Farmed and dangerous

Unless you seek out wild fish, the chances are that most of the fish you see in shops and restaurants were raised on a fish farm in an environment very different to what their wild counterparts would have experienced. One of the main differences on many fish farms is the stocking density - imagine having to fight your way through the January sales every day just to get something to eat. This is the type of scenario many farmed fish endure.

Fish species raised by fish farms include salmon, catfish, tilapia, cod, carp, trout and others. Just as we see with other farmed animals such as the dairy cow, intensive farming methods results in a cheaper end product (in terms of quality and price). This is why farmed salmon has been called 'the battery chicken of the seas'. This may not concern you if the supposed health benefits are the same. However, they are not.

From a nutritional and health perspective, there are several important differences between farmed and wild fish. In the wild, salmon can eat 10 times their own body weight per day. Providing a similar diet to farmed fish would mean grinding up to 10 pounds of sardines, anchovies, mackerel, herring and other fish for every pound of pale and sickly farmed salmon produced. This is clearly uneconomical for fish farmers and heralds an ecological disaster as one-third of the global fish catch ends up as fishmeal or fish oil and fish farms use about half of the fishmeal and more than 80 per cent of the fish oil (Soil Association, 2008).

It is much cheaper to manufacture feed pellets from soya, rapeseed or corn with animal by-products and vitamin and mineral supplements. In Canada and Chile, it is common to use other protein sources such as feather or blood meal by-products of chicken and pig production (Soil Association, 2008a). Consequently, farmed fish tend to contain more total fat, but less omega-3s than their wild counterparts (Weaver et al., 2008). In other words, the levels of good and bad fats (the fatty acid profile) of farmed fish vary widely from that of wild fish.  

Using cheaper vegetable-based feeds drives up the level of omega-6 fats found in the fish. Farmed tilapia (the most rapidly expanding fish in terms of world and US consumption), contain some of the highest levels of the omega-6 fatty acid arachidonic acid found in our food chain (Weaver et al., 2008). These and other farmed fish have a fatty acid profile that would generally be considered as unhealthy. Indeed, marked changes in the fishing industry during the past decade have produced widely eaten fish that have fatty acid characteristics that are generally accepted to be inflammatory by the health care community (Weaver et al., 2008).

The fish used in organic fish feeds come from the discarded filleting wastes (blood, guts, tails and heads) of fish caught for human consumption and should not contain fish caught specifically for fish feed. However, this does mean the supply is sustainable; human demand for fish also exceeds supply. Compared to conventional fish feed, organic fish feed may use more fish-based ingredients than non-organic fish feed but still might only have 40 per cent fishmeal and about 22-25 per cent fish oil (Soil Association, 2008a). This means that 35 per cent of the feed could be vegetable-based.    

Farmed fish can also contain chemical pesticide residues as well as dangerous levels of toxic man-made chemicals including PCBs. A 2002 study investigating the levels of toxins in commercial salmon feeds, farmed salmon and wild salmon found that the farmed salmon had consistently higher levels of a range of contaminants including PCBs (Easton et al., 2002). The authors suggested that the higher levels seen in the farmed salmon probably resulted from the elevated level of contamination found in the commercial salmon feed. They concluded that this analysis indicates a safety concern for individuals who, on a regular weekly basis, consume farmed salmon produced from contaminated feed. Since then, other studies have indicated that commercial feed is likely to be a major source of PCBs in farmed salmon (Carlson et al., 2005).

So, farmed fish are very far from the safe choice we are led to believe and from a health perspective, when fish are farmed, they lose some of their protective fats. This is a ridiculous situation where the one possible argument in favour of fish consumption (their omega-3 content) is being eroded by intensive farming methods. There remains little, if any, argument for consuming fish.

Fish oil supplements

Some people prefer to take fish oil supplements rather than eat oily fish. However, fish oil supplements have also been linked to negative health effects in numerous studies. This is particularly worrying as they are increasingly popular as clever marketing persuades people to buy them.

Most fish oil supplement manufacturers publicise their meticulous manufacturing techniques reassuring us that all toxins are removed from their products. However, in March 2006, the FSA announced that the fish oil supplement manufacturer Seven Seas Ltd withdrew a number of batches of its own fish oil supplements because the levels of pollutants present (FSA, 2006). Less than a month later Boots withdrew fish oil capsules for the same reason (FSA, 2006a). In both cases they said although there was no health risk associated with consumption of this product, the level of dioxins found in fish oil used to produce these capsules exceeded statutory limits. This is a bizarre statement which seems to be saying that a little bit of poison should be all right!

The official position - not budging 

The seriousness of the potential health risks of consuming toxins in fish prompted a joint subgroup of two advisory committees, the Scientific Advisory Committee on Nutrition (SACN) and the Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT), to consider the benefits and risks of fish consumption (SACN, 2004).

