As referenced earlier, here is a post on bulgur. I'll also talk a little about steamed buns and boiled wheat generally.
In the USA and western Europe, we eat a lot of wheat (although western Asia surpasses even our high consumption - http://www.fao.org/docrep/006/Y4011E/y4011e04.htm). We eat our wheat primarily in two forms: 1) moderately-wet dough baked at relatively high temperatures over/in dry heat and 2) boiled-then-drained noodles. The first method of preparation lacks long periods of significant amounts of water molecules energetically vibrating in and around and breaking down plant cell walls, which would mean less TMG becomes freed. The second method obviously includes boiling water, but the trimethylglycine (TMG) dissolved into the boiling water (typically around 60-80% of food's TMG content - http://www.sciencedirect.com/science/article/pii/S0308814603000633) is subsequently drained away.
Why do we like our wheat products so dry in the USA? Bread, buns, crackers, cookies, pizza, drained pasta, bran flakes, and so forth are convenient, less messy, and store well. In medieval times, the countries of western Europe used to eat gruel and porridge made of high TMG grains like wheat and rye, however, except for oats, porridge has mostly fallen out of favor in those regions.
Yet in other--usually much poorer--parts of the world, wheat is still prepared in ways that allow for consumption of easily-absorbed TMG. Bulgur wheat is a parboiled-then-dried cracked-wheat product that is prepared at home for consumption by being placed in very hot/boiling water until the water has been absorbed. The water is sometimes drained away afterward, but it is not drained away when bulgur is utilized in pilaf dishes, which are intentionally made so as to absorb all the cooking liquid. The parboiling, or partial cooking, process is often carried out with steam rather than actual boiling. Parboiling retains enough nutrients that bulgur is classified as a whole grain product. Thus bulgur is twice treated with steam/hot water, which helps release TMG from the bulgur's cell walls without carrying it all away, while the nutrients in the water used to prepare bulgur are usually retained and ingested.
Look at which countries and cultures are eating large amounts of bulgur. They're the ones all around the Mediterranean, especially Turkey and the region called "the Levant." These countries also don't seem to have much of a societal burden from autism. Other societal burdens, they have aplenty. But not autism. Remember the low autism prevalence in Israel and how it was lowest of all for rural Israeli Arabs? And over in Turkey, despite evidence that medical and nursing schools there are doing a good job of teaching their students about autism (https://www.ncbi.nlm.nih.gov/pubmed/27524519), Turkey simply is not dealing with the same levels of autism as the US and western Europe (http://www.tpfund.org/2013/03/lets-talk-about-autism-in-turkey/).
Eastern Asia generally eats less wheat than Europe and western Asia, but in Chinese-influenced cuisines, it's normal to eat that wheat in steamed buns, dumplings, and noodle soup. Western-style bread, while becoming more popular, is not normally a staple of eastern Asian diets. (https://chinafoodingredients.wordpress.com/2014/05/19/bread-in-china-from-snack-to-staple-though-for-the-young-urban/) The steaming process seems as it if would help break down cell walls to allow the egress of TMG while not carrying it away as full-on boiling would do. Where dumplings and noodles have been cooked in soup, TMG leaching from them into the soup broth will end up being ingested. China also consumes a lot of stewed spinach and other greens, so I suspect that its traditional cuisines include enough easily absorbed TMG to protect to some degree against autism. Unfortunately, data about autism in China are currently considered inadequate. (https://molecularautism.biomedcentral.com/articles/10.1186/2040-2392-4-7) (I wouldn't be surprised if the Chinese data turn out to be pretty accurate in the end. I've never understood why autism-awareness advocates online insist that the other countries of the world are all misdiagnosing children if they don't find the same rate of autism as the USA. That seems arrogant.)
My takeaway from this? Ingest liquids in which wheat was cooked. To quote an online cooking writer, "when you dump the remaining pasta water down the drain, that's where you make the pasta gods cry." (http://www.cookinglight.com/cooking-101/your-pasta-water-is-liquid-gold)