Iron in a nutshell
Iron is a vital component of hemoglobin – the oxygen (and carbon dioxide) carrying component of red blood cells. However, too much iron can be as dangerous as too little.
What Is Iron?
When America's generation of Baby Boomers were young, there were three choices on television, ABC, CBS, and NBC. There were basically three types of television shows, news, a genre then known as shoot-'em-ups, and comedy. And there were three big advertisers, cigarette companies, gasoline companies, and Geritol, the makers of an alcoholic tonic laced with just enough iron to be passed off as healthy.
Alternative names: Iron. The most common form of iron used in supplements is ferrous sulfate, which is also known as iron (II) sulfate. Ferrous fumarate is also used in prescription medications for iron-deficiency anemia. Heme iron polypeptide is used when other supplements are poorly absorbed; it the same form of iron found in animal blood (in meat) and it is up to 24 times better absorbed than other iron supplements.
The best way to understand what iron does in living organisms is to consider how iron turns into rust. Every living thing on our planet contains iron. In the form iron appears in living organisms, it forms bonds with negatively charged substances. Just as iron can combine with oxygen from the air and form rust, iron in an enzyme can “grab” oxygen and other similarly charged elements like sulfur. It can hold on to them during a series of chemical reactions and then let go of them at just the right time.
Even single-cell microorganisms use iron to make a detoxifying (and in some cases, pre-toxifying) enzyme called cytochrome P450. Living things ranging from bacteria to people use different kinds of P450 to transform chemicals from their environment into forms that are safe inside the organism, and also to recycle waste products out of the organism. In human beings, various kinds of cytochrome P450 make toxic substances non-toxic or sometimes make non-toxic substances toxic, activate vitamins, and create and recycle hormones and cholesterol.
Iron is also an essential component of myoglobin and hemoglobin. Myoglobin forms a loose bond with molecular oxygen in muscles, ensuring that the muscles have a steady supply. Hemoglobin forms a loose bond with molecular oxygen in red blood cells, transporting oxygen through the bloodstream. Hemoglobin also carries carbon dioxide to the lungs where it is exhaled.
Humans and most other living things store iron in the form of ferritin. This protein stores iron in a safe form and carries it where it is needed without damage to tissues. Without ferritin to serve as a buffer between elemental iron and the tissues, iron would react with oxygen and release free radicals that could disrupt every part of cells all over the body.
Most plants and animals increase their production of ferritin when they are infected or they are under stress. Making more ferritin keeps iron out of circulation so it does not feed pathogenic microorganisms or add to stress caused by other kinds of production of free radicals.
What Does Iron Do in the Human Body?
Part I. The Perils of Too Much Iron.
The horn of eastern Africa was struck by drought and famine in 2011, but it has been struck by drought and famine many times before. In the 1970's kindhearted missionaries set up a feeding mission in Ethiopia and set about the task of bringing hundreds of children back from starvation. But a miscalculation was soon to result in tragedy.
A nutritionist with the mission group suggested that the children looked anemic and they would benefit from iron and vitamin B12 shots. About 500 children got the injections, and within a month, about 300 died and most of the remaining 200 were deathly ill. Iron, the missionaries learned to their horror, is essential not just for children but also for malarial parasites.
Too much iron is as dangerous as too little. In Africa, many people of Bantu descent have a hereditary condition in which a defect of a gene that causes a condition known as African iron overload. Elsewhere in the world, about 1% of people of European descent, particularly people whose ancestors lived in the British Isles, have carry a mutation of a different gene that causes a disease known as hemochromatosis. Both conditions involve a defect in a protein called ferroportin, which moves iron from inside a cell to outside a cell.
Both African iron overload and hemochromatosis create a kind of ferroportin that does not release iron from the white blood cells that carry it to the bones for the creation of the hemoglobin that gives red blood cells their ability to carry oxygen. Since the bones don't get enough iron, they send a signal to the intestines to absorb more iron out of digested food. This new iron, too, tends to accumulate in the white blood cells.
