Why eating oily fish is good for you, and how to cook it

Oily fish are having a moment, after a new study suggested that replacing red meat consumption with “forage fish” like sardines and anchovies has the potential to save 750,000 lives.

The study, conducted by a team of Japanese and Australian researchers and published in the journal BMJ Global Health earlier this month, found that eating more oily fish and reducing red meat can drastically reduce the global number of deaths from diet-related diseases.

This type of fish is a staple in Mediterranean and Atlantic diets, in which fish play an important role. They are known to be highly nutritious, on top of being environmentally friendly as they have one of the lowest carbon footprint of any animal food source, the researchers noted.

The scientists said in their report: "To improve human health and the health of the planet, we should limit the consumption of red meat and move towards foods that are both healthy and environmentally friendly."

What fish species are considered ‘oily fish’?

Fish that tend to have coloured or darker flesh, like trout, salmon, mackerel, sardines, herring, anchovies, and fresh tuna are considered oily fish.

Of these, smaller, cheaper fish like sardines, mackerel, anchovies and herring are categorised as “forage fish”, which means they are eaten by larger fish.

What are the nutritional benefits of oily fish?

Lucy Kerrison, consultant dietician at King Edward VII’s Hospital, explains that oily fish typically contain high levels of omega-3 fatty acids, which has plenty of benefits.

"Oily fish contain high levels of omega-3 fatty acids which can reduce inflammation, improve cardiovascular disease and arthritis, and can be protective against cancer and cancer growth," she tells Yahoo UK.

"Omega-3s play an important role in brain health, eye health, skin health and kidney function. Oily fish is the only food-based source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are the fatty acids shown to have positive biological effects."

You can get omega-3 fatty acids from plant-based foods, but Kerrison says that while these "can be converted into DHA & EPA", it is not all converted. "So it can be much more challenging to obtain adequate EPA & DHA without oily fish in the diet."

Oily fish are also a good source of prebiotics that feed the gut microbiome. Kerrison adds that they also "provide protein as well as essential vitamins and minerals including vitamin A, B vitamins, D, zinc, iron and selenium".

How much oily fish should you eat?

Most people should eat between two to four portions of oily fish per week, with a portion being 140g uncooked, Kerrison advises. However, this also depends on your age and lifestyle.

"Girls under 16 and those who are pregnant or planning to become pregnant in the future should eat no more than two portions per week," she adds.

"This is because the higher levels of pollutants, such as mercury, found in oily fish can build up in the body and affect the future development of a baby in the womb."

As for whether we should be swapping red meat for oily fish, Kerrison confirms that this is something that would benefit us significantly.

"Processed red meats are associated with bowel cancer and should be minimised within the diet. Lean, unprocessed red meat can be consumed as part of a balanced diet, and I recommend this is capped at once per week for the general population," she says.

"Increasing oily fish in the diet and swapping processed and red meat for oily fish can improve the microbiome, help to prevent colon cancer and can support inflammatory conditions and overall health."

Oily fish recipes to cook at home

Aromatic Coconut Salmon Curry by Dominique Woolf

Serves: Four

Ingredients:

• 1 tablespoon neutral oil

• 1 onion, finely chopped

• 2 cloves garlic, finely chopped

• 1 tablespoon grated fresh ginger

• 1/2 teaspoon Chinese five-spice

• 1 tablespoon curry powder

• 1 teaspoon chilli flakes (optional)

• 1 medium tomato, chopped

• 1 400ml tin of coconut milk

• 150ml water

• 2 tablespoons light soy sauce

• 2 teaspoons sugar

• 4 skinless salmon fillets, approximately 500g, cut into 3cm pieces

• 250g asparagus, cut into 3cm-4cm pieces

Method:

1. Heat 1 tablespoon of oil in a large deep frying pan over a medium heat. Add the onion with a pinch of salt and cook for three minutes, stirring occasionally. Add the garlic and ginger, and stir-fry for a further two to three minutes, until softened.

