Happiness, these days, comes in a crisp packet - at least, it does, if you believe the claims of an American crisp tycoon.

Jane Hughes reports

He has created what he says is the world's first mood enhancing bag of crisps.

The snacks are on sale in the United States now, and about to appear in shops in the UK and the rest of Europe.

Happy crisps, as they are called, contain St John's Wort, a natural antidepressant.

It is a legal herb known for its mood-enhancing properties, which is thought to affect the neurotransmitters linked to depression and anxiety. Scientists say its properties are largely untested.

Life enhancing crisps

That does not deter the President of Robert's American Gourmet, which manufactures the crisps, though. Robert Ehrlich could hardly be said to be modest in his claims for them.

The St John's Wort crisps could improve mood, say the makers

"You can't imagine the calls and letters we get every day from people who for the bag of a price of crisps have changed their lives," he says.

"These are life enhancing crisps, and they love them."

The snacks are already selling so well in the United States, Mr Ehrlich has introduced a range of other mood improving snacks.

He sells corn chips enhanced with Gincko to improve memory power, Ginseng flavoured tortilla chips to aid relaxation, and, for anyone needing an intellectual boost, there are Smart Puffs.

But a group of health conscious employees at a New York Gym were unconvinced.

Annalise did not take kindly to the taste of Happy Crisps.

"They have a bit of an aftertaste," she complained, "and they're way too salty. I don't know about these."

Eddie opted for Smart Puffs, and was not much more impressed.

"They taste too plain, like cardboard," he said.

For Nais, though, the corn chips enhanced with Ginseng were just the kind of relaxation she needed.

"These taste good - they are crunchy, not too greasy, they are relaxing me already."

But a couple of hours later, none of them could really feel any difference.

Happiness is a full stomach

"I feel happier because I was hungry, and they've filled me up," says Annalise. "Nothing more."

"I need to be smarter to make more membership sales," adds Eddie. "Bring me another bag tomorrow, and I'll see how they do then."

Robert Ehrlich responded to this somewhat unscientific test by saying the benefits took effect more gradually.

But dieticians are highly sceptical about what some regard as the Orwellian notion of using snacks to improve people's moods - not least because they fear that people who try to cheer themselves up by eating these snacks will simply plunge into deeper depression if the crisps make them gain weight.

"Herbals like St John's Wort have a very very short record, with very few clinical trials," said Professor Barbara Levine, from Cornell Medical School in New York.

"People could be thinking they're getting something they're really not getting. It may not be safe and it may not be effective."