…Iron-willed…
… strong as iron…
“Gold has its uses, but war is won with iron” … George R.R. Martin – A Dance With Dragons
There’re a host of expressions about iron, Fe, atomic number 26, the second-most abundant metal on the earth’s crust. Ironically, (ouch), the iron I’m on about in this post is the mineral, one of seven essential minerals crucial for keeping our bodies performing optimally.
Iron deficiency is one of the most common nutritional deficiencies in athletes. The problem affects as many as one in two healthy South African women, and women endurance athletes are particularly at risk.
Having been an ultra-distance endurance runner for the past 25 years, I’ve long been aware of the risk of low iron stores. From time to time I’ve suffered from iron deficiency, particularly when picking up training intensity before an ultra, and for years I’ve not been able to donate blood (the blood services don’t recommend it if your training intensity is high).
It’s such a common problem – mainly, but not exclusively, for women athletes, that I decided it’s time I researched the issue, interviewed some experts, and put out a call on social media for personal experiences of runners. I interviewed:
~ Dr Jarrad van Zuydam, a Johannesburg-based sports physician with a special interest in endurance sports medicine, and team doctor for the Dimension Data pro cycling team
~ Mariella Dierks, a registered dietician, elite triathlete and winner of the 2018 Durban Ironman 70.3.
The result is this blog post, which I hope creates awareness amongst runners – men and women – and is shared far and wide.

What is iron?
Iron is a micronutrient needed for the synthesis of the protein haemoglobin in the body. Haemoglobin in the blood carries oxygen from the lungs around the body, cells then use the oxygen delivered to them to generate the energy needed for cellular processes. Haemoglobin accounts for about 70% of the iron in the body. If our iron levels are low, our cells receive less oxygen, leaving them less able to generate energy. When iron levels become so low that the iron reservoirs in the body become depleted and the level of red blood cells is lower than normal, we have full-blown iron deficiency anaemia. (But more about that later.)
Who is particularly vulnerable to iron deficiency?
Women are particularly vulnerable, because when we menstruate, we lose blood, and with it, red blood cells and iron. Women who do sport are at additional risk. We have greater iron requirements than non-athletes – our dietary iron recommendations are 1.3 to 1.7 times higher, and meeting them is often difficult.
In addition, iron can be lost through heavy sweating, and repeated strenuous movement such as running can lead to red blood cell destruction or haemolysis, and blood loss. Blood loss has also been reported from the digestive tract and through urine after extreme events like marathons.
Non meat-eaters are another large risk group. There are two types of iron – heme iron (iron from animal sources) and non-heme iron (iron from plant-based sources). Heme iron is better absorbed by the body than non-heme iron.
Foods containing non-heme iron form an important part of a nutritious, well-balanced diet, but the iron contained in these foods won’t be absorbed as completely as the iron in meat. We only absorb between two and 10 percent of the non-heme iron that we consume.
Dr van Zuydam was quick to point out that it’s not to say you can’t meet your Fe requirements as a vegetarian or a vegan, but you just need to be more careful about what you eat, ensuring you’re eating foods that are iron rich, and avoiding foods that may inhibit iron absorption.
“Female ultra-endurance athletes who are also vegetarian are probably the Bermuda Triangle of iron deficiency – their risk is that high.”
What’s the difference between low iron stores and anaemia?
You need to think of iron deficiency and anaemia almost as two separate entities. Anaemia is a low level of haemoglobin in the blood. There’s a whole range of conditions that can result in anaemia, from nutritional deficiency of iron or vit B12, to bleeding, genetic issues, chronic disease, HIV or chronic infection.
This means that not everyone who is anaemic has an iron deficiency. Iron deficiency is one possible cause of anaemia – and in athletes, it’s probably the most common cause.
In the case of iron deficiency, you’ll only start becoming anaemic once that iron deficiency is severe. The body will be unable to produce more haemoglobin, and you become anaemic.
Importantly for athletes and runners, both anaemia and iron deficiency can cause a drop in exercise performance.
What is pseudoanaemia?
By definition pseudoanaemia is not a true anaemia. The definition of anaemia is a low level of haemoglobin in the blood. That haemoglobin is measured as a concentration in g/DL. Usually the absolute mass of haemoglobin in the blood is not measured (it can be, but it’s a more expensive test) – instead labs generally measure the concentration of haemoglobin in the blood.
What happens in athletes when we train is that we adapt to the training by producing more plasma, the liquid component of the blood. This helps to increase our cardiac output as well as the distribution of oxygen and nutrients to the muscles as we exercise – it’s a positive spin-off as one of the things that make us fitter, faster and stronger. But when we’re producing more plasma, the cellular component of the blood doesn’t increase as fast as the liquid component, which in effect creates a dilution.