Eventually these white blood cells die and release their iron. The body makes ferritin to capture the iron so it cannot “rust” tissues. Eventually the ferritin becomes so saturated that it is impossible to prevent iron from destroying organs all over the body. The insulin-making cells of the pancreas, the testosterone-making cells in the testes in men and the estrogen-making cells in the ovaries in men slowly fail. Iron accumulates in the skin, causing a permanent bronze to orange color in the skin, and accumulates in the eyes and brain. Death usually results from liver cancer or the complications of diabetes.
What Does Iron Do in the Human Body?
Part II. The Perils of Too Little Iron.
Just as dangerous to human health, however, is the failure to absorb enough iron from food. Iron-deficiency anemia is the inability of the body to make red blood cells because of not having enough iron, as contrasted to having tremendous amounts of iron that the cells that make hemoglobin cannot use.
The underlying cause of iron-deficiency anemia may be diet, eating foods that are devoid of iron. But since almost all foods made with flour in the United States and Canada are fortified with supplemental iron, inadequate diet from the diet is very rare in North American and it is uncommon anywhere in the world. Iron-deficiency anemia is most commonly caused by blood loss:
- People who have bleeding during surgery without replacement transfusions sometimes develop iron deficiency.
- Women who have heavy periods and/or fibroid tumors sometimes experience enough bleeding that they become iron-deficient.
- Pregnancy often causes blood loss and iron deficiency.
- Insufficient production of stomach acid, over a period of years, can cause iron-deficiency anemia because not enough iron is absorbed through the small bowel.
- People who have “short bowel syndrome” sometimes do not absorb enough iron to prevent deficiency.
- Crohn's disease, irritable bowel syndrome, inflammatory bowel disease, colon or bowel surgery, and gastric bypass surgery for weight loss can cause iron deficiency.
- Celiac disease, caused by a sensitivity to gluten in wheat and other grains, can cause iron-deficiency anemia.
- Intestinal parasites can cause iron-deficiency anemia.
- Pica, the practice of eating substances that are not food (such as ice cubes, laundry starch, dirt, or clay) can coat the small intestine and prevent the absorption of iron and other nutrients.
- Heart valve disease, which breaks down red blood cells, can cause iron-deficiency anemia.
- Bleeding ulcers or bleeding gums can cause iron-deficiency anemia.
- Outside the United States and Canada, people who have very limited incomes and who try to live on bread and tea often develop iron-deficiency anemia. In the United States and Canada, bread is usually a high-iron food due to fortification at the flour mill.
- People who consume foods that are high in phytates (such as whole grain breads), oxalates (such as lamb's quarters or spinach), phosphates (such as certain cured meats and hot dogs), or tannins (tea and herbal tea) may have trouble absorbing iron and other minerals.
- Children in developing countries who walk barefoot sometimes develop hookworm infections that cause iron depletion.
- People who run barefoot sometimes develop iron deficiency, due to the breakdown of red blood cells.
- Vigorous outdoor activity can cause a condition known as march hemoglobinuria. Once common when soldiers marched to their battlefields, this condition causes loss of hemoglobin through the urine due to severe stress on the bladder.
- Vitamin C deficiency aggravates iron deficiency.
- Dialysis can break down red blood cells and cause iron-deficiency anemia.
When there isn't enough iron for the body to make hemoglobin to carry oxygen through the bloodstream, anemia causes a predictable series of symptoms.
- Usually people who have iron-deficiency anemia can point to a specific event that seems to have triggered their symptoms, such as loss of a large amount of blood, or the beginning of pain from uterine fibroids, or the first attack of Crohn's disease or gluten sensitivity. (Some people become gluten sensitive after they have bowel surgery.)
- People who have iron-deficiency anemia often develop pagophagia, cravings for ice or ice-cold drinks. This also occurs in people who have hemochromatosis.
- There may be fatigue when climbing stairs or walking up an incline.
- Deficiency of iron-bound proteins other than hemoglobin may cause attention deficit, restless legs syndrome, muscle dysfunction, and the growth of webbing in the throat that interferes with swallowing.
