This study looks at a smallish group of 230 children with autism, pdd-nos, or aspergers and looks at the serum level of zinc and copper. It finds that the mean that the zinc / copper ratio of the group is lower than it should be and suggests that this could be an indicator of " heavy metal, particularly mercury, toxicity in children with ASDs".
I find this study interesting because my twins both show abnormally low levels of zinc and abnormally high levels of copper. When we started down the path of treating autism a little over two years ago we had numerous blood tests done on both to look for a variety of factors. We looked for fragile-x and other known genetic abnormalities, we looked at immune system function, and we looked at levels of nutrients.
The results were interesting to say the least. On the nutrient side one of the things that came up was that both girls had zinc levels that were half of the bottom lower limit of the scale and that both were at the top of the scale for copper.
What that means is that their zinc copper ratio was something like 0.3 which is half of the 0.6 level that is reported in the study. Or in other words, their zinc / copper was badly out of wack.
Since that time we have, under a doctors supervision, been supplementing both girls with zinc in at attempt to bring their zinc / copper levels back up to normal. So far it is getting closer - their zinc levels have doubled so that they are now at the bottom of the scale and their copper levels have fallen. But their ratio is still out of whack.