What Foods Contain Lactobacillus Reuteri?

Updated July 2026

Lactobacillus reuteri (often shortened to L. reuteri) is one of the most talked-about probiotic bacteria in gut health circles right now, thanks to a wave of interest in "reuteri yoghurt" recipes and home fermentation. But which everyday foods actually contain it, how much can you realistically get from your diet, and does it matter which strain you're getting? This guide pulls together the latest research and the questions people are asking most, so you can make sense of it all in one place.

What is Lactobacillus reuteri?

L. reuteri is a species of lactic acid bacteria that occurs naturally in the human gut, mouth and, in nursing mothers, breast milk. It's also found in the gut of many other mammals and birds. Unlike some probiotic species that only live in the gut temporarily, certain L. reuteri strains are able to colonise and persist there for longer periods, which is part of why it's attracted so much scientific attention.

One important thing to understand before we get into the food list: "L. reuteri" isn't a single, uniform organism. Researchers have identified and studied dozens of distinct strains, each with its own reference code (DSM 17938, ATCC PTA 6475, RC-14, and so on), and the research findings on one strain don't automatically apply to the others. We'll come back to why that matters.

Quick answer: which foods contain Lactobacillus reuteri?

If you're short on time, here's the shortlist. Foods that may naturally contain L. reuteri, or that are traditionally fermented in a way that can support its growth, include:

• Bio or "live" yoghurt (not all yoghurt, see below)
• Kefir
• Sourdough bread
• Traditionally fermented vegetables, such as sauerkraut, kimchi and fermented cucumbers
• Some traditional, unpasteurised or raw-milk cheeses
• Miso
• Tempeh

Keep in mind that naturally occurring levels of L. reuteri in food vary enormously and aren't standardised or tested, which is a key difference from a supplement with a stated live culture count. More on that below.

Does yoghurt contain Lactobacillus reuteri?

This is one of the questions we get asked most, so it's worth answering properly. Standard, mass-market yoghurt is made using a starter culture of Lactobacillus bulgaricus and Streptococcus thermophilus. These are the two strains that are legally required for a product to be called "yoghurt" in the UK and EU, and on their own they don't include L. reuteri.

Some "bio" or "live" yoghurts add extra probiotic cultures on top of the standard starter, and depending on the brand, these can include L. reuteri or related Lactobacillus species. The only way to know for certain is to check the ingredients label for the named strain.

Greek yoghurt follows the same rule: being labelled "Greek style" or "Greek yoghurt" refers to the straining process that makes it thicker, not the bacterial content, so most Greek yoghurt on UK supermarket shelves does not contain L. reuteri unless it's specifically added and stated on the pack.

This is also why a trend has grown up around making "reuteri yoghurt" at home, using milk fermented with opened L. reuteri probiotic capsules as a starter, rather than relying on a shop-bought product.

The full list of foods that may contain Lactobacillus reuteri

Bio and live yoghurt

As above, look for yoghurts that specifically list "Lactobacillus reuteri" among the live cultures on the ingredients panel, rather than assuming any yoghurt will do.

Kefir

Kefir is a fermented milk drink made using a "kefir grain," a symbiotic culture of multiple bacteria and yeasts. Because it typically contains a broader and more diverse range of live cultures than yoghurt, some kefir products do include L. reuteri, though this again depends on the specific culture blend used by the manufacturer.

Sourdough bread

Traditional sourdough is leavened using a long-fermented starter of wild yeast and lactic acid bacteria, and Lactobacillus species, including some reuteri strains, have been identified in sourdough starters. It's worth noting that baking heat will kill live bacteria, so any probiotic content in the raw starter isn't necessarily present in the finished, baked loaf.

Fermented vegetables: sauerkraut, kimchi and fermented cucumbers

Traditionally lacto-fermented vegetables rely on naturally occurring lactic acid bacteria to preserve and flavour the food. Raw, unpasteurised versions (kept in the chiller section rather than shelf-stable, vinegar-pickled versions) are more likely to retain live cultures, potentially including L. reuteri.

Traditional and raw-milk cheeses

Certain aged and raw-milk cheeses, including some Cheddar and Parmigiano Reggiano-style cheeses, have been found to harbour non-starter lactic acid bacteria, a group that can include L. reuteri, in addition to their primary starter cultures.

Miso and tempeh

These traditional fermented soy products are long-standing staples in Japanese and Indonesian cuisine respectively. As with other fermented foods, the specific bacterial makeup depends on the fermentation method and starter culture used, and can include various Lactobacillus species.

Breast milk

L. reuteri has been identified in human breast milk, which is thought to be one of the ways breastfed infants are naturally exposed to the strain early in life. This is a feeding and infant health topic rather than a "food" in the everyday sense, and any questions about infant probiotics are best directed to a GP, midwife or health visitor rather than answered from a food list.

