Already a big hit on the West Coast of America, wheatgrass is grown from wheat seeds in organic manure, harvested after six to eight days then squeezed in a special juicer. The result is a bright green residue that sounds about as appetising as liquid hay. Yet health aficionados who quaff the substance - at pounds 1.35 for a 1oz shot - claim it has a range of benefits: reducing wrinkles, getting rid of grey hair, providing energy and decreasing appetite.
Model Heather Mills, who lost her leg after an accident three years ago, is a committed convert. She claims that three daily shots of wheatgrass juice and two wheatgrass enemas (!) enabled her final recovery.
Although wheatgrass is available in powder form, health junkies aren't satisfied with anything less than juice. Troy, shop manager at Planet Organic, explains: "Juices are a real fad right now. Juice is a living, active thing, so you get the maximum energy and enzyme activity when you drink it." Apparently, wheatgrass is so "alive", it has to be consumed within 20 minutes, otherwise it oxidises and loses much of its potency. Wheatgrass advocate Christopher Maguire, who's been growing the stuff for about 20 years, explains, "Drinking it fresh is the only way; it boosts your enzyme levels, detoxifies and cleanses the system."
Professor Vincent Marks, dean of medicine at the University of Surrey, is unconvinced by such glowing reports. "To make juice, you destroy the cells and homogenise it, which means it's dead - not alive. And boosting enzymes isn't necessarily a good thing - it can be bad." He adds, "There's not a shred of evidence to support any of their claims."
Yet Troy is still convinced the juice is highly therapeutic, although he can only really speak for himself. "I've been taking it every day for years and I can definitely feel the difference. It's a high, like an energy boost. I don't get sick either, because the product assists the immune system." Another wheatgrass enthusiast, Perry, says, "It's like one of those background feel-good factors that gives you a slight buzz."
And it's starting to sell well, according to Troy, Planet Organic - who claim to sell the juice exclusively - are shifting anything between 40- 60 ounces a day. They can also deliver wheatgrass fresh to your home (pounds 7.99 or pounds 10 per tray). If that's too pricey, Professor Marks sceptically suggests a cheaper alternative. "You'd do as much good nibbling away at ordinary grass - in fact it would probably be better because you'd be getting real roughage as well."