Fermented foods have been riding a wave of wellness buzz, praised for their probiotic potential and gut-loving benefits. But if you’re navigating a low FODMAP diet, you might be wondering: Are these flavour packed foods friend or foe?

First, a Quick Slice of Science

Fermentation is a process where microbes (like bacteria or yeast) break down sugars and starches in food. This can make foods easier to digest and sometimes reduce their FODMAP content.

There is some evidence that fermented foods can be a rich source of beneficial microorganisms (potential probiotics), as well as bioactive peptides, phytochemicals and vitamins.

But not all fermented foods are created equal. Some remain high in FODMAPs, while others become surprisingly gut-friendly.

And Some History

Fermentation has been used for millennia to preserve food. Yoghurt dates back over 4,000 years to Central Asia and the Middle East, where nomadic herders discovered that milk stored in animal skins naturally fermented into a tangy, nourishing food. Kombucha, a fermented tea, originated in northeast China around 220 BCE and later spread to Japan and Russia.

Even Worcestershire sauce, developed in 19th-century England by Lea & Perrins, owes its umami punch to fermented anchovies, echoing the Roman love for garum, a pungent fish sauce prized across the empire. I like to think of think of those ancient Romans as I add a dash of Worcestershire sauce to my Bolognese sauce. These culinary echoes remind us that fermentation isn’t a modern trend, it’s a timeless technique.

There’s a Fermented Food for Everyone

Unsurprisingly fermented foods are found across many cultures, from Sauerkraut in Germany to Kimchi in Korea and can be a great way to express your culture.

Our background experiences often drive our taste preferences for these sour or umami-rich foods, but trying something new may prove a pleasant surprise. Check out the list of fermented foods below and be ready to experiment with a new one each week.

Taken Dead or Alive

Some fermented foods contain live beneficial cultures (probiotics), for example, Lactic acid producing bacteria found in Greek yoghurt or kefir and many soy-based products. These have the strongest evidence for beneficial effects.
For some fermented foods, fermentation is just one step in the production process, and the foods are typically pasteurized or cooked before serving. Worcestershire sauce, Tabasco, soy sauce or vegemite fit into this category.

Heating kills off the microbes, but there is growing evidence (largely from animal studies at this point) that these inactive forms, known as postbiotics, can still play a valuable role beyond building great flavour. They may support immune function, reinforce the gut’s protective lining, and communicate with other microbes residing in the digestive tract.

Where to Start?

✅ Low FODMAP-Friendly Fermented Foods

Here are some options that can be safely enjoyed during the elimination phase of the low FODMAP diet:

Lactose-Free Kefir: Traditional kefir is often high in lactose, but lactose-free versions retain probiotic benefits without the FODMAP load. Table of plenty has a Monash Certified lactose-free option with a generous 250 ml low FODMAP serving size.
Hard Cheeses: Aged cheeses like cheddar, parmesan, and Swiss are naturally low in lactose due to fermentation and aging. A 40g serve of most hard cheese is low in FODMAPs. See our blog on the topic.
Sourdough Wheat Bread: The traditional fermentation process breaks down the oliogos-fructans to make this bread low FODMAP in small serves (1–2 slices).
Tempeh: A fermented soy product that’s low FODMAP in moderate portions (up to 170g) and a great plant-based protein source. Fresh tempeh contains live cultures, but these are killed when cooked. Watch out for any added garlic or onion.
Pickled Vegetables (with care): Homemade or store-bought pickles made without garlic, or high-FODMAP sweeteners can be suitable. Ideally, look for ingredients like cucumber or carrot, or make your own. Try blanching carrots then pickling with some caraway seeds. Surprisingly, there is a low FODMAP serving of pickled onions - 60g for large onions, but only 3g for small onions according to the Monash app. The FODMAP friendly app suggests 43g as a maximum serve, so we’d ere on the side of caution here and opt for just one regular pickled onion.
Miso Paste: White or red miso is low FODMAP in small amounts (1 tbsp or less), perfect for soups or dressings.
Apple Cider Vinegar: 2 tbsp is low in FODMAPs. Apple cider vinegar is home to live cultures (the mother). Traditionally made balsamic vinegar also contains live cultures, but has a smaller low FODMAP serving size – 1 tbsp. Even without live cultures, pasteurised balsamic vinegar and other vinegars can still be a gut-friendly addition to meals due to components like acetic acid and prebiotics including phenols. Check out our blog on the health benefits of balsamic vinegar to find out more.
Soy Sauce: This provides great flavour and 2 tbsp per meal is low in FODMAPS.
Worcestershire Sauce: 2 tablespoons per meal is low FODMAP, but adding just a dash to a stew or sauce is sufficient.
Fish Sauce: Another flavour packed option. And again 2 tbsp is low FODMAP.
Vegemite: Love it or hate it, this Aussie classic has been certified low FODMAP by Monash University for a 1 tsp serve.

⚠️ Fermented Foods to Approach with Caution

Sauerkraut: While fermented, it’s only low FODMAP in very small amounts (1 tablespoon), as cabbage is high in mannitol. To ensure live cultures are present, look for sauerkraut in the refrigerated section of the grocery store.
Kimchi: Often contains garlic and onion, which are high FODMAP. Look for garlic/onion-free versions or make your own. Also check for the label to see if it is ‘naturally fermented’ – these will have live cultures.
Kombucha: Can be high in excess fructose and FODMAPs depending on how it’s brewed. Stick to small serves (around 180ml) and monitor symptoms. I prefer the “pet-nat" versions with gentle fizz and a less vinegary flavour than some commercial brands.
Yogurt: Yoghurt can be a great source of beneficial microbes, but regular yogurt is high in lactose. Choose lactose-free or coconut-based versions with live cultures, but avoid any coconut yoghurts with chicory root or inulin.

💡 Tips for Including Fermented Foods on a Low FODMAP Diet

Start small: Introduce one fermented food at a time and monitor your symptoms.
Read labels: Watch for high-FODMAP ingredients like inulin, honey, garlic, or onion.
Tap into tradition: Many cultures have long-standing fermented recipes or umami-rich ingredients that are naturally low in FODMAPs - like Japanese miso soup or Italian aged cheeses like pecorino and parmesan. Exploring these can be both gut-friendly and a delicious way to explore your own and other food cultures.

References:

Balasubramanian, R., et al. (2024). Fermented foods: Harnessing their potential to modulate the microbiota-gut-brain axis for mental health. Neuroscience and biobehavioral reviews, 158, 105562. PMID: 38278378

Leeuwendaal, N. K., et al. (2022). Fermented Foods, Health and the Gut Microbiome. Nutrients, 14(7), 1527. PMID: 35406140

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