Combining recent research on autism spectrum disorders with regional diets and epidemiology studies led me to the conclusion that beets are behind the lower rates of autism seen in eastern Europe.
This is a bold claim to make, especially because some seem to think that countries like Russia are just in denial about autism spectrum disorders (ASD) occurrence, so I’ll sketch out how I came to this conclusion:
Prenatal brain changes are correlated with ASD, so I reject the controversial claim that early childhood vaccines might cause ASD. Instead, interference with the major homocysteine-to-methionine pathway appears linked to development of ASD. The major pathway needs cobalamin (B12) and a specific form of folate that is made by the enzyme methylene tetrahydrofolate reductase (MTHFR), polymorphisms of which gene are linked to ASD in countries that don’t have widespread folic acid supplementation. (I favor supplementation with other forms of folate over folic acid for reasons that I set forth in this 2016 letter to the editor.)
There is a minor homocysteine-to-methionine pathway that uses glycine betaine, a substance found in beetroots. Beetroots are very popular in eastern European cuisines. Eastern Europe generally does not seem to have experienced the very large rise in ASD that has been seen in western Europe and the USA during the past couple decades; many think that is because of diagnosis and health care disparities, but a recent survey in Poland–an EU country with strong ties to the United Kingdom and so unlikely to be unaware of ASD–found that the ASD prevalence in Poland is 1/50th that of the USA. I think that by eating more glycine betaine via beets, eastern Europeans support the minor homocysteine-to-methionine pathway enough to diminish the impact of deficiencies in the major homocysteine-to-methionine pathway.
The upshot of it all is that I think beet juice and beet-containing soups are a wise addition to the diet of any expectant mother or young child.