Associate Parliamentary
Food & Health Forum
Fish consumption - matching nutritional needs & sustainable fish supplies
Tuesday 16 March 2010
Committee Room 3, House of Lords
Minutes
Introduction
Lord Rea welcomed members and introduced the subject of the meeting: how we can best balance the need to increase consumption of the nutrients provided by fish with concern about the sustainability of fish stocks. Lord Rea noted that the Food Standards Agency (FSA)had issued advice in 2004 – based on a joint SACN/COT report – encouraging people to eat more fish, especially oily fish, for the sake of their health. The Forum’s own inquiry report on the links between diet and mental health, published in January 2008, recommended that the FSA shouldreconsider its advice to pregnant women about fish consumption, with a view toencouraging them to eat two portions of oily fish, or the equivalent in omega3 polyunsaturated fatty acids (PUFAs) aweek.
In recent years, however,the consensus that we should eat more fish for the sake of our health has increasingly been matched by concern about declining fish stocks and how we can manage sustainable fish consumption. The FSA held a public consultationin early 2009 on its dietary advice to consumers on fish consumption with a view to amending that advice to take into account nutrition, food safety and wider sustainability issues. The outcome of that review is newguidance, which is available on the FSA’s “eatwell” website. It suggests that people who eat a lot of fish every week should try to eat as wide a variety as possible not only for good health, but also because of concern about fish stocks.The FSA also draws attention to the role sustainable aquaculture could play in meeting our demand for fish and shellfish.
Lord Rea introduced the guest speakers: Jack Winkler,Professor of Nutrition Policy atLondonMetropolitanUniversity; Professor CallumRoberts of York University; and Andy Beadle of BASF.
Professor Jack Winkler, LondonMetropolitanUniversity
Jack Winkler said there are many good reasons to be concerned about the sustainability of fish supplies. From a nutritional point of view we look at fish as a rich source of nutrients and omega 3 fatty acids are a key object of attention for the reason that we cannot make them for ourselves, so we must derive them from our diet. Fish are the richest source of omega 3 fatty acids, from which the long chain PUFAs, EPA (EicosapentaenoicAcid) and DHA (Docosahexaenoic Acid) are derived.
If we look at fish in nutritional terms, we are interested in sustainable supplies of omega 3. This begs two further questions: how much do we need and can fish supply it?
If we look at the 2004 SACN report, the population recommendations (para 1.10) is that we should “eat at least two portions of fish per week, of which one should be oily…two portions of fish per
week, one white and one oily,contain approximately0.45g/d LC n-3 PUFA”. SACN’s recommendation is taken as authoritative not only by the FSA, but by many nutritionists and dietitians in the UK. However, two paragraphs after this recommendation, SACN’s report (para 1.12) states that “this recommendation represents aminimal and achievable average population goaland does not correspond to the level of fish consumptionrequired for maximum nutritional benefit”. There are 397 scientific references in the SACN report, but not one of them that attaches to their population recommendation. There is no explanation to demonstrate why or how they reached this minimal recommendation. It appears to be a guess by six scientists unsubstantiated by any evidence.
It is certainly a minimal recommendation. Four paragraphs before (at para 1.8), they say that “at least 1.5g a day of LC n-3 PUFAis required for demonstrable beneficial effects on cardiovascular risk factors” but they recommended a third of that amount.
In addition to showing nutritional caution, they were very cautious about the toxicological contamination associated with eating fish. They set the tolerable intake on the basis that people would eat that level every day for a lifetime. At the time they said they took this stance because there was no risk/benefit analysis applicable to fish; now there is. The US Food and Drug Administration undertook a risk/benefit analysis and published their report in 2009. This review[1] took into account mental health as well as physical health, which is something SACN failed to do. The conclusion of this review is that eating fish produces only healthy benefits up to a high level of consumption. Of course Americans eat different fish to the British and they have different toxicological risks associated with them, but we also have British evidence on the risks and benefits of fish consumption derived from the ALSPAC Study (the Avon Longitudinal Study of Parents and Children). It concluded that there is no discernible risk to babies of mothers who ate well in excess of SACN’s recommended levels of fish per week. In sum, our recommendations on fish consumption are too low.
Current fish consumption is 50g per person per week on average in the UK, compared to the target of 280 grams per person per week. SACN’s minimum recommendation is thus 5.5 times the current level of consumption in the UK. In its 2009 consultation the FSA said that it was not likely that we would achieve SACN’s target levels. If the current rate of consumption continues it will be 2100before the target is reached. If we look at the target for fish consumption set for cardiovascular health, it is18 times the current level of consumption. Can we increase our intake from sustainable fish sources to meet the recommended levels of fish consumption? The answer is: we probably cannot.