So it’s not to say we have low haemoglobin, but rather a low haemoglobin concentration – the total haemoglobin in our system remains the same, if not a little more, as another athlete.
Doctors need to be mindful of this dilutional effect when testing endurance athletes – aware that the test results may show anaemia, but actually simply appear that way.
(The other common occurrence of a dilution is during pregnancy – almost all pregnant women show a mild anaemia, which is actually a pseudoanaemia.)
What is the simplest, quickest and most inexpensive way to have iron levels checked?
The diagnosis of iron deficiency and iron deficiency anaemia can be tricky, so ideally we need some lab tests done. Labs don’t test for iron directly – what they test for is a molecule called ferritin, which is the storage form of iron. Once we consume iron, and it is absorbed through the gut, it’s then stored as a molecule called ferritin. This becomes our measure of the body’s iron stores. It can fluctuate in certain disease states due to inflammation, but generally it’s relatively stable. Doctors usually look at a cut-off of about 30 for ferritin levels – anything below 30 they recommend iron supplementation.
There’s a newly launched rapid test that’s available over the counter in pharmacies here in South Africa – it’s a pin prick blood test with results presented immediately. The test is fairly limited – it only shows a yes/no result – if your ferritin is above 30, you’ll test negative, and if below 30 it’ll show positive. If we test positive, we need a full blood count, which looks at our haemoglobin levels to see whether we’re iron deficient AND anaemic, or if it’s a mild iron deficiency.
So, the simplest place to start is with the rapid check, which will at least give us peace of mind in terms of a yes/no answer as to whether we’re iron deficient or not.
Point to note: the rapid test cannot distinguish between anaemia and pseudoanaemia. It’s only measuring ferritin – our storage of iron in the blood, not our haemoglobin levels. It’s able to diagnose iron deficiency, but not anaemia. Anaemia needs to be diagnosed by a full-blown blood count.
Iron toxicity and the risks of self-diagnosis
Dr van Zuydam strongly discourages self-diagnosis and self-treatment of iron deficiency. The rapid test can detect whether we’re below 30, but it won’t show the extent to which we’re low. If our ferritin is low enough and we’re already anaemic, we may even need intravenous iron. On the other hand, it may be slightly low and we need only make some dietary changes and use supplementation.
The human body has no automatic mechanism of eliminating excess iron, unless we bleed regularly. The risk of excess iron accumulating becomes high, and eventually it gets deposited into various organ systems and we can suffer renal, kidney, liver and even heart issues. So it’s really not something to play around with. Better to have a formal test to check our iron levels, and then be professionally advised as to the best course of treatment.
How to choose the best iron supplement?
There’re many iron supplements available, and with many formulations, so it can be confusing deciding which is most suitable. The older treatments were iron salts like ferrous sulphate, ferrous gluconate and a few others. The ferrous salts are better absorbed than the ferric salts, but both have quite high levels of side effects, particularly gastrointestinal side effects like constipation, nausea, vomiting.
Some of the newer iron supplements available are more complex molecules bonded with sugar, like polymaltose, and these are better tolerated. Unlike iron salts, these can be taken with food which helps minimise side effects.
Iron supplements can lead to constipation. Counter that by taking in enough liquids and fibre in your daily diet.
But it’s important to note that iron supplementation is not a quick fix – we can’t expect to take iron supplements for a week and be cured. If we’re diagnosed with an iron deficiency, we need to stay on supplementation for at least three months before being retested. The doctor will then re-evaluate whether we need to slightly decrease the dose, or to come off and simply make some dietary changes.
Can running at high altitude make us iron deficient?
It is commonly said that at altitude, the air is thinner. What’s really happening is that the partial pressure of oxygen becomes lower, the higher above sea level we get. The decrease in pressure is sensed by our body, which tries to adapt to that altitude by producing more red blood cells. Within the red blood cells there is haemoglobin, the molecule where iron is so important in its production. If our iron stores are low and we head up to altitude, the body will be trying to produce new red blood cells to help us deal with the lower oxygen environment, but because our iron stores are low we won’t have sufficient iron to produce the extra haemoglobin.
Usually, elite athletes heading up to a high altitude camp for the purposes of increasing performance before an important competition like the Olympics, for example, would have their iron levels checked before leaving. Normal runners not going up to altitude, would have healthy ferritin levels of 30 or 40. Sports doctors prefer levels to be on the higher side of that number, knowing the body will be pulling from those reserves to produce the additional haemoglobin.
