Eating fruits, vegetables may help lower blood pressure: study

Eating foods rich in potassium such as bananas, spinach, beans and even coffee may help lower your blood pressure, a new study has found.
Decreasing sodium intake is a well-established way to lower blood pressure. However, evidence suggests that increasing dietary potassium may have an equally important effect on hypertension, said Alicia McDonough of University of Southern California (USC) in the US.
Hypertension, or high blood pressure, is a global health issue that affects more than one billion people worldwide.
The World Health Organisation (WHO) estimates that hypertension is responsible for at least 51 per cent of deaths due to stroke and 45 per cent of deaths due to heart disease.

Researchers reviewed previous studies to illustrate the mechanisms for potassium benefits in rodent models.
The studies indicated that the body does a balancing act that uses sodium to maintain close control of potassium levels in the blood, which is critical to normal heart, nerve and muscle function.

The review found several population studies demonstrating that higher dietary potassium was associated with lower blood pressure, regardless of sodium intake.
Interventional studies with potassium supplementation also suggested that potassium provides a direct benefit, researchers said.
"When dietary potassium is high, kidneys excrete more salt and water, which increases potassium excretion. Eating a high potassium diet is like taking a diuretic," said McDonough.

Our early ancestors ate primitive diets that were high in fruits, roots, vegetables, beans and grains (all higher in potassium) and very low in sodium. As a result, humans evolved to crave sodium - but not potassium, she said.
Modern diets, however, have changed drastically since then. Processed food companies add salt to satisfy our cravings, and processed foods are usually low in potassium, researchers said.
"If you eat a typical Western diet, your sodium intake is high and your potassium intake is low. This significantly increases your chances of developing high blood pressure," McDonough said.
"When dietary potassium is low, the balancing act uses sodium retention to hold onto the limited potassium, which is like eating a higher sodium diet," she said.

The study was published in the American Journal of Physiology - Endocrinology and Metabolism.