Pescatarian diet fish seafood
5 min read
Fish and seafood are good sources of essential nutrients and commonly consumed by Australians. However, the health and environmental impacts vary and should be considered when choosing which fish to eat and enjoy...

Health impacts 

Fish and seafood provide a good source of protein, iodine, selenium, zinc, iodine, and long chain omega 3- fatty acids. However, it has been found that fish imported to Australia may have lower nutrient density (namely omega-3 fatty acids) than local Australian seafood, and about 70% of our fish is imported.


For those on an omnivore or pescatarian diet, the Australian Dietary Guidelines recommend eating two serves of fish or seafood per week, with a serve being equivalent to 100g cooked weight. Diets high in fish (2 or more serves per week) have been associated with lower risk of dementia in older adults, cardiovascular diseases, and macular degeneration.


The National Heart Foundation of Australia recommends people try to eat 2 to 3 serves of fish per week for good heart health. However, they recommend people do not take fish oil supplements (unless people have high blood triglyceride levels) because the benefit is not the same as eating whole fish. It is suggested that this is due to the nutrients within the fish working together to bring benefit.


If you don’t eat fish or seafood, you can meet your nutrient requirements (including your omega-3 fatty acid requirements) through plant-based sources. Read here for more information.


Environmental impacts

Australia now imports about 70% of its fish, making the environmental impact of eating fish greater (due to high food miles). Evidence suggests fish (in general) have a similar global warming potential (GWP) to chicken but varies depending on species, what they’re fed (if farmed) and where they’re eaten. For example, salmon may be a more environmentally friendly option in Alaska than it is in Australia.


It has been suggested that it is difficult to compare environmental impact (life cycle analysis) values for fish, compared to land animals as the method for assessing the impact is designed for land-based foods. Here are some general guidelines on the environmental impact of different fish and seafood sources:

  • Low global warming potential: herring, sardines and mackerel
  • Medium global warming potential: Salmon, swordfish, and trout
  • High global warming potential: Prawns and crayfish


However, the specific impact in your area and the sustainability of the population in terms of overfishing depends on the populations that are feeding you. Some things to consider are consumer demand, by-catch, farmed vs wild caught, other environmental impacts from farming. As such, these guidelines should be taken with a grain of salt. 


The current Australian Dietary Guidelines recommend a maximum of about 200 grams of fish or seafood per week. However, our intakes are lower than this. If all Australian’s met these fish recommendations in the Dietary Guidelines, we would need to increase our current intakes by 40%, and our fish stocks could not be sustained.


A UK study suggested the public need to be informed of how to choose fish that is certified as ‘sustainable’ to protect fish stocks. The health and environmental experts at Eat Sustainably agree and believe Australian buyers should also be better informed.


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