Taking vitamin E eases the severe period pains that affect thousands of teenage girls, research suggested yesterday.

The condition, known as dysmenorrhea, can disrupt the girls' lives, but trials in Iran found that girls given daily doses of about 200mg before periods started and during the early days of menstruation had significantly less pain, spread over a shorter time.

They also experienced less blood loss, according to a report in the British Journal of Obstetrics and Gynaecology.

Researchers at Tarbiat Modares University, Tehran, gave vitamin E to 137 girls aged 15-17. A similar number received dummy treatments over four consecutive cycles. Those taking the vitamin reported far less use of painkillers and those with the most severe pains reported the biggest decreases in intensity. The researchers said vitamin E would particularly benefit adolescents because of the absence of significant side effects.

Peter Bowen-Simpkins, of the Royal College of Obstetricians and Gynaecologists, said: "This may be a breakthrough in a condition affecting thousands of young girls."