People in the UK eat 50g per person per week despite fish and chips being a traditional UK food. People in the UK eat even less oily fish – most of our herring and mackerel catches are exported to continental Europe. So we find ourselves in a bizarre situation: even if we did have sustainable sources of the right type of fish, people in the UK would probably not eat the target amounts. If we are to eat enough omega 3 fatty acids where will they come from?
Jack circulated a diagram (see attached) which shows possible sources of omega 3. One primary source is caught fish. If we do not have enough caught fish, we can develop aquaculture. However, the way we farm fish in Europe depends to an extent on caught fish so even a substantial expansion of aquaculture in Europe may not provide enough omega 3 fatty acids. Plants are another source of omega 3. Land based sources of essential fatty acids (EFAs), plants, are difficult for humans to convert into the long chain (LC) PUFAs that we need (EPA and DHA). So traditional land based plant sources cannot provide the solution to our needs. Algae are another source, particularly fermented algae, but at the moment these are relatively expensive. EFAs could also come from genetically modified plant sources – plants in which genes for LC PUFAs have been inserted - but this is a controversial issue. Europe, almost alone among all the continents, is still very resistant to GM crops. One can distinguish between agronomic genetic modification, which helps plants to grow better (for example, pest resistant cotton) which delivers benefits for producers, but no discernible benefit for consumers; and nutritionally genetically modified foods which are designed to produce a benefit for consumers, such as golden rice, which has been developed by non commercial sources in a Swiss Government laboratory funded by the Rockefeller Foundation with a higher than normal level of vitamin D content in order to deliver nutritional benefits in developing countries.
Pending the development of genetically modified foods we can get omega 3 PUFAs from processed foods, either from fish products or non fish products fortified with PUFAs. Omega 3 is a very popular food fortificant with manufacturers and has been for a decade.
One final option is to derive the omega 3 PUFAs we need from supplements, but their manufacture depends on a sustainable source of fish oil.
Alan Long of Vega Research asked Jack to comment on the omega 3 content of fresh-water and salt-water fish and between farmed and wild fish, noting that farmed fish have less muscle tissue.
Jack Winkler said there are considerable differences in omega 3 content between different types of fish, both maritime and farmed. The FSA consultation paper does give a lot of helpful information about this. We also have to differentiate between inland fish farms, for example in China, and UK fish farms which are largely maritime. Overall, we are not likely to get enough omega 3 from fish, however it is produced, so we need to consider other sources.
Professor Callum Roberts, University of York
Callum Roberts began by thanking Jack for summarising in a nutshell the background to what he wanted to say about sustainable fish sources. He noted that attitudes have changed considerably over the last century. At the end of World War II, we thought the resources of the sea were inexhaustible, but capitalisation of fishing fleets has brought us to the point where we are now wondering whether all the fish have gone.
One important component of UK fish supplies are fish caught by trawling the sea bed. Records of landings of “bottom fish” first began in 1889, when complaints were first made that it was a wasteful and destructive way of catching fish. Slide 3 shows how landings increased over the years until the mid twentieth century and then collapsed to present levels.
Callum said that fish landings need to be assessed in relation to the availability of fish stocks and our capacity for fishing. For example, during both World Wars it was too dangerous to fish. So it is more useful to look at landings per unit of fishing power – that is, the effort we put into fishing. After World War I, we found that local fishing was no longer economically successful, so we built boats capable of going further afield and landings peaked in the late 1950s (see slide 4) as we reached the limits of stocks in distant seas. The EU Common Fisheries Policy (CFP) has come in for a lot of criticism but it is not responsible for falling landings per unit of fishing power.
We have been arguing that we should eat more fish since the 1930s. In order to look at supply per person, we have to look at sea sources of fish and shellfish and river sources. The peak in fish landings on this basis occurred in the early twentieth century (see slide 6). If we convert this into the availability of fish per person per week, we see that we have 50g per person per week, taking into account the amount of fish available for consumption (the whole fish is not completely edible) (see slide 7). In slide 7, the red line indicates the amount of fish available to the UK population based on landings and imports minus exports. It shows an average of 150g per person per week is available, even if only 50g per person per week is eaten.
The recent decline from the1980s onwards of landed fish has been made up by imported fish. If we add the fish sourced from aquaculture (see the black line in slide 8) we still do not have enough fish to feed everyone at the level recommended by the FSA. There have only been two periods in history when we have had enough fish to satisfy the FSA recommendation, after both World Wars.
