A sugary ingredient in processed foods and soft drinks could be a recipe for high blood pressure, research suggests.

High fructose corn syrup (HFCS) is abundant in many types of foods and beverages and was originally viewed as a "healthy" method of sweetening.

Its introduction 20 years ago has caused consumption of the fruit sugar fructose to rise sharply, alongside increasing levels of obesity.

Although healthy amounts of fructose exist naturally in fruit, excessive amounts of the sugar may be harmful. Large quantities of fructose cause the liver to pump fats into the bloodstream that may damage arteries.

Researchers who carried out the new study in the US looked at more than 4,500 adults with no prior history of high blood pressure, also known as hypertension.

Fructose intake was calculated using a dietary questionnaire which asked participants to rate their consumption of foods such as fruit juices, soft drinks, bakery products and confectionery.

The study found that people who ate or drank more than 74 grams of fructose per day - equivalent to 2.5 sugary soft drinks - increased their risk of developing high blood pressure.

Blood pressure readings consist of two figures. The first "systolic" reading relates to when the heart is actively pumping. The second "diastolic" reading shows the blood pressure between beats. "Normal" blood pressure is said to be a reading of around 120/80 millimetres of mercury (mmHg) depending on age.

Consuming more than 74 grams of fructose a day increased the chances of a reading of 135/85mmHg by 28%, the study found. It also raised the risk of higher readings of 140/90mmHg and 160/100mmHg by 36% and 87% respectively.