“So it’s not that you become iron deficient at altitude, but more that you may go through iron a little faster while you’re up there, adapting to that altitude,” says Van Zuydam.
Symptoms of iron deficiency
Fatigue
Pale skin and fingernails
Weakness
Dizziness
Headaches
Tender tongue

Best dietary sources of iron
All red meats, liver, pork, chicken, turkey, eggs, sardines, tuna, salmon, mackerel, haddock
Best vegan sources of iron
Beans & lentils, tofu, chickpeas, sweet potatoes, cashews, dark green leafy vegetables, cooked spinach and chard, broccoli, peas, kale, pumpkin, squash, fortified cereals, wholegrains, wheatgerm, pumpkin seeds, dried apricots, prunes, raisins, dates, strawberries, figs, watermelon, sesame seeds, pecans, walnuts, tomato paste, molasses, quinoa, cooked soy beans, spirulina
~ iron enhancers
Vitamin C increases iron absorption, so all foods rich in vit C (citrus fruits, strawberries, peppers, tomatoes, etc.) Also vit E and folic acid. Heme iron itself also aids the absorption of non-heme iron, so eating green leafy vegetables with your meat provides a double iron boost.
~ iron inhibitors
The most common robbers of iron are tannins (tea and coffee), so best to reduce your intake on these, and certainly don’t take them within an hour or so before/after an iron-rich meal.
Calcium is also an iron inhibitor, so avoid high-calcium foods during/before/after eating iron-rich foods.
Best iron supplement
Amino acid chelated iron is three times more absorbable than iron sulphate or iron oxide.
Best way to prevent iron deficiency happening again?
The best way to prevent iron deficiency is to have adequate red meat in your diet (twice weekly will do the trick). Ideally, have your ferritin level checked every four to six months and, if it is between 30 and 50, then take a good iron supplement, on the recommendation of your doctor. Make the necessary changes to your diet, boosting what you eat with foods that are rich in iron. Get savvy with what your body needs, so you can be fuelling it for the performance you’re wanting out of it!

Iron-related experiences from South African trail runners
India Baird (55, running for 32 years, vegetarian)
I have been mostly vegetarian for 30 years, about the same number of years I’ve been running long distance (first road then trail 10 years ago). Nineteen years ago I had a very easy pregnancy with my son. Two years later I had a stillbirth at full term, followed by a number of miscarriages, all seemingly without cause. I was sent to an endocrinologist in New York for full blood work, and she found I have pernicious anaemia – my body can’t process iron even if I was to eat 10 steaks a day. I began getting regular B12 injections (they hurt like hell!), had our daughter in 2004 and have been having the B12 jabs regularly ever since. My energy levels definitely improve after I have them.
Anouk Baars (40, running for 3.5 years, eats meat)
As I was slogging it out during Diagonal de Fous 100 miler, I made it to the 50km mark where I had decided to drop out. I finally realised something was properly wrong. In my build up to the race, I’d only had mediocre training days – every time I would do a run I would be so tired, even though I’d been resting so much in between the runs to be able to give my best on the next run. Even after rest days, I found I wasn’t even able to keep up with friends on training runs. When I had that DNF in Reunion, I knew there was something wrong.
When I got back to SA I had blood tests, colonoscopy and all the checks, due to the very low irons levels that were so obvious in the results. I started working together with my doctor and a sports nutritionist who did some additional tests, which showed I had the early stages of adrenal fatigue. People had been telling me I might be overtrained, but I knew I had trained very little in comparison with others, and that I had rested well between runs. The doctors couldn’t find any way I had been losing blood, so the gastroenterologist concluded it was caused by the running breaking down red blood cells through the pounding on my feet. As simple as that.
I started taking high doses of chelated iron (I am on Thorne research and Xymogen 100mg a day, some adrenal support supplements, a blood test every 3-4 months, and I eat wisely – I’ve cut out a lot of sugar and caffeine so that I can properly tell how my body is feeling every day without getting spikes.
Nowadays I take 60mg a day, and during my period or after a long race I increase the dosage for about 4 days to 90mg.
After about 5 months, things started to improve, and after 7-8 months I started to feel on fire! Suddenly I could do my big training weeks AND have energy for the rest of day.
Most people will drive long distance to fetch their phone if they’ve forgotten it at home. I’m like that with my iron tablets!
