Chewing khat leaves — a practice common in East Africa and the Arabian Peninsula — can cause severe heart problems, warn researchers in the June issue of the Journal of the Royal Society of Medicine.
People have chewed the leaves as a stimulant for centuries, in a social tradition that predates coffee drinking.
But according to Sagar Saha and Clare Dollery of the Heart Hospital in London, United Kingdom, long term chewing can lead to heart attacks, liver damage, tooth loss and throat cancer.
Dollery, a consultant cardiologist, says khat seems to affect blood clotting and cause spasms in the arteries supplying blood to the heart.
The findings support previous research done in Yemen that found that khat chewers were at higher risk of heart attack than people who do not chew the leaves. The practice is also popular in Ethiopia and Somalia, and among emigrant communities from these countries.
Kamran Abbasi, editor of the Journal of the Royal Society of Medicine, says there needs to be greater awareness of the dangers of chewing khat.
"Unless there is a public awareness, khat will continue to cause serious harm to the health of many people in developing countries and disadvantaged migrant communities in European countries where khat is not banned," said Kamran.
Canada, Ireland, Norway, Sweden and the United States have all banned the leaf.
The shrub (Catha edulis) from which the leaves are harvested is largely grown in East Africa and Yemen. It is a major export crop in Ethiopia.
According to Saha: "There are no guidelines on how to treat and manage khat-induced harm, which in turn affects the ability of doctors to provide holistic treatment."