If iron deficiency is dangerous for health, so is excess iron. What are the consequences of too much iron? Symptoms ? How to eliminate it? Foods to avoid? Explanations by Pr Thierry Leblanc, pediatric hematologist at Robert-Debré Hospital.
From how much do we speak of excess iron in the blood?
“It is considered that there is an iron overload in the blood when the values are above the usual values of the martial balance. This includes the serum iron assay (level of iron circulating in the blood), the transferrin saturation (protein that allows the transport of iron in the body) and the ferritin assay (means of estimating iron stores in the body)”explains Professor Thierry Leblanc.
► The normal rate of serum iron in the blood is between 70 and 175 μg/dl (micrograms per decilitre) in men and between 50 and 150 μg/dl in women.
► The reference values of the rate of transferrin vary according to age:
- Newborn: 1.6-2.8 g/L
- Infant-child: 2.0-4.0 g/L
- Adults: 2.0-3.2 g/L
The transferrin saturation coefficient is usually 15 to 35% in women; slightly higher in men. A rate higher than 45% is in favor of an iron overload.
► The reference values of the ferritin are included:
- between 30 and 280 µg/L in humans;
- between 30 and 280 µg/L in women over 50;
- between 20 and 120 µg/L in women under 50.
“For genetic forms, we consider for example that bleeding should start if transferrin saturation is greater than 45% and ferritin greater than 200 µg/L in women, and 300 µg/L in men. Iron overload can also be evaluated by an MRI which makes it possible to determine the degree of iron overload in the liver (calculation of the CHF: hepatic iron load) or a cardiac MRI (measurement of the relaxation time)”specifies the pediatric hematologist.
What are the causes of excess iron?
The causes of excess iron are:
► Genetic hemochromatosis: these hereditary diseases are characterized by an excessive absorption of iron in the organism. Hemochromatosis type 1 (variants of the HFE gene) is the most common genetic disease in European subjects; it should be noted that due to menstruation and possible pregnancies, genetic hemochromatosis is expressed much less in women than in men. The other types (2 to 4) are very rare diseases.
► Excess iron intake by mouth : they can be associated with alcoholism or excessive intake of iron-fortified foods or iron supplements, knowing that in the absence of underlying genetic hemochromatosis, it is rare that iron intake lead to a real overload.
► Repeated blood transfusions : hemochromatosis is then called secondary. It occurs systematically in patients regularly transfused and requires treatment beyond 10 to 20 transfusions.
What are the symptoms of too much iron?
Mild to moderate iron overload usually does not cause symptoms. Hemochromatosis can be manifested by:
- Fatigue
- Endocrine disorders: pituitary iron overload, hypogonadism, hypothyroidism, hypoparathyroidism, diabetes
- Heart failure (myocardial iron overload)
- Cirrhosis
- Gray discoloration of the skin (melanoderma)
- Joint and muscle pain
- Diarrhea
- Hair loss
What are the consequences of too much iron?
Excess iron is toxic to the body because we we have no way to eliminate excess iron (excluding bleeding). In people who suffer from hemochromatosis (the most common genetic disease in France), the level of iron in the blood and the iron stores can be very high because iron is continuously absorbed and stored in the organs. Iron overload will mainly target certain organs : pituitary, endocrine glands, heart and liver and also skin and joints. The accumulation is very progressive and the clinical signs are late. In advanced forms, the vital prognosis can be engaged (liver or heart damage).
What treatment to eliminate excess iron in the blood?
Treatment consists of reducing the level of iron in the body. “In case of genetic hemochromatosis, treatment is based on bloodletting. In post-transfusion forms, iron chelating drugs, which are able to remove excess iron, will be prescribed. These drugs can be taken orally, as for deferasirox or the deferiproneor subcutaneously (night infusion over a period of 10 to 12 hours), for deferoxamine. In very severe profiles, and depending on the age of the patients, these drugs can be combined”, says the specialist.
What foods to avoid in case of excess iron?
Contrary to popular belief, it is not useful to avoid iron-rich foods in case of excess iron or hemochromatosis. “A subject with an iron overload should not deprive himself of eating black pudding if he likes it… The diet will not modify his blood iron level significantly; we will simply exclude foods artificially fortified with iron like many cereal-based preparations offered for breakfast. The best of diets is to adopt a varied and balanced diet.nuance Professor Thierry Leblanc.
Thanks to Pr Thierry Leblanc, pediatric hematologist at Robert-Debré Hospital