Betel quid or paan - a popular psychoactive substance in India - which contains arcea nut can act as a direct carcinogen, a new study has claimed.
Scientists recently showed that the substances in BQ could be changed into carcinogens in the body, leading to oral cancer.
Researchers explored substances in the arcea nut that can cause cancer directly, without any need for the body to "activate" them.
They discovered that compounds in the arcea nut can "alkylate" the genetic material DNA, causing changes that increase the risk of cancer, and they are present in betel quid in amounts high enough to do so.
The study found that betel quid, the fourth most popular psychoactive substance in the world after tobacco, alcohol and caffeine - exposes its 600 million users to substances that act as direct carcinogens.
BQ is popular in India, China and other Asian countries.