Good Nutrition Nutrition

Nutrition Notes Topics

Iron (Fe)

Iron needs to be absorbed and maintained in the body within a narrow range for optimal health. Iron absorption is regulated. Several different proteins have been identified as contributors to the process. Iron disorders are generated by both Fe deficiency and Fe overload.

Iron deficiency is the best advertised, and perhaps most common nutrient deficiency. The advertised image of "tired blood" has prompted generations of tired people to take iron supplements. Iron deficiency causes a characteristic anemia with small pale red blood cells, deficient in oxygen-carrying hemoglobin. Iron supplementation cures this anemia, and is one of the more gratifying treatments in the medical repertoire. Iron is stored in the bone marrow, and once full, can supply enough iron for several months of dietary iron deficiency. Women store less iron than men, and lose iron monthly in menstrual blood, and are therefore much more likely to suffer iron deficiency than men. Infants are born with iron stores sufficient for 4-6 months, and thereafter need to ingest sufficient iron to supply absorption of 0.5-0.8 mg/day. Both breast milk, and cow's milk need iron supplementation, after 4 months.

Iron absorption is impaired by teas, coffee, cereal grains, antacids, and ulcer medications (cimetadine). Absorption is enhanced by VM.C, fish, and meat. Iron deficiency is routine in patients with inflammatory bowel disease, especially Crohn's disease. Injection of iron into buttock muscles is often necessary when iron absorption is blocked by a diseased small intestine. Diets often do not supply the RDA level of 10 mg/day, and iron supplements for high risk groups, especially menstruating, and pregnant women, infants and children with limited diets. Marginal iron deficiency, before the appearance of anemia, can impair exercise tolerance via malfunction of iron-using enzymes in the energy system. Increased lactic acid production with exertion is one of the markers of subtle iron deficiency. Iron intake of athletes should be carefully monitored. High doses of iron are definitely to be avoided. Iron may have a negative side. Higher blood levels have been correlated with increased risk of heart attacks. Iron surplus may aggravate hypersensitivity states. Storage of excess iron in body tissues is disease causing.

Iron Excess Iron has a negative side. Higher blood levels have been correlated with increased risk of heart attacks. Iron surplus may aggravate hypersensitivity states. Iron overload is less common than iron deficiency, but can result in serious disease, including cirrhosis, primary liver cancer, diabetes, cardiomyopathy and arthritis.

Fernández-Real et al provide convincing arguments that link iron and type 2 diabetes. They stated: “The relationship is bi-directional—iron affects glucose metabolism, and glucose metabolism impinges on several iron metabolic pathways. Oxidative stress and inflammatory cytokines influence these relationships, amplifying and potentiating the initiated events. The impact of these interactions depends on both the genetic predisposition and the time frame in which this network of closely related signals acts. In recent years, increased iron stores have been found to predict the development of type 2 diabetes while iron depletion was protective. Iron-induced damage might also modulate the development of chronic diabetes complications. Iron depletion has been demonstrated to be beneficial in coronary artery responses, endothelial dysfunction, insulin secretion, insulin action, and metabolic control in type 2 diabetes.“

Lower iron levels are associated with reduced cancer incidence in older men. Men with a mean age 67 years were assigned to repeated blood collections (n = 636) or to a control group (n = 641), originally for prevention of atherosclerotic complications. the mean ferritin levels at baseline were 122 ng/mL. Phlebotomy was scheduled every 6 months to maintain ferritin levels between 25 and 60 ng/mL. During a mean follow-up of 4.5 years, there were 60 new visceral malignancies in the control patients and 38 in the iron-reduction patients (p = 0.023). The risk of new malignancy (hazard ratio 0.65, p = 0.036) was significantly lower in the phlebotomy group. Among patients who did develop cancer, cancer-specific mortality (HR 0.39, p = 0.003) and all-cause mortality (HR 0.49, p = 0.009) were lower in the phlebotomy group.

To avoid iron overload, the best strategy is to avoid iron supplementation in males over 35 and females over 45. Any suspicion of increased iron stores in adults should be investigated with serum ferritin as the screening test – if elevated, a complete iron investigation should be undertaken.

Abnormal storage of iron in body tissues is hemosiderosis; iron accumulates in tissues in the genetic disorder, hereditary haemochromatosis (HHC), an autosomal recessive disorder. Mutations in the HFE protein cause HHC. Early symptoms of iron storage disease are arthritis, especially of the thumb and index finger and bronzing of the skin. Iron is transported in the blood by the protein, Transferrrin - in men, the carrier is up to 60% saturated and up to 50% in women.

There are different opinions as to a desirable range of iron saturation. A middle range with a mean less than 40 % is probably healthier than higher levels. Iron saturation in a small group of female college students was less than 16%, considered to be too low, but all the subjects measured were physical fit, high performing athletes with no evidence of iron deficiency anemia.


Iron is often conjugated or chelated for supplement purposes; ferrous fumarate, and gluconate are commonly available. Ferrous sulphate is the cheapest iron supplement. Iron preparations tend to be constipating. Unabsorbed iron tends to darken stool color. Iron may be taken with vitamin C to enhance absorption, but copper intake may be impaired, and produce the same iron-deficiency effect. Iron supplements in the range of 10-30 mg per day may be desirable for some children, adolescents and women of child-bearing age.