The health benefits of oily fish including salmon, herring, trout and sardines.
Oily fish are those fish whose fat or oils are distributed throughout their flesh rather than solely in the liver as in white fish. This means that when we consume oily fish, we will also be consuming their oils, whereas in white fish we won't.
For this reason oily fish are slightly more calorific and fattening, however the fats that these fish contain are essential, beneficial and will actually improve one's health and protect us from certain diseases.
As the fat is contained within the flesh of the fish, you will find that it is slightly darker in colour than white fish and also somewhat harder to digest.
High protein food
Oily fish is an excellent source of protein and although it may not contain as much protein as red meat, it does contain fewer harmful fats and calories and is therefore much better for you.
A 3½oz (100g) portion of fresh tuna contains 23.5g of protein, salmon contains around 20g and sardines around 21g.
In comparison, a similar quantity of red meat contains around 25g of protein, so you see that there is actually not that much difference between them.
Meat, especially processed meat, contains high levels of saturated fats. These fats are very harmful to the body if consumed in excess and it is these fats that cause cholesterol levels in the blood to rise when consumed.
High levels of cholesterol cause arteries to become blocked with deposits of hard fat, which in turn lead to a whole host of serious health problems such as heart disease including high blood pressure, heart attacks and stroke.
Oily fish may contain certain amounts of fat, but most of this fat is in fact in the form of polyunsaturated fats, which are extremely good for the body, as we shall see later.
Oily fish actually contains very little saturated fat, although it does contain some.
Some fat in our diet is essential in order for certain processes within the body to take place. Around 35% of our calorie intake should come from fats, but only 10% from saturated fats.
100g of herring contains a total of 13g of fat, but only 3.3g of the total fat is in the form of saturated fat. Similarly, salmon contains 11g of total fat with only 1.9g being saturated and sardines contain 9g of fat with 0g of saturated fat.
The healthy fats in oily fish
Oily fish such as sardines, herring and mackerel are very rich sources of certain polyunsaturated fats known as omega-6 and omega-3 essential fatty acids. These fatty acids cannot be manufactured by the body and have to be obtained from food.
We have only recently become more aware of how important these types of fats are and what a positive effect they have on our health. There are small amounts of these fats in white fish, but oily fish have significantly higher levels.
100g of cod (white fish), mackerel, sardines and fresh tuna contain 0.3g, 3.3g, 1.7g and 1.6g of omega-3 fatty acids respectively.
The benefits of omega-3
Researchers have now discovered and identified the many benefits of omega-3 essential fatty acids and we have listed them below:
- They reduce the levels of "bad" LDL cholesterol in the blood.
- They can alleviate inflammatory diseases such as arthritis and help to reduce the amount of medication taken for them.
- They lower blood pressure.
- They prevent the blood from forming clots, which therefore reduces the risk of heart attack and stroke.
- Omega-3 protects against heart and circulatory problems.
- It is good for the healthy development of the brain and eyes.
- It reduces the risk of thrombosis.
- It is good for sufferers of gout.
- Omega-3 clears cholesterol from the arteries, widening the artery walls and increasing elasticity.
- Omega-3 increases the levels of "good" HDL cholesterol in the blood, which protects the heart.
- People who regularly consume oily fish are less likely to suffer dementia or Alzheimer's.
- Oily fish consumption reduces the risk of depression and helps people who are depressed to overcome it.
- Omega-3 is good for the development of a healthy baby, although pregnant women should limit themselves to no more than two portions of oily fish a week.
What else do oily fish contain?
Oily fish are also rich in many vitamins and minerals that are vital for the correct functioning of the body.
Fat-soluble vitamins are plentiful in oily fish, due to the fact that they are absorbed by the fats contained within the fish. The fat-soluble vitamins are A, D, E and K and all are found in significant amounts in oily fish.
Vitamin D can be manufactured by the body when exposed to sunlight every day, but in the UK, you are not necessarily guaranteed sunshine every week let alone every day and therefore it may be necessary to acquire vitamin D from foods.
Oily fish is also a very good source of important minerals such as iodine, selenium, calcium, zinc, phosphorous and magnesium.
Calcium is obtained when the bones of small fish are eaten such as in sardines, whitebait or anchovies and iodine is important for the thyroid to work properly. A deficiency in iodine will cause the thyroid gland in the neck to swell and it will leave you feeling extremely tired and lethargic. It can often cause people to put on weight and make it very difficult for them to subsequently lose it.
How much oily fish should we eat?
Although there are numerous health benefits to be gained from consuming oily fish, there are still limitations on the amount of fish that we should consume per week. This is because some types of oily fish are prone to absorbing metals and toxins that have been pumped into our rivers and seas.
We are advised to eat one portion of oily fish a week, with one portion being the equivalent to 140g or 5oz.
As white fish do not contain such toxins within their flesh, it is possible to eat as much white fish as you like.
Pregnant women are asked to completely avoid swordfish, shark and marlin due to the possible health risks.
Types of oily fish
Some of the most popular types of oily fish are: salmon, trout, sardines, swordfish, whitebait, fresh tuna, anchovies, eel, kipper, mackerel, carp, bloater, smelt, bluefish and sprats.
Take note that although fresh tuna is an oily fish, tinned tuna is not regarded so, as most of the oil is removed in the canning process. However, other types of oily fish that can be tinned such as sardines and anchovies, still count as oily fish.
In the same way, smoked oily fish also still counts as oily fish.
Cooking methods for oily fish
As oily fish contain a certain amount of fat in their flesh, it is best to use cooking methods where additional oil is not needed. Therefore, grilling, baking, steaming and pan-frying are ideal for oily fish but shallow frying and deep-fat frying aren't.