Iron + The Athlete: Considerations for Intake and Absorption

I took my first formal nutrition class back in 2014. At the time, I already had a ton of nutrition knowledge, both from on-the-job training and from personal study, but I was beginning to realize I wanted to shift my career from public health into individual nutrition.

As a female and athlete (with digestive issues), I had always struggled with iron, despite eating a fairly high iron diet. At first, I also ate some red meat, and in my nutrition class, we had to complete a three-day food log and perform a nutritional analysis. I was easily meeting the recommended dietary allowance (RDA) for iron. When I asked my instructor about it, a locally practicing registered dietician, she told me, “If you’re consuming the RDA in iron,  you should not have low iron status.”  

That conversation turned out to be a good jumping off point for wanting to know a whole lot more about nutrition, and nutrient and lifestyle interactions.

If you’re an athlete (male or female), and you’ve ever wondered about what all the hype is on iron, or why you have low iron, or what exercise has to do with iron regulation and absorption, this article is for you.

The Role of Iron and How Iron Deficiency Impacts Athletic Performance

First let’s review what iron does in the body. When we speak about iron, we’re often speaking about it in the context of iron-deficiency anemia. There are many reasons for anemia, not just low iron stores, but iron-deficiency anemia is the most common. Anemia at its most literal means “without blood.” And that’s where we start to talk about iron (though again there are other nutrient depletions that can also cause anemia). 

Iron is an essential part of oxygen transport and energy production at a cellular level, and is important for cognitive and immune function (1,2). Hence the reason you feel fatigued when your body is without iron. Note that low energy is also a feature of many nutrient deficiencies since many nutrients are involved in cellular energy production.

For endurance athletes, iron is dually important because it is used for multiple metabolic pathways, including 1) it is used for oxygen transport to the exercising muscle and 2) the production of ATP (energy) is highly reliant on iron.  

Common symptoms of compromised iron status include fatigue, lethargy, negative mood, and poor performance during endurance exercise. 

A Hormone Called Hepcidin and its Impact on Iron Absorption  

Hepcidin is an inflammatory and iron-regulatory hormone that increases for 3 to 6 hours after exercise. This is likely a result of the exercise-induced inflammatory response, and associated increases in an inflammatory cytokine, interleukin-6 (IL-6). Increases in hepcidin result in a decrease in iron absorption as well as decreases in recycling iron from the gut.  

So there’s likely a window of time following exercise where the body has altered iron metabolism. 

Who is at risk for iron deficiency? The mechanisms that influence iron absorption in athletes

Traditionally, we think of compromised iron status as something that females suffer from. This is because women in their menstruating years generally lose iron through blood loss each month; whereas men should not be losing blood. However, active women are estimated to be twice as likely to present with Iron Deficiency Non-Anemia (stage 2 of iron deficiency) than sedentary, non-active women. Among athletes, we see much higher iron deficiency rates than in the general population with estimates of greater than 50% of female athletes and up to 30% of male athletes having compromised iron stores (1).

Both testosterone and estrogen can influence iron metabolism because they suppress hepcidin (more on this hormone above). When women are exercising at a high training load, this may result in an altered hormonal profile, with gonadotropin-releasing hormone (GnRH), which is a sex-hormone precursor, being suppressed. Consequently, luteinising hormone (LH), follicle stimulating hormone (FSH), and then estrogen will be suppressed. So lower estrogen leads to higher hepcidin (or at least less suppression of hepcidin), and thus more difficulty in absorbing iron. 

Likewise, the same result can happen in males with a high training load, with gonadotropin-releasing hormone being suppressed, and consequently suppressed testosterone, and less suppression of hepcidin. In turn, chronically low testosterone in males may be linked to higher hepcidin levels, potentially impairing iron regulation. 

Another variable is relative energy deficiency- what I call not eating enough for one’s activity level. Overall low energy availability (LEA) and energy intake may relate to either an overall deficit in dietary iron intake, and/or a dysfunction in iron absorption from the foods that are consumed. 

Further, we’re also finding that the makeup of one’s microbiome also affects iron absorption, with iron-deficient individuals lacking lactobacilli species–a key species often cited with good health. Many other bacteria also require iron for growth (3).

Otherwise, vegetarian and vegan / plant-based diets can also impact iron absorption and stores since non-heme plant sources of iron are more difficult to absorb. A big one though, is the general state of your digestion. You have to have good digestive function to assimilate the nutrient.

Finally, some good news: the inflammatory response following exercise can be reduced after long exercise bouts of two hours or longer by consuming carbohydrates during exercise. Eating during exercise decreases the depletion of glycogen stores in the muscle (2), and ingesting carbohydrate during exercise has also been shown to improve the recovery response from long/high intensity efforts.

