Alginates isolated from certain types of seaweed may have potential in weight loss supplements and foods, according to new research.
The study, published in Food Chemistry, shows that alginate from sea kelp can suppress the digestion of fat in the gut – opening up ‘exciting possibilities’ for making everyday foods healthier.
Led by Professor Jeff Pearson of Newcastle University, and backed by the BBSRC, the team identified the chemical properties of alginates which prevent fat from being digested by our bodies, noting that if we can reduce the amount digested, we reduce also the amount absorbed.
Their findings were then used to produce a ‘league table’ of the most effective seaweeds – with the scientists suggesting that the use of certain seaweeds in everyday foods could prevent help to the absorption of fat from our diets.
“What we have shown is that the seaweeds with a high level of guluronate stop the body breaking down and absorbing fat,” explained co-author Dr Matthew Wilcox, also of Newcastle University.
“As they are already used in the food industry in small amounts, we are looking at increasing their levels in foods which could reduce the amount of fat that we get which could help in weight management.”
Indeed, the team suggested that it could reduce the amount of fat available for absorption in the body by around 75%.
“We have already added alginate to bread and initial taste tests have been extremely encouraging,” added Pearson. “Now the next step is to carry out clinical trials to find out how effective they are when eaten as part of a normal diet.”
The team are already in talks with several major food companies with a view to producing alginate-supplemented products, revealing that while more testing is needed the first products could be on supermarket shelves next year.
The team used bread as a vehicle for the delivery of the alginate a further during trial – finding that even a small amount reduced people's fat intake by a third, while a four-fold increase in the alginate led to 75% of fat being blocked.
The research team was also able to identify which types of alginate are most effective.
Pearson and colleagues also tested to see which seaweeds contained the right alginates in the highest levels, revealing that those most effective at preventing the digestion of fat are:
- Tangle or Cuvie, Laminarea hyperborea a brown sea kelp G= 0.49
- Bladderwrack, Lessonia nigrescens, the giant grey weed, is a kelp species G = 0.45
- Bull kelp, Durvillea potatororum a brown algae G= 0.35
“The data presented here suggests that if the alginate is released in the small intestinal phase, this may have an inhibitory effect on the activity of pancreatic lipase,” said the New castle research team – adding that further work is now needed to assess if the alginate bread is able to block fat digestion a model gut, before then recruiting volunteers to study whether the effects they have modelled in the lab can be reproduced in real people, and whether such foods are truly acceptable in a normal diet.
Source: Food Chemistry
Volume 151, Pages 352–357, doi: 10.1016/j.foodchem.2013.11.070
"Method for quantifying alginate and determining release from a food vehicle in gastrointestinal digesta"
Authors: David Houghton, Matthew D. Wilcox, et al