Omega-3 is one of the most important fat families in our diet. It is linked to cardiovascular health, proper brain function, reducing inflammatory processes in the body, maintaining blood vessel elasticity, and is also researched in the context of healthy aging, mood, memory, and cognitive health.
But here it is important to be precise: When talking about omega-3 from fish, the intention is mainly toward two particularly active fatty acids called EPA and DHA. These are the forms that the body uses in a relatively direct manner, and they are found mainly in fatty fish and certain seafood. Contrary to what many think, not every fish is a good source of omega-3, and the differences between fish can be immense.
There are fish of which a single serving can provide a very nice amount of omega-3 for almost an entire week, and there are fish that, although considered healthy, their contribution to omega-3 is relatively small.
The fish leading in the amount of omega-3
The fish that contain the most omega-3 are mainly fatty fish, meaning fish whose meat contains a higher fat percentage. This is not a negative thing, on the contrary. In this case, it is a very high-quality fat, a significant part of which is omega-3.
Among the leading fish are mackerel, salmon, herring, kipper, sardines, and anchovies. These fish can contain, in a single serving of 100 to 150 grams of ready-to-eat fish, approximately 1,000 to 2,500 mg of EPA and DHA combined, and sometimes even more, depending on the type of fish and its source.
Mackerel, for example, is considered one of the fish richest in omega-3. Sardines are also an excellent choice, especially because they are usually eaten with the soft bones, and thus one also receives an addition of calcium. Herring and kipper are very rich in omega-3, but it must be remembered that in pickled or salted versions they might contain a lot of salt, and therefore are not suitable in a large amount for everyone, especially for those who suffer from high blood pressure or need to reduce sodium.
Salmon is probably the fish most identified with omega-3, and rightly so. It contains a nice amount of EPA and DHA, but here too there are differences between fresh, frozen, canned, wild, or farmed salmon. Wild salmon is usually different in its fat composition from farmed salmon, but farmed salmon can also be a good source of omega-3, depending on the fish's diet and the quality of the product.
Anchovy is a very concentrated source of omega-3, but because of its salty and strong flavor, smaller amounts of it are usually eaten. Therefore, it can contribute to the menu, but usually it will not be the primary source of omega-3, unless it is integrated regularly in salads, sauces, or spreads.
Fish with a relatively low amount of omega-3
There are fish that are considered very healthy as a source of high-quality protein, vitamin B12, iodine, selenium, and sometimes also iron, but they are not necessarily a significant source of omega-3. One of the common examples is tilapia. Tilapia is a relatively low-fat fish, and therefore in most cases it contains a lower amount of omega-3 compared to fatty fish like salmon, sardines, mackerel, or herring.
Canned light tuna also usually contains less omega-3 than fatty fish. It can be a convenient and available source of protein, but it is not advisable to rely on it as the primary source of omega-3. Red tuna or certain types of fresh tuna can contain more fat, but they are less common, more expensive, and also raise additional considerations like mercury content, and therefore are not always the recommended choice for frequent consumption.
White and low-fat fish as well, such as cod, sole, or sea bream in certain cases, can be integrated into a healthy diet, but in terms of omega-3 they usually do not compare to fatty fish. Therefore, whoever eats fish mainly to obtain omega-3, should deliberately choose the appropriate fish, and not settle for the general definition "fish".
The preparation method also has an effect
Omega-3 is relatively sensitive to heat, oxygen, and light. This does not mean that any cooking or baking destroys it, and it definitely does not mean that one must eat raw fish to enjoy their benefits. But it is worthwhile to know that the preparation method can affect the quality of the fat and the amount that remains in the serving.
Prolonged frying at high heat, especially in an open pan, might reduce some of the delicate fatty acids and cause oxidation processes in the fat. When the fat oxidizes, it loses part of its health quality, and in certain cases unwanted oxidation products are formed in the body. The problem increases when frying in oils that are relatively sensitive to heat, such as soybean oil or corn oil, and especially if it is oil that has already undergone repeated use.
In addition, when frying fish coated in breadcrumbs or batter, a completely different dish is obtained from a nutritional standpoint. Instead of a fish rich in protein and high-quality fat, one sometimes receives a dish high in oil, calories, and fried carbohydrates. The fish can still contain omega-3, but the overall health benefit of the dish is smaller.
So how is it preferable to prepare fish?
Steaming, gentle cooking, baking in the oven, or grilling at moderate heat are usually the best options. It is possible to use herbs, lemon, garlic, black pepper, a little olive oil, and vegetables, and thus obtain a tasty and healthy dish without harming the quality of the fat. A short and quick stir-fry can also be reasonable once in a while, especially if using high-quality olive oil, not burning the oil, and not frying for a prolonged time.
Plant-based sources of omega-3
Not everyone eats fish (I too am a vegetarian who does not eat fish), and there are also those who eat fish only rarely. Here enter the picture the plant-based sources of omega-3: Flaxseeds, walnuts, chia seeds, flaxseed oil, and sometimes also canola oil in a certain amount. But it is important to understand that the omega-3 from plants is not exactly the same omega-3 that is in fish.
The difference – in plants there is mainly a fatty acid called ALA. This is an essential fatty acid, meaning the body does not know how to produce it by itself and needs to receive it from food. The body can convert part of it to EPA and DHA, but this conversion is very limited, and depends on many factors: Age, health status, diet composition, omega-6 consumption, hormonal status, and more.
Therefore, from a practical standpoint, eating flax or chia is not identical to eating salmon or sardines.
And yet, plant-based sources have an important nutritional value. Ground flaxseeds, for example, also contribute dietary fiber and plant-based substances called lignans. It is important to consume them ground, because whole flaxseeds might pass through the digestive system almost without being digested.
Chia seeds also contribute fiber, create a gel texture in contact with liquids, and can help with the feeling of satiety and digestion. Walnuts are one of the nuts richest in ALA, and additionally contain magnesium, antioxidants, and monounsaturated fat.
For someone who does not eat fish at all, it is advisable to integrate daily a tablespoon of ground flaxseeds or a tablespoon of chia, along with a few walnuts. This is a good way to improve the quality of fat on the menu. In certain cases, especially with vegans, vegetarians, pregnant women, or those who do not eat fish at all, one can consider an omega-3 supplement from an algae source, which contains DHA and sometimes also EPA, but it is advisable to customize this personally.