IRON - Yes or No?
By William Misner, Ph.D.
Iron, as most athletes know, is found in every cell in the body, as it is an important mineral for all body functions. Most of the body's iron is in the form of hemoglobin, found in the red blood cells. A smaller portion of iron is found in myoglobin, a type of hemoglobin that is found in muscle tissue, and in the oxidative enzymes within the mitochondria. Hemoglobin is responsible for oxygen transport from the lungs to the muscles. Both myoglobin and oxidative enzymes are major components in energy production. Iron is also very important in immune system function.
It's apparent that iron is an extremely important nutrient, especially for endurance athletes. An iron deficiency can negatively effect oxygen transport to the muscles if below-levels of hemoglobin are detected. An iron deficiency can also impair energy production if myoglobin and mitochondrial enzymes are sub-normal. However, there are also risks involved (increased free radical production being one) from too-high iron intake. So do we need to take supplemental iron? Why don't Premium Insurance Caps contain iron?
Most Americans if they consume adequate calories via balanced menu, consume enough iron without the need to supplement iron. Lieberman & Bruning (1990) recommend an Optimal Daily Allowance (ODA) of 15-25 mg. for men and 20-30 mg. for women, daily iron intake. It is very easy to exceed these values from food alone. In humans, high levels of storage iron as well as low iron binding capacity are considered at-risk for ischemic heart disease progression. The mechanism for this is likely elevated hydroxyl radical production due to an enlarged transit iron pool. Researchers van Jaarsveld, Kuyl, & Wiid determined whether diet-containing iron concentrations near the recommended upper limit tended to alter the degree of myocardial ischemic/reperfusion injury in rats or whether simultaneous antioxidant supplementation had cardiovascular-debilitating effects. [Res Commun Mol Pathol Pharmacol 1994 Dec;86(3):273-85]
If an athlete consumes excessive above RDA levels of dietary iron, they may experience an increase in harmful free radical oxygen species damages. Such increases in free radical levels may impose premature fatigue or further neutralize the supply circulating exogenous antioxidants.
IRON INTAKE FROM FOOD INTAKE OF ATHLETES AND NON-ATHLETES
The above results may implicate an iron-supplemented diet as imposing increased degree of oxidative injury if simultaneous antioxidant supplementation prevented much of this increase. Twenty three customers, 16 athletes and 9 non-athlete's iron food intake was determined by computer-generated dietary analysis performed over a 36-month period.
|Males - Daily Iron Intake From Foods||N=9||AVERAGE=279%|
|Females - Daily Iron Intake From Foods||N=7||AVERAGE=193%|
SEDENTARY NON ATHLETES
|Males - Daily Iron Intake From Foods||N=4||AVERAGE=158%|
|Females - Daily Iron Intake From Foods||N=5||AVERAGE=115%|
Male athletes [279% x RDA] and female athletes [193% x RDA] consume more calories than sedentary counterparts, therefore their total iron intake from food sources exceeds dramatically their required daily allowance (by a combined average of average of 241% x RDA). This along with the advice of a cardiovascular surgeon led us to remove iron from Premium Insurance Caps.
This also is the basis for the suggestion that blood serum markers of iron deficiency substantiate and be medically monitored during any sort of iron supplementation, dose, and duration. Editors at the Life Extension Foundation have suggested not taking iron supplements unless a blood test reveals a deficiency. According to the Foundation, "Most people have too much iron in their body. Excess iron generates massive free radical reactions. Human epidemiological studies show that those with high iron levels are far more likely to contract cancer and heart disease. A growing body of evidence implicates iron in neurological disorders such as Parkinson's disease."
So for the majority of us, adequate iron is easily obtained from the diet and supplemental amounts are not necessary. If you aren't sure about your iron status, a CBC (Complete Blood Count)/Chemistry Profile blood test will determine what your iron status is and whether supplementation is necessary.