At a recent symposium arranged by the Association for Dietetics in SA, speakers from GeneCare in Cape Town spoke about the important new developments in genetic testing.
Genetic testing can be used to pinpoint genetic diseases and tendencies so as to provide the correct diet treatment for patients. One condition that came under the spotlight was iron overload, or haemochromatosis.
What is 'iron overload'?
Haemochromatosis is a hereditary condition where excessive absorption of iron from normal diets leads to the body being overloaded with iron.
Unfortunately, we are not able to rid our bodies of excess iron, which accumulates in the liver, pancreas, heart and other organs. If left untreated, it can lead to organ failure.
Who is affected?
Generally, symptoms of iron overload occur in middle age after years of damage to organs caused by the deposit of excess iron. But cases do also occur in young people in their twenties and even in some children.
What causes iron overload?
Hereditary haemochromatosis is an inherited disorder caused by a genetic defect. Up to 80% of sufferers have three gene mutations which predispose them to developing this disease.
Symptoms of iron overload
According to the literature distributed by GeneCare, haemochromatosis can cause some of the following symptoms, although not all patients exhibit all of these manifestations:
- Chronic fatigue
- Arthritis, which may affect all joints, but especially the knuckles of the 1st and 2nd fingers (so-called iron fist)
- Cirrhosis and enlarged liver
- Diabetes, caused by damage to the pancreas due to the iron deposits
- Impotence due to loss of libido and atrophy of the testicles
- Irregular menstruation or lack of periods (amenorrhoea)
- Abdominal pain, especially in the upper-right side of the abdomen
- Frequent diarrhoea
- Mood swings and depression
- Irregular heartbeat or arrhythmias
Iron overload is not as rare as was always believed. Studies carried out in South Africa have identified that about 17% of whites (one out of six) carry the most common haemochromatosis gene.
In addition, up to one in 115 whites may have inherited this gene from both parents and are thus exposed to serious risk of iron overload. Despite this relatively high incidence, iron overload is usually unrecognised, misdiagnosed and missed by many doctors.
Populations at risk in South Africa are whites descended from Irish, Scots, French and English forebears.
People with a family history of arthritis, diabetes, liver disease and heart failure are also potentially at risk of hereditary iron overload.
All relatives of patients suffering from haemochromatosis should have genetic tests done to determine if they are carriers of the relevant gene.
If two carriers of the gene marry, their children have a 25% chance of developing iron overload. It is estimated that one in a 100 South Africans of European descent are affected.
Non-hereditary or acquired iron overload
Black South Africans are also at risk of iron overload. In this population group, the disease is not hereditary, but caused by the excessive iron content of foods and beverages prepared in iron cooking pots (e.g. potjies).
Foods with an acid pH and sorghum beer can leach iron out of the cooking vessel and overload the body when these iron-loaded foods and drinks are consumed.
If you suspect that you may be suffering from iron overload, or if any member of your family has been diagnosed with haemochromatosis, it may be prudent to ask your doctor to have iron and genetic tests done for you.
Iron tests will be carried out by local pathology laboratories. Genetic testing for haemochromatosis is available from GeneCare Molecular Genetics (Tel: (021) 422-5538) in Cape Town. You can also contact a genetic counsellor at (012) 997-4908.
Regular blood donation is the recommended treatment for patients with genetic iron overload. Removing blood at regular intervals (initially every week and then at two or three monthly intervals) will lower the iron content of the blood and prevent further deposits in vital organs.
From a dietary point of view, haemochromatosis patients should avoid eating red meat, liver, kidneys, and iron-fortified cereals and breads. These patients should also not take any vitamin and mineral supplements that contain vitamin C or iron.
Vitamin C, ironically, improves iron absorption from foods (which is why patients with iron-deficiency are encouraged to drink orange juice with their iron-fortified cereals).
So, in iron overload, no excess vitamin C in the form of supplements should be taken as this could exacerbate the condition and cause palpitations.
Standard tea or Ceylon tea as it is often called in SA (not rooibos) should be consumed with meals to reduce iron uptake. Compounds in standard tea bind with iron in food and reduce its availability.
Patients with haemochromatosis should under all circumstances avoid alcohol, particularly if the iron deposits have already caused liver damage such as cirrhosis.
Patients with iron overload can also contact The Haemochromatosis Society of South Africa, which aims to increase public awareness of this disease in SA.
Besides providing members with information, the organisation also establishes support groups for sufferers and has compiled a registry of doctors and specialists who treat iron overload. Contact Kirsten Alberts at (011) 791-2919 for more information about this Society.
Iron overload or hereditary haemochromatosis is more common than was previously believed. If you suspect that you may be affected, contact your doctor so that the relevant blood and genetic tests can be carried out. – (Dr Ingrid van Heerden, DietDoc)
(Kotze MJ et al (2005). Preventing organ damage by genetic testing for hereditary haemochromatosis. SA Fam Prac, 47(2):44-45; GeneCare Brochure. Iron Overload).
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