I understand the concern about thiamine causing refeeding syndrome, but despite a lot of discussion about it possibly causing potassium deficiency I haven't seen a single primary source that confirms that. That might be because i'm not parsing things too well with my brain fog, so correct me if Im wrong.
I just saw this thread today. Thiamine actually induced a phosphorous deficiency for me, not potassium. Methylfolate induced a potassium deficiency for me, although interestingly it was after the methylfolate-induced potassium deficiency that I realized the severe fatigue was very familiar - I'd had it before I started taking the methylfolate, only I never knew what it was. Persons with ME/CFS often have low intracellular potassium despite normal blood work. (
https://forums.phoenixrising.me/thr...ded-in-methylation-treatmt.18670/#post-291422)
I've been taking supplemental potassium daily since 2010 and no longer experience symptoms of low potassium, or if I do, they're very mild (foot twitches or cramps) and easily corrected.
Re thiamine - I started taking thiamine a few years ago after reading how it had helped some people a lot with energy. I took 100 mg. and the next day I felt great - the energy was fabulous - and then the next severe fatigue hit. This had happened an earlier time several years ago when I tried thiamine, boom and bust, so I had to stop it the first time out, but this time I tried to sort it out. It felt different than low potassium - no muscle twitches and also potassium did nothing for this particular severe fatigue.
I had read that hypophosphatemia was the hallmark of refeeding syndrome, and I wondered if perhaps I was experiencing low phosphorous. The symptoms of low phosphorous include severe fatigue. So I read about food sources, dairy is a major source of phosphorous, I drank several glasses of kefir and within several hours the horrible fatigue started to dissipate. I eventually bought a monosodium phosphate supplement as I don't do well with a lot of dairy, and I've been able to keep taking the thiamine and have even increased it. Probably 3 times a week I take extra phosphate - it's in small doses. It's not like potassium where I could drink a couple of glasses of low-sodium V8 and get of potassium. I'm a lot more careful with the phosphorous.
Here's an article on refeeding syndrome which made me think of hypophosphatemia:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2440847/
Refeeding syndrome can be defined as the potentially fatal shifts in fluids and electrolytes that may occur in malnourished patients receiving artificial refeeding (whether enterally or parenterally
5). These shifts result from hormonal and metabolic changes and may cause serious clinical complications. The hallmark biochemical feature of refeeding syndrome is hypophosphataemia. However, the syndrome is complex and may also feature abnormal sodium and fluid balance; changes in glucose, protein, and fat metabolism; thiamine deficiency; hypokalaemia; and hypomagnesaemia
