As I’ve noted elsewhere, thiamine forms part of a suite of supplements that might counteract energy problems in ME/CFS. In any case, thiamine (or thiamin) is vital to energy production and other biological processes.
A lot of people think that coffee or tea is vital to getting enough energy, too. For years I was one of those people, and I looked for the instant tea with the highest tea and caffeine content. Yet I noticed over many hiatuses from tea – but not caffeine – that I actually felt moderately better without it. How could this be?
It turns out that tea, coffee, raw shellfish, raw freshwater fish, and other foods contain “anti-thiamine factors.” Through different mechanisms, these substances stop thiamine from being used, although this effect might differ from person to person.
Personally, I could tell that tea consistently exacerbated my illness, so I now get my caffeine and flavonoids from other foods. If you have ME/CFS or energy problems for some other reason, you might consider making this change, too.