Standing beside her yak-hide tent at the southern end of the Tibetan Himalayas, an elderly nomad woman examines a packet of dried red berries, pours some out into her hand and asks: 'What are these?' Yangzim Lhamo has spent a lifetime wandering these mountain valleys. If something grows there, she should know. So it comes as something of a surprise that in her 60 years she has never seen one of these berries before.
In western supermarkets and health food stores, the sweet fruit, called the goji berry, is being sold as Tibet's 'true miracle food' - a centuries-old tonic that allegedly fights cancer, wards off heart disease, boosts energy, improves sex lives and helps people to live to over 100.
Launched last December, already a huge hit in America and Britain and soon to go on sale in Italy, Spain, Germany and Singapore, the berries are said to be enjoyed by celebrities including Madonna, Kate Moss, Brooke Shields and Steven Seagal.
The company that ships them around the world at the rate of about 50 tonnes a month is called Tibet Authentic. But Ms Yangzim and her husband Tsedak, 59, who herd yaks across an 80km stretch of Nyingtri in Tibet were bemused at the sight of the goji berries.
'We have some berries high in the mountains here, but there is nothing like this,' Mr Tsedak said. His reaction is not unusual. After a week in Tibet on the trail of the superfruit, hardly anyone we spoke to had even heard of locally grown goji berries.
The man who bears most of the responsibility for the extraordinary hype surrounding Tibetan goji berries and their introduction to the west is a flamboyant Australian called Antony Jacobson. The founder and president of Tibet Authentic, Mr Jacobson said he 'discovered' the goji berry four years ago when he took a break from his Melbourne-based patenting business and travelled through the Himalayas in search of new health products.