Iron is needed to form the haem part of haemoglobin, which carries oxygen around the body. In the blood, iron is mainly carried bound to a protein called transferrin. Prolonged iron deficiency will lead to anaemia.
Symptoms of anaemia include fatigue, pallor, breathlessness on exertion, feeling dizzy on standing, mood changes and depression. A chronic low iron level is associated with other symptoms other than those related to anaemia including; hair loss, brittle nails, Plummer-Vinson syndrome (painful mucous membrane covering the tongue, mouth and throat); reduced immunity.
Causes of iron deficiency:
Bleeding; Excessive menstrual bleeding
Recent surgery or trauma
Bleeding from the GI tract (ulcers or cancer of the gullet, stomach, bowel)
Bleeding from nose throat or lungs
Substances (in diet or drugs) interfering with iron absorption
Malabsorption syndromes (Crohn’s disease, bowel surgery)
Treatment of iron deficiency:
Before any treatment is commenced there should be definitive diagnosis of the underlying cause for iron deficiency, particularly in non-menstruating females and men. This would often involve a blood test measuring iron and other vitamin levels such as vitamin B12 and folate. If there is a definite unexplained iron deficiency patients generally are required to have an endoscope and colonoscope to exclude cancer of the gut. When iron deficiency has been diagnosed and causes of blood loss established and treated the iron deficiency can be treated with iron supplements in the form of ferrous sulphate or gluconate tablets. There are, however, concerns with long-term iron supplementation (see below). Dietary measures can help restore iron levels or prevent recurrence after treatment with iron.
Food sources of iron:
Mild iron deficiency can be prevented or corrected by eating iron-rich foods. Because iron is a requirement for most plants and animals, a wide range of foods contain iron. Good sources of dietary iron include;
- Liver and liver pate
- Red meat, poultry, game
- Lentils, beans, chickpeas, black-eyed peas and other pulses
- Fish particularly tinned sardines, tuna, swordfish and salmon
- Leafy green vegetables such as and kale
- Green cruciferous vegetable such as broccoli and Brussel sprouts.
- Tofu, fortified bread and breakfast cereals.
Iron from different foods is absorbed and processed differently by the body; for instance, iron in meat (haem iron source) is more easily broken down and absorbed than iron in grains and vegetables (“non-haem” iron source). Minerals and chemicals in one type of food may also inhibit absorption of iron from another type of food eaten at the same time:
Oxalates form insoluble complexes, which bind iron in the gut before it can be absorbed. Oxalate occurs in many plants, where it is synthesized via the incomplete oxidation of carbohydrates. Food rich in oxalates include spinach, Swiss chard, fat hen, sorrel, rhubarb, buckwheat, quinoa and star fruit. Leaves of the tea plant contain high concentrations of oxalic acid relative to other plants. However the infusion beverage typically contains only low to moderate amounts of oxalic acid per serving, due to the small mass of leaves used for brewing.
Phytic acid forms insoluble complexes which bind iron in the gut before it can be absorbed. Phytic acid is used as a preservative with E number E391.
Cadmium encourages the transformation of vitamin C into oxalic acid reducing iron absorption. This can be a problem for people exposed to high levels of cadmium in the diet, in the workplace, or most commonly smoking.
Vitamin C reduces the affect of phytic acid and enhances the absorption of iron.
Probiotics such as lactobacilli can create a more favorable PH and environment for oxalic acid excretion and hence increase iron absorption.
Caution with Iron supplements: Free iron is needed for bacterial growth, which is one reason why iron is protein bound in transferrin in the blood. To reduce bacterial growth, plasma concentrations of iron are lowered in fever and following surgery after open wounds where it acts as a protection against infection. There is a theory that iron supplementation can increase free iron bioavailability and hence bacterial growth. It may be sensible to stop iron supplements in the presence of a systemic bacterial infection. However, the haem iron from the blood in red meat has been implicated with an increased risk of bowel cancer.
In summary, if you are iron deficient consider red meat once or twice a week and a higher intake of dark fish, dark green vegetables and beans at other times. Whilst eating meat avoid intake of oxalate rich foods such as spinach, quinoa or buck wheat. Increase intake of live yoghurts and probiotics and vitamin C containing foods. If relevant stop s