We also do research into how food from the oceans can contribute to global food security. Amongst other things, food security means having safe and nutritious food available at all times. In other words, we must have enough food to feed the world’s population, and it must contain the right nutrients.
Seafood contains nutrients such as omega-3 fatty acids, vitamin D, iodine and selenium. These nutrients are not found in many other foods.
Nutrients in seafood
Fish and other seafood are a source of high-quality proteins. Seafood also contains marine-derived omega-3 fatty acids that our body struggles to make itself.
Fatty fish is a source of vitamin D, while lean fish like cod is one of the best sources of iodine within the Norwegian diet.
Omega-3 fatty acids
There are two main types of omega-3 fatty acids in our diet.
Plant-derived omega-3 fatty acids are mainly found in plants and farmed meat. The highest levels are found in certain plant oils.
Marine-derived omega-3 fatty acids are almost exclusively found in fish and other seafood. This is one of the reasons why the health authorities recommend including seafood in our diets. Fatty fish is especially rich in omega-3 fatty acids. Cod-liver oil and other fish oils also contain high levels of marine-derived omega-3 fatty acids.
It has been documented that the marine-derived omega-3 fatty acids EPA and DHA can reduce the risk of cardiovascular disease when consumed in our food. (FIND OUT MORE ON OUR PAGE ON HEALTH).
Plant-derived omega-3 can be converted into these fatty acids in our body, but the process is inefficient.
Omega-6 fatty acids
Linoleic acid is an essential omega-6 fatty acid that is important for our skin, mucous membranes and cells. Our body cannot produce linoleic acid itself, so we must consume it in our food.
Omega-6 fatty acids are mainly found in plants and in foods made from farmed animals. Plant oils such as soybean oil, maize oil and sunflower oil are particularly rich in omega-6 fatty acids.
Modern agriculture has increased the omega-6 levels in many types of food, including meat, eggs and dairy products. With our modern diet, it isn’t difficult for us to obtain enough omega-6; in fact, the reverse is true. Recent research indicates that a high ratio of omega-6 to omega-3 fatty acids can lead to weight gain and obesity.
On account of the plant-based ingredients in their feed, farmed salmon also provide just as much omega-6 as omega-3. Nevertheless, farmed salmon contain high levels of marine-derived omega-3.
Vitamin D
Vitamin D is a fat-soluble vitamin that is stored in our liver. Fatty fish, fish liver and cod-liver oil are all rich in it.
In Norway, vitamin D is added to some types of milk and dairy products. In summer, our body can make vitamin D in our skin with the help of sunlight. For the rest of the year, our diet determines our vitamin D levels.
The most important role of vitamin D is to maintain a stable level of calcium in our blood. Serious vitamin D deficiency can lead to skeletal disorders, such as rickets in children and osteomalacia in adults. The consequences of mild vitamin D deficiency are less well documented.
The Norwegian population generally has good vitamin D levels, particularly in summer. However, part of the population has low vitamin D levels in winter. Children, pregnant and breastfeeding women and the elderly are most affected. As people with darker skin types produce less vitamin D in their skin, non-Western immigrants are particularly at risk of vitamin D deficiency in Norway.
Selenium
Selenium is a chemical element that is found in lean and fatty fish, as well as in products made from grains. Elements found in small quantities in living organisms are known as “trace elements”.
Selenium plays an important role in areas such as reproduction and our immune system. It may also play a role in cardiovascular disease, cancer and mental health.
We have 5-15 milligrams of selenium in our body, in our cells and tissues, with most of it being in our liver and kidneys. We consume it through a variety of foods.
Our daily intake is thought to be 70-80 micrograms, but the amount we need has not been ascertained.
Nutrients and unwanted substances interact
When we eat, we don’t eat nutrients or unwanted substances one by one. We eat a combination of them – the whole food product, in other words. When discussing how food products affect our health, we have to take into account all of their contents. Their combined effect may be different from the sum of their individual ones.
Even if a food product contains substances that may be harmful to health, their negative impact may be outweighed by positive ones. The dietary advice given by the health authorities is the result of weighing up positive and negative impacts. The reason they recommend eating a certain amount of seafood per week is that research shows that the positive impacts are bigger than the potential negative ones.
For example, the Food and Agriculture Organization of the United Nations recently confirmed that the protection provided by marine omega-3 fatty acids against cardiovascular disease is much more significant than the risk of developing cancer due to unwanted substances in seafood.
Unwanted substances in seafood
All food contains certain levels of unwanted substances. In the case of farmed fish, these may be substances that are used to make food production more efficient (such as delousing agents), or substances in the environment from either natural or human sources. They include organic pollutants such as dioxins and dioxin-like PCBs, as well as heavy metals like lead and cadmium. Seafood may also contain parasites and bacteria that either affect its quality as a food product or cause illness in humans.
The Institute of Marine Research monitors the levels of unwanted substances in various types of both farmed and wild seafood.(link to article on safe seafood).
