FROM blueberries and broccoli to tea and tomatoes, the widely-lauded "superfoods" are credited with a host of amazing powers - from helping us look younger to protecting us from deadly cancers and heart disease. But does the constant expansion of the list of must-eat items compromise the claims of food manufacturers that these should be an essential part of a healthy diet?
A study by researchers at Ulster University yesterday revealed that the watercress diet, favoured by celebrities such as Liz Hurley, can dramatically cut the risk of cancer.
The research - funded by the Watercress Alliance - found the salad leaf can inhibit the growth of cancer cells and even kill them. But nutritionists yesterday expressed scepticism that the results were any use to shoppers. The trial involved 60 men and women eating an 85g bag (a cereal-bowlful) of watercress a day for eight weeks.
"That's completely impractical for a normal person," said Carina Norris, a Fife-based nutritionist. "Watercress has quite a peppery taste, so while it might work as an extra ingredient in a salad or a sandwich, there is no way any sensible person would consume that much. You are better getting your nutrients and vitamins from a range of sources."
She added: "The worrying aspect of this obsession with superfoods is that consumers hear too many claims of this kind and will simply get bored of the notion and go back to eating less healthy food."
Karol Sikora, professor of cancer medicine at Imperial College, said the watercress claims were "grossly overstated". He added: "Fruits and vegetables all affect DNA damage, hence the five-a-day strategy to prevent cancer. There is nothing special about watercress.
"I don't think people will seriously convert to eating 85g of the stuff each day. That's an awful lot of cress! You might even turn green. Much better to look holistically at your diet and ensure that there's plenty of fruit and vegetables, fibre and as little fat as possible.
"The other weakness in the study is that it doesn't actually show a reduction in cancer incidence - it's only a long-term surrogate that's changed." He said a long-term study would take 20 years, "by which time the investigators and their subjects would be rather bored".
Although their benefits can be overstated - a large dollop of retailer marketing goes towards promoting them - superfoods are a worthwhile addition to any diet.
Source - Scotsman