But now the humble seaweed has been put forward as the miracle cure for the western world’s obesity epidemic.
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The material in sea kelp, called alginate, was better at preventing fat absorption than most over-the-counter slimming treatments, laboratory tests showed.
Dr Iain Brownlee, who co-led the University of Newcastle team, said: “This suggests that if we can add the natural fibre to products commonly eaten daily -- such as bread, biscuits and yoghurts -- up to three quarters of the fat contained in that meal could simply pass through the body.
“We have already added the alginate to bread and initial taste tests have been extremely encouraging. Now the next step is to carry out clinical trials to find out how effective it is when eaten as part of a normal diet.”
The scientists used an “artificial gut” to test the effectiveness of 60 different natural fibres by measuring the extent to which they affected the digestion of fat.
They are presenting their findings today at the American Chemical Society’s spring meeting in San Francisco.
Dr Brownlee said the aim was to see if the same effects
modelled in the laboratory could be reproduced in living volunteers.
“Our initial findings are that alginates significantly reduce fat digestion,” he said.
The research is part of a three-year project funded by the
Biotechnology and Biological Sciences Research Council and addresses new European regulations that insist on scientific
evidence backing any health claims made on a food label.
“There are countless claims about miracle cures for weight loss but only a few offer sound evidence to back up these claims,” said Dr Brownlee.
Alginates not only have great potential for weight management -- adding them to food also has the added advantage of boosting overall fibre content.
Alginates are already used as thickeners and stabilisers in small amounts in toothpastes and foods such as ice cream, jelly and salad dressing. In blind taste tests bread with added alginate actually scored higher for texture and richness than a standard white loaf. It also extended the bread’s shelf life.
Co-researcher Professor Jeff Pearson warned: “There are current treatments for obesity which are fat blockers but you need to have another pair of underpants with you. They block the fat but it just goes into the large bowel and that causes diarrhoea.”
He said alginate was not a wonder cure and would only work if overweight people were willing to change their ways.
He said: “People shouldn’t think alginate will do it for you. This will help people lose weight but you can’t just use alginate and then go and eat 100 cream buns. It isn’t a magic bullet, nothing is.”
Kelp is already prized by the cosmetics and pharmaceutical industries and commercial kelp harvesting is now up and running in the Western Isles. Laverbread is a Welsh delicacy made from seaweed and most commercial laverbread is now made from seaweed gathered from western Scotland.
During the Highland Clearances, many crofters were forced to the coast and into kelping -- producing soda ash fertiliser from kelp ashes -- after being driven from their land.
Harvest of the sea
Seaweed belongs to one of several groups of multi-cellular algae: red algae, green algae, and brown algae.
It is packed with vitamins and minerals.
Seaweeds are popular in the Far East, but also in Indonesia, Belize and Peru.
It was once a vital part of the Scottish diet. Giant kelp was boiled and served with butter as a vegetable, made into soups, or dried.
Laverbread is a traditional Welsh delicacy made from seaweed. It is boiled, minced then fried with bacon and cockles for breakfast.
Other useful seaweeds include dulse, popular in Ireland, where it is mixed with potatoes and butter; in France it is boiled with kelp to make pain d’algues.