Iron is an essential mineral to keep in balance.
by John R. Lee, M.D.
It used to be conventional medical wisdom that iron was an important part of a daily multivitamin. Now we know that excess iron can be very harmful, and that very few people should supplement it: women who are pregnant may need it, and perimenopausal women who are bleeding heavily month after month may become anemic and need it. In fact, it’s thought that people who are regular blood donors—men in particular—benefit from the blood loss involved because it lowers their iron levels. Having said this, it’s also true that iron deficiency is one of the most common nutrient deficiencies in Western cultures, primarily due to poor diet among those living at poverty levels.
What is it about iron that makes it so essential to health, and yet dangerous in excess?
Iron is Uniquely Essential
Among the various metallic elements that are essential to humans, iron is unique in a number of ways. The total quantity of iron in the adult human body is quite small, only 4 grams, about the amount found in a 3-inch nail. Its primary role is as a component of hemoglobin (in red blood cells) and myoglobin (in muscle cells), but it is also essential in small amounts for iron-containing proteins, such as in cytochromes, which are vital for normal cellular functions. In a typical adult, 2.72 grams are in red blood cells, 0.12 grams are in myoglobin, 1 gram is stored in the liver and spleen, 0.003 grams is found in transferrin (more about that shortly), and only 0.0035 grams are in cytochromes.
Iron is a very reactive mineral, perpetually in a dynamic state in the body, moving rapidly from one molecule to another. This reactive quality is what makes it useful in the transport of oxygen, but it’s also what makes it dangerous in excess. Iron exists in two primary forms in the body, either as ferrous iron or ferric iron. Ferrous iron is more active and available for use, while ferric iron tends to be a storage form. Excessive oxidation (from free radicals, for example) changes the iron to the ferric form, which will not function as an oxygen carrier.
Iron in Your Body
The majority of your body’s iron is found in hemoglobin, the part of red blood cells that carries oxygen for delivery to your cells. Hemoglobin is a highly complex molecule that has one atom of iron at its center. That one atom is what gives blood its red coloring.
After your bone marrow makes red blood cells they circulate in the blood for about 120 days, at which time they grow old and are destroyed. Thus, each day, nearly 1 percent of our red blood cells are destroyed and 25 mg of iron is released from their hemoglobin. However, the majority of this iron is conserved and reused. This is a bit odd since our environment provides abundant iron, leading some experts to theorize that at an earlier evolutionary epoch, iron may have been scarce.
Unlike other essential minerals, iron is not excreted in the urine, which serves to conserve it even further. However, iron is lost from the body by bleeding (including menstrual flow), from the gastrointestinal tract, in bile which is eliminated in feces, and in the shedding of mucosal and skin cells, and in hair. In males and non-menstruating females, the daily loss of iron is approximately 1.0 mg. Iron loss in menstruating females runs from 1.4 to 3.2 mg per day, depending on the blood volume of the menstrual flow. To remain healthy, the daily loss of iron, however slight it may seem, must be made up by a sufficient daily dietary intake.
People who are iron deficient (anemic) are often pale, irritable, and tire easily. Other symptoms can include increased blood pressure, dizziness, foggy thinking, muscle weakness, heart palpitations, impaired immune function, restless legs, itchy skin, hair loss and ringing in the ears.
Excessive iron in body tissues (hemochromatosis) is not desired either. The liver and spleen are the normal storage sites for excess iron. Excess iron leads to a number of undesirable conditions such as enlarged liver and cirrhosis, diabetes, hypogonadism and atrophy of the testes, joint degeneration, heart disease, dusty brown skin pigmentation and death usually due to cancer of the colon or liver. Excess iron is toxic to cells and creates oxidation reactions, often stimulating the growth of cancers due to other causes.
Excess iron can result from a genetic hemochromatosis abnormality, which occurs in approximately 4 percent of adults, albeit to varying levels of risk.
Excess dietary iron intake is uncommon in Western cultures: its most common cause is probably in patients whose doctors advised unnecessarily high doses in supplements. It can also be caused by cooking in iron pots and pans. A common result of excess iron intake is very black feces. This can be confusing since it can also indicate bleeding within the GI tract.
