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Fish oil helps adults with autism and ADHD by improving their attention and working memory

Fish oil helps adults with autism and ADHD by improving their attention and working memoryThe rate of autism and ADHD has exploded over the past decades, and the problem comes with an enormous human and socio-economic price tag. A study from the University of Copenhagen has shown that fish oil helps adults with autism and ADHD by improving their attention and working memory. In the study that is published in British Journal of Nutrition, the scientists look closer at omega-3 fatty acids in fish oil and their vital role in the brain and nervous system.

Autism affects around 1.6 percent of the population in the Western countries, and the rate is going up. There are different degrees of autism and they are characterized by people developing differently from others in areas like language, communication, and social behavior. Autism is also linked to impaired working memory, inhibitions, and lack of flexibility. In addition, autism is often related to other complications such as ADHD and depression.
Symptoms typically linger on into adulthood and current therapies are not all that effective and even have serious side effects. Scientists are constantly on the lookout for better and healthier alternatives, and fish oil is of the things that has attracted most attention over the last decades.
Fish oil contains the two omega-3 fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) that we humans can easily utilize. We have EPA and DHA in our cell membranes where they support a host of different physiological functions. DHA is particularly important for brain development and the central nervous system, while EPA has anti-inflammatory properties. This is useful in connection with the different inflammatory processes that occur in the brain and are seen with depression.
Studies show that children with autism and ADHD often have too little omega-3 in their blood, and this is linked to impaired cognitive function. Research shows that fish oil supplements can help in such cases. But larger meta-analyses are needed to deliver solid proof.
Moreover, the effect of fish oil on autism in adults has only been demonstrated in small, uncontrolled studies, and scientists have yet to study whether fish oil supplements can affect related problems such as ADHD and depression.
The scientists from the University of Copenhagen therefore wanted to look closer at this connection in a large, placebo-controlled, randomized cross-over study.

Fish oil and its positive effect on autists with ADHD-like symptoms

The Danish researchers investigated if fish oil supplements given to adults with autism were able to affect cognitive function and problems such as ADHD. The study included 26 autistic patients aged 18-40 years. The participants were split in two groups. During the first four-week period, one group received 5.2 grams of fish oil daily in capsules (2.4 grams of EPA and 1.6 grams of DHA), while the other group got capsules with a safflower oil placebo. After four weeks, the two groups switched treatments.
At baseline and after each intervention period, the scientists looked at different parameters such as attention (d2 test), visuospatial working memory test (Corsi test), and other secondary parameters such as flexibility (Stroop Color and Word Test), ADHD symptoms (Conners scale), executive function (Behavioral Inventory of Executive Function), and social behavior (Social Responsiveness Scale)
In the participants who got fish oil, ADHD symptoms improved (Conners scale) compared with the group that got safflower oil.
Participants without ADHD symptoms experienced the most significant improvements in terms of attention (d2 test).
Fish oil did not have any effect on autism symptoms, but fish oil may improve attention and working memory in adults with autism and improve related complications such as ADHD symptoms.
The new study is published in British Journal of Nutrition.
The fish oil quantities used in the study were about the same as you would get by eating a large serving of free-range salmon.
Even though the fish oil is absorbed in the bloodstream after a few hours only it may take a month or more for EPA and DHA to become embedded in the body’s cells, including the cells in the central nervous system and the brain.
Therefore, if you take fish oil for longer than the four weeks in the above-mentioned study you can expect an even better effect.
So, don’t expect a fish oil supplement to deliver fast results. On the other hand, if you decide to stop taking the supplement, it takes some time for the omega-3 fatty acids to leave the cell membranes. This delayed reaction can make it difficult to assess the effect of supplementing with fish oil.

DHA and EPA and their role in the brain and nervous system

  • Development of the brain and central nervous system
  • Involved in processes in the synapses that exchange information between neurons in the brain
  • Increase the blood flow, thereby improving the ability to solve cognitively challenging tasks
  • Formation of neurotransmitters – including dopamine and serotonin that are important for our mood
  • Counteract brain inflammation that is seen in connection with depression

Oily fish and fish oil supplements

Oily fish contain a lot of EPA and DHA. Unfortunately, the omega-3 content in industrially farmed fish is not optimal because the fish get unnatural animal feed. Stick with free-range salmon, mackerel, and herring from clean waters and avoid predatory fish that tend to accumulate heavy metals.
When buying fish oil supplements, always study the label to see how much EPA and DHA they contain. Fish oil in supplement form should always be within the official threshold levels for peroxide values and environmental toxins.


Lundbergh, B et al. Fish oil supplementation may improve attention, working memory, and ADHD symptoms in adults with autism spectrum disorder: A randomized crossover trial. British Journal of Nutrition. 2022

Emily Henderson. Adolescents with higher levels of omega-3 fatty acids less likely to develop psychotic disorder. News Medical Life Sciences, Jun 1 2021

James J. Dicolantonio and James H. O´Keefe. The Importance of Marine Omega-3s for Brain Development and the Prevention and treatment of Behavior, Mood, and Other Brain Disorders. Nutrients. 2020

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