Boussingault in the 1860's was the first to regard iron as an essential nutrient for animals. During the 1920's feeding rats on an exclusive milk diet created an animal model for iron deficiency research.

In a healthy adult human there is 3 to 5 gms of iron. The newborn infant has nearly double the amount of iron per kg than adults. Sixty to 70 percent of tissue iron is classed as essential or functional iron, and 30 to 40 percent as storage iron. The essential iron is found as an integral part of hemoglobin, myoglobin (muscle oxygen storing pigments - particularly rich in deep diving animals such as whales, walrus, seals, etc.) and respiratory enzymes involved with intracellular oxidation-reduction processes.

Functions of iron include cofactor and activator of enzymes and metalloenzymes; respiratory pigments (hemoglobin - iron is to hemoglobin what Mg is to chlorophyll) and electron transfer for utilization of oxygen.

Iron is stored in bone marrow and liver (i.e.- hemosiderin and ferritin). Heme iron from meat is 10 percent available for absorption while iron from fresh plant sources are only one percent available because of the presence of phytates. Absorption takes place primarily in the duodenum where the intestinal environment is still acid.

Experimental evidence shows very clearly that "pica" is a specific sign of iron deficiency. Pica can drive children and adults to eat ice (pagophagia), dirt (geophagia) or lead paint.

Iron deficiency results from pregnancy, menstruation, chronic infections, hypochlorhydria (low stomach acid from salt restricted diets), chronic diarrhea, chronic bleeding (i.e.- cancer, ulcers, parasites, etc.) and impaired absorption (high fat diets, celiac disease, etc.).

Symptoms of iron deficiency include listlessness, fatigue, heart palpitations on exertion, reduced cognition, memory deficits, sore tongue, angular stomatitis, dysphagia, and hypochromic microcytic anemia.

Stomach hydrochloric acid is required for optimal absorption of iron, ascorbic acid increases absorption of iron, and clays and phytates decrease absorption of iron. The RDA of 18 mg per day as metallic iron is very low if one is a vegan eating high fiber, high phytate plant material.

Iron can cause cirrhosis of the liver, fibrosis of the pancreas, diabetes and heart failure - these diseases are not direct affects of iron per se, but rather the increased iron causes increased needs for selenium, copper, zinc, etc.

NOTE:

I have found, clinically, that the above-noted iron related toxicity could be avoided if the iron is in the water-soluble form. I have also noted in my practice that when looking at hundreds of blood chemistry results that about 75 % of American females are anemic – suffering from low RBC’s, low hemoglobin and/or low hematocrit. Most of the medical community is missing these important blood chemistry factors.

Iron is a versatile trace mineral nutrient that performs essential functions in the body. The presence of iron is responsible for the red color of blood. Red blood cells contain vast amounts of hemoglobin, the red oxygen transport protein of blood. Hemoglobin is red because it contains heme, the red, iron-rich pigment that actually binds oxygen and transports it to tissues. Iron deficiency leads to decreased red blood cells (anemia). Muscles contain a red, iron-containing protein called myoglobin, which stores oxygen for muscle contraction. The body contains a total of 3 to 5 gm of iron. Hemoglobin represents 65% of this iron; about 30% occurs as ferritin, the iron storage complex found in the liver, spleen and bone marrow.

Iron plays many roles. It is required to oxidize fuels to produce energy needed to maintain tissue functioning. Iron functions in cytochromes and other mitochondrial enzymes that burn carbohydrates and fat to form ATP, the cell's chemical energy currency. In this context, it is noteworthy that iron promotes the formation of carnitine, a compound required to transport fatty acids into mitochondria to be burned.

Connective Tissue This is the matrix that holds cells and tissues together. Iron-containing enzymes are involved in the formation of structural proteins collagen and elastin, required to form connective tissue.

Defensive cells The bacteria-killing white blood cells (neutrophils) depend upon iron to help generate highly reactive forms of oxygen (superoxide) that function as bactericides (bacteria destroying agents). Inadequate iron reduces the effectiveness of the immune system. The production of T-lymphocytes and red blood cells requires rapid DNA synthesis. An iron-dependent enzyme synthesizes DEOXYRIBOSE, the carbohydrate building block of DNA. Iron deficiency slows DNA synthesis.

Nervous System Iron is required in the synthesis of neurotransmitters, dopamine, serotonin and norepinephrine. Neurotransmitters are chemicals that help conduct impulses between nerve cells.

Liver Glucose (blood sugar) formation from amino acids requires iron. CYTOCHROME P450 is an iron-dependent enzyme system that helps the liver destroy toxic chemicals and waste products.

Antioxidant Enzyme Iron assists the action of catalase, a ubiquitous enzyme that degrades hydrogen peroxide to water and oxygen. Hydrogen peroxide is a by-product of cellular reactions and it is a powerful oxidizing agent unless inactivated.

