The ASA received two complaints against the Soil Association for describing organic as "healthy" and "more humane to animals".
Two years after the UK government launched an organic action plan for the entire food supply chain, the country has seen a 46 per cent rise in organic produce provided by UK farms.
At the beginning of 2004 696,000 hectares, about 4 per cent, of UK farmland was under organic production, up from 30,000 hectares in 1993. The market is projected to grow by 9 per cent a year to 2007.
Such growth in organic foods has been speared in part by quality, taste and ethical concerns.
But the ASA upheld complaints on two claims in a leaflet made by the Soil Association last year: that "organic farming produces healthy food" and that it is "more humane to animals".
ASA said the claims could not be substantiated scientifically.
According to a report on the BBC, the organic industry body has recently submitted new evidence to the ASA which means it can now legitimately state that no other food has higher amounts of beneficial minerals and vitamins.
And it argues no other system of farming has higher levels of animal welfare standards.