2. Add the Chinese five-spice, curry powder and chilli flakes, and fry for a further minute, adding another drizzle of oil if necessary.

3. Tip in the tomato along with the coconut milk, water, soy and sugar. Turn the heat up to medium high and bring to a boil. Bubble for five minutes, until the sauce thickens slightly, then taste the sauce and add any extra soy, salt or sugar as needed.

4. Add the salmon and coat in the sauce. Reduce the heat to medium and cook for three minutes, stirring and turning over the salmon pieces occasionally. Add the asparagus and also coat in the sauce, being careful not to break up the salmon. Simmer for a further two to three minutes or so, until the salmon and asparagus are both cooked.

5. Serve with rice and/or flatbreads and sprinkle with coriander leaves.

Pre-order The Asian Pantry by Dominique Woolf (Penguin Michael Joseph, 20 June 2024)

Jersey Royal, green vegetables and salmon stew by Stellar

Serves: Four

Ingredients:

• 2 tablespoons olive oil

• 2 shallots, finely chopped

• 1 small leek, washed and sliced

• 2 garlic cloves, peeled and crushed

• 500g Jersey Royal potatoes, scrubbed and cut into pieces if large

• 100ml dry white wine

• 250ml vegetable stock

• 100ml creme fraiche or single cream

• 4 salmon fillets

• 125g asparagus tips

• 100g frozen peas

• 1 small bunch of chives, snipped

• 1 teaspoon lemon zest

• Salt

• Pepper

Method:

1. Heat the oil in a saute pan. Add the shallots, leek and garlic and fry over a low heat until the shallots have softened but not coloured. Add a pinch of salt and freshly ground pepper.

2. Add the new potatoes and pour in the wine. Bring to the boil, cook for 2 minutes before adding the stock. Cover the pan with a lid and cook for 10 minutes or until the potatoes are almost cooked.

3. Stir in the crème fraiche or cream and place the salmon fillets in the pan pressing down gently. Cover and simmer for 5 minutes.

4. Remove the lid, add the asparagus tips and cook for 2-3 minutes, then add the peas for the final few minutes of cooking.

5. Divide the stew between 4 bowls, sprinkle with lemon zest and fresh chives.

Grilled mackerel with rhubarb sauce by Bonne Maman

Serves: Six

Ingredients:

• 6 fresh mackerel weighing around 225g each, gutted and cleaned

• 1 lemon, cut into 12 half slices

• 1.5 unwaxed lemons, zested and juiced

• 15g butter, melted

• 1 tablespoon chopped fresh parsley

• 9 tablespoons Bonne Maman Rhubarb Compote

• 3 tablespoons white wine vinegar

• 1cm piece of ginger, peeled and sliced

• Salt

• Ground white pepper

Method:

1. Place all the sauce ingredients in a stainless steel saucepan and heat gently over a low heat for 3-5 mins, until combined and reduced to a coating consistency. Remove from the heat, discard the ginger and allow to cool.

2. Preheat the grill to a high heat.

3. Pat the mackerel dry with kitchen paper. Make 2 or 3 deep slashes in the side of each fish and lightly season the cavities; add 2 half slices of lemon to each fish.

4. Place the mackerel in a shallow roasting tin or edged baking sheet. Brush both sides with melted butter and season lightly.

5. Reduce the grill to a medium heat and cook the fish placed 5-7.5cm (2-3in) from the heat source for 6-8 mins, then turn over and grill the other side. Serve sprinkled with the chopped parsley and with the warm rhubarb sauce.

Read more about food and diets:

• What is the Atlantic diet, 'cousin' of the Mediterranean diet? (Yahoo Life UK, 4-min read)

• How avocados contribute to a healthy gut microbiome (Yahoo Life UK, 7-min read)

• A kimchi a day keeps obesity at bay, study suggests (Yahoo Life UK, 7-min read)