The Stages of Iron Deficiency:

Stage 1: Iron Deficiency: Iron stores in the bone marrow, liver, and spleen are depleted, indicated by ferritin values less than 35ug/L, Hemoglobin values > 115 g/L, (11.5) and transferrin saturation >16%

Stage 2: Iron-Deficient Non-Anemia: Red blood cell production decreases as the iron supply to the bone marrow is reduced, indicated by ferritin values less than 20ug/L, Hemoglobin >115 g/L (11.5), and transferrin saturation < 16%

Stage 3: Iron Deficiency Anemia: Hemoglobin production falls, resulting in anemia, indicated by ferritin values less than 12 ug/L, Hemoglobin <115 g/L, transferrin saturation less than 16%. 

From current research, it appears that depleted iron stores (in stage 1) have minimal or no impact on physical performance, but this is likely particular to you as an individual–some athletes will notice the impact sooner.

What You Are Eating in Your Diet and Iron Status

The timing, amount and source of iron from your diet, in combination with the overall composition of the diet are all important factors to consider when looking at iron status. The most easily absorbed source of iron is heme iron (from meat).

The presence of Vitamin C can enhance non-heme iron absorption, but vitamin C is destroyed by heat (and light), so cooking a vitamin C-rich food into a dish will likely not help much. A couple squeezes of citrus juice at the end of cooking when the food is on your plate can be an effective method to get around this.

Otherwise, polyphenols, phytates, oxalates, calcium, zinc, copper, and vitamin E, which are all part of many nutritious, plant-rich diets and in particular are in whole grains, legumes, leafy greens, and tea and coffee, can decrease the amount of non-heme iron that is absorbed in a meal. Suddenly, your (or my) quinoa salad bowl with nuts, seeds, lentils, spinach and other dark leafy greens, and tahini or almond sauce is not a recipe for a hearty, iron-absorptive meal. Note, these are foods that are frequently on the high-in-iron list! And there are ways to prepare them to make their iron more absorbable, such as soaking, sprouting, fermenting, etc.

Want to Know More?

Within my nutrition practice, I specialize in endurance athletes and digestive imbalances. If you’ve struggled with chronically low iron, or recently have experienced it, I encourage you to reach out to me for more personalized support about how to boost iron around your exercise load.

References:

1). Sim, M., Garvican-Lewis, L.A., Cox, G.R., Govus, A., McKay, A.K.A.,…and Peeling, P. (2019). Iron considerations for the athlete: a narrative review. European Journal of Applied Physiology, 119: 1463-1478. https://doi.org/10.1007/s00421-019-04157-y

2). McKay, A.K.A., Pyne, D.B., Burke, L.M. and Peeling, P. (2020). Iron Metabolism: Interactions with Energy and Carbohydrate Availability. Nutrients, 12: 3692. https://doi.org/10.3390/nu12123692

3. Frame, L. (2021, October 7th). Mixed Diet and the Microbiome- Challenges with Complexity. Linus Pauling Institute Diet and Optimum Health Conference, Corvallis, OR, United States. 

Barriers to Healing: Ownership or Attachment to our Struggles

I’ve been reminded lately of barriers we put in place that prevent us from healing chronic health challenges, or negative habits.

That barrier is how we attach ourselves to and start to own our struggles.

Here are a few example statements that illustrate this:
– My typical GI struggles.
– I’ve always hated vegetables.
– I’ve always struggled with digestion. So have my parents.
– I’ve had that ever since I was kid. I’ve always had it.
– I never recover well during a (marathon) training cycle, and never get my nutrition and health to go right enough to be prepared for the race.
– My anemia pattern.

Another example is identifying with our diagnosis or diet pattern as if it were a job title. This is often easily visible on social media. You might witness or use something like IBS Warrior or Ulcerative Colitis Warrior, or Celiac next to a name in a bio, as an example.

I’ll use my past self as another example. For a long time, I felt like whatever medical mystery that presented as something autoimmune meant I’d be in daily chronic pain forever. This began at age 27. I was in constant fear and anxiety about the pain, and I felt like I couldn’t get outside that experience, even temporarily. Fast forward seven years and my body and mind feel remarkably different. The cloud of bleakness hanging over me, the fear of pain, the internal anguish that I couldn’t understand is no longer part of my everyday.

Yes, when it comes to healing something that has been chronic, finding the right nutrition plan and lifestyle practices are incredibly important. But healing is also energetic. You have to believe it’s possible. And you have to change your mindset and the energy you put around the process.

You have to believe your body is meant to heal.

