Since the 1950s, the rate of asthma has increased dramatically, especially among children and adolescents. Altered diet habits play a significant role, and now a Swedish population study shows that children who get too little omega-3 and too much omega-6 in their diets have an increased risk of developing asthma later in life. There is also evidence that increased intake of omega-3 fatty acids from oily fish or from fish oil supplements can counteract the inflammatory processes that are seen with asthma.
Our immune defense is designed to use inflammatory processes to help us fight germs, swiftly and effectively. But with asthma, it’s different. This condition is characterized by unwanted, chronic inflammation in the airways that is triggered by virus infections and airborne allergens. When our immune system overreacts it produces far too much histamine, a natural compound that causes bronchial constriction and breathing difficulty. The chronic inflammation also results in an overproduction of phlegm and a constant urge to cough it up. The result of this is fatigue that is only made worse by poor sleep.
Most cases of asthma start in childhood and the rate is growing. Current therapies are mainly based on the use of steroid inhalers that reduce the inflammatory processes in the respiratory tract and the other symptoms that follow in the wake of this. This type of therapy, however, does not address the actual cause and it comes with the risk of various side effects.
In recent decades, science has had increasing focus on the diet, including people’s improperly balanced intake of omega-3 and omega-6 fatty acids.
Why the omega-3/omega-6 ratio is so vital
We primarily get omega-3 from oily fish, while we get our omega-6 from many different plant oils. Both fatty acids are essential and are found naturally in our cell membranes where they support a host of biochemical processes, including ones that involve inflammation.
The balance between the two types of fatty acids is extremely important. If you get too little omega-3 and too much omega-6, it sets the stage for chronic inflammation.
It’s also important what form of the fatty acids you consume. Oily fish contain two types of omega-3 known as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) that inhibit the inflammatory processes in the airways (and other places). They do this by suppressing the body’s production of pro-inflammatory compounds like C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-a).
The Swedish study confirms that more omega-3 and less omega-6 counteracts asthma
Many studies have looked at pregnant women’s intake of omega-3 to see if it can lower their children’s risk of developing asthma and allergies later in life. Only few studies have looked at the child’s own intake of omega-3 and how this can affect the risk of developing asthma later on. A group of Swedish scientists wanted to look closer at this and did so by analyzing the results of a population study called “Barn, Allergi, Miljö, Stockholm och Epidemi” (BAMSE). The study included 4,000 participants born between 1994 and 1996 in Stockholm. The children were asked to fill in questionnaires regularly to provide data about their diet, lifestyle, environmental factors, and allergies – including asthma. The parents provided any needed help for these questionnaires. The scientists also made calculations of the children’s total intake of omega-3 (ALA, EPA, and DHA) and omega-6 (LA and AA) and looked at the balance between the different fatty acids.
Furthermore, blood samples were collected to analyze the blood’s content of omega-3 and omega-6.
Based on the questionnaires, the number of asthma cases was reported at ages 8, 16, and 24 years. Also, the pulmonary function of the participants was measured.
It turned out that those with a high intake of omega-6 in the period from eight to 16 years had an increased risk of developing asthma when they reached an age of 24. In contrast, those with a higher intake of omega-3 during the same period in life had a lower risk of developing asthma in their mid-twenties. The scientists did not find a direct link between the intake of the two types of fatty acids and pulmonary function.
The Swedish study is published in the American Journal of Clinical Nutrition.
It is also worth mentioning that a British population study from Queen Mary University of London has shown that higher intake of omega-3 fatty acids at the age of around seven can lower the risk of developing asthma at 11-14 years of age. However, this only applies to children with a certain gene variant.
The results of both studies support earlier research where it has been seen that increased intake of omega-3 fatty acids from diet or supplements often has a good effect on asthma and helps lower the need for medicine, even among adults. It is also a good idea to reduce the intake of omega-6 fatty acids from plant oils, margarine, deep-fried foods, and junk-food.
Oily fish and fish oil supplements
According to the official dietary guidelines, older children and adults should consume at least 350 grams of fish per week, where 200 grams of the intake should come from oily fish like salmon, trout, mackerel, herrings, and anchovies. Unfortunately, farmed fish do no contain optimal levels of omega-3 because they get unnatural animal feed. It is a good idea to stick with free-range salmon, herring, and anchovies from pure and clean waters and to avoid predatory fish like tuna that often contain high levels of heavy metals. People with asthma and inflammation in the body may have an even larger need for omega-3 than others.
If you are not fond of fish or just don’t eat fish often enough, a fish oil supplement can be useful.
Sandra Ekström. Dietary intake and plasma concentrations of PUFAs in childhood and adolescence in relation to asthma and lung function up to adulthood. The American Journal of Clinical Nutrition March 2022
Mohammad Talaei et al. Intake of n-3 polyunsaturated fatty acids in childhood, FADS genotype, and incident asthma. European respiratory Journal. 2021
Queen Mary University of London. Consuming omega-3 fatty acids could prevent asthma, study suggest. ScienceDaily. January 27, 2021
Isobel Stoodley et al. Higher omega-3 Index Is Associated with better Asthma Control and Lower Medication Dose: A Cross-sectional Study. Nutrients 2020
Emily P Brigham et al. Omega-3 and Omega-6 intake Modifies Asthma Severity and Response to Indoor American Journal of respiratory and Clinical Care Medicine. 2019
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