Fish Oil May Not Be as Beneficial for Asthma as You've Heard

I've been hearing for years about the possible benefits of fish oil in treating asthma. I even took a fish oil supplement myself for a few years a while back. And wouldn't it be great if a "natural" supplement rather than a man-made chemical was the answer to relieving asthma symptoms?

Unfortunately, fish oil may not have as much promise as you've heard or as many believed. New research sheds some doubt on that possibility.

What is fish oil & why might it help?

Fish oil is a dietary supplement, in fact, one of the most commonly used. It's popular because it is rich in omega-3 fatty acids.1 Oily or fatty fish, such as salmon, mackerel, and sardines are the best source of omegas known as DHA and EPA.2 But not everyone includes these fish in their daily intake, at least not in numbers enough to tap into the so-called power of fish oil.

Another source of omega fatty acids is in certain plants that contain alpha linoleic acid that the body converts to DHA and EPA. This includes:

  • Flaxseed
  • Chia seeds
  • Walnuts
  • Pumpkin seeds
  • Canola oil

But again, not everyone wants to include any of those plant products in their dietary intake.

This explains the popularity of fish oil and other omega supplements. Our bodies are unable to make omega-3 fatty acids, so getting them from either diet or supplements is your only option. But why is this important?

Omega-3 fatty acids have been proven to help with3:

  • Brain function
  • Growth and development
  • Inflammation

Fish oil supplements have been promoted using claims of such benefits as:

  • Easing of inflammation
  • Protection of the heart
  • Better mental health
  • Longer life

Whether these claims are completely valid is something else.

The apparent effect of omega-3 fatty acids on inflammation is one of the reasons fish oil has been touted as helpful in treating asthma. Asthma is a disease signified by airway inflammation. In fact, previous studies have shown some promising results with using fish oil supplements in people with asthma.4, 5 However, both studies noted the limits of their findings and that more research would be needed to support the use of fish oil with asthma.

New Research

Now, a study just published in the Annals of the American Thoracic Society found that fish oil may not help certain groups of people who have asthma as much as had been thought.6

This was a relatively small study, but still, it raises some doubts about whether even high doses of fish oil supplements can be useful in controlling people with more severe asthma. Here are the details:

  • 98 participants in the study
  • Participants were adolescents and young adults, age 12 to 20
  • All were either overweight or obese, with poorly controlled asthma
  • All used a daily inhaled steroid for asthma
  • 3/4 of the participants took 4 grams of fish oil per day for 6 months
  • 1/4 of them took a soy oil supplement as a placebo

The results were somewhat surprising, given previous research. However, similar results were noted by the University of Rochester researchers in regards to asthmatics on high doses of steroids (which indicates poorer asthma control). Here's how this latest study measured their results:

  • Questionnaire
  • Breathing tests
  • Urgent care visits
  • Severity of asthma symptoms

In the end, they found that fish oil supplements did not improve asthma control in overweight or obese young people with uncontrolled asthma. Researchers aren't sure exactly why this would be, but have suggested some possible reasons7:

  • Evidence from other studies suggests that obesity is linked to body-wide inflammation. This widespread effect may be too much for the fish oil to reverse.
  • Certain genes in some people might interfere with drugs used to treat asthma.
  • The University of Rochester study suggested that high doses of oral steroids (often given in poorly-controlled asthma) might hinder the beneficial effects of omega-3 fatty acids. 8

In Summary

Fish oil and omega-3 fatty acids may provide some protective or beneficial effect to people with asthma, especially those who do not fall into the persistent severe classification of asthma.

But it appears that much more comprehensive research may be needed before we completely understand all of the factors at work in this area. Meanwhile, you may want to discuss with your doctor whether it makes sense--or not--to add some sort of omega supplement to your treatment plan. Meanwhile, don't stop following the rest of your treatment plan, including taking your daily controller medicine, whether it's an inhaled steroid or something else.

By providing your email address, you are agreeing to our privacy policy. We never sell or share your email address.

More on this topic

This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.

Join the conversation

or create an account to comment.