And we start to believe what we say about ourselves. By saying we always struggle with something, that means deep down that we probably believe we will always struggle with it.

This simple, though definitely not easy, nugget of first changing what we say (out loud and internally) is what catalyzes healing. We start to believe lasting healing is possible. We seek out and then are put into connection with individuals who further light the healing pathway from whatever we’re currently experiencing – an autoimmune condition, IBS, chronic fatigue, a lifetime of emotional and disordered eating and body hate, weight woes, medical diagnoses that are largely written off, etc.

And sometimes our catalyst for healing is just an example from another person.

For instance, we all operate within a community, whether that’s in person in our daily lives, or people we follow online who influence us. Often, we identify with individuals who have journeyed through similar experiences and challenges as us.

What often distinguishes individuals who are incredibly good at healing themselves for the long term, and those that have chronic set-backs, lies in what the first group don’t spend their time doing.

These “experts at healing” don’t hang out in forums or self-help groups with individuals discussing the woes of their symptoms or how bad it is. They get out of their negative head space as soon as they notice they’ve fallen into it. They change their language in how they talk about their health. Instead of statements like “I always struggle with….” or “My faulty digestion….”, they view a health challenge as a temporary setback. My digestion is currently less than ideal — That’s a less permanent way to state that.

Or I haven’t yet arrived at the end of a training cycle feeling like I’ve nailed my nutrition and recovery strategies, but I believe it’s possible and I’m committed to exploring what has prevented me in the past.

Or My doctor believes I have lupus that I’ve put into semi-remission enough to be below the threshold for clinical diagnosis. I am not a victim. And I’m committed to my nutrition and lifestyle practices to continue my journey towards complete healing. This statement was my personal example.

In my case, I refused to mentally identify with or use the word lupus. For one, I didn’t have an actual diagnosis. But for me, that choice was energetic. This is similar to (before then) never using the words celiac, IBS, or dysbiosis about myself–though they were all either likely or true. These words we attach ourselves to are incredibly powerful. And here I am a handful of years later, and I haven’t thought about the words “autoimmune” or “lupus,” “IBS,” or “dysbiosis” as it relates to myself in quite a while.

Think about how you can shift the statements you make about your health. Catch yourself when you say what “you’ve always” said about your situation. Restate it in a less attached, or less in ownership, way.

Let the way you speak be a catalyst for how you think about your health.

*Note on the book pictured above: I don’t remember the plot. But I do remember it was part of my finding joy and rewiring how I thought about my health process.

A simple digestion tip for when you’re struggling

The last few weeks, I’ve dropped back into a pattern I always wish to avoid. Feeling those frequent low-grade, lower belly aches, and sometimes feeling simultaneously heavy and like a giant airy balloon resides in my midsection. It’s most noticeable two to three hours after a meal, when the food has left my stomach and reached my small intestine, and around the time I’m either about to begin or am in the first few miles of my daily run or workout. 

Not so enjoyable.

This used to be my norm. It used to be so much my norm that if it were just these mild symptoms, I wouldn’t have noticed it  or done anything about it at all. I wasn’t quite as in tune with my body then, you could say. But then it became chronic. And got a lot worse before I figured out, with help, how to make the sour, painful digestion situation better.

So when you come to me and say, “I can’t believe I’m telling you this,” well, I know what you’re talking about and it’s not something that should be hush hush or shameful — at least not when you’re talking to a nutritionist. 

In the interest of providing some guidance before you start removing random foods, purchasing specialty digestive products or just holding your belly and whimpering / running to the bathroom, here’s one quick tip to improve digestion for you. 

Try One Simple Shift

It’s a shift that worked for me the last couple weeks as I switched from eating more cold/raw summer meals to putting those same foods in meals and gently cooking them.

That’s right. That’s the shift. 

Just switch to eating all your meals warm and gently cooked. 

It’s simple but especially in the end-of-summer warm days, you might have to remind yourself daily, if not with every meal, to just heat everything up. I don’t heat up some foods, and eat others raw, like including a side salad with a meal. Warm all of it up. Do a quick 30 second to 1 minute sauté of your salad ingredients in your vinaigrette in a sauté pan, if that’s easiest. Oh, and chew it all well.

Think of your digestive ability like a campfire. Too hot and everything burns up and gets singed too quickly, like that marshmallow or hot dog you’re roasting. Too cold and nothing really cooks at all. It just smolders along half-heartedly. That smoldering is what we’re trying to avoid here, since it’s most common when you struggle with symptoms of the lower GI.

If you’re interested in more simple digestion shifts, I wrote a mini-guide for improved digestion featuring no products, special foods, or diets which you can download. Or check out the last few blog articles on improving digestion for more ideas.