Why Animal Products Harm – Fish

Fish is not a health food by any means. Widespread pollution makes fish and shellfish so dangerous to eat that health experts recommend limits for their consumption. Fish oil is not the miracle cure-all it was promised to be either – it doesn’t prevent heart disease and may be contaminated too. Going fish-free can protect your health and contribute to a more sustainable future.

Toxins in fish

All the world’s oceans and rivers, and many lakes, are contaminated with chemicals and heavy metals, such as mercury. These toxins build up in the fat in fish, particularly in oily fish. Lake Victoria, for example, is growing increasingly more polluted with sewage, industrial waste, micro plastics, pharmaceutical pollutants and more. It resulted in mass fish deaths in the past and the fish living there certainly carry a heavy load of toxins.

Many of the chemicals belong in a group called endocrine disruptors – that means they may interfere with your hormones and have adverse effects on your reproductive and nervous system, immunity, may increase your risk of cancer and may affect development in children. In short, they are chemicals that can seriously damage your health.

Cooking fish at high temperatures destroys some bacteria and so makes fish safer to eat but on the other hand, it also creates new compounds, such as polycyclic aromatic hydrocarbons (PAHs), which can cause cancer. One study found that the level of PAHs in grilled fish was even higher than in grilled meat. Marine fatty fish such as salmon, hake and fresh tuna have a higher fat content and so produce more PAHs than other types of fish when cooked.

Experts advise that children, pregnant and breastfeeding women, and even those who may become pregnant one day, should never eat shark, swordfish or marlin and to limit oily fish (salmon, sardines, trout, mackerel) to two portions a week because of the pollutants they contain. Premenopausal women are also advised not to eat more than two servings of oily fish a week and pregnant and breastfeeding women are urged to not eat fish liver oil. The latter is not just because of the pollutants but also because it contains high levels of vitamin A that may be toxic to an unborn baby.

Farmed fish are not the answer. They contain even more toxins than wild-caught fish which could mean considerable health risks for those who regularly eat them.

There is no ‘safe’ fish and with many pollutants remaining in the environment for decades if not more, the situation isn’t going to get better anytime soon. To spare yourself ingesting a whole lot of chemicals every time you eat fish, it’s best to leave it off the menu.

Fats in fish and oily fish

The recommendations to eat fish are centred around the omega-3 fats fish contain – and so-called oily fish are a particularly rich source. Oily fish include herring, pilchards, salmon, sardines, sprats, trout and mackerel.

Omega 3 fats are essential for us – we cannot make them so we have to have them in our diet but fish are neither the only nor the best source. There are three types of omega-3 fats. The one called ALA (alpha-linolenic acid) is found in seeds, such as flaxseed, chia or hemp seeds and walnuts. Your body converts ALA to EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) which are then used for various purposes. Fish oils contain ready-made EPA and DHA which is why some people think they are better sources of omega-3s, but due to the widespread contamination and overfishing, this is simply not true.

What’s more, fish only contain these omega-3s (EPA and DHA) because they eat tiny algae – called microalgae – that produce them. There is a wide range of algal omega-3 supplements available and they are much healthier and more sustainable than fish and their oils.

Fish oil, with its omega-3 fats, is widely recommended as a supplement meant to reduce your risk of heart disease. It has become big business and many people wrongly believe that popping a fish oil capsule daily will protect their heart. 

The most comprehensive review of evidence on the subject – a Cochrane review – found that taking omega-3 supplements (from any source) may ever so slightly reduce your risk of major cardiovascular events (heart attack or stroke) and dying from heart disease. However, these supplements do not reduce the risk of heart disease developing in the first place. The authors also noted that eating fish did not seem to have any effect.

Several studies found a concerning effect of fish oil supplements – they may actually increase the risk of atrial fibrillation (irregular heartbeat) by 25 per cent and if you take more than one gram daily, the risk may increase by up to 49 per cent. Interestingly, plant-based omega-3s (ALA from flaxseed or flaxseed oil, chia seeds, hemp seed, walnuts or rapeseed oil) lower the risk.

