Low potassium as a risk factor for stroke

Older individuals who do not eat enough potassium-rich foods (a mineral found in bananas, tomato sauce and orange juice) may be more susceptible to stroke as reported by a recent study. Numerous studies have found that low potassium intake and low serum potassium are linked with increased stroke mortality, but data regarding stroke incidence have been limited. In this study, potassium levels in the blood, dietary potassium intake, and diuretic use in relation to the risk for stroke was investigated. The researchers at the Queen's Medical Centre in Honolulu, Hawaii carried out this study that comprised 5,600 men and women older than 65 years who were free of stroke at the time of enrolment. They measured levels of potassium in the blood of healthy individuals who had never suffered a stroke, recorded dietary potassium intake and diuretic use. High potassium intake was defined as more than 4 grams a day and low potassium intake was defined as less than 2.4 grams a day. Participants were followed for 4 to 8 years, and the incidence and types of strokes were recorded. They found that those with the lowest dietary intake of potassium were 1.5 times more likely to have a stroke over the next 4 to 8 years than their peers with higher intakes of potassium. Among individuals taking diuretics (promoting the excretion of urine, they lower blood pressure and reduce stroke risk but can also lower levels of potassium in the blood), the risk of stroke was 2.5 times higher when blood levels of potassium were low. The risk of stroke was 10 times higher among diuretic users with an irregular heart rhythm and low potassium intake, compared with those with a normal heart rhythm and high intake of potassium. It can be concluded that lower levels of potassium in the blood in diuretic users, and low potassium intake in those not taking diuretics were associated with increased stroke incidence among older individuals. The study is observational and does not prove that low potassium level is the cause for the higher stroke risk. It is possible that some unknown factor may reduce potassium level and raise stroke risk. Nor do the findings support any recommendations regarding dietary potassium intake. People taking diuretics may benefit from potassium supplementation and periodic monitoring of their potassium level. However, it is advisable to eat a well balanced diet that includes plenty of fruits and vegetables.