Iron in Your Food
In food, iron is found in two forms: heme or organic iron (e.g. from red meat), and nonheme or inorganic iron (e.g. from vegetables and grains). Relatively speaking, absorption of iron is low. Absorption of nonheme iron from vegetables and grains is about 10 percent, while absorption of heme iron from meat is about 30 percent. Further, heme, itself, increases absorption of other dietary iron. That’s why a little red meat now and then is good for the blood.
Some foods enhance iron absorbability and other foods inhibit it. For example, iron from corn is better absorbed when eaten with fish or meat, whereas milk inhibits iron absorption. Vitamin C increases iron absorption by a factor of four. Being a powerful reducing (antioxidant) agent, it changes ferric iron to the better absorbed ferrous form and helps maintain it there. The amino acid cysteine is also thought to play a role in maintaining the ferrous form of iron.
Absorption of iron may also be inhibited by coffee, tea, soy products and excessive calcium. It’s best to take iron and calcium supplements separately.
Iron can reduce the absorption of zinc and thyroid supplements, so take those separately also (calcium can also block thyroid absorption).
Some types of iron deficiency may have to do with a reduced capacity to convert stored ferric iron (ferritin) to the ferrous form, which may indicate a need for vitamin B12 and B6, folic acid, copper and molybdenum.
A balanced diet with a wide variety of foods, combined with adequate vitamin C, usually provides sufficient iron absorption for usual daily needs. In women with heavy periods who become anemic, it is my experience that the addition of vitamin C with meals will often restore normal hemoglobin levels.
In my first week of medical practice, I was called by a farm family to see a two-year-old boy with fever and seizures. The young boy was extremely pale. I admitted him to the local hospital for further evaluation. I could find no cause of his pallor. The next day, he broke out with measles. In talking with his parents, I discovered the boy’s diet to be mostly milk. Rather than spend a lot of their money on unnecessary tests, I convinced the family it was time to give him meat and vegetables. His hemoglobin returned to normal in record time. However, because of his admission to the hospital, which lacked an isolation room for kids that age, the whole hospital was quarantined for two weeks! What a great way to start practice.
How Your Body Maintains Iron Balance
The body’s ability to maintain proper iron levels is quite amazing. Iron absorption varies relative to iron stores in the body. When iron stores are low, absorption is greater than when iron stores are high. The mechanism for this control of iron absorption is quite unique.
In the mucosal cells of the intestine, iron is transferred to a small iron-binding protein, which is then transferred to the plasma (the watery part of the blood) where it is bound to an iron transport protein called transferrin, or to a iron storage protein called ferritin. Since the life span of intestinal mucosal cells is only 3 to 5 days, the iron that is bound to ferritin is constantly lost with the degraded cells in the feces. This process acts as a buffer to prevent iron overload. Iron transported in blood by transferrin is always in the ferric form. Once released into body tissues, the iron is changed (reduced) to the more active ferrous form. Iron that is bound to ferritin, on the other hand, is transported primarily to the main storage sites, the liver and the spleen. This plays an important role as a protection against excessive iron intake and as reservoir for future use in times of low iron intake.
Measuring Iron Levels
The concentration of transferrin-bound iron can be used to evaluate one’s iron status. When anemic, the iron concentration of transferrin is low, and, in the case of iron overload, the concentration is high, to the point that the iron-binding sites of the transferrin are fully saturated with iron. This concentration can be tested (serum ferritin), and is an especially helpful as an indictor of iron deficiency or iron overload.
Iron-deficiency anemia appears in three different types relative to red blood cell appearance:
1) With excessive blood loss such as occurs during heavy menstrual bleeding or the GI bleeding often caused by taking NSAIDs such as aspirin, red blood cells appear normal in size and hemoglobin content, but their number in circulation is reduced. This test is called a red blood count (RBC).
