Scientists unravel bioavailability of brown seaweed

By Louisa Richards

- Last updated on GMT

The EU-funded SAFAX study demonstrates for the first time that these polyphenols are taken in and metabolised by humans © iStock.com / TimAwe
The EU-funded SAFAX study demonstrates for the first time that these polyphenols are taken in and metabolised by humans © iStock.com / TimAwe
Phlorotannins in brown seaweed are metabolised and absorbed in the large intestine and may have anti-inflammatory potential, an EU-funded study suggests.

The study was part of the SAFAX (seaweed derived anti-inflammatory agents and antioxidants) project, an EU-funded initiative for small and medium enterprises (SME’s) to produce polyphenol-rich extracts from seaweed with antioxidant and anti-inflammatory potential in humans.

“It’s important to realise this is a first study and as with many studies carried out on seaweed bioactives we’re still academically and commercially a long way from understanding certainly the molecular structure of some of these compounds and how to characterise them properly, so there’s a lot of research ongoing at the moment but there’s a lot of potential and its worth pursuing,” ​researcher Dr Sarah Hotchkiss from extract developer Cybercolloids Ltd told us.

Life’s a beach

Phlorotannins are a type of phenolic compound only found in brown seaweeds increasingly investigated for their promising potential for food and pharma applications due to an array of suggested biological activities including anti-cancer, anti-bacterial and anti-diabetic.

Data on bioavailability of phlorotannins in humans is lacking and the SAFAX study results demonstrate for the first time these polyphenols are taken in and metabolised by humans, Dr Hotchkiss said.

‘Raw material availability’ 

Compared to an increase in worldwide seaweed production of nearly 6% yearly, European production has decreased by a third since 2000, according to European macroalgae industry network NETALGAE.

“We looked at the speciesAscophyllum nodosum because it is the only truly commercially available seaweed in Europe at the moment, of any significant commercial potential because we have a lot of seaweeds in Europe but our seaweed industry is quite small compared with the rest of the world and obviously if you’re developing something with the potential commercial application then you have to develop it from a species where you’ve got raw material availability,” ​said Dr Hotchkiss. 

Study details 

A Cybercolloids extraction of Scottish brown seaweed Ascophyllum nodosum​, also known as knotted or egg wrack seaweed, was analysed in vitro and in 24 healthy volunteers. They consumed it in a capsules containing 101.89 mg of polyphenols. Urine and plasma analysis during a 24-hour period suggested colonic metabolism of the phlorotannins. 

A significant increase in the cytokine IL-8 (interleukin-8) was observed eight hours after the intervention, warranting further detailed studies into phlorotannins’ anti-inflammatory potential. 

Other types of seaweed extracts with different polyphenol molecular weight size or concentrations for the polyphenols could be looked at in future, said Hotchkiss.

The study was a ​one off snapshot”​ and there was “quite a lot of work to be done before this would be available for human supplements, and more clinical studies would be needed to take it any further”.

She said more funding was needed to take the research forward given the SWAFAX project and its funding had now come to an end and the SME’s supporting the project did not have the resources to go it alone. 

 

Source:  British Journal of Nutrition​ 

Published online ahead of print, http://dx.doi.org/10.1017/S0007114516000210 

Gastrointestinal modifications and bioavailability of brown seaweed phlorotannins and effects on inflammatory markers 

Authors: G. Corona et al.

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