Iron. The metal that had its own age. A metal we consistently find in extra-terrestrial material. A metal that carries several important roles in numerous bodily functions. A metal that even has its own superhero. It is in relation to the body and health that I will look at iron connected to autism and a few other things (although I am tempted to talk more about Iron Man given my childhood love of the Marvel comics).
I have, in a previous post, hinted at a possible issue with iron in some cases of autism. The limited research done on the topic of iron deficiency in autism suggests that it might be more widespread than you think.When taking into account ferritin levels as possible indicators of iron deficiency, the research does get a little bit serious in terms of the numbers potentially deficient. This last piece of research also suggests that things get potentially worse as chronological age increases.
So why is iron so important to autism and why might we be seeing the scientific results that we are?
Well like everything it is complicated. I will do my best but can't guarantee making things any clearer by the end of this post. We get our iron from a few sources: endogenous recycling following hemoglobin breakdown, dietary intake and the various supplements that we seem to be taking ever more of. Iron is important for lots of different bodily processes and where not enough is present, anaemia is diagnosed. For children, anaemia can affect growth measurements among other things.
One could assume that given the potential for dietary issues in some cases of autism, there might be some problem in consuming adequate levels of dietary iron. Indeed, quite a few studies have suggested that the recommended nutritional intake of iron (and lots of other things) might be less in autism than what they should be. I would however temper that statement by saying that controls were also tending to be low in iron intake also. Levels of ascorbic acid (vitamin C) which is also pretty important for the absorption of non-heme dietary iron has also been suggested to be 'different' in some cases of autism.
There is some suggestion that supplementing iron in autism might have some interesting knock-on effects with regards to ferritin levels and also sleeping patterns. The ferritin levels bit suggests that the metabolism of iron might not be particularly problematic in autism; rather low intake or some mechanism that depletes iron being more important. This is where I am going to be a bit speculative so please get that pinch of salt ready.
Regular readers might know that I talk quite a bit about coeliac disease as being potentially quite an important co-morbidity to some cases of autism. Coeliac disease has also been associated with iron deficiency whether through poor absorption of dietary iron or more controversially as a result of blood loss.
Question: could the low levels of iron present in some cases of autism be due to similar mechanisms?
I am not suggesting that every case of low iron in autism is due to coeliac disease; indeed nothing close. What I do however wonder is whether the proposed 3% of the autistic population with co-morbid coeliac disease might be populous in our low iron group? What about those with gut hyperpermeability also potentially affecting the amount of iron absorbed from diet?
If you want more information on testing for levels of iron, please have a look here on what testing involves and speak to your medical physician.
Because I can't resist it, here is a Marvel link that many of you may remember from days gone by.
[Update: 23 September 2014: Here is my take on the paper by Schmidt and colleagues looking at maternal iron supplementation during pregnancy and offspring autism risk]