I did get a chance to read over some interesting papers yesterday. Unfortunately, my home computer stopped working yesterday while I was on twitter. That's probably the universe telling me something. Our interventions seem unable to bring the dead PC back to life. So I'm a little cranky. Also, since it is more difficult to link things on the iPad, it will probably take me a few days to link the papers. In the mean time, you are just going to have to take my word for it. What do you think - is a Macbook is really worth it?
It will not surprise you to know that folks have been looking at the O6:O3 ratio in ADHD - as researchers have been looking at the same thing in depressive disorders and other psychiatric disorders. It may also not surprise you to learn that much of the early research is fairly useless, as ADHD was not defined rigorously and things like medicine, IQ, and education were not always controlled for. However, since 2007, more meaningful work has been done, and several smallish studies have found similar trends to the previous research. The punch line is that folks with ADHD tend to have significantly higher O6:O3 ratios in their bodies than folks without the disorder. Also, kids and young adults with ADHD have lower DHA.
When O3 supplementation has been tried (typically just DHA or EPA and DHA), it has been a bit of a bust (just like the trials with Alzheimer's and several of the trials with depression). Some parents and teacher ratings noted less temper tantrums and better ability to pay attention, but more objective ratings (such as cognitive testing) and independent raters of behavior didn't notice any difference. It is important to keep in mind that O3 supplementation trials have always been more successful in milder and earlier forms of illness - mild cognitive impairment, depressive disorders not complicated with anxiety. Also, to my knowledge decreasing O6 at the same time has never been studied. In addition, while sometimes the placebos are soybean oil or something like that, other times olive oil is used, and there is some evidence that oleic acid might also have beneficial effects on behavior and mood. ADHD strikes young and sticks around. Therefore it is a tough disorder that is in part hard-wired, and in my mind, *just* O3 supplementation is unlikely to be of much benefit.
One more very interesting thing to keep in mind - at least in these studies, overall the diets of the ADHD kids did not differ significantly from the control kids (diets were typically measured with 1-3 day diet logs, so take from that what you will). So the control kids ate just as much O6 and just as little O3 as the ADHD kids. In the study of young adults, the ADHD kids were significantly more likely to take a vitamin pill, and their micronutrient profile on blood testing was actually better or not different than the controls with respect to magnesium levels, iron, folate, zinc, B6, B12, etc. Independent studies of many of those micronutrients showed benefit for ADHD in kids who were deficient in small trials also. Yet despite the similarity in diet, the ADHD kids still had more O6 hanging around in the body, and less O3.
Some other interesting things popped up while reading these papers. In one study, the researchers looked for signs of "essential fatty acid deficiency." People who are too low in PUFAs in general will have dry mouth, thirst, frequent urination, dry and flaky skin, brittle nails, and dandruff. Sure enough, kids with ADHD were more likely to have these symptoms, and the kids with these symptoms had a more out-of-whack O6-O3 ratio and less DHA in the body. Their out-of-whack ratios also responded more robustly to dietary supplementation with DHA than the kids who didn't have symptoms of essential fatty acid deficiency. However, the absolute levels of essential fatty acids in these kids weren't, in the strict sense, deficient, despite the symptoms.
How do we pull all this information together? Well, in my mind, something very important is going on in a subset of kids with ADHD and their needs for PUFAs, and their utilization of them. DHA is vital for neuroplasticity, proper nerve communication, and nerve repair. Once more you will not be surprised that kids and young adults with ADHD have signs of inflammation - higher ferritin, higher IL-1, etc. etc. etc. The inflammatory process may also change PUFA metabolism or utilization, while the PUFA ratio could affect how the inflammatory process is played out. One small study showed that families with an allele of a gene that was super-robust at making a form of the inflammatory cytokine IL-1 had much higher rates of ADHD. It would make sense that certain families are genetically more prone to brain insults caused, perhaps, by lifelong DHA deficiency or O6 excess while the brain is developing. Or it could mean that some of these families have problems with how O6 and O3 are transported or stored or something, so even sufficient amounts in the diet don't add up to enough for them.
We also should keep in mind that the only large dietary study (a dietary pattern study in Australia, and we know that dietary pattern studies may be more problematic than they are worth) showed a higher risk of ADHD in folks who ate a Western diet. Also, boys in the Australian study and in these O6:O3 studies trended towards being more affected by diets or out of whack ratios, and benefited more from supplementation than girls.
Clearly this issue is a rich area for more research. In the meantime, it doesn't hurt to get enough O3 (particularly DHA). If you eat higher fat, enough O6 will naturally come along for the ride, so no eating extra O6 either.
Next week - one or more posts cleaned up and migrated to Psychology Today, updating this post to add references, and who knows what will come down the line so far as papers and new stuff. And probably, a new computer. Sigh.