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Swapping meat for seafood provides greater nutrition and reduced climate impacts, study reveals

Deciding whether to go for a greasy burger, chicken chow mein or a fish and chips is a conundrum that sparks family debates every Friday.

But a new study from Dalhousie University may be able to help you make up your mind, as researchers have found that seafood is more nutritious and climate-friendly than meat.

Economists from Canada and Sweden calculated the nutrient density and climate impacts of various fish sources.

They found that half of the fish species they studied had a higher nutrient density and emit less greenhouse gases than beef, pork and chicken.

Of the most common fish eaten in the UK, wild-caught salmon, herring and mackerel are the species with the lowest climate impacts relative to their diets.

The findings suggest that policies to promote seafood in the diet as a substitute for other animal proteins could improve future food security and help tackle climate change.

Researchers found that half of the fish species they studied had a higher nutrient density and emitted less greenhouse gases than beef, pork and chicken (stock image)

Researchers found that half of the fish species they studied had a higher nutrient density and emitted less greenhouse gases than beef, pork and chicken (stock image)

SEAFOOD WITH THE LOWEST CLIMATE INFLUENCE WITH REGARD TO NUTRITION

  • Wild-caught salmon
  • Herring
  • Mackerel
  • anchovies
  • Cultured mussels
  • Farmed oysters

Speaking to MailOnline, Peter Tyedmers, a professor at Dalhousie University’s School for Resource and Environmental Studies, said: “This work shows that many of us can achieve real climate mitigation through the choices we make about which animal foods we include in our diets.” .

“The shift from beef, pork and often even chicken to seafood will almost always result in lower production-related emissions that will ultimately be necessary if we are to address the climate crisis in a meaningful way.”

With the world population set to reach 8 billion this year, scientists have predicted that we will face major food shortages in the future.

This will be accompanied by an increase in the impacts of climate change, so challenges may arise in meeting nutritional needs while reducing emissions.

While meat is high in protein, consuming large amounts has been linked to heart disease and other health problems.

Its production has devastating effects on the planet as livestock farming on a large scale destroys habitats and generates greenhouse gases.

However, seafood is known to be a good source of protein, fatty acids, vitamins and minerals.

Professor Tyedmers investigated whether these nutritional benefits outweigh the greenhouse gases emitted by production.

His team analyzed the nutrient density and climate impacts of globally important sources of seafood from a wide range of fishing and aquaculture activities.

Farmed mussels found to have strong nutritional value and low climate impact (stock image)

Farmed mussels found to have strong nutritional value and low climate impact (stock image)

Wild-caught salmon found to have strong nutritional value and low climate impacts (stock image)

Wild-caught salmon found to have strong nutritional value and low climate impacts (stock image)

For each seafood product, including farmed mussels (left) and wild-caught salmon (right), the researchers calculated a Nutrient Density Score and the greenhouse gas emissions as a percentage of the catch weight (stock images)

WHICH FOODS HAVE THE HIGHEST INFLUENCE ON THE ENVIRONMENT?

  1. Beef and lamb
  2. Nuts and dried fruit
  3. Coffee
  4. Cheese
  5. Fish and seafood
  6. Tea
  7. Cakes, quiches and party food
  8. Jam
  9. Chocolate
  10. Ready-made meals

Source: Oxford University

For each seafood product, they calculated a Nutrient Density Score, using data from the uFishJ Food Composition Database, Canada Nutrient File, the Japan Standard Tables of Food Composition, or the Swedish Food Composition Database.

They created a composition profile of 19 desirable nutrients, including protein and vitamins A, D and B12, and two unwanted nutrients of saturated fatty acids and sodium.

To assess the climate impacts of the seafood from aquaculture, they identified the kilograms of carbon dioxide emitted per kilogram of live weight from nine appropriate life cycle assessments.

For the species derived from wild catch fisheries, data from fishing vessel fuel consumption studies was used to calculate GHG emissions per tonne of landed catch.

Greenhouse gas emissions for the terrestrial beef, pork and poultry meat were based on data from published life cycle assessments, while the nutritional data was from the Canada Nutrient File database.

The study, published today in Communications Earth & Environment, reveals that seafood can provide people with more nutrition with lower greenhouse gas emissions than meat.

Wild-caught salmon, herring, mackerel and anchovies, as well as farmed mussels and oysters, had the lowest climate impacts relative to their nutritional value.

The fish species with the highest nutritional density turned out to be pink salmon, with a score of 6.3, but capelin has the lowest climate impact, emitting 498 kg of carbon dioxide per tonne caught.

In comparison, the greenhouse gas emissions for beef turned out to be 56 kg of carbon dioxide per kilogram of edible product and almost 7 kg for pork.

NUTRITIONAL DENSITY AND SEAFOOD EMISSIONS
Seafood Nutritional Density Score Greenhouse gas emissions (kg CO2 per tonne of edible)
Alaska pollock 2.1 1120
American lobster 3.7 11137
Atlantic cod 2.3 2905
Atlantic herring 4.3 623
Atlantic mackerel 5.1 811
Atlantic salmon 5.4 6978
Blue mussel 3.5 1354
Cape hake 1.8 4500
Carp 4.8 3235
European sprat 5.4 836
Giant tiger shrimp 3.6 3977
green mussel 3.7 1354
Haddock 2.5 3998
Japanese anchovies 5 3998
Northern shrimp 2.8 20619
Pacific oyster 3.8 682
pink salmon 6.3 932
yellowfin tuna 4.5 4843
NUTRITIONAL DENSITY AND EMISSIONS FROM MEAT
Meat Nutritional Density Score Greenhouse gas emissions (kg CO2 per kg store weight)
Beef 3.56 56.24
Pork 3.74 6.96
Chicken 2.38 3.5

The researchers conclude that seafood can be a sustainable source of nutritious food that also benefits the climate.

Professor Tyedmers added: ‘In many ways, this study confirms insights that many of us have long realized: that seafood in general is sources of highly nutritious foods whose production results in a relatively low impact on the climate, especially in comparison to the climate effects of beef, pork and often even chicken.

“But in confirming this, we did this with the best available data for the broadest set of globally important fish species that are important in different diets around the world.”

“However, we go further and emphasize the wide diversity of nutritional characteristics of different types of seafood that may be relevant to individuals or subpopulations whose diets are limited in a few key nutrients.”

HOW DOES FOOD PRODUCTION HARM THE ENVIRONMENT?

Meat and dairy are responsible for 57 percent of food-induced greenhouse gas emissions, according to a new computer modeling study.

The study, led by Urbana-Champaign of the University of Illinois, found that food-based agriculture is responsible for 17.318 billion tons of greenhouse gas emissions per year. This is 35 percent of all man-made greenhouse gas emissions.

Broken down by type of food:

– Animal food emissions contribute 57 percent (9.8 billion metric tons)

– Plant food emissions contribute 29 percent (5.1 billion tons)

– ‘Non-food’ uses such as cotton and rubber production contribute 14 percent

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