When it comes to choosing fish that provide the greatest health benefits, species like salmon, tuna, mackerel and sardines are widely recognised for their high content of omega-3 fatty acids. However, according to Kunchit Judprasong, an associate professor at Mahidol University’s Institute of Nutrition, other popular types of marine and freshwater fish commonly found in local markets can also contain useful levels of DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), omega-3 fatty acids that are known to be good for both the heart and the brain.
Steamed fish is an ideal food for the elderly and for people with high cholesterol levels.
In a recent study he conducted of 17 different fish species, Kunchit found that fish, both salt- and freshwater kinds, which were raised under hygienic conditions in a closed farm system can also contain a good level of omega-3 fatty acids if they are fed on by-products from the canned-fish industry and on small dried fish.
“Fish that are fed with foods containing omega-3 fatty acids can themselves contain lots of healthy fatty acids when they grow to maturity,” the academic observed.
In his study, 100g cooked portions of several popular freshwater and marine fish were analysed and found to vary widely in their omega-3 fatty acid content, with figures ranging from 20mg all the way up to 840mg. Farm-raised catfish (pla duk), for example, was discovered to have a total fat content of 14.7g, of which 460mg comprised omega-3 fatty acids. White pomfret (pla jaramed khao) by contrast, was found to contain only 6.8g of fat in total, but 840mg of this was contributed by omega-3 fatty acids. Black-banded trevally (pla samlee), another commonly eaten fish, contains 9.2g of fat (470mg of omega-3 fatty acids) while snakehead fish (pla chon) have 8.5g of fat in total (including 440mg of omega-3 fatty acids), silver barb (pla tapein) have 7.4g of fat (240mg of omega-3 fatty acids) and short-bodied mackerel (pla tu) have 3.8g of fat (220mg of omega-3 fatty acids).
“Our study found that farm-raised fish had a larger quantity of fat, omega-3 fatty acids in particular, than fish caught in the wild,” Kunchit noted.
Healthy fatty acids like DHA and EPA are often found stored in the bodies of fish. These fatty acids are initially produced by algae and phytoplankton, ocean denizens which are able to extract energy from sunlight. The algae and phytoplankton are eaten by small fish which are, in turn, devoured by larger fish like sardines and mackerel which is how the DHA and EPA ultimately end up being ingested by humans at the very top of the food chain
As part of a healthy diet, most doctors recommend the consumption of at least two to three portions of fish, preferably fatty fish, per week. A portion, in this case, is about 100g of cooked fish, approximately what you would get from cooking a whole, medium-sized pla tu, half a catfish or a quarter of a medium-sized snakehead fish.
To ensure one gets enough omega-3 fatty acids in one’s diet, one can boost one’s intake by frying one’s choice of fatty fish in a vegetable oil extracted from soya beans, pumpkin seeds or sunflower seeds, all of which naturally contain ALA (alpha-linolenic acid), another important type of omega-3 fatty acid.
“Eating fried pla tu [short-bodied mackerel], one will not only get DHA, EPA and other omega-3 fatty acids from an animal source [the fish], but ALA from a plant source [the vegetable oil] as well,” Kunchit explained.
Fried fish may not be an ideal food for the elderly, however, or for people with high blood cholesterol levels who have to be careful of their fat intake. Steaming or grilling the fish would be a better option in such cases, he said.
“Fish is a good source of protein and of various vitamins and minerals needed by the body in order to function well. It is highly recommended as a food for the elderly since the protein in fish is easily digestible. Also, fatty fish do not have a high content of saturated fat. And they are much healthier for you than meat products like beef, pork or even chicken which tend to contain a large amount of saturated fats.”
It is much better, Kunchit went on, to include foods rich in omega-3 fatty acids in one’s diet rather than trying to increase one’s omega-3 intake by taking dietary supplements which usually come in a form of capsules or a liquid (cod-liver oil and similar products). Taking a high dose of omega-3 capsules over a certain period of time may put one at greater risk of bleeding more profusely if one is involved in an accident, for instance. And people with certain medical conditions should consult a health professional before starting a course of omega-3 capsules, he said, as fatty acids can interfere with blood-thinning medication prescribed for patients with heart diseases.
“Your best bet,” he said in conclusion, “is to get omega-3 fatty acids and other useful nutrients from eating fish rather than from taking supplements.”
Farm-raised catfish have been found to contain a reasonable amount of omega-3 fatty acids.
