Iron deficiency: symptoms to be aware of

What purpose does iron serve in the body?

The adult body contains between 2.5g and 4g of iron. It is a key component of haemoglobin, the protein responsible for transporting oxygen in the blood, which is essential for the formation of red blood cells. Iron is thus crucial for oxygenating all the body’s cells, but it is also involved in many other vital processes such as energy metabolism, detoxification, optimal immune system function and DNA synthesis.

Women of childbearing age need at least 25 mg/day (due to blood loss during menstruation), while adult males and post-menopausal women need at least 12 mg/day. This balance can be achieved over the course of a week, but the diet needs to be rich in iron in order to meet our long-term needs.

Symptoms of iron deficiency

A lack of iron can lead to haemoglobin deficiency in the body: this is referred to as iron-deficiency anaemia. The body’s iron levels are too low to produce this essential protein making it impossible to create optimal numbers of ‘working’ red blood cells. This deficit, which poses a risk to health, can be detected by a simple blood test which identifies levels of haemoglobin, haematocrit, ferritin (less than 15 µg/L in the blood) and a red blood cell count all below normal values.

In mild anaemia, symptoms usually go unnoticed. They only start to be felt when haemoglobin levels fall below 80g/L and include:

• a pale complexion;
• abnormal fatigue;
• breathlessness on exertion;
• frequent dizziness and light-headedness (especially when getting up from a chair);
• headaches;
• muscle weakness;
• cold hands and feet;
• a potential decline in mental performance, especially a lack of focus.

Other signs indicating a possible lack of iron (1) : brittle nails, dry skin and hair, problems concentrating, irritability, sleep issues, onset of restless leg syndrome… These symptoms usually appear gradually, as anaemia develops very slowly.

In pregnant women, a lack of iron has implications for the foetus: it can lead to premature birth, mental deficits in the unborn child and low birthweight (2).

Main causes of iron deficiency

There are three factors which, over time, can lead to a lack of iron (iron deficiency or sideropenia) : a a diet persistently low in iron (malnutrition, special diet, unbalanced diet …), problems with iron absorption at a digestive level (inflammatory bowel disease, for example) and significant blood loss.

In light of these causes, several population groups are at risk of iron deficiency:

• women who experience heavy periods, as iron is lost in menstrual blood;
• pregnant women and those who have had multiple pregnancies close together, as satisfying their baby’s needs results in their own iron reserves becoming depleted;
• long-distance runners (marathon, trail), as they lose a lot of iron through sweat and haemolysis (destruction of red blood cells during exercise) ;
• people suffering from diseases associated with iron malabsorption, such as Crohn’s or coeliac disease;
• people with a health problem involving chronic blood loss in stools, such as a peptic ulcer or benign polyps in the colon;
• vegetarians and especially vegans;
• undernourished people or those eating an unbalanced diet low in meat, fish, pulses and green vegetables;
• those who regularly take medication for heartburn, such as proton pump inhibitor-type antacids. Stomach acidity enables the body to absorb dietary iron;
• those suffering from kidney failure, especially if they’re on dialysis, etc.

How to correct a lack of iron and eliminate its symptoms

Remedies and treatments for iron deficiency depend on its severity: only a health professional can recommend the right solution for you. In all cases, however, it’s important to increase your dietary intake by incorporating more iron-rich foods into your daily diet.

Haem and non-haem iron

There are two main forms of iron: haem iron (found in animal-source foods), which is easily metabolised by the body (with an absorption rate of around 25%), and non-haem iron (present in plant-source foods), which is less well-absorbed (around 5%).

The difference in absorption is explained by the presence of phytic acid and tannins in plants : non-haem iron has to first be ‘released’ by stomach acidity, before being converted by intestinal cell membranes.

Main dietary sources of iron

Sources of haem iron include: liver, beef, poultry, sardines, shellfish.

Sources of non-haem iron include: tofu, dried fruit, pulses, green vegetables, nuts and seeds.

Perfect for rectifying iron deficiency: iron supplements

On the advice of a health professional, and only when iron deficiency has actually been diagnosed, taking an iron supplement can be really helpful in rapidly restoring your iron reserves. An iron infusion may even be recommended, particularly for pregnant women who are iron-deficient.

In both cases, medical supervision is required, since taking too much iron carries its own risks. Below are some effective measures to accompany any treatment for iron deficiency :

• don’t consistently eat too many animal-source iron-rich foods as, in general, they are not good for your long term health. Use sparingly, alternating them with foods containing non-haem iron;
• avoid eating iron-rich foods at the same time as dairy products as they make the iron less bioavailable (3) ;
• before cooking, soak uncooked pulses for 48 hours, with frequent changes of water, in order to remove any compounds that inhibit the uptake of non-haem iron;
• include foods rich in vitamin C (peppers, broccoli, Brussels sprouts clementines, orange juice, etc.) and vitamin A (sweet potatoes, carrots, spinach, pumpkin, etc.) in meals containing sources of non-haem iron as they improve its absorption in the gut ;
• opt for supplements in the form of bisglycinate (such as Iron Bisglycinate), as they offer the best bioavailability and the fewest side effects (4).