Scientists at ZOE looked at what happens when people increase their intake of fermented foods — like yogurt, kimchi, sauerkraut, kefir and miso — by around three servings a day. Early results point to some exciting effects on wellbeing:
Fermented foods are rich in live microbes and the compounds they produce, which can support a healthier, more diverse gut ecosystem. A diverse gut microbiome is linked with better digestion and immune function.
Better digestion and gut microbiome diversity
Participants who boosted their fermented food intake reported feeling less bloated, hungrier less often, and having more energy and better mood — suggesting fermented foods might influence digestive comfort and daily wellbeing.
Why this matters
Fermented foods are more than a trend — they contain probiotics and other beneficial compounds that help nurture gut microbes, which in turn may affect everything from inflammation to appetite signals.
Simple takeaway: Adding a few more fermented foods to your meals each day could be a small change with noticeable effects on digestion and how you feel overall.
Not everyone thrives on fermented foods
Fermented foods are powerful — but they aren’t universally beneficial. Some people can feel worse, not better, when they increase them.
You may need to be cautious if you have:
DAO is the enzyme that clears histamine from food. If your DAO genes are slow or impaired, fermented foods (which are naturally high in histamine)
Can trigger symptoms like:
For these people, more fermented foods = more histamine load.
Histamine-producing gut bacteria
Some gut microbes (like Morganella, Klebsiella and certain Lactobacillus strains) actually make histamine.
If these are overgrown in your microbiome, fermented foods can act like fuel on the fire — worsening inflammation, gut irritation and systemic symptoms.
SIBO (Small Intestinal Bacterial Overgrowth)
In SIBO, probiotics and fermented foods often backfire until the overgrowth is cleared.
Fermented foods can be incredibly healing — when your gut and genes are ready for them.
But if you have histamine intolerance, certain gut bacteria, or SIBO, piling them on can actually push symptoms in the wrong direction.
This is where personalised gut testing and genetics matter — because the same food can be medicine for one person and a trigger for another.
HOW TO ADD FERMENTED FOODS (without overwhelming your gut)
Here are some easy, gut-friendly ways to include them:
Kefir & yoghurt
These provide beneficial microbes plus protein to stabilise blood sugar.
Miso
These provide beneficial microbes plus protein to stabilise blood sugar.
Sauerkraut & fermented vegetables
Aged cheeses
How much is enough?
ZOE’s research suggests that about 2–3 small servings per day is where benefits begin to appear — but that doesn’t mean you need to eat them all at once. Spread them across meals.
A FINAL TIP
Fermented foods work best when paired with prebiotic fibres (vegetables, legumes, oats, seeds).
The microbes from fermented foods need something to feed on — otherwise they don’t stick around.
