Who is affected by iron deficiency?
Although almost anyone can experience iron deficiency, it is a condition that occurs more commonly in athletes than in the general population. There is a higher demand for iron with regular intense exercise, and this higher demand is caused in-part by the following factors:
- Increase in red cell mass (hard training stimulates an increase in blood cell and blood vessel production, increasing the demand for iron).
- Increased loss of iron through sweat
- Foot strike hemolysis (the destruction of red blood cells from the impact of running)
- Blood loss.
Why is iron so important?
Iron plays an important role in oxygen delivery. It is a constituent of hemoglobinin the blood, and myoglobin in skeletal muscle cells, making it possible for oxygen molecules to bond properly and to be delivered to working tissue. This becomes extremely important during athletics as the demand for oxygen is greatly increased in the skeletal muscle. Adequate iron stores are also vital with respect to optimal functioning of mitochondrial respiration, so that more subtle deficiencies (even in the absence of frank anemia) have been associated with impaired endurance performance.
How much iron does an athlete need?
The recommended daily iron allowance for adults is 10 mg (elemental iron) in males and 15 mg in premenopausal women. It is not known exactly how much more iron is required for athletes in particular sports, but it is known that overall needs are increased in athletes relative to the general population.
What are the different types of iron that can be consumed?
There are two types of iron that are found in foods: heme iron and non-heme iron. Of the two, heme iron is absorbed into the body more rapidly, but the absorption rate of non-heme iron can be increased by administering it with vitamin-C or with other heme-iron sources.
Sources of Heme iron include:
- Red meat (beef, liver, pork, lamb)
- Chicken
- Fish/seafood
Sources of Non-heme iron include:
- Dried beans
- Dried fruits
- Eggs
- Cereals
- Whole grains
- Almonds
- Broccoli
- Spinach
Is supplementation necessary?
Many athletes want to know if taking iron supplementation will optimize energy for competition or training. Most athletes can obtain adequate amounts of iron through their diet, but there is still a significant minority of female (typically endurance) athletes whose baseline iron stores are inadequate. It is not recommended that any athlete take iron supplements without the direction of a physician, and then only after proper laboratory evaluation. This is especially important in male athletes. Athletes with the genetic predisposition for hemochromatosis absorb excessive amounts of iron into the body. This can cause irreversible organ damage, and blind supplementation in this setting is potentially dangerous. Even in the absence of hemochromatosis, excessive iron intake can actually induce zinc and copper deficiencies. Screening asymptomatic athletic populations at high-risk is therefore justifiable, and is relatively common among health care providers dealing with major intercollegiate athletic or other elite populations.
It is important to remember that barring a genetic problem, if an athlete is practicing proper nutrition, they will not be at risk of iron overload and will usually avoid iron deficiency as well. Most importantly, it is vital to ensure that athletes are educated on sound nutritional guidelines as pertain to their training and competition.