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| Bananas are rich in potassium |
A banana a day could prevent a deficiency which, scientists say, might increase the risk of stroke.
The tropical fruit is rich in potassium, and a study of 5,600 people aged over 65 suggested that those with the lowest intake of the mineral were 50% more likely to suffer a stroke.
The study also suggested that people who take diuretic drugs - which increase the amount of water excreted in the urine - may also increase the risk, perhaps because they stop potassium from the diet being absorbed by the body.
Diuretics are frequently prescribed to older people - ironically, to control blood pressure and reduce the chance of one type of stroke.
Patients with heart failure also take the drugs to relieve the strain on their heart and lungs.
Patients taking diuretics with the lowest levels of potassium in their blood were two-and-a-half times more likely to have a stroke compared with diuretic takers who had the highest levels of potassium.
The study was carried out by doctors at the Queen's Medical Center in Honolulu, and published in the journal Neurology.
Extra potassium
Dr Deborah Green, who led the study, suggested that patients who have to take diuretics for valid medical reasons might benefit from extra potassium in their diets.
She said: "Diuretics clearly prevent stroke by controlling high blood pressure, but we wanted to see whether their effect on potassium levels would affect the risk of stroke.
"The question is whether diuretics would be even more effective with adequate potassium intake."
Blood pressure
Neurologist Dr Steven Levine, of the Mount Sinai School of Medicine in New York, said that while the increased risk in isolation was small, when added to other risk factors it could be significant.
He said: "But overall, despite this potential adverse effect, evidence shows that low-dose diuretics are highly-effective anti-high blood pressure therapies for preventing both stroke and heart disease."
A spokesman for the Stroke Association, which funds research into the effects of diet on stroke, said that the connection between the mineral and stroke was not fully understood.
She said: "There clearly is a link between potassium and stroke although the extent of this is not known at present.
"Sodium levels in the body are kept in balance by the mineral potassium, which is found in fruit and vegetables."
http://news.bbc.co.uk/2/hi/health/2189201.stm
http://news.bbc.co.uk/2/hi/health/2189201.stm
