We talked to Juliette Kellow, Consultant Nutritionist at Seafish to get the lowdown on why we should be including plenty of seafood in our diets
Why should I include more seafood in my diet?
Fish is a nutrient-dense food – in other words, you get a lot of nutrients in proportion to the calorie content. It’s packed with protein and a wide range of essential vitamins and minerals, depending on the variety. White fish like monkfish or hake, in particular, are low in fat, while oily fish like herring are high in omega-3 fatty acids, which contribute to the normal function of the heart and brain. Seafood of any variety – whether crab, mackerel or coley – can play an important role in a healthy, balanced diet.
What nutrients are contained in some of the most commonly eaten types of fish/seafood?
All varieties – white, oily and shellfish – are packed with protein, a nutrient that supports the growth and maintenance of muscle. Seafood also supplies a range of vitamins and minerals. These vary depending on the variety but most fish provide phosphorus for healthy bones and teeth. Most also contain selenium, which helps maintain normal hair and nails, supports the immune system and is vital for our thyroid to work properly.
All types of fish are rich in vitamin B12, a nutrient that’s important for making red blood cells and helps to reduce tiredness and fatigue. Many varieties are also rich in iodine, which is particularly important for children and teenagers where it contributes to cognitive development in pre-schoolers and is important for normal growth. It’s also important for our nervous system and is needed to make thyroid hormones and keep the thyroid gland working properly, which in turn helps to regulate the body’s metabolism. White fish are generally low in fat and usually provide potassium, which helps to maintain normal blood pressure, and vitamins B3 and B6, which aid our psychological wellbeing and help release energy from the food we eat.
Shellfish are also usually low in fat and often contain copper and zinc, which are needed for the normal functioning of our immune system. Oily fish also provide potassium and vitamins B3, B6 and are one of the few naturally rich food sources of vitamin D, which is needed for bones, teeth and muscles and our immune system. The hero nutrient in fish though is long-chain omega-3 fats. All varieties include these fats – even white fish and shellfish – but oily fish contain the most. These specific fats help the heart to work normally and maintain normal blood pressure and blood triglyceride levels. One of the omega-3 fats found naturally in fish (DHA) is also important for normal brain development in babies and children and for maintaining normal brain function and vision.
Is seafood a good source of protein?
Seafood provides a high-quality, complete protein source, which means it contains all of the essential amino acids – protein building blocks – needed for optimum health. All fish is a rich source of protein., although the exact amount varies according to the species. On average, 100g grilled monkfish, grilled hake, grilled mackerel, cooked crab and boiled mussels provide around 17-23g protein. The Reference Intake – the recommended daily amount – is 50g protein.
Is fish a good thing to eat if I’m trying to lose weight?
Ensuring muscles are strong helps to boost our metabolic rate, which is the rate at which the body burns calories. This means the more muscle we have, the more calories we burn, even when we’re resting. While exercise helps us to build muscle, protein also contributes to a growth in muscle mass. Fish, especially white fish and shellfish, often contain fewer calories than many other animal sources of protein, which can aid weight control.
According to the British Nutrition Foundation, foods that are high in protein help to make us feel fuller than foods that are high in fat or carbohydrates. This is because protein takes longer for the body to digest, which delays hunger so we eat less and find it easier to control our weight. Enjoying a protein-rich food at each meal is a great way to keep us fuller for longer.
I’ve heard that oysters are an aphrodisiac, is that true?
There’s been a lot of speculation around whether oysters are an aphrodisiac but there unfortunately aren’t any concrete findings that suggest this is true. Oysters are a good source of zinc, which contribute to normal fertility and reproduction, but there is no link to oysters increasing an individual’s sexual desire.
Why is eating oily fish important?
Oily fish is rich in omega-3 fats, which have several roles to play in supporting heart health: they contribute to the normal function of the heart and help to maintain normal blood pressure and levels of triglycerides – a type of fat – in the blood. One of the omega-3 fats called DHA also helps to keep the brain functioning normally and helps to maintain normal vision. Oily fish is also one of the few foods that are naturally rich in vitamin D. Including more vitamin D in our diet is especially useful if we don’t expose our skin to the sun very much – for example, if we always cover up, don’t go outside much or are housebound (this is because vitamin D is made in our body when skin is exposed to summer sunlight). Vitamin D is important for maintaining normal bones and teeth – it helps the body to absorb and use calcium and phosphorus. It’s also important for normal muscle function and our immune system.
