Minerals and trace elements - Potassium
Potassium is essential for water and electrolyte balance and the normal functioning of cells, including nerves. Increased dietary intakes of potassium have been associated with a decrease in blood pressure, as it promotes loss of sodium in the urine. It is suggested that an increase in potassium intakes may offset the impact of some of the sodium in the diet, therefore helping to protect cardiovascular health.
Low blood potassium levels (hypokalaemia) can result from severe diarrhoea. Symptoms include weakness, mental confusion and, if extreme, heart failure.
Low dietary potassium intakes have been observed in the UK: in the NDNS of adults about 1 in 5 women had intakes below the LRNI and in common with some other minerals, potassium intakes were lower among younger women. In the NDNS of young people, 10–15% of boys had intakes below the LRNI but among girls, about 1 in 5 11-14 year olds and about 2 in 5 15–18 year olds had intakes below the LRNI.
High supplementary doses of potassium can be harmful especially if the kidneys are not functioning properly.
Potassium is present in almost all foods but fruit (particularly bananas), vegetables, meat, fish, shellfish, nuts, seeds, pulses and milk are useful sources. Processed foods typically contain less than raw foods.
© British Nutrition Foundation