US sales of the natural sweetener stevia continue to blossom despite regulatory restrictions on its use and the way it is marketed. The sweetener, derived from a South American plant that is 300 times sweeter than sucrose, can only be sold as a dietary supplement in the US because of ongoing Food & Drug Administration concerns about its safety.

It has been banned as a sweetener since 1995 because the FDA says "available toxicological information on stevia is inadequate to demonstrate its safety as a food additive or to affirm its status as GRAS (generally recognized as safe)." It cannot be used as an ingredient by food manufacturers

Despite being permitted only as a dietary supplement or supplement ingredient, stevia is sold in other forms such as teas and shake formulations marketed as dietary supplements. It is also sold in a stand-alone form that for all intents and purposes is a sweetener, while being marketed as a dietary supplement.

Yet its popularity continues to soar with revenue up 25 per cent to $45 million in 2005, according to Nutrition Business Journal. New retail avenues have helped its situation and it is now stocked in major health and specialty food chains such as Whole Foods and Trader Joe's.

But stevia will not realise its potential until it gains official recognition from the FDA as a sweetener, said Steve May, the chief operating officer of Arizona-based stevia distributor Wisdom Natural Brands. "The market would be $100 million larger if the government allowed its use as a sweetener," he said.

Stevia's increased US demand has been a factor in raw ingredient prices doubling in the past 18 months, along with increased sales in parts of Asia, Europe and South America. Stevia is not available in the European Union because of safety concerns although it is available in non-EU countries such as Switzerland and some eastern European nations.