Maintaining a balance between the various vitamins and minerals in the body while performing at a high level is essential, but can also be tricky to maintain through food alone.
Iron is a mineral that is vital for health and performance in both males and females and is needed for multiple cellular functions and physiological systems. Iron deficiency is one of the most common deficiencies in sport.
Athlete's iron requirements are higher due to the increased erythropoietic drive caused by high volume training. EPO (erythropoietin) is the hormone produced by the kidneys and released when blood oxygen levels are low.
The key function of iron is to facilitate oxygen transport by haemoglobin of red blood cells carrying oxygen from the lungs to all parts of the body.
Iron balance is particularly difficult for female athletes as its under the control of many factors.
NOT JUST A BIT FATIGUED
Female athletes are particularly prone to iron deficiency due to menstruation, there are however, many other aspects that contribute to anaemia or iron deficiency.
Besides menstrual blood loss, other factors such as the peptide hormone hepcidin which controls iron absorption, vegetarian and vegan diets, energy deficient diets, eating disorders, environmental stressors such as altitude, exercise, and of course, genetics.
Haemoglobin is carried in red blood cells which are produced and cleared at a rate of approximately 2 million per second, therefore total haemoglobin mass (tHb-mass) is a primary determinant of VO2max and very reliant on iron stores.
Iron is a necessary cofactor in mitochondrial (power-house of the cell) function , and is also essential for brain function and cognitive performance.
Iron deficiency could hamper decision-making, concentration and affect motivation.
Factors such as sweat rate, foot strike hemolysis (also called runner's anaemia), celiac disease, Crohn's disease, and other gastrointestinal issues may also cause iron deficiency through blood loss.
The average adult intake of iron is about 10-15mg per day, of which we only absorb about 1-2mg, while the rest passes out of the body in stool.
Cells in the section of the small intestine (duodenum) absorb iron after enzymes convert iron in food from ferric iron (Fe3+) to a more absorbable ferrous iron (Fe2+). Genetics (and diet)and gastric PH levels play a major role in enzyme function and conversion and absorption rates differ between individuals.
A full blood analysis is the safest method to determine iron status. Anaemia, deficiency, or iron overload will all result in health issues, and of course, loss in performance.
TOO MUCH OF A GOOD THING?
Iron overload can be the result of excessive oral supplementation or a genetic variation resulting in haemochromatosis. Iron is highly sensitive to oxidation and may result in damage, a bit like human rusting.
Hereditary haemochromatosis is a genetic disorder in which there is excessive accumulation of iron in the body. Genetic mutation in HFE gene is considered to be the most common hereditary diseases in Caucasian populations, with European Caucasians showing a prevalence of 1:400.
The HFE protein regulates the production of the protein hepcidin, which is located on the surface of cells, primarily liver and intestinal cells. Hepcidin is considered the 'master' regulatory hormone and determines how much iron is absorbed from the diet and determines how much iron is released from storage sites in the body.
Iron absorption is tightly regulated and on average a human absorbs 10% of dietary iron. In individuals with hereditary haemochromatosis, the daily absorption of iron from the intestines is greater than the amount needed to replace losses and this excess is accumulates in the body.
Individuals with the HFE mutation receive regular blood draws (phlebotomy), regular blood donations, and should follow a low iron diet.
TEST, DON'T GUESS
Female athletes as well as males, should have regular iron panels particularly if they are vegetarian or vegan. Don't wait until competitions kick in! Depending on the severity, supplementation to correct iron deficiency may take a while, and many doctors will provide iron injections. A nutritional therapist or dietician will also determine the correct iron supplementation and nutrition for you.
REFERENCES
Charles R. Pedlar et al. Iron balance and iron supplementation for the female athlete: A practical approach. European J. of Sport Science (2018)18 (2): 295-305
Dellavalle et al. (2012) Iron status is associated with endurance performance in and training in female rowers. Medicine & Science in Sport & Exercise 44(8), 1552-1559
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