I read an article recently which suggested that mild to moderate forms of TMAU could be managed by dietary restriction of precursors of trimethylamine.
You should therefore look to restrict foods rich in choline which include eggs, liver,kidney,peas,beans,peanuts,soya products and brassicas including rapeseed products such as oil and flour.
You should also avoid eating seafood.
In addition to being a source of trimethylamine precursors brassicas (Brussels sprouts, broccoli, cabbage and cauliflower) contain INDOLES, which may inhibit FMO3 enzyme activity and thus increase urinatory excretion of trimethylamine
You should also take a look at the research undertaken in Japan by visiting the CHAMPEX website. http://www.champex.co.uk
The research suggests that CHAMPEX acts by destroying odoriferous compounds such as (methane, trimethylamine indole and scatol ) directly in the intestines where they begin.
Hope this helps.