journal of Sport Nutrition and Exercise Metabolism showed hepcidin spiked in runners who run longer than 60 minutes and stay elevated for up to six hours afterwards, meaning any iron consumed in that time period may not be well absorbed.
However, if you think you might be low in iron, never (ever) self-diagnose. The only way to know for sure is to get a blood test done and have your doctor diagnose you. There are dangers to supplementing with iron if you are not iron-deficient. According to Austin and Seebohar in Performance Nutrition, large doses of iron both create free radicals which damage body tissues and may lead to zinc deficiency, since zinc and iron compete for absorption in the body. And too much iron can lead to hemochromatosis in some people. One in 250 people is said to have this genetic disorder which results in a gradual, organ-damaging buildup of stored iron, increasing the risk of diabetes, heart attack, cancer, Alzheimer’s and Parkinson’s.
Diet is important in getting enough iron, but so is gastrointestinal health. It’s not just about what you eat, but what you absorb. A healthful diet is one that both supports our gastrointestinal health and provides iron. Of course there’s two types of iron: heme iron, found only in meat, and non-heme iron, found in plant sources. The National Institutes of Health claim heme iron is absorbed at a rate of 15 to 35 percent and non-heme at a rate of 2 to 20 percent. It is interesting to note, however, that iron is absorbed at a greater rate when the body requires it. However, if not enough iron-rich foods are being consumed, the result will eventually be iron-deficiency.
Sometimes, you might be eating enough iron but it’s just not getting absorbed. Think about the hormone hepcidin mentioned above, which affects all types of iron from being absorbed post-run.
Further, in order to absorb non-heme iron – which typically enters the body in the ferric form – it must be reduced to a ferrous form before absorption. Vitamin C is known to act as a reducing agent, but better yet, so is hydrochloric acid (your stomach acid). The problem is many people suffer from hypochlorhydria, or in other words, low stomach acid.
So if you’re tired, not performing well, and think you may be low on iron, it’s time to make a trip to the doctor’s office and get your blood levels checked. In the meantime, choose from these iron-rich sources of food:
- Venison (3 oz) – 3.8 mg heme iron
- Lentils, uncooked (1/4 cup) – 3.8mg non-heme iron
- Blackstrap molasses (1 Tbsp) – 3.6 mg non-heme iron
- Spinach, boiled (1/2 cup) – 3.2 mg non-heme iron
- Lean beef sirloin (3 oz) – 2.9 mg heme iron
- Red kidney beans, cooked (1/2 cup) – 2.6 mg non-heme iron
- Tahini (2 Tbsp) – 2.6 mg non-heme iron
- Pumpkin seeds (1 oz) – 2.5 mg non-heme iron
- Chickpeas, cooked (1/2 cup) – 2.3 mg non-heme iron
- Asparagus (6 spears) – 2.1 mg non-heme iron
- Tofu, firm (1/2 cup) – 2 mg non-heme iron
- Quinoa, uncooked (1/4 cup) – 2 mg non-heme iron
- Potato with skin (1 large) – 1.9 mg non-heme iron
- Cashews, raw & unsalted (1 oz) – 1.9 mg non-heme iron
- Skinless chicken breast (3 oz) – 1.8 mg heme iron
- Spinach, raw (2oz /2cups) – 1.6 mg non-heme iron
- Artichokes (1) – 1.6 mg non-heme iron
- Tomato sauce, plain (1/2 cup) – 1.3 mg non-heme iron
- Kale, cooked (1 cup) – 1.2 mg non-heme iron
- Almond butter (2 Tbsp) – 1.2 mg non-heme iron
- Kale, raw (1 cup chopped) – 1.1 mg non-heme iron
- Rolled oats, dry (1/3 cup) – 1.1 mg non-heme iron
- Almonds, raw & unsalted (1 oz) – 1 mg non-heme iron
- Tomato paste (2 Tbsp) – 1 mg non-heme iron
- Egg (1 large) – 0.9 mg non-heme iron
- Raisons (1/4 cup) – 0.9 mg non-heme iron
- Potato without skin (1 large) – 0.9 mg non-heme iron
- Green beans (1/2 cup) – 0.8 mg non-heme iron
- Apricots, dried (5 halves) – 0.8 mg non-heme iron
- Chia seeds (1 Tbsp) – 0.7 mg non-heme iron
- Cocoa powder (1 Tbsp) – 0.7 mg non-heme iron
- Beets (1 med) – 0.7 mg non-heme iron
- Yam (1 cup cubed) 0.7 mg non-heme iron
- Salmon (3 oz) – 0.7 mg heme iron
- Dates (3) – 0.6 mg non-heme iron
- Avocado (1/2 a fruit) – 0.5 mg non-heme iron
For the record, the established recommended daily intake for iron is 8 mg per day for men and 18 mg per day for women. However, some studies recommend iron intakes of 17.5 mg per day for male distance runners and 23 mg per day for normally menstruating female distance runners.
If you want help evaluating your diet to ensure you’re getting enough iron, please contact me.
Happy running 🙂
Sarah J Cuff, RNH, PTS