Sunday, 13 May 2012

SOD it: AA & DHA on ASCs (and a PUFA DJ)

Acronyms. I love them. OMG, LOL, IMO or even IMHO. David Cameron (the current UK prime minister) also likes to use them - even if only to mean 'lots of love'! My old English schoolteacher would probably be horrified at such flagrant disregard for the correct use of my mother tongue; IMO that is.

The acronyms making up the title of this post have already been discussed on this blog with relation to the research on fatty acids and autism. AA, also known as ARA, stands for arachidonic acid and DHA, docosahexaenoic acid. PUFA refers to a polyunsaturated fatty acid. I assume most people understand that ASCs are the autism spectrum conditions.

I am returning to fatty acids in light of some fairly new research by Kunio Yui and colleagues - paper 1* - (full-text) who reported on the results of a small trial of AA/DHA for autism. I have labelled this manuscript paper 1 simply because there is another paper** by the same authors which seems to recite the same study but based on different outcome measures (paper 2) which I shall also briefly touch on.

Paper 1 is open-access but to summarise:

  • The effect of large doses of AA added to DHA on social interaction and repetitive behaviour in individuals diagnosed with autism was examined in this double-blind, randomised, placebo-controlled trial. That and the measurement of plasma levels of PUFAs such as AA, DHA and EPA, eicosapentaenoic acid, following supplementation.
  • Thirteen participants (I said it was a small trial) were randomly assigned to either active (n=7) or placebo groups (n=6). Active treatment consisted in the most part of 6 capsule of this stuff (SUNTGA40S) per day, compared against olive oil placebo for 16 weeks. Assessments of social and repetitive behaviours were undertaken using the Aberrant Behaviour Checklist (ABC) and repetitive behaviour subdomains of the ADI-R at 4 week intervals.
  • Results: social withdrawal as measured via the ABC and repetitive behaviour measures on the ADI-R showed significant reductions compared with the placebo group scores. The number of individuals achieving 50% improvements in total scores for the ADI-R subdomain analysed was significantly greater than the placebo group.
  • A significant increase in plasma levels of AA were noted in the experimental group over controls when comparing baseline and 16 week levels. The authors have kinda focused on this point quite a bit with regards to the behavioural improvement noted.

I am still waiting to get hold of paper 2 in its full-text form but from what I gather it was based on the same number and grouping of participants, the same supplementary regime over the same time period although using slightly different outcome measures and scales. The net result from that study was that various facets of the social interactive part of autism seemed to be positively affected by the fatty acid supplement. That and levels of transferrin and superoxidase dismutase (SOD) seem to be affected by supplementation although at the present time I can't say in which direction and of what relevance this might be.

To reiterate, although gold standard in terms of methodology, this was a very, very small trial in terms of participant numbers. I know that I seem to be posting on quite a few small-scale studies recently but that's how the cards have fallen. Whether also the use of the ADI-R over 4 week periods might introduce some kind of 'practice' effects also remains to be answered.

So what does this all mean I hear you ask? Well, I can't profess to be the wise (not so old) sage in this case because my fatty acid chemistry is pretty basic at best. Quite a good overview of the whole lipid metabolism area in relation to autism can be found here by Tamiji & Crawford*** (full-text) and provides a good introduction to the evidence base so far.

AA is an omega 6 fatty acid which in some circles has been taken to mean 'bad' particularly when talking about the omega 3: omega 6 ratio of our modern day diets. Similar things have been reported in cases of autism. Like just about everything related to biochemistry, the hype however hides a number of important functions for AA, primarily because AA is a PUFA, the same as DHA, and an important intermediary in the production of things like prostaglandins (certain ones of which have recently been linked to cerebellar development with autism in mind). The authors speculate in paper 1 on the connection between AA and ".. up-regulation of signal transduction in relation to neuronal network function..". In this way I think they are suggesting that AA might actually be a good thing for autism and in particular how various systems / brain areas communicate with each other. The flip side to large doses of AA potentially having a central effect is the view of some of the compounds linked to AA which might not be all that optimal in terms of things like inflammation.

The whole fatty acids thing both in relation to autism and more generally to population health is still in need of quite a bit more investigation and at the moment I would like to see a little more done on AA before this becomes mainstream.

To finish, there is a DJ in the title to this post so without further ado, I present Mr Robbie Williams and Rock DJ (probably not a good video to watch if you are currently eating, or are vegetarian, or both).

* Yui K. et al. Efficacy of adding large doses of arachidonic acid to docosahexaenoic acid against restricted repetitive behaviors in individuals with autism spectrum disorders: a placebo-controlled trial. Journal of Addiction Research & Therapy. December 2011.
DOI: 10.4172/2155-6105.S4-006

** Yui K. et al. Effects of large doses of arachidonic acid added to docosahexaenoic acid on social impairment in individuals with autism spectrum disorders: a double-blind, placebo-controlled, randomized trial. Journal of Clinical Psychopathology. February 2012.

*** Tamiji J. & Crawford DA. The neurobiology of lipid metabolism in autism spectrum disorders. Neuro-signals. 2010; 18: 98-112.
DOI: 10.1159/00032318