UPDATED: Observer plugs fish oil for concentration, ADHD and depression

I was surprised to see the usually excellent Guardian Science tweeting that “Fish oil helps schoolchildren to concentrate”. This linked to Denis Campbell’s Observer article, reporting that

Fish oil helps schoolchildren to concentrate
US academics discover high doses of omega-3 fish oil combat hyperactivity and attention deficit disorder
Children can learn better at school by taking omega-3 fish oil supplements which boost their concentration, scientists say.

Boys aged eight to 11 who were given doses once or twice a day of docosahexaenoic acid, an essential fatty acid known as DHA, showed big improvements in their performance during tasks involving attention.

Dr Robert McNamara, of the University of Cincinnati, who led the team of American researchers, said their findings could help pupils to study more effectively and potentially help to tackle both attention deficit hyperactivity disorder (ADHD) and depression.

Unfortunately, the Observer’s claims about fish oil are not evidence-based.

I excitedly looked for the paper (not linked in the article): it would be great if fish oils could offer a relatively safe, cheap and easy means of cognitive enhancement and a treatment for ADHD and depression. However, as far as I can tell, this is the article referred to.

The article concludes that “Dietary DHA intake and associated elevations in erythrocyte DHA composition are associated with alterations in functional activity in cortical attention networks during sustained attention in healthy boys.” This is interesting – but certainly doesn’t show that fish oil pills are any good for improving outcomes like concentration. The published article actually finds that, at 8 weeks:

time x dose interaction was not significant for percentage correct, commission errors, discriminability, or reaction time. Among all subjects (n = 33), erythrocyte DHA composition was inversely correlated with reaction time at baseline (r = –0.43, P = 0.01) and endpoint (r = –0.41, P = 0.02), but was not correlated with other performance measures.

While interesting, this clearly does not show that fish oil pills help with concentration, ADHD or depression. As DVMBishop comments on the Observer site, the article

does *not* show that fish oil helps children to concentrate. What the study showed was that there were some brain regions where activity increased during an attention task more in those given fish oil (groups of 9 and 12 children) than in a placebo group (10 children).

Also, as noted by Campbell, the trial in question involved only 33 subjects (all boys): it is therefore too small to be definitive even with regards to what it does find and there is also the question of whether the trial’s results also apply to girls.

Interestingly, there has been other research into fish oil for ADHD and depression. Results of a trial in 75 children with ADHD have been less-than-inspiring. A 2007 Drugs and Therapeutics Bulletin review of fish oil for depression found that

Despite observational evidence linking depression with reduced intake of long-chain omega-3 fatty acids, there is no convincing basis for using these nutrients as a sole treatment for the condition. There is limited evidence suggesting that long-chain omega-3 fatty acid supplements might help to relieve depression when given in addition toexisting antidepressant medication. However, this needs confirming before we can recommend the routine use of such supplements in patients with depression.

In conclusion, Campbell’s Observer article suggests that fish oil can be useful for concentration, ADHD and depression – based, so far as I can tell, on a trial which does not demonstrate its efficacy for improving concentration or for treating any condition. Moreover, Campbell’s article does not mention previous research – with more immediate relevance to fish oil for ADHD and depression – which gives reason to, at least, be cautious about some of the stronger claims made for fish oil.

Science coverage on the Guardian website is normally pretty good. This is, frankly, a really disappointing bit of journalism – hopefully it will be corrected ASAP.

Update: A comment on the Guardian site (from Dr McNamara?) notes that the trial used algal DHA, not fish oil; Campbell’s article does focus on fish oil, though. McNamara’s article makes this perfectly clear – I somehow managed to miss it yesterday.

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7 Comments

Filed under ADHD, depression, fish

7 responses to “UPDATED: Observer plugs fish oil for concentration, ADHD and depression

  1. Nicholas

    Why is it that the Observer is so dreadful when it comes to reporting anything science based, and the Guardian is good? (Broad generalisations I know – but there does appear to be a trend here).

  2. E. Brown

    Found this post via Bad Science.
    Amused by the Google Ads generated by your post – here’s a copy and paste (which doubtless will only make it worse!):

    Ads by Google
    Omega 3 for depression
    How omega 3 fish oil Vegepa helps manage symptoms of depression
    igennus-hn.com/health-benefi

    Omega 3 – 1000mg
    Buy Quality High Strength Omega 3 For A Healthy Heart. Free P&P.
    http://www.Healthspan.co.uk

    Short ADD/ADHD Survey
    Can sleeping with head covered have any impact on the severity of ADHD?
    sites.google.com/site/rebreathing

    Moving Minds
    Therapeutic services focusing on children and learning in Merseyside
    http://www.movingminds.org.uk

  3. Don Cox

    If fish oil improves your intelligence, how come fish are so stupid?

  4. Pingback: That Ben Goldacre fuss | Code for Life

  5. Mariana

    I wonder what is Holdford’s “miracle” cure for depression?

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