Dr. Michael Merzenich wrote “I received a wonderful comment about the hypothesis that early umbilical cord clamping might contribute to the risk of origin of autism from a wonderful former colleague, Dr. David Blake, a researcher in the Department of Neurology at the Medical College of Georgia.”
Oxygen deprivation in the last trimester has been suspected as the cause for autism. Also autism has higher incidence in the united states than anywhere else in the world.
Circumstantial evidence is strong enough that further research is needed in this area.
Or is it the lack of exposure to sun during pregnancy and after birth that’s causing vitamin D deficiency and as a result causing autism to develop?
One comment (reproduced here verbatim) raises that iron deficiency may be a cause
This may be a long post. I’ve been doing a lot more research on perinatal indicators and autism and anoxia and anemia. I’d like to make the case for iron deficiency being the cause of autism (and possibly also ADD). Here is the logic.
There is a brilliant paper done at Harvard in 1955 (look for Duncan E. Reid as last author, Clement A. Smith as first). They injected pregnant women with radioactive iron. It hardly seems ethical today, but times change. The babies were born, and the authors tracked iron in these babies. Specifically, they looked at the fraction of heme iron that was radioactive. They also looked at the fraction of the blood that was red blood cells, or the hematocrit. What they found was that infants CANNOT incorporate dietary iron into their hemoglobin iron for the first six months of life! This is an incredible finding! Most infants use their red blood cells as a source of iron. They double in size in six months, and the loss of hematocrit donates iron for other body parts (like the brain). So the natural course of action is to burn through your iron for six months, at which time you can regulate its absorption in the GI tract. Of course, this means babies, at birth, have a higher iron-blood requirement than most other people.
On to my second brilliant study. This one was performed by a graduate student nutritionist at UC Davis named Camilla Chaparro, and published in 2006 in Lancet. They went to a Mexican hospital, and randomized normal full-term births. One group had the umbilical cord clamped at 15 seconds after the shoulder passed. The other had the umbilical cord clamped after a few minutes. The significance of this is that in normal full-term babies, the umbilical cord pumps an extra 50% blood volume into a newborn over the first few minutes. When Camilla and colleagues did blood work on these newborns at 6 months, they found that 4% of the infants were IRON DEFICIENT ANEMIC – but only in the early cord clamping group. The other group had none.
What is the significance of iron deficiency anemia? Well, the two biggest brain-related pathways involved are production of “myelin basic protein”, and “dopamine”. The former is a basic building block that every developing brain needs, and there are a number of well-described issues in brain myelination in autism, and in antibody responses specifically to myelin basic protein. The dopamine pathway you may recognize from its role in treating ADD. The ADD child gets a dopamine “booster”, and it normalizes their behavior. A side effect of the dopamine metabolic abnormality with iron deficiency anemia is urinary noradrenaline – this is also found in autistics. Another interesting finding is that iron supplementation helps autistics. But critically, if there is a significant insult to development at such an early age, there will be a limit to how much “catch-up” you can do. The brain is programmed to develop in sequence, and screwing up one step in the sequence can have enduring consequences.
I mentioned this to a very smart friend of mine (another Duke alumnus) who works in pediatric medicine. He said that malaria should cause autism, because it causes severe anemia. In fact, there is a paper out of Tanzania in which the doctor-authors are wondering why they are seeing infants with severe malaria get autism…perhaps the malaria causes the anemia, which includes iron deficiency, and then autism symptomologies set in.
You cannot supplement an infant in the first six months of life with iron, because the infant cannot absorb iron yet. Studies that have tried to treat early anemia with dietary iron fail miserably when evaluated at six months. There are many unanswered questions left by this line of inquiry. Do ADD and autism have the same cause and different genetic susceptibility? What, exactly, is the iron status of babies at six months who later become autistic (insurance companies only pay for blood work at 9 or 12 months, and this blood work is not suitable for addressing iron status except indirectly). I think enough of this line of thinking that I am organizing a line of my own work to pursue the latter question – if you had a group of autistic kids, and you could go back in time to when they were 6 months old, would they all be iron deficient? Any bets?