Fish oil, just like any other ‘miracle cure’ cannot make your heart healthy if your overall diet and lifestyle are lacking and thanks to the pollutants it contains, it might be even harmful. On the other hand, plant oils are healthy and may help to protect your heart, especially if you also have a wholesome vegan diet.

Fish farming and antibiotic resistance

Fish farming means that huge numbers of fish are reared in permanently overcrowded conditions that put the fish under chronic stress and make them more susceptible to diseases. These conditions are the ideal breeding grounds for infectious bacteria and parasites. As a result, large amounts of antibiotics are thrown into the water with feed in an attempt to halt the spread of dangerous bacteria. 

However, these drugs are not just eaten by the fish – they are eaten and absorbed by many other aquatic organisms and contribute to the evolution of antibiotic-resistant bacteria or ‘superbugs’. Once antibiotic-resistant bacteria spread, they pose a major threat to global health as minor injuries, such as cuts or insect bites, may become infected and untreatable because antibiotics won’t work and the infection may become life-threatening.

Fish farming is a relatively new type of farming and every country has different regulations on antibiotic use and monitoring. Many different types of antibiotics may be used but the one that is the most popular across the world is tetracycline. It is also the antibiotic that’s commonly used to treat infections of the skin, digestive system, lungs, urinary tract, genitals and more and it cures diseases such as cholera, plague, malaria and syphilis. If this antibiotic stops working because enough bacteria develop a resistance to it, the world will be a very different place.

Food poisoning

Fish can carry a wide variety of bacteria, viruses and parasites that can cause a host of nasty illnesses. Even if you cook fish thoroughly, it doesn’t always prevent food poisoning because raw fish can contaminate kitchen surfaces.

Experts advise that pregnant women, babies and children should avoid eating raw shellfish (such as mussels, clams and oysters) because of the high risk of food poisoning. Both raw and cooked shellfish can also contain some toxins that may cause nausea, vomiting, diarrhoea, headaches, numbness, breathing difficulties, memory loss, disorientation and tummy ache.


Gout is a painful condition which affects the joints and it has characteristic flare-ups called gout attacks. It develops when uric acid crystals accumulate in the joints, causing chronic inflammation and irritation. During gout attacks, people experience intense joint pain and often also swelling and redness of the affected joints. 

Your body produces uric acid when it breaks down purines – these are compounds found naturally in your body but also in many foods. The richest sources of purines by far are red meat and organ meats, such as liver or kidneys, and also anchovies, sardines, trout, tuna, mussels and scallops.

As one review neatly summarised, seafood, red meat, alcohol and fructose increase the risk of gout, while soya and other pulses (peas, beans, lentils) and coffee lower the risk. This highlights that there’s no need to avoid pulses as was once recommended because of their purine content – they contain much less than meat, fish or shellfish and also offer a wide range of healthful nutrients.

Fishing and fish-farming and the environment

About a third of commercial fish stocks are caught at unsustainable levels – they cannot reproduce quickly enough to keep the populations up – and 90 per cent of fisheries are exploited to their maximum capacity. This puts an incredibly high pressure on the oceans and coastal waters and it’s also the reason why fish farms are cropping up at an unprecedented rate. Almost a half of all fish consumed now come from fish farms.

Commercial fishing not only exploits wild fish populations to the maximum, it is also responsible for devastating levels of plastic pollution. Discarded fishing gear is the biggest plastic pollutant in the oceans – it is estimated that about 30 million pounds of plastic fishing gear are dumped into the oceans each year. 

There are also many commercial fishing practices that have a devastating impact, such as bottom trawling that destroys the ocean floor or longline fishing that catches anything in the way. Both of these lead to large amounts of “bycatch” – animals caught by accident and discarded or ground into fishmeal that can be fed to farmed animals and fish. This is also the fate of many endangered species.

Fish farms are not the answer because they cause serious environmental, welfare and public health issues. They can be both inland and in coastal areas but regardless of where they are, they have one thing in common – the huge numbers of fish kept there require massive amounts of feed, antibiotics and other veterinary drugs and produce large amounts of waste that throws the surrounding ecosystems off balance. Many of the farmed fish are predators so they need to eat smaller fish and it leads to more fishing to keep supplying fish farms with enough feed – an utterly unsustainable practice.

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