How to make Lactobacillus reuteri yoghurt at home

A popular DIY method has emerged online (sometimes associated with the "Dr Davis" or SIBO yoghurt protocols) for making a concentrated reuteri yoghurt at home. In broad terms, it involves:

1. Dissolving the contents of specific L. reuteri probiotic capsules into milk (dairy or a suitable plant-based alternative, such as coconut milk, for dairy-free versions)
2. Adding a small amount of a prebiotic, such as inulin powder, to help feed the bacteria
3. Fermenting the mixture in a yoghurt maker at a low, controlled temperature (broadly 36 to 41°C) for an extended period, typically 24 to 36 hours, considerably longer than standard yoghurt fermentation

A few honest caveats worth flagging: this is a home fermentation trend rather than a clinically tested or regulated process, the final live bacteria count isn't verified, and food safety practices (clean equipment, fresh ingredients, proper storage) matter. If you have a health condition, are pregnant, are considering this for a baby or young child, or are immunocompromised, check with your GP first.

How to increase Lactobacillus reuteri naturally

Alongside the food sources above, certain "prebiotic" foods, meaning foods rich in fibres that beneficial gut bacteria can feed on, may help support a favourable gut environment more broadly. These include:

• Bananas
• Garlic and onions
• Leeks
• Oats
• Chicory root and Jerusalem artichokes

These prebiotic foods are safe to eat alongside a probiotic supplement or probiotic-rich foods, so there's no need to avoid them if you're already taking a daily probiotic.

Fermented foods vs. supplements: which is more reliable?

This is a fair question, and the honest answer is that they serve different purposes. Fermented and cultured foods are a normal, enjoyable part of a varied diet, but the live bacteria count and exact strain present in any batch of home-made kimchi or a supermarket kefir isn't tested or guaranteed, and can vary considerably from one batch, brand or shop to the next.

A probiotic supplement, by contrast, states a specific strain and a guaranteed number of live cultures (measured in CFU, or colony-forming units) at the time of manufacture, which is why many people use both: fermented foods as part of a generally healthy, varied diet, and a supplement when they want a specified, consistent dose of a named strain.

Wellgard's own probiotic range reflects this approach, with different live culture counts and formulations for different life stages:

• Wellgard Gutstar, formulated for teens and adults
• Wellgard Vitaflora, formulated for women

As with any probiotic supplement, these are intended to contribute live bacterial cultures to the gut microbiome, and it's always worth reading the product label for the specific strains and CFU count rather than relying on the category name "probiotic" alone.

Frequently asked questions

What foods are highest in L. reuteri?
There's no published, standardised ranking of L. reuteri content across foods, because commercial testing for this specific strain isn't routinely carried out or published by food manufacturers. Traditionally fermented, unpasteurised foods (live yoghurt with the strain named on the label, kefir, raw sauerkraut and kimchi) are generally considered more likely sources than heavily processed or pasteurised versions of the same foods.

Does Greek yoghurt contain Lactobacillus reuteri?
Not by default. "Greek yoghurt" describes the straining method, not the bacterial cultures used, so you'd need to check the label of a specific product for L. reuteri to be listed as an added culture.

What's the best form of L. reuteri, food or supplement?
Neither is universally "best," they answer different questions. Food sources contribute to a varied, enjoyable diet but don't offer a guaranteed dose. Supplements offer a stated strain and CFU count, which matters if you're trying to align with a specific area of research.

How can I increase Lactobacillus reuteri naturally?
Eating a varied diet that includes traditionally fermented foods (where the label confirms the strain), alongside fibre-rich prebiotic foods like bananas, garlic, onions and oats, supports a generally healthy gut environment. A supplement is the only way to get a stated, consistent amount of a specific strain.

Are there any side effects of Lactobacillus reuteri?
Some people notice mild, temporary bloating or changes in bowel habits in the first few days of starting a new probiotic or increasing fermented food intake, which typically settles within a short period. If symptoms are severe, persistent, or you have an underlying health condition, speak to a pharmacist or GP.

Can I take Lactobacillus reuteri every day?
Most probiotic supplements, including fermented foods, are intended for regular, ongoing use as part of a normal diet. Always follow the dosage on the specific product label, and check with a healthcare professional if you're pregnant, breastfeeding, immunocompromised, or considering a probiotic for an infant or young child.

A quick note on this article

This guide is intended for general information and does not constitute medical advice or a health claim for any specific food or product. If you have ongoing digestive symptoms, or questions about probiotics for a specific health condition, please speak to your GP, pharmacist or a registered dietitian.

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