In recent decades we have been outsourcing our overfishing. The EU has brokered deals with developing countries – which are often under pressure because of debt levels and the poverty of their people and these countries are often affected by corrupt practices. Under scrutiny these agreements are not sustainable and many appear to be unethical.
Looking at the global picture (slide 11) we see that the availability of supply from wild fish and aquaculture is rising slowly, as a result of the rapid expansion of aquaculture since the 1950s, but this still provides less fish per person per week than recommended by the FSA. The volume of global fish available after processing (see slide 12) is derived from various sources, including illegal catches. The average recommended adult weekly fish intake for nine nations is 366g per person per week, which means we need another 39.2 million metric tonnes to feed the global population at 2005 levels and over 85.2 million metric tonnes more to feed the world population at the levels predicted for 2050 (9.1 billion people) (see slide 13).
There is a way that we can get more fish out of the seas. There has been a 90%+ decline in wild fish in the sea since 1889, but if we took less fish annually, the fish stocks would grow. Taking a sustainable proportion of fish through improved ocean management would lead to a 30-40% increase in fish supplies, although this would still not provide enough fish to meet the FSA’s recommended intake levels.
There has been an increase in aquaculture over recent years. The figures may include inflated figures from China, but show an annual average increase of 7%. In order to achieve the level required for recommended fish consumption, we need an annual average increase of 3.5%, year on year, but this will be challenging.
Alternative sources of EFAs include algae and, at the bottom of the sea food chain, plankton, but this is probably not what most people would want to eat.
Andy Beadle, BASF Plant Science
Andy said an important key message, illustrated by Jack, is that not all fats are bad. Certain fats, the polyunsaturated fatty acids (PUFAs) are essential components of our bodies. They are regarded as essential because the body cannot synthesise them well, so we must derive them from our diet. Certain PUFAs derived from marine sources, the LC-PUFAs, have long term health benefits: Arachidonic Acid (ARA) is beneficial for the brain and the development of the eye in infants; EPA and DHA have repeatedly been shown to decrease the risk of cardiovascular diseases and reduce lipid levels in blood, preventing arteriosclerosis in adults. There are various authoritative recommendations concerning optimum EFA intakes for human health. The World Health Organisation (WHO) recommends 0.5 g/day of EPA/DHA (the equivalent of two portions of fish per week) and the European Food Safety Authority (EFSA) recommends 0.25 g/day of EPA/DHA. By contrast, typical Western diets contain 0.1 g/day of EPA/DHA.
A recent study by Harvard School of Public Health demonstrated that an estimated 80,000 American deaths could be prevented each year via an increased dietary intake of EPA/DHA. The recommendations on EPA/DHA intake levels are increasinglywell recognised by consumers, which has lead to increased public interest and increased demand for dietary supplements (growing at 10% a year) and fish (farmed fish consumption is growing at 8% a year).
Plants do not produce EPA/DHAbut they are produced by marinealgae, which is where fish get them. We have heard that world fish stocks are limited and it is unlikely that we can get enough EPA/DHA for the world population from wild fish alone. Fermentation of algae to produce EPA/DHA is possible, but expensive. One way of increasing availability of EPA/DHA is through the farming of certain species of oily fish (salmon and trout) Such aquaculture production requires the farmed fish to be fed with fish oil, but demand for fish oil is exceeding supply and algae fermentation is expensive, so the medium term sustainable production of EFAs is questionable. Having reached this conclusion, BASF looked at possible alternatives including production of LC PUFAs, especially EPA and DHA in canola.
Slide 6 illustrates demand and supply in the fish oil market and shows the outlook for production and demand from 1995 to 2015. As the market has grown and demand has grown, aquaculture has taken more fish oil. The balance goes into supplement production. The graph makes it clear that the supply is relatively fixed. As a result, we have an excess of demand over supply, driving prices up. The long term average price of fish oil has been $300-400 per tonne, now it is trading at $900 per tonne and 18 months ago, it was trading at $2000 tonne. It peaked in this period because there was concern that EU regulatory changes would reduce the supply so traders tried to buy two years worth of stock.
Farmed fish (salmon)feed is supplemented with fish oil to elevate the levels of EPA/DHA in the salmon, such that one 100g serving of salmon per week would deliver the recommended weekly intake of EPA/DHA. Consequently farmed salmon is not only nutritious, but also extremely healthy. At BASF we wanted to produce canola that would contain EPA/DHA, but in order to reach that stage we had to introduce a complete biosynthetic pathway in to canola, so that C18:1n-9 (Oleic acid) goes through a series of desaturation and elongation steps, to produce DHAultimately. The genes we used are those found in algae, the same genes that produce EPA/DHA consumed by wild fish.