Transferrin saturation determines an individual’s iron status by using the ratio of serum iron concentration and total iron binding capacity (TIBC) as a percentage. [1]
A transferrin saturation test tells us how much iron in the blood is bound to transferrin. A low transferrin saturation usually indicates iron deficiency while a high saturation often confirms haemochromatosis.
You can test your iron levels by purchasing a simple at-home finger prick test kit which is then analysed at an accredited lab. Forth offers a number of blood tests which include iron markers such as our best-selling Baseline Plus health check or our Nutri-check test. A transferrin saturation blood test is also available in some of our bigger blood test profiles such as Vitality which tests over 30 biomarkers integral to good health.
A transferrin saturation test shows how much serum iron is bound to transferrin.
Transferrin is a glycoprotein produced in the liver whose main function is in iron metabolism and transporting iron around the body via the blood to various tissues.[2] The percentage of transferrin saturation increases or decreases depending on iron status.
Changes in transferrin levels in the blood can indicate iron-related conditions. For example, a low transferrin saturation percentage is often seen in cases of iron deficiency, anaemia and pregnancy. If plasma transferrin levels rise then this causes a decrease in transferrin iron saturation, which together causes an increase in total iron binding capacity in states of iron deficiency.
An increased transferrin saturation percentage in the plasma is seen in diseases which cause iron overload.
If you are worried about your iron levels or just want to check where you fall on the range, you can test your iron levels with a simple at-home blood test.
Iron deficiency causes increases TIBC and transferrin levels, but a low transferrin saturation percentage. Iron deficiency can be caused by malnutrition where physiological requirements are unable to be met by iron absorption from the diet.[3] Therefore, if we do not consume enough iron in our diet, then we are at risk of becoming deficient. There are two types of iron haem and non-haem. Haem iron comes from animal sources and non-haem from plant sources. Individuals who follow plant-based diets are at an increased risk of iron deficiency because less than 10% of non-haem iron is absorbed.[3]
Low transferrin and TIBC levels alongside an increased transferrin saturation percentage are caused by chronic diseases or haemochromatosis. Haemochromatosis is also known as iron overload and is caused by several medical conditions, commonly an inherited disorder.
Genetic haemochromatosis is caused by a faulty gene which increases the amount of iron entering the body.[4] Individuals with haemochromatosis absorb twice as much iron as normal which is toxic for the body and can be life-threatening.
The common symptoms of iron deficiency anaemia are:
Haemochromatosis causes symptoms, like:
Iron is essential for red blood cell health. A good source of iron is red meat and liver. It is recommended that red meat is consumed once per week to help keep iron levels within normal parameters. Women who are of menstruating age need to keep their iron intake increased particularly around the time of their periods. Individuals who follow a vegan or vegetarian diet will need to get their iron from plant-based sources.
Good food sources of iron are:
The absorption of iron from plant-based sources is better when vitamin C is present. [6] For example, fortified breakfast cereals paired with a glass of orange juice. Tea can affect the absorption of iron, so you should refrain from drinking tea with your meals and switch to drinking it between meals. [7]
It is possible to get all the iron you need from a varied and balanced diet. Therefore, there should be no need to take iron supplements. However, a doctor may recommend supplements if your iron levels are considerably low.
Iron levels can be influenced by too much or too little exercise. Not having enough iron can affect your muscles ability to recover following exercise.
If you have haemochromatosis, you may need a genetic test to determine whether you carry a genetic mutation which causes the disease. There are some lifestyle choices you can make to help control your iron intake if you experience iron overload.
You should avoid:
Drinking alcohol can speed up and worsen the impact of haemochromatosis and if you already have liver cirrhosis you should avoid alcohol completely.
[1] Worwood, M., May, A, M and Bain, B, J. (2017). 9 – Iron Deficiency Anaemia and Iron Overload. In: Dacie and Lewis Practical Haematology (Twelfth Edition).
[2] Ogun AS, Adeyinka A. (2016). Biochemistry, Transferrin. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Available from: https://www.ncbi.nlm.nih.gov/books/NBK532928/
[3] Zimmerman, M, B and Hurrell, R, F. (2007). Nutritional Iron Deficiency. Lancet: 370, pp 511-520.
[4] British Liver Trust. (2019). Haemochromatosis. Available at: https://www.britishlivertrust.org.uk/liver-information/liver-conditions/haemochromatosis/
[5] NHS. (2018). Iron Deficiency Anaemia. Available at: https://www.nhs.uk/conditions/iron-deficiency-anaemia/
[6] Lane, D, J, R and Richardson, D, R. (2014). The Active Role of Vitamin C in Mammalian Iron Metabolism: Much More than Just Enhanced Iron Absorption. Free Radical Biology and Medicine: 75, pp 69-83.
[7] Zijp, I, M., Korver, O and Tijburg, L, B, M. (2000). Effect of Tea and Other Dietary Factors on Iron Absorption. Critical Reviews in Food Science and Nutrition: 40(5), pp 371-398.