Performance: Iron Deficient Man
Iron is essential for making the red blood cells that carry oxygen around your body. Reduced haemoglobin synthesis generally means reduced performance, which is why adequate iron levels are so important for athletes.
Endurance athletes are particularly at risk of suffering the effects of iron deficiency. Appropriate dietary modifications or supplementation might be required with a big emphasis on ‘might’. Too much iron can be very dangerous potentially leading to organ damage so make sure you see your GP and get tested before turning into a vampire and switching to cow blood smoothies.
Low Iron/Anaemia Symptoms
Common symptoms include fatigue, poor sleep, weakness and poor performance. The problem with the symptoms of iron deficiency or anaemia is that the symptoms are much the same as what most athletes feel when you’re in a heavy training phase. The important distinction is that when you’re not in periods of hard training that ‘whacked’ feeling still remains. The ‘irony’ of iron status is that it’s very normal to have lower iron stores and reduced haematocrit (the ratio of the volume of red blood cells to the total volume of blood) during periods of heavy training or racing. During extended periods of rest tends to be when your iron count and haematocrit go up. Incredibly, professional cyclists of 10 – 20 years ago would finish 3-week tours with a haematocrit of 49-50 (pretty much the maximum ‘natural’ limit). Or perhaps not so incredibly now we know what we know. Regardless, don’t freak out if you’re iron is a little low especially if you’re 6 weeks out from an Ironman and cranking out multiple long runs each week. Don’t be tricked into thinking that training for an Ironman is really healthy or normal. Put your body under a lot of physical stress and it’s going to be very difficult to have above average iron stores. When you’re well below the range of normal, that’s the time to freak out and make some changes to the training load and diet.
When you’re well below the range of normal, that’s the time to freak out and make some changes to the training load and diet.
Why endurance athletes are more at risk
- High requirements due an increased red blood cell mass especially when consistently exercising in hot environments
- Iron loss through sweat
- Foot strike haemolysis – basically, the continual pounding of our feet on the ground from running breaks down red blood cells
- Triathletes often exercise multiple times per day which can mean extended periods where blood is shunted away from our gastrointesintal tract to our muscles leading to poor absorption of the nutrients in the food we’ve eaten during that period of time. Additionally, GI bleeding can occur during strenuous exercise
- Some athletes rely heavily on coffee (which inhibits iron absorption), and snack on ‘quick fix’ foods to help fuel the high energy demands at the cost of more nutrient dense meals
Getting iron from your diet
There are two forms of iron in the food we eat. ‘Heme’ and ‘Non-heme’ Iron. Heme Iron is basically found in meat sources and is much easier for humans to absorb than Non-heme iron. People typically absorb 15-35% of the heme iron they consume (Insel et al 2003) while examples of non-heme sources like spinach and soybeans will only offer 2 and 7% of their iron to be absorbed respectively.
Probably the most well known way to maximise the absorption of iron from your iron containing food is Vitamin C. Chow down an orange for desert after your steak. Vitamin C has shown to increase absorption of iron by nearly 3 times than without Vitamin C.
There are a whole host of foods that inhibit the absorption of iron. I’m not recommending that if you’re looking to maximise iron absorption that you should cut out these foods. Rather, time them separately to the foods or meals where you plan on absorbing iron. Examples of inhibitors include Phytic Acid found in grains, legumes and other plant foods, coffee, cocoa or cacau, fibre, tannic acid in tea and minerals that compete with iron for absorption such as calcium, zinc and magnesium.
I’ve changed my diet but my iron is still low
A few options are available. As mentioned, it can be difficult to rebuild your iron stores during heavy training regardless of how perfect your diet is. It’s crucial to plan periods of rest into your annual training plan to ensure that your body has time to replenish fully, including your iron stores.
Other considerations that can drastically affect iron status include conditions such as Coeliac Disease, lactose intolerance and Inflammatory Bowel Disease (IBS) to name a few. If you’re ticking all the right boxes with diet and rest and you’re still really low, then a trip to your GP might be in order.