Riana van der Merwe (53, been running for about 11 years, eats meat)
About 10 years ago, during a routine visit to a specialist physician for a check-up, he discovered such low iron levels that I had to have urgent and multiple iron infusions, done under supervision in case of anaphylactic shock. This was after two pregnancies about 3 years apart.
I was not much of an ultra-distance trail runner then. I only ran to train for high altitude mountaineering, which had been our sport for that previous 10 years til the kids came along.
I started to run longer races at the age of 42. After children I have been using the mirena as a contraceptive, with success and no side effects, so I don’t lose blood due to periods at all.
About a year ago, I started to donate blood again as part of a project at our son’s school. I donated every 3-4 months, three times in a row. I started feeling as if I had no energy at all. I had other issues like an alcoholic father that affected me badly and at first thought that’s why I was so slow and weak. I still did races, but was extremely slow. About six weeks before TDS this year, I did everything I could to get out of the race. But it would’ve meant we’d lose the money we’d paid for the entries, so I had no choice. I decided I’ll just run half way or go along to enjoy Chamonix.
I always have annual blood tests to test for my iron as well as my thyroid. Ten years ago half my thyroid, and my parathyroid gland were removed due to a lump. The tests in January this year showed everything was normal in terms of thyroid and no cancer, but that my iron levels were 2, instead of 12 tot 15. My GP gave me 5 iron injections, under supervision, over 4 weeks. Even after the first injection, I could feel the difference while training.
The rest is history. Since then I finished the TDS and Skyrun. I have decided to not donate blood again, to listen to my body, and to have scientific tests done instead of self-diagnosing. I’m taking iron supplements for another few months.
Jess du Toit (33, been running for 3 years, mostly vegan)
I’m mostly vegan and have had 2 iron infusions.
The second time I found out about my devastatingly low ferritin and haemoglobin levels was when I went to see a psychiatrist for panic attacks and severe exhaustion. I was feeling worse than I’d ever felt in my life. I was completely exhausted all the time, no matter how much I slept. I could barely run for 3 minutes at a time, when previously I’d been able to run marathons. I had a foggy brain and was unable to think or concentrate at work. I’d become a shell of the person I’d been, and my relationships suffered. My self-confidence was at an all-time low and I started having the panic attacks.
One of the first things the psychiatrist did was test my haemoglobin and my iron levels. The results revealed the probable cause of practically all my symptoms! She recommended I see a haematologist for an iron infusion, as that would be the quickest way to have me return to feeling normal. She also put me onto Ferrimed – which I’m likely to be on for the rest of my life because I’m mostly vegan. It took a couple of weeks after the infusion to start feeling normal again. But the way I manage now is to be extremely careful about what I eat, and to not drink anything containing tannin, before or after a meal. I take my iron supplement religiously, and will do so for the rest of my life. I also go for blood tests every 3 months or so to monitor my iron levels.
Oriole Bolus (34, been running for 8 years, eats meat)
In early 2014 an iron deficiency came unexpected. It would’ve been my second year of trail running and I was just starting to get good at it. In my first year (2013), I used to join the MATES trail running group. I would say this group introduced me to most of the trails in Cape Town. By 2014 I was running quite a bit. Batrun was on the horizon and I had heard about this race through MATES. My technical and mountain ability had improved considerably, and so I decided to push the training for this race. At the time I was only doing about max 50-60km a week, which was a lot of time on the trail considering my longest race would be Batrun. Leading up the race, there were some expectations for me to do well and so I tried to even push the training even more.
About 10 days before the race I started to feel weak in the mornings and really struggled to get up. I thought I had some kind of flu. I tried to go for a run, but had no energy – almost the opposite to how I’d felt a few weeks before. I still stood on the start line of Batrun, but only made it up and down Devils Peak before having to pull out. It was a weird feeling, I wasn’t sure whether I was sick or not. I thought it would pass but it didn’t. Two weeks later, I still didn’t feel normal on runs. So I went home to spend some time with my family in Plett and they sent me to a doctor who said there was no sign of flu or a virus, and suspected I may have depression. At the time I was busy with my Masters, and that was challenge in itself. After about a week I went back to Cape Town and tried to be as healthy as possible. I ate healthily and cut out coffee. My diet at the time was mostly vegetarian – lentil dishes with brown rice, and occasionally some fish. I also didn’t have much dairy. There was still no improvement, so I went to a doctor in Tokai who practices both conventional and homeopathy. Blood tests showed my iron levels were really low, and she recommended that I take iron supplements. It took about a month on the Fe supplements before I felt energised while running again, and another 3 months before I felt I could race again.