2) When deficient in folic acid or vitamin B12, the red blood cells are generally larger (called macrocytic) and the number in circulation is reduced. This is found, for example, in pernicious anemia, which occurs in people who lack intrinsic factor, the protein that is necessary for B12 absorption. This test is called the mean corpuscular volume (MCV), which measures the volume of red blood cells. A related test is the mean corpuscular hemoglobin (MCH), which measures the amount of hemoglobin in a single red blood cell. An increased MCH and MCV are a good indicator of the above vitamin deficiency, while a decreased MCH and MCV often point to iron deficiency anemia.
3) Simple iron deficiency causes the cells to be smaller than normal and have a reduced hemoglobin content. Most doctors doing standard blood tests (a chem panel) will test hemoglobin (HBG) as a matter of course.
Treatment of these conditions requires proper diagnosis of the cause of the anemia. If bleeding is suspected, the cause must be found. Low grade bleeding from the gastrointestinal (GI) tract such as from taking aspirin, ulcers, colitis or colon cancer often are first revealed by anemia. Pernicious anemia often causes neuro-motor problems before the anemia is evident and is often mistaken for senility in the elderly. Even before anemia is evident, iron deficiency can be found by measuring plasma iron levels (serum iron) and the total iron-binding capacity of plasma transferrin (serum ferritin). It is desirable to diagnose, and thereby prevent iron deficiency, before anemia develops.
The Bottom Line
It’s important to eat a wholesome diet that includes a variety of iron-containing foods, so that you can maintain your body’s iron levels. It’s equally important not to take iron as a supplement unless you’ve tested deficient and are sure you need it. It’s a good idea for perimenopausal women, or women who bleed heavily during menstruation, to have their iron levels tested at least once a year to check for iron deficiency anemia. If you do have your iron levels tested, be sure that your doctor is doing the tests that will determine the underlying cause of the deficiency.
That's A Good Question
Q: My doctor wants me to take iron supplements because I have anemia caused by heavy menstrual bleeding, but when I take them I get really sick to my stomach and feel terrible all over. What do you recommend?
A: Many women are advised to take an iron supplement at some point during their lives, either during pregnancy or due to heavy bleeding during perimenopause, which can cause iron-deficiency anemia. NSAIDs (non-steroidal anti-inflammatory drugs such as aspirin and ibuprofen) can cause chronic gastrointestinal bleeding that can also result in enough blood loss to cause anemia. Women with anemia tend to be pale and tire easily, and they tend to bleed more readily, which only exacerbates the problem.
Taking an iron supplement supplies the bone marrow with the material it needs to make hemoglobin, a part of red blood cells. However, iron deficiency may be caused not only by blood loss, but also by poor iron absorption. There are two factors that need to be recognized in regard to iron absorption. One is the benefit of heme iron, such as found in meat. Heme iron stimulates iron absorption. It only takes a small amount of meat in the diet (such as in Asian diets) to stimulate good iron absorption. Those folks who totally abstain from meat are denied that benefit.
The second factor in iron absorption is vitamin C. The addition of a small amount of vitamin C with meals increases iron absorption from food six-fold. The total daily amount of vitamin C needs to be only about 500 mg per day to create this benefit. Milk, on the other hand, inhibits iron absorption, which is one more reason among many to stay away from it.
In my practice over the years I encountered many women with heavy periods, leading to anemia, who I treated without adding iron supplements. I encouraged them to avoid milk, add a little meat (especially liver—organic please) two or three times a week, and to add 250 mg of vitamin C with meals.
If you continue to have anemia despite the above approach, and iron supplements make you sick, a substance called lactoferrin might help. This glyco-protein is found in very high amounts in colostrum, the first milk secreted by mammalian breasts after birth, and in small amounts in regular milk. Lactoferrin enhances iron absorption, and at the same time protects the body from the negative, oxidative effects of excess iron. It can decrease or eliminate the side effects of nausea and constipation caused by iron supplementation. Recent research suggests that lactoferrin may also have beneficial effects in regulating the immune system, as well as anti-inflammatory, anti-bacterial and viral, and antioxidant effects.
Lactoferrin is listed as an ingredient in some colostrum products, which you can find at your local health food store. It only takes about 20 mg of lactoferrin, taken with the iron, to reduce or eliminate the side effects.
This article was originally published in the John R. Lee, M.D. Medical Letter.