It is common knowledge that vegetables are an essential component of a healthy, balanced diet, but which are the best kind for lowering blood pressure?

According to Blood Pressure UK, the following vegetables may be the most helpful in lowering blood pressure:

Potatoes
Sweet Potatoes
Asparagus
Spinach
Cabbage
Sprouts

Why? Because they are rich in potassium. Potassium helps to lower blood pressure by countering the negative effects of salt.

The health site explained: “Your kidneys help to control your blood pressure by controlling the amount of fluid stored in your body. The more fluid, the higher your blood pressure.

“Your kidneys do this by filtering your blood and sucking out any extra fluid, which it then stores in your bladder as urine.

“This process uses a delicate balance of sodium and potassium to pull the water across a wall of cells from the bloodstream into a collecting channel that leads to the bladder.”

Salt raises the amount of sodium in the bloodstream, disrupting the delicate balance. Eating more fruit and vegetables ups the sodium levels and restores the balance, notes the health body.

“This will help your kidneys to work more efficiently - and help to lower your blood pressure to a healthy level,” it added.

Underscoring the importance of eating potassium-rich vegetables, research presented at the at the 242nd National Meeting & Exposition of the American Chemical Society (ACS) suggested that just a couple of servings of potato a day reduces blood pressure almost as much as oatmeal without causing weight gain.

18 patients who were primarily overweight/obese with high blood pressure ate six to eight purple potatoes (each about the size of a golf ball) with skins twice daily for a month.

They used purple potatoes because the pigment, or colouring material, in fruits and vegetables is especially rich in beneficial phytochemicals. Phytochemicals are compounds found in plants that may benefit human health, according to Harvard Health.

Scientists monitored the patients' blood pressure, both systolic (the higher number in a blood pressure reading like 120/80) and diastolic. The average diastolic blood pressure dropped by 4.3 percent and the systolic pressure decreased by 3.5 percent, said Vinson, who is with the University of Scranton in Pennsylvania and has done extensive research on healthful components in foods.

Systolic blood pressure and diastolic blood pressure are the numbers used to measure blood pressure. Systolic blood pressure measures the pressure in a person’s blood vessels when their heart beats. Diastolic blood pressure measures the pressure in a person’s blood vessels when your heart rests between beats.

The majority of subjects took anti-hypertensive medication and still had a reduction in blood pressure. None of the study participants gained weight.