The consequences of sideremia

The sideremia test may be useful if hematocrit and haemoglobin values are abnormal.

The term sideremia indicates the concentration of iron present in the blood. This is in particular iron not bound to hemoglobin, also called transport iron. Assessing the levels of sideremia is very simple as a blood sample is sufficient to have information on the amount of circulating iron.

The iron present in the body is divided into three categories, depending on the molecule, and in particular the protein, to which it is bound:

  • iron bound to hemoglobin and contained in red blood cells
  • iron deposited in the liver, bound to ferritin
  • iron transported by transferrin, essential for the formation of hemoglobin and red blood cells.

The remainder is contained in certain enzymes involved in cell metabolism.

Iron metabolism

Iron is a mineral that plays the fundamental role of capturing oxygen and then releasing it to the tissues. More specifically, iron is used to produce hemoglobin, which allows the transport of oxygen in the blood from the lungs to the entire human body.

Iron is also present in many enzymes, regulates the synthesis of certain hormones and produces myoglobin, a protein that fixes oxygen in the muscles.

In the body of an adult person, there are on average about 3.5 grams in men and 2.5 grams in women. This difference between men and women in the adult population is due to the smaller build, lower androgen levels and the reduction in iron stores that in women can occur during pregnancy and at the menstrual cycle.

Iron is introduced into the body through food. After being transformed by the gastric juices present in the stomach, it passes into the intestine where it is absorbed. At this point it is transported in the blood by transferrin until it reaches the liver where it accumulates and binds to ferritin, ready to be released when the body requires it.

Ferritin indicates the levels of storage iron present in the body, i.e. the reserves from which the body draws in case of lower intake than required or in the presence of situations that require a greater amount of oxygen: during intense physical effort for example, but especially during pregnancy and breastfeeding.

Ferritin values below normal indicate a lack of iron in the reserves, a situation that precedes anemia, and is called ferritinemia.

Transferrin is instead the protein responsible for transporting iron to deposits and bone marrow, where it is used for hemoglobin synthesis. Transferrin provides information on the state of iron absorption. Values below normal indicate that the body does not use available iron properly.

Dosage of sideremia

The sideremia test does not belong to the category of first-level analyzes, but it is an examination that can be prescribed in the second instance by medical specialists if the values of hematocrit and hemoglobin, obtained with the execution of the blood count, are abnormal, and may therefore be an indication of an underlying problem, or in any case if excess or defective iron levels in the blood are suspected.

The hematocrit expresses the ratio between the corpuscular part of the blood, consisting mainly of red blood cells, and the liquid part of the blood, or plasma and indicates the share of red blood cells present in the blood.

If hemoglobin and hematocrit values are low, measuring serum iron can help you understand the cause. The test is also used to evaluate the effectiveness of a therapy for iron deficiency and as a screening test for the early diagnosis of hemochromatosis, a disease that causes an abnormal ability to absorb iron ingested with food and that, if left untreated, can lead to a particular form of diabetes or liver cirrhosis.

Excess iron, a condition known as hemosiderosis, can in fact lead to its progressive accumulation to damage the liver, heart and pancreas. For this reason, any supplements of this mineral should only take place on medical prescription, in order to avoid a possible overload that could have important consequences and require specific therapies.

To get a complete picture of an individual’s iron levels, however, the value of serum iron cannot be considered in isolation, but must be read together with ferritin and transferrin levels.

Levels of serum iron vary according to gender, age, and general health status of the person. Normal values range from 75 to 150 μg/dL for men and 60 to 140 μg/dL for women. The value changes according to the hours of the day, and is maximum in the early hours of the morning.

Circulating iron levels are also affected by the menstrual cycle as they decrease if the test is carried out during the flow. On the contrary, they increase with the consumption of red meat (especially beef and horse, rich in iron) and the intake of supplements containing iron. For this reason, such behaviour must be suspended within 48 hours prior to blood tests to measure sideremia.

Values above the upper limit indicate a condition of hypersideremia, or an excessive concentration of iron. The causes of this situation can range from having undergone multiple transfusions, to the use of the contraceptive pill up to the presence of diseases such as thalassemia, viral hepatitis or hemochromatosis. Finally, the dosage of sideremia is also high in the particular case of lead poisoning.

Hypersideremia can be associated with metabolic, osteoarticular, cardiac, nervous system disorders (such as arrhythmia, heart failure, joint pain and osteoarthritis, thyroid dysfunction, mood disorders and increased liver transaminases).

Paradoxically, hypersideremia could also be linked to a state of anemia, as a result of which there is a reduced use of iron in the body and consequently its excess accumulation.

Lower than normal serum iron values indicate, on the contrary, that the amount of circulating iron is insufficient. Also in this case the causes lie in different situations:

  • blood loss
  • Bleeding
  • menstrual flows too abundant
  • occult bleeding in the gastrointestinal, for example due to an ulcer, polyp or tumour
  • improper nutrition, fasting, unregulated lifestyle
  • pathologies of various kinds, for example affecting the cardiovascular system or the digestive system.

