Salad bags lack nutrients

Beezy Marsh13 April 2012

They may make the most convenient salads, but leaves bought in pre-washed packs are missing vital nutrients, scientists have found.

Research has shown that a manufacturing technique used to keep the greens crispy for longer also destroys vitamins and protective anti-oxidants.

The process, called modified atmosphere packaging, is particularly damaging to vitamin C.

Levels of nutritious p-coumaric acid, caffeic acid and quercetin are also depleted in bags of salad, the scientists at Cornell University in the U.S. claim.

The findings, published in the British Journal of Nutrition, mean that shoppers who rely on pre-packed leaves to help them eat the recommended five portions of fruit and vegetables a day are, unwittingly, not having as healthy a diet as they think.

Convenience shoppers are drawn to the handy-sized bags because they cut down on the fuss of making salad.

The greens usually appear particularly crisp and fresh, and supermarkets often offer an array of more unusual leaves, including lollo rosso, lamb's lettuce, rocket and radicchio.

Their shelf-life is extended using modified atmosphere packaging, which creates a balance of gases inside the bag to retain moisture and prevent browning.

Dr Frankie Robinson of the British Nutrition Foundation said this can harm vitamin C and some nutrients, because they are easily oxidised.

She stressed, however, that packaged salads are still nutritious. 'Basically, eating a bag of salad is better than eating no salad or vegetables,' Dr Robinson said.

'Something is better than nothing. The problem is people are already not eating enough fruit and vegetables on a daily basis, and so while the research is interesting, we would not want to put people off.'

Dr Robinson said bags of salad which are packaged using the technique would still retain fibre and phytonutrients, as well as vitamin K - which is crucial for healthy bones.

She added: 'If people were to buy a whole lettuce they may chop it up and store it in the fridge for days - so it would lose its vitamin content anyway.

'Shops have to find ways of keeping things fresh and making foods attractive and easy to use - and bags of salad are easy to use without having to spend ages preparing them.

'Once we have got people eating enough vegetables, then we can worry about whether packaging is destroying some vitamins,' Dr Robinson added.

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