Their report formed the basis of the FSA advice that pregnant and breastfeeding women should limit their consumption of oily fish to one to two 140 gram portions per week. This group (and children under 16) they say, should avoid shark, marlin and swordfish and not eat large amounts of tuna because of the potential methylmercury exposure. Men, boys and women past childbearing age or who are not intending to have children can eat up to four portions of oily fish a week before the possible risks might start to outweigh the benefits.

The report highlights the presence of dioxins in herring, salmon, mackerel and to a lesser degree in trout, and voices concerns about the presence of other pollutants such as brominated flame retardants. The FSA states that occasionally eating more than the recommended amounts of oily fish will not be harmful. It says that the risks from chemicals such as dioxins are not immediate; they develop as the chemicals accumulate in the body over a long period of time. Surely it is better to avoid these hazardous chemicals altogether?

Confused? You will be!

The FSA advises that fish oils protect against CVD and that long chain omega-3s are vital for the development of the central nervous system of the foetus and the breast-feeding infant (SACN, 2004). However, the FSA warns pregnant and breast-feeding women to restrict their intake of oily fish to limit their exposure to harmful toxins. So just when your intake of omega-3 really matters, during pregnancy and when you are breastfeeding, the Government warns you to limit your intake! Consumers are unsurprisingly confused; the information given is neither comprehensive nor consistent.

In 2002, Which? magazine reported the findings of a Consumers' Association survey which asked 972 adults about their awareness of, eating habits and attitudes to oily fish (Consumers' Association, 2002). The survey found that only a sixth of fish-eaters knew that the FSA's advice is to eat oily fish once a week; over half thought the advice was to eat two or more portions. A shocking 61 per cent of people had no idea that oily fish may contain contaminants. One per cent knew that pregnant women should avoid certain fish but nobody could name them. Most people in the survey were confused by what was meant by oily fish (14 per cent thought that cod was an oily fish). It is not just the public who are confused; the Consumers' Association states that the FSA couldn't provide any clear answers about the health implications of eating more than one portion of oily fish per week.  

It's no clearer in the US. In 2002 the American Heart Association (AHA) issued a statement supporting the recommendation for at least two servings of fish (particularly oily fish) per week (Kris-Etherton et al., 2002). However, the AHA warned that the recommendations on fish consumption need to be balanced with concerns over contamination of fish with environmental pollutants (particularly mercury and PCBs). This is an incredibly important proviso which seriously challenges the idea that fish is 'healthy'. It should be noted that the AHA also recommended plant foods that are high in the plant omega-3 ALA such as soya beans, rapeseed, walnuts and flaxseed and oils made from them.

In the joint WHO/FAO 2003 report Diet, Nutrition and the Prevention of Chronic Diseases, regular fish consumption of one to two servings per week is recommended to protect against CVD (WHO/FAO, 2003). However, whilst it also states that vegetarians can ensure adequate intakes of the omega-3 fatty acid ALA from plant sources, the report fails to give any warnings about the dangers of environmental contamination.

This conflicting advice has led to much confusion. Who should the public listen to? Who can they believe?

Fish is not a popular food

Despite the constant barrage of fish-promoting marketing and hype, the UK public just don't buy it! The FSA says that on average, people in the UK eat only a third of a portion of oily fish a week (FSA, 2004). Indeed, fish is so unpopular that the FSA admits that seven out of 10 people in the UK don't eat any oily fish at all. Clearly then, oily fish is not a significant contributor of omega-3 fatty acids in the diets of many people.   

From a public health perspective, encouraging people to eat more fish in order to gain healthy amounts of omega-3 fats is simply not working. Even if people did start to consume more, the oceans simply cannot cope with any more demand, and as we have seen, farmed fish is definitely not the solution.

The upshot of all this confusion and dislike for fish is that many people fail to understand the importance of omega-3s and do not realise how easy it is to obtain them from every-day plant foods. Promoting oily fish as the only 'heart friendly' solution could actually deter individuals from making the fundamental dietary changes necessary for real long-term heart and body health. A healthier and simpler solution would be to promote a plant-based diet containing EFA-rich seeds, nuts and oils. Plants, not fish, are the way forward for good health.

Plant EFAs leading the way to good health

The good news is you don't have to eat neurotoxins and carcinogens to get your omega-3 fatty acids; there are perfectly safe plant sources that can benefit your health.   

Antioxidants in plants protect EFAs

The antioxidant vitamins C, E and beta-carotene (the precursor of vitamin A) are found in abundance in plant foods such as fresh fruits, vegetables, nuts and seeds. They are thought to be one of the body's main defences against damaging molecules called free radicals. They are also vital for another important function that demonstrates why plant sources of fatty acids are superior to fish-derived versions.

Most people (especially those who cook a lot) know that certain fats are more likely to 'go off' when they are exposed to air. The difference arises from the number of double bonds in the fat as they make fats vulnerable to attack from oxygen molecules. This is why we cover food with plastic wrap or submerge it in water to protect it. This is why fish oils are prone to oxidation and give off a characteristic 'fishy' smell.   