Low levels of sideremia can also be caused by surgery and increased iron requirements by the body in the presence of intestinal conditions or diseases that interfere with nutrient absorption, such as alcoholism, abuse of laxatives, chronic diarrheaceliac disease and other chronic diseases.

Even vegetarian or vegan diets, conducted without careful control of the balance of nutrients, can in the long run result in an insufficient intake of iron or be a cause of its reduced absorption, with the possible onset of anemia. Low iron levels also occur in infectious diseases, cancers and following heart attack. And again, in old age and in case of diabetes and kidney failure.

Sideremia values Causes
Hyposideremia Men < 75 μg/dL

Women < 60 μg/dL

Blood loss


Menstrual flows too abundant

Occult bleeding in the gastrointestinal



Abuse of laxatives

Chronic diarrhea

Celiac disease

Infectious diseases





Hypersideremia Men > 150 μg/dL

Women > 140 μg/dL

Multiple transfusions

Contraceptive pill




Lead poisoning.

Joint pain and osteoarthritis

Arrhythmia, heart failure

Thyroid dysfunction

Mood disorders

Increased transaminases


Symptoms of iron deficiency

When the levels of iron concentration in the blood decrease, the body tends progressively to use the stores accumulated in the tissues.

Iron deficiency causes insufficient hemoglobin production and therefore poor tissue oxygenation. To compensate for the decrease in oxygen, the heart and lungs are subjected to increased work, with the appearance of tachycardia and various ailments.

Symptoms of anemia due to iron deficiency occur gradually. In the initial phase they are mild because the body uses iron contained in the deposits to make up for the deficit.

Over time, if anemias arise, the typical symptoms of iron deficiency soon appear:

  • asthenia
  • feeling out of breath
  • fatigue
  • easy fatigue
  • headache
  • greater susceptibility to infections
  • tingling
  • pain in the arms and chest
  • feeling cold in the extremities
  • insomnia.

The hair is weakened and the nails are brittle. The tissue of the skin and that of the mucous membranes can also be affected by iron deficiency and manifest pallor, as well as the appearance of fissures at the corners of the mouth and on the tongue. Other manifestations are drowsiness, dizziness, and difficulty concentrating. Many people happen to be tired already when they wake up and then remain fatigued during the day.

Iron deficiency is the most frequent cause of iron deficiency anemia. Anaemia can occur in all age groups; However, particular attention should be paid to children and adolescents, women of childbearing age, pregnant and breastfeeding (this is because these periods place the woman in a more delicate health condition and which increasingly requires more attention).

Anemia can result from the decrease in the production of red blood cells, and therefore their number, their hemoglobin content or their volume.

Remember, however, that it is not enough to find certain symptoms to identify a problem in iron absorption: it is essential to always contact cardiology professionals for samples and targeted clinical analyzes. Only once the report has been obtained will it be possible to understand if there are actually some parameters out of the norm regarding the levels of ferritin and iron in the blood, and what are therefore the nutritional needs that must be met (or the drug to be used).

Iron, how to introduce it with food

Iron follows a “closed” cycle: that contained in the cells that end their life cycle is reused by the body. It is not exchanged with the outside except minimally, which, however, must be replenished with the diet.

Iron is absorbed in the intestine. A diet that ensures an adequate intake, and that guarantees good prevention against any deficiency, should contain foods that are rich in it, such as:

  • red meat
  • pork
  • green leafy vegetables
  • dried fruit
  • legumes
  • chicken
  • mollusks, especially clams.

If it is true that even the recipe chosen for each food can influence the food intake and the intake of nutrients, micronutrients and similar substances, however, as regards the absorption of iron in the body, in general there are no particular tips and tricks to follow at the level of preparation in the kitchen.

Not all the iron introduced with the diet, however, is used by the body, which in some cases fails to metabolize it. The high consumption of whole grains, bran, tea tannates, polyphenols and certain drugs such as antacids and some antibiotics, for example tetracyclines, hinder the absorption of iron.

This mineral is in fact contained in various foods in different formsIron “heme” is easily absorbed and is only found in foods of animal origin such as meat. “Non-heme” iron is contained in plant foods. Spinach, for example, is rich in iron, but in a poorly available form. The intake of vitamin C, in general and together with these foods, improves the body’s ability to absorb “non-heme” iron by increasing its bioavailability.

Finally, remember that in the event that blood tests reveal after a few months that the situation has not changed, and the symptoms of a possible iron deficiency persist despite the change in diet, it is advisable to contact your doctor for a targeted visit , or consult specialists directly. In this way it will be possible to obtain the most appropriate treatment depending on the cases and risk conditions of individual patients, opting for the use of a simple food supplement or a more targeted medicine.

Joycelyn Elders is the author and creator of EmpowerEssence, a health and wellness blog. Elders is a respected public health advocate and pediatrician dedicated to promoting general health and well-being.

The blog covers a wide range of topics related to health and wellness, with articles organized into several categories.

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