Overview
About Miso paste
Miso paste is fermented soybean, and its deep savoury taste is a clue to its triggers.
The long koji ferment builds free glutamate, which is the umami you taste and the reason miso reads like a natural MSG, and it also raises histamine and tyramine. On top of that the soybean base is high in GOS, a FODMAP, and many misos are cultured on barley so they are not reliably gluten-free. If a bowl of miso soup leaves you flushed, headachey or bloated, the fermentation and the soy are usually behind it.
Sensitivities
How Miso paste scores
Watch for
What trips people up
- High in free glutamate from fermentation, the umami hit that can read like MSG for people who are glutamate sensitive
- High in histamine and tyramine because it is aged for months, so it can drive flushing and headaches
- High in GOS from the soybean, a FODMAP that can cause gas and bloating
- Often made with barley koji, so it is not dependably gluten-free unless labelled
Diet fit
Where it fits
Swap ideas
More alternatives
FAQ
Common questions about Miso paste
Is miso high in histamine?
Yes. Miso is aged for months, and that slow ferment builds both histamine and tyramine, so it sits among the fermented foods people limit on a low-histamine diet. The older and darker the miso, generally the more has accumulated.
Does miso contain gluten?
It can. Miso is often cultured on barley or a barley-and-rice koji, which brings gluten in, and even rice or soybean misos can be processed alongside grains. If you are coeliac or gluten sensitive, only use a miso that is specifically labelled gluten-free.
Why does miso taste like MSG?
Because fermentation frees up glutamate, the same amino acid behind MSG and the source of umami. Miso is graded high in free glutamate, which is why a small spoonful flavours a whole bowl, and why glutamate-sensitive people sometimes react to it.
References
Read the background
Ratings reflect the Triggerbites ingredient database and may vary with portion size and preparation.