What counts as an oily fish, and what doesn’t?
Most of us are familiar with mackerel, sardines, pilchards and salmon, which all count as oily fish. But there are plenty of other varieties, too. These include trout, herring, kippers, sprats, whitebait and anchovies. Health guidelines recommend we eat two portions of fish a week, with one of these being an oily variety. A portion should be around 140g when cooked.
Does tinned fish (ie tuna, sardines etc) contain the same nutrients as fresh fish?
Tinned fish is prepared, packaged, sealed and then pressure-cooked in the can. As well as giving tinned fish its long shelf life and maintaining its flavour, this locks in the nutrients.
Indeed, like fresh and frozen, tinned seafood such as tuna and crab is packed with nutrients and counts towards the recommended two portions of fish each week. In particular, tinned oil-rich fish like mackerel, sardines and herring are all rich in omega-3 fats, which help the heart to work normally, and maintain normal blood pressure and levels of triglycerides (a type of fat in the blood).
Added to this, all tinned fish is rich in protein, and different varieties contribute nutrients ranging from B vitamins and selenium to vitamin D and zinc, depending on the type you choose. Fish that’s tinned in oil is usually higher in fat, while those in sauces can be higher in salt. Looking at the nutrition panels on labels will help you identify the amount.
What about frozen fish?
Frozen fish often contains just as many nutrients as fresh fish. This is because fish is frozen within just a few hours of it being caught so it retains its nutrients.
Contrary to popular belief, no artificial additives are used in the freezing process – it’s the cold temperature alone that preserves the fish. With such great taste, quality and nutrition credentials it should come as no surprise that frozen fish, like fresh, is include in the recommendation to eat two portions a week, where a portion weighs 170g before cooking or 140g once cooked.
Do shellfish and crustaceans offer the same health benefits as fish?
Shellfish such as mussels and crab are packed with protein and contain all of the essential amino acids necessary for a healthy diet. These amino acids are ones that your body can’t make on its own so need to be supplied in the food we eat.
Shellfish flesh is also low in fat. Meanwhile, mussels and crab, for example, provide minerals including zinc, selenium and iodine. Clams, cockles, crayfish, mussels and oysters also contain iron, which is needed for normal cognitive function, making red blood cells, transporting oxygen around the body and making us feel less tired. Most shellfish are also abundant in copper, which is important for our immune and nervous systems, protecting our cells from oxidative damage and keeping normal pigmentation in our skin and hair.
Is it likely that I’ll get food poisoning from eating seafood?
In short, it’s unlikely you’ll get food poisoning from eating seafood as long as you source your seafood from a reputable place, cook it properly and follow good hygiene and food safety rules when it comes to storing, preparing and cooking it. To start with, always wash your hands before and after handling seafood. Make sure it’s stored properly – raw and cooked fish should be kept separate and well wrapped (raw fish should be kept on the bottom shelf of the fridge so that any juices can’t run onto other food). Use separate chopping boards, knives and plates for preparing raw seafood and make sure it doesn’t come into contact with any other raw or cooked foods. If you’re using frozen fish, make sure it’s properly defrosted – preferably overnight in the fridge – and it goes without saying to make sure you use it within the ‘use-by’ date.
I’ve heard that eating fish will improve my skin and hair – is that true?
Seafood contains a variety of nutrients that are linked to keeping skin and hair in good condition. For hair, these nutrients include biotin, zinc and selenium. Zinc and biotin are also important for maintaining normal skin, together with iodine and three B vitamins – riboflavin (B2), niacin (B3) and biotin. Different varieties of fish provide a range of these nutrients. For example, many shellfish provide zinc and copper. Meanwhile, a variety of white, oily and shellfish provide iodine and niacin. Riboflavin is found in crab, flounder, herring, mussels, mackerel, whiting and sardines. And biotin is found in cockles, basa, white crabmeat, oysters, plaice and sardines.