Tuesday, August 30, 2011

Suicide, Omega 3, and the Military

Another one for the marine-derived highly unsaturated fatty acids are probably really important for proper brain function files:  This new paper has been tweeted quite a bit lately: Suicide Deaths of Active Duty US Military and Omega-3 Fatty Acid Status:  A Case-Control Comparison

It is an observational study, but large for a suicide study (suicide is, fortunately, quite rare).  All told, 800 randomly selected suicide victims in the armed services were selected between 2002-2008, and compared to 800 matched controls.  Cases were matched for time and theater of deployment, exposure to stress during deployment, report of mental health status, and demographics among other data points.  (Though later the paper says 99.1% of the controls had been deployed vs. only 61.9% of the suicides, so the deployment location and duration were not added as covariates to the end calculations).

So, fatty acid of the blood of the participants - in short, the lower the DHA in the blood, the more likely the person was to have committed suicide.  The relationship was linear and true of all octiles studied.  There were only 70 women in the samples, and they tended to have higher DHA levels than the men, and lower suicides (among women, the omega 3 status to suicide relationship was not statistically significant as it was clearly so among the men).  Men in the lowest DHA octile were 62% more likely to commit suicide than those in the highest octile.

Other fatty acids of interest - lower levels of stearic acid (saturated! My goodness! Found in chocolate!  And steak!) were found to be associated with increased risk of suicide (my preliminary conclusion - eat more chocolate - though it is only observational - I'll risk it and eat your chocolate if you are uncertain).  Also, higher palmitoleic acid (a monounsaturated acid made from the saturated palmitic acid) levels correlated with a lower level of suicide risk.

In this study, US military personnel were found to have, on average, a lower DHA level than average North American, Australian, Mediterranean, and Asian populations (unlike the medical students I wrote about a few articles ago, who had higher levels than the general population).  In fact, among Chinese suicide attempters, nearly all of them had higher levels of omega 3 DHA than the highest octile of the US military personnel studied.  And when both populations were studied together, the lowest DHA levels coincided with a 5-6 fold increased risk of suicide.  For perspective, this risk increase coincides with the risk of undergoing severe stress under deployment (seeing wounded, killed, or dead comrades, for example) and the risk of suicide.

We can't determine causality, but common sense and and evolutionary perspective should surely make us suspicious - eat those marine omega3s and keep your 6:3 ratio minimal.  The paper recommends 2 grams daily of marine omega 3s..  Seems reasonable.


  1. Palmitoleic acid is most prevalent in butter. So we have our steak, we have our chocolate, and we're covering everything in butter. And of course can't forget oysters with the butter. If this was me 2 years ago I would think it was crazy, but then again I was pretty depressed back then. Go figure!

    The psychologist in me wants to say that all of these yummy foods keep people happy so they don't kill themselves, but I know better. You generally don't get people killing themselves unless there is something seriously wrong with their brain, and so the inflammation/metabolic syndrome, and deficiency explanation seems to be the best one.

    Our good buddy Dr. Bill Lands did a talk to the military about PUFA ratio a few years ago. It's on youtube here http://www.youtube.com/watch?v=dgU3cNppzO0 for anyone who hasn't seen it.

  2. Emily do you regularly check patients O6/O3 ratio? If you do, do you have a O6/O3 ratio you shoot for clinically? I ask because I do and I am wonder aloud since we both work on the brain in some fashion if we have the same target. I think O6/O3 ratio's are critical importance clinically. Dr. K

  3. An interesting paper. The military represent quite a good study group for lots of things based on the excellent healthcare available to them and being a 'captive audience'. I wonder how these results might tie up with the recent paper from David Niebuhr and colleagues on IgG antibodies to casein being linked to onset of schizophrenia? http://www.ncbi.nlm.nih.gov/pubmed/21376538
    What is the fatty acid constitution of dairy cows milk and does it contain enough DHA or as a few people have suggested not?

  4. It seems like it's on the military's radar - they held a big conference on it in 2009. Links to videos of speakers are available here - as well as an overview of all the talks -

  5. It is telling that the military personnel have lower O3 than all those populations. Captive audience eating government approved food - with deadly results? Shameful.

  6. Sorry to post here but wondered if you can direct me to some reading on inattentive ADHD - used to be called ADD. My nephew has been diagnosed with it. Is a gluten-free diet the first step?

  7. I suspect it would also make sense, for similar reasons, to recommend higher consumption of seafood for those seeking to lose body fat. The reason is that calorie restriction of any kind seems to lead to a psychological response that is similar to that of stress.

    Plus, seafood is generally low in calories, but nutritious nevertheless. I am not a big fan of supplements, including fish oil capsules.

  8. Sue, I'm not a doctor but I am someone with adult ADD who follows Paleo principles to deal with it. I have a lot of personal experience dealing with it and a lot of insights from my younger years when my doctor overmedicated me etc. etc.

    If you need some insights, feel free to talk to me. I might not be the textbook expert, but I've dealt with this problem my whole life and know a lot that can't be translated into science (not dissing the science--it's been very helpful to my goals!)

  9. Sue - here is my article on ADHD from psych today - also check the "map" section of this blog. http://www.psychologytoday.com/blog/evolutionary-psychiatry/201106/how-does-diet-affect-symptoms-adhd

    These just reference the food and sleep piece - there are a number of very useful behavioral things to do, and lots of books on the subject. And, of course, there are medication options too. A personalized evaluation/work-up is key.

  10. Thanks a lot Alex - I have sent you an email.
    Thanks Emily.