A collaborative approach to managing iron deficiency

Iron deficiency (ID) is not only common in Australia; it is the most common nutrient deficiency across the globe, with iron deficiency anaemia (IDA) believed to be affecting roughly one-third of the world’s population.

The Role of Iron in Health

Iron is an essential mineral for good health. It is necessary for energy production, physical growth, neurological development, cellular functioning, immunity and hormone synthesis. It is obtained exclusively through diet, absorbed in the small intestine, where it is transported by transferrin to the cells or the bone marrow for erythropoiesis; the production of red blood cells (RBCs). Most iron in the body is present in RBCs, where it is a crucial component of haemoglobin (Hb), and in muscle cells as myoglobin. The remaining can be found stored in the liver as ferritin or circulating in the plasma, bound to ferroportin, with a small amount used as a component of certain proteins and enzymes.

When iron levels are inadequate, Hb concentrations can begin to drop, which can starve the body of oxygen, presenting symptoms of fatigue, weakness, dizziness, shortness of breath, decreased cognitive performance and reduced immune function. In excess amounts, iron can have toxic effects: damaging tissues and increasing the risk of cancers and heart disease. Since a careful balance is required, iron homoeostasis is tightly controlled, with iron highly conserved and not readily lost from the body (with the exception of obligatory losses from sweat and intestinal cell desquamation amounting to 1–2 mg per day) and a restricted daily absorption (1–2 mg to compensate for losses).

Who is at Risk of Low Iron?

Iron deficiency can usually be attributed to inadequate dietary intake, poor absorption of iron in GIT, increased losses of iron (i.e., internal bleeding) and/or increased physiological need for iron (i.e., pregnancy).4 Yet the risk is not shared equally, with the following population groups considered to be at a higher risk:

• pregnant women

• menstruating women

• vegetarians/vegans

• elderly

• athletes with high oxygen requirements and/or restrictive diets

• patients with GIT pre-existing conditions such as Coeliac disease, Crohn’s Disease or Ulcerative Colitis

• patients consuming excessive dairy

• patients who chronically use pharmacologic agents such as salicylates, NSAIDs, anticoagulants and corticosteroids

Recommendations to Manage Low Iron

Once iron deficiency has been identified, there are a number of steps that can be taken to manage the condition. There are three stages of iron deficiency:

1. Iron depletion – when Hb concentrations are normal, but blood ferritin concentrations are below average. Patients at this stage will usually present with no obvious symptoms.

2. Iron deficiency – when Hb concentrations are mostly normal but transferrin saturation decreases. Patients at this stage may present with mild symptoms. Iron deficiency anaemia – when Hb concentrations drop below the reference range. Patients at this stage will present with obvious and often severe symptoms.

ENSURE ADEQUATE CONSUMPTION OF DIETARY IRON

In early stages, adjusting dietary intake to achieve Recommended Dietary Intake (RDI) should be enough to prevent and manage iron deficiency. In Australia, RDIs are as follows:

• males over the age of 19 and females over 51 years of age: 8 mg/day

• females of menstruating age: 18 mg/day

• pregnant women: 27 mg/day.

Dietary iron consists of haem (meat, poultry and fish) and non-haem (grains, vegetables, nuts and seeds) iron. Haem iron is bound to Hb and myoglobin in animal flesh and is better absorbed than non-haem iron, with the body able to absorb 15–25% of available haem iron compared to only 5–12% of non-haem iron.

Patients who are comfortable consuming meat-based products should be encouraged to incorporate haem iron sources into their diet 2–3 times per week; this can include products such as beef, pork, lamb, seafood, kangaroo, other game and poultry. A quick reference is the redder the meat, the more iron rich.

CONSUME VITAMIN C RICH FOODS WITH NON-HAEM IRON SOURCES

Vitamin C (Ascorbic Acid) is the only common food element known to increase non-haem iron absorption. The enhancing effect is largely due to its ability to reduce ferric iron present in non-haem iron to ferrous iron, the latter of which is more bioavailable.

Patients should be recommended to consume vitamin C rich foods alongside non-haem iron sources; this can include citrus fruits, berries, broccoli, brussels sprouts, tomato and capsicum.

LIMIT THE CONSUMPTION OF PHYTATES, CALCIUM AND TANNINS WITH IRON SOURCES

In contrast, iron absorption is inhibited by simultaneous consumption of certain foods, including phytates, tannins and calcium.

Phytates, found in unprocessed whole grains, legumes and some vegetables, are the main inhibitor of non-haem iron absorption. Yet they do not necessarily need to be avoided since cooking, soaking, sprouting, leavening and/or fermenting these foods can break down the phytate content. Therefore, patients should be encouraged to properly prepare phytate-containing foods when consumed with non-haem iron.

In addition, studies have demonstrated that non-haem iron absorption can be reduced when consumed with tannins, which are found in tea, coffee and wine.8 Patients should be encouraged to avoid consuming these foods at the same time as non-haem iron food sources.

Unlike other inhibitors that prevent only non-haem iron absorption, calcium (whether it is given as Ca salts or in dairy products) inhibits both haem and non-haem iron. Patients should be encouraged to avoid consuming these foods at the same time as all iron-rich food sources.

SUPPLEMENTATION

For patients experiencing IDA, adjusting dietary intake is insufficient. In these circumstances, patients must be recommended to consume an iron supplement as a first-line therapy. Similar to iron absorption from food, patients can be advised to consume supplements with vitamin C rich foods or liquids, such as orange juice, to enhance absorption.