Iron Deficiency

Iron deficiency is one of the most prevalent nutritional problems worldwide. Perhaps 1 billion people are to some extent iron-deficient. Half the world's inner city and rural poor may not be getting enough iron. Iron deficiency is the major nutritional deficiency among children, notably 1-to 2-year-olds and older children from low-income households. This is a concern in developing nations where the diet is inadequate (predominantly vegetarian) and parasitic diseases like schistosomiasis and malaria are common. As indicated by iron depletion data, as many as 60% of the U.S. population may not get enough iron. Teenagers, who rely on a junk food diet, dieters and pregnant or lactating women, individuals with liver disorders or blood loss, and low-income elderly persons may develop iron deficiency. An estimated 10 to 20% of women of childbearing age in the United States, Japan and England may be anemic (severely iron deficient) due to poor eating habits and blood loss through menstruation. Inadequate iron absorption among the elderly, due to use of antacids and low stomach acidity, frequently causes iron deficiency.

Subclinical (mild) iron deficiency, due to diminished iron storage without full-blown symptoms of iron deficiency, occurs long before anemia develops. Symptoms include fatigue, decreased alertness and learning problems in children, muscle weakness, susceptibility to chronic infections and frequent colds, low stomach acid and poor digestion, slow growth, dizziness and rapid heartbeat. Iron deficiency impairs work capacity and endurance.

Anemia represents the final stage of chronic, severe iron deficiency. Depleted iron reserves cause excessive fatigue due to inadequate oxygen delivery to tissues. Iron supplementation will cure anemia due to iron deficiency, but it will not cure pernicious anemia, which is due to vitamin B12 deficiency, nor will iron cure anemias based on other nutritional deficiencies such as vitamin B₆.

A variety of laboratory tests are used to evaluate iron deficiency. The most sensitive clinical test for mild iron deficiency measures serum ferritin. Serum ferritin may decline to 12 mcg/liter without visible symptoms. With serious iron deficiencies, the level of the iron-transport protein in the blood, transferrin, is elevated, but it contains less iron than usual (less than 16% saturation). With severe deficiency hemoglobin levels decline and small red blood cells appear, a condition called microcytic anemia, and the packed volume of red blood cells, the HEMATOCRIT, declines.

Requirements

The body hoards iron and efficiently recycles it; only small amounts (1.0 mg per day for adults) are excreted. The RECOMMENDED DIETARY ALLOWANCE (RDA) for pre-menopausal women (15 mg/day) is higher than for men (10 mg/day) to compensate for blood losses.

The RDA for iron varies with age, and the RDA during pregnancy and lactation is greater. The recommended daily intake during pregnancy is 60 mg per day. Iron supplements are required to achieve this level and are usually prescribed for pregnant women in the United States. Treatment of iron deficiency anemia calls for increased dietary iron, under professional guidance. A chronic iron deficiency may set the stage for excessive menstrual blood loss thus causing a vicious cycle. Iron supplementation can remedy this situation. Iron supplements should be taken at a different time than vitamin E because iron rapidly oxidizes vitamin E. Iron supplements often contain chelated iron, that is, iron bound to organic compounds in order to facilitate absorption. Examples include iron gluconate and iron aspartate.

Safety

Iron supplements may cause stomachache, diarrhea, constipation and dark stools, though iron complexed with protein may cause fewer side effects.

NOTE: These symptoms usually result from the use of hard to digest and hard to absorb forms of iron like Ferrous Sulfate (Feosol). Ferrous Gluconate and Ferrous Fumarate types of iron supplements are much more easily absorbed and cause much less, if any, of the above-noted side effects. Also, there is a new water-soluble iron product (i.e., just iron and water) available at 1000 ppm.

Iron overload can occur with inherited iron storage disease (hemochromatosis), a common trait. Particularly men who are susceptible to hemochromatosis and who take high iron supplements for long periods may develop iron overload. They should probably avoid iron supplements. Iron supplements should probably be avoided by healthy, nondeficient people for additional reasons: Excessive iron suppresses the immune system. High blood levels of iron are associated with increased risk of free radical damage and cancer. Stored iron (ferritin) can be a risk factor for coronary diseases. U.S. men with high blood concentrations of ferritin (more than 200 mcg per liter) are more likely to suffer heart attacks as men with lower ferritin values. It is postulated that too much iron can promote the formation of highly reactive forms of oxygen (free radicals) that can attack low-density lipoproteins (LDL), a particularly dangerous type of cholesterol. Oxidized LDL is more likely to stick to arterial walls and trigger fatty plaque buildup, which can clog arteries. Scientists also speculate that free radicals themselves damage arterial walls and heart muscle tissue. Do not exceed 18 mg of iron per day unless advised to do so by a physician.

Several thousand children are poisoned each year by iron supplements. As few as six iron supplement tablets can kill a child. Get the child to a hospital immediately if consumption of iron supplements is suspected.

Pollitt, E., "'Iron Deficiency and Cognitive Function," Annual Review of Nutrition, 13 (1993), pp. 521-37.

NOTE: It has been my clinical experience in reviewing hundreds of blood chemistries and blood count that probably 75% of American females are anemic. Therefore it is critical that these ladies use a good water-soluble iron product. And take extra vitamin B₁₂, either 2000 mcg orally 3 times weekly or 2cc intramuscular injection of vitamin B₁₂ twice weekly for 2 to 3 months, at which time then you can switch to the oral vitamin B₁₂. Most physicians are letting these ladies slip through the system and not catching this subclinical anemia.