Tuesday, 28 May 2013

Seaweed for sustainable prosperity: why is it a public health issue and why would I go to a seaweed symposium?

Posted by Duika Burges Watson

I recently returned from Indonesia and the 21st International Seaweed Symposium. It’s been a bit of a fascination since my honours thesis in Indonesia documenting the international seaweed trade and the relationship between the hundred of thousands of farmers and the main consumers of the resource – us in the west. In my PhD I focused on one extract from seaweed, carrageenan, and considered how perceptions of risk in the public health sphere have influenced where and when it is used.

When I say ‘seaweed’ to a UK audience the common response is that people have tried ‘crispy seaweed’ in Chinese restaurants - and like it. The use of seaweed in the western diet and health applications is far more extensive than most people realise, and the potential of seaweeds to mitigate impacts of climate change, to address worsening food security issues and to provide some astonishing preventive health technologies (including as a barrier to viruses like HIV and HPV and for immune function) is not what most people would think about. The ‘story’ of seaweed is a rapidly developing one, and at the International Seaweed Symposium I was exposed to the many ways that we need to start thinking differently not just about this expanding and plentiful resource, but it also how we are going to address food security, climate change and health prevention issues in the future. 

Indonesian women make new food products from seaweed to sell at local markets
Climate change is having a major impact on agriculture. What we can grow is changing, the needs for more food increasing, and yet we have limited fresh water and land. Most of the world is covered by salt water. The United Nations is promoting ‘climate smart agriculture’- but how will this conversion happen with such limited space? Seaweed doesn’t need fresh water to grow and in 2010, the 20 million tonnes of seaweed that was grown around the world was from aquaculture. The Indonesian government alone estimates 1,110,900 hectares are undeveloped and suitable for aquaculture of seaweed – and they are promoting its development like crazy.

We don’t currently eat much seaweed ‘direct’, but we are the major consumers of extracts from seaweed; and seaweeds are used in foods for animals, fish and plants. At the conference there were many discussions about using seaweed in animal and fish feeds – the latter has taken awhile to develop. The UN's Food & Agriculture Organization is now talking about non-carnivorous fish as more environmentally friendly (vegi-fish!). Supplementing fish feeds with seaweed (currently mostly fed on fish with less than perfect ‘conversion ratios’) and aquaculture of seaweed eating fish were topics at the conference.
Indonesian farmers were in force at the ISS; the bulk of the Indonesian seaweed gets used for additives and winds up in processed food and health products in the west. There were presentations on new food uses, both as novel food products made from the ‘raw’ material and for functional extracts for nutraceuticals. Seaweeds contain things that land plants do not. Some of these values are erroneously called ‘micro-nutrients’ but there is nothing micro about their impact on health. I was struck by the presentation for example, by a senior lecturer from the Menzies Institute for Health in Australia on the immune modulation values of ‘fucoidans’ from brown seaweeds. I came home wanting to eat more brown seaweeds.

On climate change I was given the honour of introducing Ik Kyo Chung’s plenary lecture on seaweeds as a carbon sink. From Pusan University in Korea, he is leading a new world movement that recognises that seaweeds ‘capture’ carbon at rates greater than any land based plant. And in Korea they are growing seaweeds on a large scale for such purposes – but as yet there is much to do to present the evidence to policy makers in order that seaweed aquaculture can be used for carbon credits.

But there was something else I needed to know. In 2007 I published an article in the leading science journal on seaweeds about the regulatory history of carrageenan. Carrageenan is ubiquitous in processed food products in the west, particularly dairy where as little as 0.1% is sufficient to suspend the cocoa in chocolate milk. The article had recently been cited in a Food and Drug Administration review of carrageenan in the States. This got taken up by a radical food advocacy group arguing that I had no right as a ‘geographer’ to be commenting on ‘science’ about the safety of carrageenan. So my name duly slurred (and along with that the field of health and medical geography) I wanted to know how the industry itself would react to the scare that the Cornucopia report was generating in the blogosphere about carrageenan safety.

My paper was a regulatory review, and the argument in the paper was about the public perception of risk. I concluded that no matter how much science you throw at it, once someone has generated a fear, it’s impossible to then put the ‘risk genie’ back in the bottle. Carrageenan is one of the most thoroughly studied polysaccharides on the planet, all regulatory agencies worldwide have declared it safe, and the number of independent reviews is staggering. The controversy over carrageenan was a result of some work done in the 1950s to develop a treatment for peptic ulcer. Scientists had a good idea that carrageenan was ‘soothing’ but to consume it in the amounts needed would gag you – it would be too viscous. So it was purposefully degraded. 

In human studies following 200 people over 2 years consuming large amounts of degraded carrageenan they found absolutely no problem at all. But a rat study showed some evidence that it might cause ulceration in the gut – and given the fear at the time related to the new discoveries around cancer – degraded carrageenan (and by association carrageenan used in foods), ulceration and cancer got irretrievably linked in the public perception of the substance. 

Since then there have been multiple reviews – and still no new evidence it is any risk to human health. Yet the more studies, the more the perception of risk appears in blogs, stories and tales written by people who do not know the history of the risk, or understand the difference between a purposefully degraded substance and an extract. In many ways this is not surprising, when ‘E’ numbers were introduced in the UK for example, rather than demonstrating to the public as the regulatory agencies hoped, that these substances were well studied and safe, people started to fear them. 

The latest fear campaign, written up as a report by the organic advocacy group Cornucopia, had been generated by studies discredited by regulatory agencies worldwide. The science on which the campaign was based even suggested consuming carrageenan-bearing seaweeds was a risk to health. Papers at the conference demonstrated multiple benefits to consuming carrageenan-bearing seaweeds. But the public perception of risk feeds on controversy, and feeds off the risk stories (particularly about food additives) far more than the scientific studies. Some ‘organic’ producers in the US have been removing carrageenan from their products as a result of the latest scare. It struck me was that if you are consuming large amounts of carrageenan, chances are you are consuming a heavily ‘processed’ food diet – in which case my public health training suggests to me there are other things to worry about than 0.1% of a seaweed extract in your chocolate milk.

The ISS is in my view a pretty unique organisation. The conference is attended by academics from multiple disciplines, industry representatives, government (the Indonesian minster of fisheries attended the whole thing) and the people who farm it. It is ‘translational’ as many of the people involved are there to find solutions that meet the needs of all stakeholders. I liked the model the conference provides for thinking about some of the issues we are going to confront, and in all the examples above, working in cross-disciplinary ways gives bigger picture answers that take more issues into account. The UK is surrounded by sea, with a wealth of seaweed resources and a great potential to do more in this field. But given that most people don’t even know that crispy seaweed is made of cabbage, there is a long way to go to convince policy makers to take this industry seriously.

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