Grapefruit 'link' to blood clots

Doctors writing in The Lancet medical journal described the unusual case of a woman who nearly lost a leg after trying a grapefruit diet.

The 42-year-old woman - who arrived at hospital complaining of shortness of breath, difficulty walking and light-headedness - underwent an ultrasound scan which revealed a deep vein thrombosis, or blood clot, extending from hip to calf.

The previous day she felt pain shooting down her left leg, which later turned purple. Three days earlier the woman, who was slightly overweight, had embarked on an aggressive diet which involved a 225 gram helping of grapefruit every morning. Previously, she had only rarely eaten grapefruit.

Her condition was so bad she was in danger of losing her leg, said four doctors from Providence St Peter Hospital in Washington, US.

In the end she was successfully treated with a clot-dissolving drug and by widening a large vein in her hip.

The woman had a number of unlucky factors that increased her chances of suffering a blood clot, said the doctors. She had a narrowed vein with damaged inner walls, a genetic clotting mutation called Factor V Leiden, and in addition was taking the contraceptive Pill.

Oestrogen in the Pill slightly raises the risk of clotting - and it was this, combined with the effect of grapefruit, which appeared to have tipped the balance. The fruit's juice blocked a key enzyme that normally breaks down ethinylestradiol, the form of oestrogen in the contraceptive.

Regular grapefruit consumption would also have had an accumulative effect, making the hazard worse, said the doctors.

They wrote: "Our patient had a constellation of potential risk factors for venous thrombosis; a heightened hypercoagulable (clotting) state from increased ehtinylestradiol serum concentration due to her three days of grapefruit for breakfast may well have tipped the balance."