Later that year, I went overseas to do a Masters exchange for 6 months in Finland, and I began to eat more meat and dairy, and not running as much. I returned to Cape Town the following year feeling normal again, and ready to tackle some bigger runs. Since then, I’ve been upping my distance every year. I make sure I eat protein consistently, but also keep a varied diet. My body seems to have adapted to more training and I’ve been doing a few ultras, yet my iron levels seem to be good. Now it’s all about managing my lifestyle to keep the energy up and try my best to be consistent and avoid injuries.
Liesl Koch (38, been running for 4 years, eats meat)
I’m a REALLY slow runner but I’d been training for UTCT with Fred Richardson and was training really hard, sometimes even twice a day. I thought I was just tired from all the training, but my running wasn’t improving at all. I was starting to think that there was something holding me back. A friend of mine had told me to get my iron levels so I decided to get my bloods done. What harm could it do.
It turned out my iron levels were very low and my haemoglobin was at 10, instead of above 13. I was told to stop all exercise, and had to have a colonoscopy and gastroscopy to check if I was bleeding internally as I have no reason to be so anaemic. The test results showed I’m healthy and just need to take iron supplements.
I’ve been taking Chela-Fer, and after just two weeks of taking the supplements I could certainly feel an improvement with my running. I’ll find out this week if my levels have improved sufficiently but I suspect they not quite there yet, as I’m really struggling with my breathing when climbing on trail. But hopefully it will improve.
Robin Sherry (68, been running for 20 years, mostly plant-based diet with fish and eggs)
I am decidedly slow to ask for help or go to my doctor – I’d rather get on with it myself and self diagnose (I managed to nearly kill myself going that route after banging my head in a fall on the boardwalk). But I do follow a pretty healthy diet (plant-based whole foods with some fish and eggs, and good coffee!) So my running and especially trying to do longer, tougher, more interesting ‘runs’, played in my favour: my horrible performance on Triple Trouble this year really got my attention.
Fortunately we have an excellent doctor who researches widely. So, after all the relevant tests to rule out underlying disease, I’m now on a diagnostic 3-month course of chelated iron supplements. This will probably confirm the problem is low absorption plus borderline low iron intake. Thanks to my doctor’s diligence, I got home to find links to relevant literature to help me inform myself. Vital. Now I know, for instance, not to drink coffee or tea within 2 hours of taking the iron. There is actually a lot to take into account for non-meat-eaters.
It has now been about 6 weeks on the iron and I’m at last feeling a lot better. I’m sure it has been a combination of lower absorption rates as I get older (68), and a lower iron intake, exacerbated by the interference of certain food/drinks when combined with the healthy foods. So in my case the running didn’t cause the problem, but rather led me to understand it. So we keep on running!
Jessica Magner (31, been running for 10 years, now eats meat)
In a nutshell I really overdid the training last year when I was training for UTCT 2017. I actually become deficient in a few things, iron included. I lost too much weight, ate badly (hardly any meat/protein), and just was not looking after myself in general. So it was not surprising that I landed up with a serious injury that put me out for 8 months!
So this year, I did things very differently. The two main things I changed were my diet (I decided meat is not so bad after all!) and I started strength training. I also took more supplements, and had regular vit B injections so that my iron levels did not drop again. It all seemed to work out this time as I had a fantastic race at UTCT! The 65km was the most epic race I’ve done, and I definitely think that supplements, right nutrition and good iron levels helped a lot!
Lynne Shepley (62, been running for 27 years, eats meat)
In about 2002 my iron levels plummeted unexpectedly. I only knew because I couldn’t run far without becoming breathless, and couldn’t walk upstairs without my heart pounding and me needing to take a rest. I had my bloods tested and found my iron levels were very low. Iron tablets sorted it, but despite camera up, camera down and a barium X-ray, they never found the cause of the low iron. All’s been fine ever since – I keep an eye on my iron levels by feel, and I make an effort to eat a well balanced, iron-rich diet.
Wow I see so many similarities in everyones stories!! It is quite scary how common it is. Awesome article Linda!!
Yes, so many similar stories! Thank you for a very interesting article, Linda – which I will share with my daughters!
Thanks, Linda ????
I will get some amino acid chelated iron today.
My iron level was 4 last year, also low haemoglobin, an endocrinologist recommended a colonoscopy and later this year a capsule endoscopy…. no intestinal problems were found so I just continue with the iron supplements. My level is now 7. It must be an absorption issue so thanks for the tip! Great article. ????
I used to give blood regularly in SA. When I arrived in Aus, I tried to donate blood and they were appalled at my iron and haemoglobin levels. I have now stopped my regular blood bank donation! ????