The Problem of Iron Excess
Research has shown that "oxidative stress" – the stress put on the body by excess iron reacting with oxygen to create oxygen free radicals – contributes to common diseases of aging such as cancer, atherosclerosis (vascular disease) and other diseases. “Anti-oxidant” foods and vitamins are widely used in attempts to combat excessive oxidative stress.
Less well known is the fact that iron accumulates in excess of body requirements as we age and causes damaging oxidative stress. Iron excess has been implicated in several diseases because susceptibility differs according to conditions in the various tissues in the body and because individuals differ in their ability to counteract excessive oxidative stress.
Iron is an essential element for almost all life forms because it is uniquely suited to react with oxygen. Normal activation of oxygen by iron is needed for cells to live, to breathe. Oxygen activated by iron reacts with food such as sugar to provide energy for life similar to the way oxygen burns with fuel to power an engine. However, the typical diet contains more iron than is needed to merely replace daily losses, and we lack the ability to shed this excess iron.
A notable exception is menstruating women who lose iron-rich blood monthly thus delaying iron accumulation until after menopause. Delayed iron accumulation because of menstruation is believed to explain why pre-menopausal women are the healthiest adults – they are generally healthier than men of comparable age.
Deterioration of health following menopause has been attributed to loss of the natural ability to reduce iron levels by menstruation. Men and women who live to old age characteristically have levels of iron in their bodies similar to those found in menstruating women, presumably because of a lifetime of relatively low dietary iron intake. Individuals who donate blood regularly also have improved health but blood donation usually does not continue throughout the adult years.
In contrast, African-American men and women typically accumulate more iron with aging than whites, which may account for why certain diseases are more prevalent and severe in blacks.
Our bodies are equipped with natural defenses that counteract disease-producing levels of oxidative stress in the form of natural anti-oxidants. However, their capacity can easily be overcome by exaggerated oxidative stress from progressive iron accumulation with aging. Oxidative damage from iron excess can “burn” vital cell structures such as cell surface lipids (fats that protect reactions inside cells) and DNA in the cell nucleus that spells out the genetic code. Exaggerated and uncompensated oxidative stress explains how excess iron can lead to cancer, atherosclerosis (vascular disease) and other diseases of aging.
Clinical research seeks to better define how much iron is “too much” and how to limit iron in the body to amounts that are safe.