Antioxidants help slow this decaying process by acting as a fall guy for the fatty acid; they take the oxygen hit and save the fat from oxidative damage. Plant sources of EFAs, such as nuts and seeds, possess their own supply of antioxidants which protect their fats (in particular vitamin E). So yet again, we see why a plant-based diet provides not only important nutrients, but valuable substances that can protect us from oxidative damage too.

Free radicals are a problem for us too! They are unstable molecules generated by normal bodily functions, cigarette smoke, pollution, ultraviolet light and stress. Free radicals are linked to cancer or other diseases as well as the aging process. Animals and plants protect themselves against free radicals with antioxidants. They are a natural self-defence mechanism which is thought to defend against many diseases in humans, including the UK's biggest killers heart disease and cancer. 

As stated, the three amigos of the antioxidant world are beta-carotene (vitamin A), vitamin C and vitamin E. The mineral selenium is another valuable antioxidant. Antioxidants are not found abundantly in meat or fish. Plant foods (including fruit, vegetables, nuts and seeds) are the best sources. In the largest, most comprehensive analysis to date of the antioxidant content of commonly consumed foods cranberries, blueberries and blackberries ranked highest among the fruits studied. Beans, artichokes and Russet potatoes topped the list of vegetables. Pecans, walnuts and hazelnuts were the top nuts and ground cloves, cinnamon and oregano ranked highest among the herbs and spices (Wu et al., 2004). As a general rule, brightly coloured vegetables (such as sweet potatoes, red cabbage and tomatoes) tend to be relatively high in antioxidants.

Again, vegans are in a win-win situation. Not only do they avoid harmful substances found in meat and fish, they also benefit from a wide range of healthy nutrients including fibre, vitamins, minerals and of course, antioxidants.

Sustainability

The widely publicised supposed health benefits of omega-3 fats from fish, together with dwindling supplies of fish caught from the wild, have spawned a dramatic expansion in aquaculture (farmed fish). Aquaculture has increased at an annual rate of 9.2 per cent compared with 1.4 per cent for caught fish (Weaver et al., 2008).

Nearly half the fish consumed as food worldwide (43 per cent) is raised on fish farms rather than caught in the wild; that's up from just nine per cent in 1980 (FAO, 2006). The level of fish caught in the wild (around 90-93 million tonnes annually) by contrast, has not changed much despite growing world population and demand. It can't. The FAO acknowledges that there is little chance of any significant increase in catches beyond these levels anyway.

The levelling off of wild catches coupled with the growing world population and increasing demand for fish spells trouble says the FAO. It estimates that an additional 40 million tonnes of aquatic food will be required by 2030 just to maintain current levels of consumption. This is clearly unsustainable, we have to look to alternatives, and fish farming is not the answer. The environmental problems such as the spread of disease, sea lice and pollution associated with farmed fish are abundant. The sensible, and in fact the only answer is to obtain our omega-3 fats from sustainable plant sources.

For more information on the environmental impact of fishing see Viva!'s guide The End of the Line.

Recommendations

A well-balanced plant-based diet containing green leafy vegetables, wholegrain foods, pulses, nuts and seeds will ensure an adequate intake of the plant omega-3 ALA. One of the best sources is flaxseed oil, containing 57 per cent ALA and 16 per cent LA with a omega-6:omega-3 ratio of 0.28:1 (Davis and Kris-Etherton, 2003). A 14 gram tablespoonful of flaxseed oil provides eight grams of ALA. Flaxseed oil must be kept in the fridge and added to sauces and dips or cooked food. Cooking with it will destroy its beneficial properties. In addition to this, try to buy and store nuts, seeds and their oils in small quantities to ensure that they are as fresh as possible and limit the amount of time the oils have to degrade.

It is difficult to say exactly how much of a certain food should be consumed to optimise EFA intake as the fatty acid content of foods varies. However, a sensible approach is to reduce consumption of omega-6 rich vegetable oils (substitute sunflower or corn oil for olive oil in cooking), while increasing omega-3 intake (found in flaxseed oil, walnuts and green leafy vegetables). Limiting or avoiding commercial oil-based processed foods will also help improve the omega-6:omega-3 ratio. Consumption of saturated fatty acids (and trans fatty acids in processed foods) should also be limited as they are unnecessary in the diet, are a risk factor for atherosclerosis and can interfere with the conversion of ALA into the longer chain omega-3s.

To improve the conversion of ALA to EPA and DHA follow these simple guidelines:

  • Consume a wide range of wholefoods everyday - remember variety is the spice of life!
  • Obtain most fat from whole foods (nuts, seeds, wholegrains, olives, avocados and soya)
  • Select monounsaturated fat (olive oil) for cooking
  • Use omega-6 fats (sunflower oil, safflower oil) with moderation
  • Use omega-3 fat (flaxseed oil) for salad dressing and in dips but do not cook with it (store it in the fridge)
  • Cut down on cholesterol (avoid eggs, meat and dairy products)
  • Avoid or cut down on processed foods, trans fats from margarines and hydrogenated vegetable oils
  • Avoid or reduce fried foods, alcohol, caffeine, sugar, smoking and stress