In the previous article we discussed what Iron is and its role within our body. Our bodies are remarkable and through the activity of the iron-regulatory hormone hepcidin, we are able to regulate our iron stores in order to maintain a ‘healthy balance’. Well I guess this is what our bodies are aiming for most days, but with our rigorous training regimes and other work and daily activities we do make this a bit of a challenge for our bodies to achieve. So we need an action plan we can refer to that can help us minimise the impact that exercise may be having on our iron levels. So I thought I would write a bit about how we can maximise our iron absorption from our diet and add in some possible treatment strategies that have assisted athletes who have had issues with low iron stores.
First and foremost we must remember that despite the fact that we rely on iron for fundamental body functions, our bodies are NOT able to manufacture iron. We can however recycle it (white blood cell activity) and absorb it from our diets. As a result, our iron stores are dependent on the iron from the food we eat. Now iron is found in a number of food sources, the foods that contain iron can be classified into two groups; haem and non-haem foods. The main difference between these two food groups is the rate as which iron from the food is absorbed into the body. For example your hem foods are your red meats, seafood and poultry and the iron absorption from these food sources is 15-18%.
Your non-haem foods, predominantly your plant-based foods (i.e cereals, vegetables, legumes and nuts) have a much lower rate of iron absorption, approximately <5%. While this rate of iron absorption from the non-haem foods is less than ideal, there are a few ways in which you can improve the absorption of non-haem iron (highly beneficial especially if you aren’t a big meat or seafood fan). One way is to combine a non-haem iron food source with a haem iron source (e.g. steak with a side of broccoli, or salmon with a spinach salad), another way is to include vitamin C rich foods with your non-haem iron foods (e.g. juice or fruit with breakfast, capsicum in a stir-fry, salad or fruit with a sandwich). Some examples of haem and non-haem iron food sources are in these tables.
I thought it would be a good idea to highlight some food substances that have been found to reduce/inhibit iron absorption. These include: excessive intakes of tea, coffee (less impact than tea but works in a dose response effect therefore the more you drink the greater the impact on iron absorption) and bran.
So now knowing how our bodies absorb iron we need to address how much we should be eating each day to ensure our iron supply demands are met. According to the recommended dietary intake (RDI) for iron in Australia this is how much we should be ingesting:
When it comes to athletes we know that we require higher iron intakes, but the actual specific amounts for each sport/activity is still unknown. What we do know is that running athletes (especially the endurance running athletes) require the highest iron intakes due to their exercise of choice, resulting in the largest iron losses (see last editions article for further details). Considering that running does contribute significantly to a triathlon, I would suggest that following a similar iron intake would be the best approach for training triathletes. This being said, research has recommended that the level of iron intake would then be 17.5 mg/day for males and around 23 mg/day for normal menstruating females. While theses levels of intake seem high they are achievable with a well structure diet. A few tips for achieving an iron rich diet include:
Choosing a cereal that contains added iron
Consume your haem iron foods 3-4 times a week, approximately 80-100g servings
Add vitamin C-rich foods (fruit, juice, capsicum, broccoli, cabbage, cauliflower) to enhance iron absorption
For vegetarian: chose the iron rich non-haem foods and combine them with vitamin C-rich foods.
Avoid or limit intake of bran
Avoid drinking strong tea and coffee with meals (Its ok to drink them between meals but not with iron rich meals)
Iron depletion is a continual process and occurs as a result of loosing iron through exercise, which is usually coupled with an inadequate iron intake. Hopefully, I have been able to provide a bit more information on how we can minimize the impact of one of those factors. A good practice, which I believe, a lot of female triathletes should incorporate into their ‘health monitoring’ regime (bit like regular visits to the physio or chiro) is regular iron status assessments. One-off blood tests are not always ideal as there are a number of influencing factors that can affect our one-off iron test (e.g. what you ate right before you had the test or even the night before). A good idea is to set up regular (~3-4 months or 2-3 months if you are prone to iron deficiency) iron status check ups with your GP, this will allow you to monitor your iron levels trends and changes and may also help you intervene at the early stages of iron deficiency.
If iron depletion has occurred and iron supplementation is required the typical treatment is oral tables with 100-300mg of iron ingested per day (with vitamin C to enhance absorption). This method of treatment is usually quite slow (3 months) and has been reported to cause GI upset (not pleasant for someone in endurance sports). A good sports physician or GP may recommend a dose of iron injections. Research has reported that iron injections are able to raise your body’s iron stores (serum ferritin levels) to a significantly higher level over a 6-week period compared with a matched iron intake of oral supplements (Garvican et al 2014). Following the dose of iron injections (usually over a 6-week period with injections evenly spread out of this time) oral iron supplements may be recommended to ensure the iron levels remain at a desirable level (especially if you continue to exercise throughout this process). If you have received iron supplementation, it is a good idea to re-check your iron stores 10-12 weeks after commencing treatment. This will help determine if supplementation should continue or not.
A ‘last resort’ iron deficiency treatment is an iron infusion. However the infusion process is not supported by WADA. Athletes who require an iron infusion (in particular top age groupers and professional) will need to apply for a special exemption from WADA before receiving this treatment.
Well, hopefully that covers everything and I hope that I have been able to help in understanding why as athletes we need iron and what we can do to prevent the development of an iron deficiency.