PARIS -- Veggie-lovers have long declared that organic food is rich in health-enhancing ingredients and a new study has handed them key scientific evidence to support that claim, AFP reported.

Food grown without insecticides, herbicides or man-made fertilizers has high levels of salicylic acid, an anti-inflammatory compound that is well known for combatting heart disease and bowel cancer, it says.

The research, published in the latest issue of **** The European Journal of Nutrition ****, compared amounts of salicylic acid among commercially sold vegetable soups in Britain whose contents were either organically or conventionally grown.

The 11 organic soups had an average of 117 nanograms of salicylic acid per gram.

That was nearly six times more than in the 24 non-organic soups they tested, which had only 20 nanograms per gram of salicylic acid.

The top performer was an organic carrot and coriander soup made by a Scottish company that was bursting with 1,040 nanograms/gram.

At the other end of the scale, four of the non-organic soups had no detectable levels of the precious compound at all.

Salicylic acid is the active ingredient in aspirin, which is the commonest but arguably one of the most effective drugs ever sold. Among its many benefits is the ability to make blood less sticky, thus easing arterial clogging that can cause heart attacks and strokes.

The researchers, from the University of Strathclyde and the Dumfries and Galloway Royal Infirmary in Scotland, have previously found that the blood of vegetarian Buddhist monks has higher concentrations of salicylic acid compared with carnivores.

Their latest study sounds a cautionary note.

They say it is possible that the organic vegetables were stored, handled and cooked better than their cheaper conventional counterparts, and this may have affected the outcome.

In addition, minor ingredients used in soups, such as herbs and spices, have high contents of salicylic acid, and so are potential contributors to higher levels of the compound.

Organic fruit and vegetables enjoy a glowing reputation as healthy things to eat, but until now there has been little scientific evidence to back it up.

One theory is that organic plants literally have to fight harder for survival and this affects their food content.

Salicylic acid occurs naturally in plants as a substance to ease stress and fight disease.

Plants that have been sprayed with fertilizers, insecticides and weedkillers have not had to combat pests or competitors for space or struggle for nutrition, they therefore contain less salicylic acid, according to this idea.