A new study has revealed that drinking a glass of grapefruit juice every day could protect against heart disease, and just half a pint a day is enough to improve circulation. This is due to the high level of health-boosting chemicals they contain, known as flavanones.

The study was undertaken by researchers at the French National Institute for Agricultural Research, and participants were 48 healthy women aged 50 to 65, one of the highest risk groups for heart disease.

Half the group were given a daily dose of 340ml of grapefruit juice, and the other half a placebo drink. After a few months the two groups then switched over.

The six-month trial found that regular consumption of flavanone containing juice significantly improved the health of blood vessels, which in turn improves circulation and prevents heart disease.

However, patients with existing heart disease should not consume grapefruit juice as it can interfere with medication.