What Should You Do to Get Your Iron Levels Right?
Both too little and too much iron cause serious health problems. If you suspect you have either a low-iron or a high-iron condition, you should not try to treat the problem entirely on your own. It is absolutely essential to have a blood test to measure your iron interpreted by a doctor to determine your nutritional status, even if you are sure you “should” have either anemia or hemochromatosis.
If you have high iron levels, you may need to have a procedure known as prophylactic phlebotomy. The doctor draws blood (a pint/500 ml or more) once to three times a week until iron levels fall to normal. It is also possible to lower blood iron levels by taking alpha-lipoic acid supplements. This antioxidant helps keep ferritin from becoming saturated and releasing free iron, but as noted in the article on lipoic acid, using the supplement successfully requires that you also take its cofactors.
If you have low iron levels, the doctor may offer you an oral iron supplement or treatment with an IV medication. The older intravenous iron medications were infamous for causing anaphylactic shock, but newer iron medications do not pose this problem. Only your doctor will know which medication is right for you.
What If You Just Want to Be Sure You Get Enough Iron in Your Diet?
Up to 1% of the population of the world has some form of iron overload disease. Up to 8% of people in industrialized countries and 20% of people in developing countries has some form of iron-deficiency anemia. But what if you have neither deficiency nor excess and you just want to be sure you get enough iron in your diet?
First of all, make it easy for your body to absorb the iron in your food:
- Avoid deficiencies of vitamin A and zinc. Both of these nutrients can interfere with your body's ability to absorb iron.
- Don't eat high-iron foods at the same meal as high-calcium foods. (Don't mix dairy and meat.) Calcium interferes with the absorption of iron.
- Don't eat high-fiber foods at the same meal as you eat high-iron foods. The phytate in high-fiber plant foods interferes with the body's ability to to absorb iron from food.
Then, plan to eat some iron-rich foods on a regular basis, enough to provide at least 25 mg but never more than 45 mg of iron per day. You can't more on some days and less on other days and your body will be able to sort out the difference by changing the rate at which it absorbs iron.
- A 3-1/2 oz (100 gram) serving of dried whale meat (not that we're recommending it) contains 72 mg of iron.
- A 3-1/2 oz (100 gram) serving of Raltson enriched bran flakes contains 68 mg of iron.
- A 3-1/2 oz (100 gram) serving of Kellogg's All-Bran or General Mills Total contains 60 mg of iron.
- A 3-1/2 oz (100 gram) serving of Malt-O-Meal or General Mills Cheerios contains 60 mg of iron.
- A 3-1/2 oz (100 gram) serving of duck or goose liver contains 31 mg of iron.
- A 3-1/2 oz (100 gram) serving of General Mills CHEX cereals (all varieties) or Quaker Cream of Wheat contains 30 mg of iron.
- A 3-1/2 oz (100 gram) serving of Quaker grits products contains 29 mg of iron.
- A 3-1/2 oz (100 gram) serving of spirulina contains 28 mg of iron.
- A 3-1/2 oz (100 gram) serving of cooked mussels contains 29 mg of iron.
- A 3-1/2 oz (100 gram) serving of cooked clams contains 14 mg of iron.
- A 3-1/2 oz (100 gram) serving of Italian turkey sausage contains 10 mg of iron.
- A 3-1/2 oz (100 gram) serving of baked potatoes with skin contains 6 mg of iron.
- A 3-1/2 oz (100 gram) serving of dried apricots or dried peaches contains 6 mg of iron.
- A 3-1/2 oz (100 gram) serving of duck breast contains 5 mg of iron.
Eating some of these foods on a daily basis ensures you will get enough iron. It also helps to cook in cast iron pots and pans and to cook with lemon juice, tomatoes, or other sources of acid in those cast iron pots and pans.
What About Using Iron to Support Recovery from Disease?
Iron supplements are sometimes helpful in recovery from restless legs syndrome, attention deficit disorder, and, of course, iron-deficiency anemia. You should not attempt to support recovery from any of these conditions with iron, however, without first seeing a physician.