Earlier this year the EAT-Lancet commission published their findings of a sustainable diet that could support the nutritional needs of our growing population whilst preserving our planet, this was called ‘The Planetary Health Diet’. I wrote a blog on it.
A follow-up from some of the authors of this commission paper was released recently and outlines the role of aquatic food on the path to sustainable and healthy diets.
The growing human population presents a challenge to provide sufficient food for a nutritional diet for our species whilst not threatening Earth systems.
In the Eat-Lancet commission, seafood was presented as a promising source of protein. In 2015 7% of all protein consumed globally was sourced via fish. It was suggested that a healthy, sustainable diet would comprise of an average daily intake of 28g of fish (range 0-100g), this translates into 1-2 servings per week. This, with current food waste levels, would necessitate a 118% production increase of fish for human consumption. However, if food waste is halved the increase would be only 60%.
The impact of seafood production on the planet
Seafood production is extremely diverse, both in terms of fish species and form of fishing, from aquaculture to capture fisheries.
This an infographic taken from the EAT foundation report representing the different planetary impacts of seafood production via aquaculture vs capture fisheries.
This is how seafood relates in terms of greenhouse gas emissions to other food commodities:
Climate change is thought to most impact fish species in capture fisheries via:
- Changes in ocean oxygen concentration
- Temperature changes
- Ocean acidification
- Oceanic toxic pollutants
For aquaculture the impact will be:
- Reduced productivity
- New diseases and thriving parasites
- Increased frequency and strength of storms
By-catch is a well-known consequence of the fishing industry. The vulnerability to by-catch depends upon the ease of catching a species and its life history, longer-living species being more vulnerable.
Bottom trawling alters the physical habitat of marine species. There can be physical destruction of the seabed and removal of habitat-forming species through this fishing method. This leads to a reduction of marine biodiversity in regions where bottom trawling occurs.
The role of seafood in human health
Seafood can be a nutritiously valuable food source. It is almost unique with respect to DHA and EPA omega-3 fatty acid provision (other sources being algae), for example. The specific net benefits seafood consumption delivers will depend upon other constituents of an individual’s diet.
One should be cautious, however about accumulation of toxins such as mercury, which often accumulates in fish with high concentrations of omega-3 fatty acids.
Seafood is not only a good source of protein and healthy fats, but several key micronutrients too.
The precise micronutrient profile of a fish depends on several factors:
- Fish species
- Fishing area caught, including wild vs farmed.
- Season caught
- Transportation and packaging
- Production, process and preparation of the food
- How cooked or preserved
- If the bones of the fish are eaten or not
Health benefits from eating fish (will depend upon fish species):
- Reduced risk of cardiovascular disease
- Neurodevelopment of the unborn and young children
- Reduced blood pressure
- Improved insulin sensitivity
- Reduced risks of type-2 diabetes, impaired cognitive function, and age-related macular degeneration
- Good dietary source of vitamin D
- Potential reduction in breast cancer
Health risks from eating fish (will depend upon fish species):
- Bioaccumulation of heavy metals (such as mercury, discussed above)
- Pregnant and lactating women are advised to minimise consumption of fish species with particularly high concentrations, such as shark and swordfish.
- Bioaccumulation of persistent organic pollutants (organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes).
- Bioaccumulation of toxins from algal blooms
- Antibiotics resistance from farmed fish
- Potential risks of microplastics consumed via the consumption of seafood.
Some of the key messages from this report were:
- Consumption of seafood has both human health benefits and risks.
- Future seafood demand will likely have to be produced via aquaculture.
- Waste reduction is key to prevent a large production-consumption shortfall.
- Biodiversity losses from both capture fisheries and aquaculture need to be modelled.
- Environmental impact of fish production can vary dramatically according to species fished and production & harvesting processes.
- Seafood production and consumption methods must change to minimise the environmental impacts of seafood.
- More research is needed.
This is a summary of some of the points raised by this report. If you are interested and would like to read more, or see references for any of the above, please view the entire report here.
As ever, I feel the takeaway messages are to be mindful of how, how much and what seafood you consume. Aim to eat food species which are not over-fished, have healthy fish stocks and produced in the most sustainable way. And, as ever, as boring as it sounds – everything in moderation! If you do choose to eat a fully plant-based diet and avoid seafood all together, this is also supported by the EAT-Lancet Commission’s Planetary Health Diet.