Stroke: a lack of iron causes blood to clot

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MunichIf you don't have enough iron in your blood, you get a stroke more easily. British researchers have now found out why this could be the case.

Defective lung filter

How the iron content is related to the risk of a stroke, researchers at Imperial College in London analyzed using data from 497 patients with "Osler syndrome". People with this condition are particularly at risk of having a stroke. With them, the blood vessels expand - including in the lungs. These in particular usually have a filter function and catch small blood clots before they continue into the arteries and from there to the brain.

The result: Even with a slight iron deficiency, the risk of a stroke doubled compared to Osler patients with normal iron values.

Hole in the heart

Osler syndrome is a rare disease, but a quarter of the population also bypasses the pulmonary blood filter - through the so-called foramen ovalis, a door-like connection between the atria of the heart. These people are also likely to be at increased risk of stroke. Many of them do not even notice their impairment, because patients do not have any noticeable disadvantage in normal everyday life. However, there is evidence that people with oval foramen are more likely to have scuba diving accidents. It may also be related to migraines. Whether there is an oval foramen can be measured with the Doppler method - the flow rate of the blood is determined with the help of ultrasound.

Clumped platelets

The study is also relevant for people with no prior disease exposure. Laboratory tests showed that the blood of healthy people with an iron deficiency also clumped faster when the researchers added a substance that caused clotting. "This phenomenon seems to be generally transferable," says study author Claire Shovlin to

The smallest cells in the blood called platelets may be to blame. If there is too little iron, they stick together particularly easily and form blood clots.

Iron tablets against the risk of stroke?

"Now we want to test whether we can reduce the likelihood of a stroke in patients at high risk by treating iron deficiency," explains the researcher.

So far, however, it is still unclear how important the stickiness of the platelets is for the entire course of a stroke, said Shovlin. Because between the clogging of a blood vessel and a final stroke, there are a number of other steps that could also play a role in the risk.

Third leading cause of death

In the event of a stroke, the brain is no longer properly supplied with blood. The resulting lack of oxygen and nutrients breaks brain cells. Six million people worldwide die of a stroke every year, and another five million remain permanently disabled. In Germany, the disease is the third most common cause of death.

Iron plays an important role in the body, for example for oxygen transport or enzymatic reactions. The human body contains between 2.5 and four grams of iron, which is mainly stored in the liver, spleen, intestinal mucosa and in the bone marrow. The metallic element is contained in almost all foods, but mostly only in small quantities. The body can absorb it better from animal products than from vegetable products. Women have to get more iron in their diet than men because they lose a lot of it during their menstrual period. 15 milligrams per day are recommended for women and ten milligrams for men. (away)

Source: Shovlin, C. et al .: Ischaemic Strokes in Patients with Pulmonary Arteriovenous Malformations and Hereditary Hemorrhagic Telangiectasia: Associations with Iron Deficiency and Platelets, PLOS ONE, February 2014

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