Wednesday, 25 May 2011

Pre- and peri-natal vitamins, genes and autism

I remember speaking a few years ago to a specialist doctor in obstetrics. We were discussing pregnancy (as two men might do!) and he made a very interesting point during our conversation. On the topic of the developing foetus and nutrition, he said "oh, they take everything they need from mum, it's mum that suffers". He implied from this statement that the developing foetus is king/queen; and that it derives all its nutrients from mum, irrespective of whether she has enough herself and irrespective of what her needs are. He is of course right; hence the umbilical cord and its very important role in nourishment and the fact that conditions such as iron deficiency / anaemia are so prevalent during pregnancy (associated also with the increased plasma volume accompanying pregnancy I might add). I do also wonder if the association between post-natal depression and low levels of certain fatty acids might also be part of this one-way 'take all I can' relationship.

For this reason, and some quite important evidence on the risk of certain conditions being reduced, nutritional supplementation is generally recommended to pregnant women, particularly during the first trimester. A new study published in the journal of Epidemiology has suggested that a lack of maternal consumption of vitamins pre- and peri-natal might be linked to autism. The author group (again from MIND!) also took a look at our old friend MTHFR and found maternal mutations in this, and in another gene (in children) involved in the metabolism of another friend, homocysteine (COMT) also raised the risk of autism. Cumulatively if vitamin/mineral supplements were not taken and the various mutations were present, the greatest increased risk of autism was observed.

Aside from incorporating both genes and environment, there are some important messages to be taken from this study. First, it needs replication. From what I gather, the question of whether or not supplements were taken pre- and peri-natally were derived from memory for the study rather than medical records. Certainly here in the UK, there are a number of questions asked by Midwives during pregnancy about whether or not supplements (mainly folic acid) are/have been taken. I don't think that this extends to the pre-conception stage; hence a more prospective study is required. Second, I would be intrigued as to whether or not the authors have actually looked at things like current plasma homocysteine levels in mums and their children involved in the study. There is some, quite recent evidence, to suggest that homocysteine levels may be elevated in some cases of autism and can potentially be lowered by simple vitamin supplementation. Finally (finally!), MTHFR (methylenetetrahydrofolate reductase) has some interesting tie-ins to the methionine cycle and some other old friends (including sulphate). There are lots of different compounds to look at in these pathways; all crying out for further study and in particular, the various ratios among the compounds in these pathways. All in all though a nice study, decent numbers, well-defined group and a valuable addition to the MIND repertoire of autism research.