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Fish oil from oily fish or supplements protects children against asthma

Fish oil from oily fish or supplements protects children against asthmaFish oil contains the omega-3 fatty acids, EPA and DHA, which are important for normal development of the baby’s brain and immune defense. Pregnant women who eat oily fish several times a week help their babies against developing asthma later in life. Oily fish and fish oil supplements have similar effects. This was shown in two studies from the University of South Florida in Tampa, USA. However, pregnant women should avoid predatory fish like tuna that contain mercury. For those who dislike the taste of fish or who simply do not eat enough, fish oil supplements are an option.

Asthma affects all age groups but children in particular seem to be affected. The disease is a chronic inflammatory condition of the lungs. The constricted bronchi cause symptoms such as breathing difficulty, coughing, and chest tightness. Asthma patients are more prone to respiratory infections, which are able to trigger an acute asthma attack.

Florida researchers reviewed two different studies, both of which had concluded that children of mothers who had consumed large quantities of omega-3 fatty acids during their third pregnancy trimester, were less likely to develop asthma and other respiratory problems. The first study, which is published in the New England Journal of Medicine, included 346 women in their third trimester of pregnancy who took fish oil supplements and 349 women in their third trimester of pregnancy who took a placebo. The study showed that children of the mothers with the lowest level of omega-3 in their blood at study start benefited the most from the omega-3 fatty acids.

Fish oil supplements and oily fish counteract asthma

The other study, which is published in Journal of Allergy and Clinical Immunology, also looked at two groups of women in the third semester of pregnancy. One group took a fish oil supplement. However, after the control group was informed about the whole purpose of the study, they were given the opportunity to consume a similar quantity of omega-3 by eating regular fish. This helped the researchers understand that children, whose mothers had consumed oily fish, also had less tendency to develop asthma later in life. Furthermore, the scientists tested the children when they reached 24 years of age. It turned out that there was less need for asthma medication among the participants, whose mothers got more omega-3 during their pregnancy – either from oily fish or from fish oil supplements. The study was published in Journal of Allergy and Nutrition in 2017.

The effect of omega-3 fatty acids from fish oil supplements or oily fish even helps children when they grow up

Why omega-3 fatty acids are so important during pregnancy

The essential omega-3 fatty acids are structural components of all cell membranes and help control different biochemical processes. Omega-3 fatty acids are especially important during the third trimester of pregnancy, which is when the baby’s brain develops rapidly, and the nervous system and immune system undergo intensive development, as well.
We humans are unable to synthesize omega-3 fatty acids and therefore depend on dietary sources. Omega-3 fatty acids have an intricate biochemical interplay with omega-6 fatty acids that our diet provides in large quantities. Getting too much omega-6 at the expense of omega-6 (which is very common in our part of the world) sets the stage for inflammatory diseases like asthma.

Omega-3 from the diet or from supplements – a simple solution

According to the scientists behind the study, Richard Lokey and Chen Hsing Lin, consuming oily fish 2-3 times per week provides the same health benefits as taking a fish oil supplement. Unfortunately, fish contains mercury and other environmental toxins that may have a negative effect on fetal development. Fish at the top part of the food chain contain the most pollution, which is why one should avoid consuming too much tuna and other types of predatory fish. There is less need to worry about salmon and smaller fish. It is best to avoid salmon from the Baltic Sea, as there may be a higher content of heavy metals and other types of pollution. If possible, stick with organic salmon. For those who dislike fish, high-quality fish oil supplements are highly useful.

Important: It is also important for the pregnant woman to make sure to get enough selenium, iodine, iron, folic acid, and other nutrients that are relevant during pregnancy.

Ethyl esters, free fatty acids, and triglycerides

There are different ways to derive and purify fish oil from oily fish. Fish oil based on free fatty acids or triglycerides are normally more stable and are more easily absorbed than fish oil based on ethyl ester. The absorption of a fish oil supplement is more important than how much omega-3 it contains, as we are unable to make use of omega-3 fatty acids unless we can absorb them.

Omega-3 content in herring, salmon, and fish oil capsules

  • 100 grams of herring or salmon contain around three grams of fish oil – or the same as three large fish oil capsules.


Chen Hsing Lin, Richard F. Lockey. Prevention of Asthma: Fish or Fish Oil? The Journal of Allergy and Clinical Immunology: In Practice, 2017

University of South Florida (USF Health). Fisk Oil or fish consumption? ScienceDaily October 30, 2017

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