L. reuteri, a lactic acid bacterium that naturally resides in the human and animal gastrointestinal tract, is a valuable addition to any diet. However, the modern diet, combined with widespread antibiotic use, has led to a decrease in its prevalence in the human gut. Restoring this beneficial microbe often requires targeted dietary choices or supplementation. The challenge lies in that naturally occurring levels in many fermented foods can be unpredictable or low. The most concentrated and consistent way to acquire it is through specific, cultured foods or supplements.
The Best Dietary Sources of L. reuteri
Unlike more common probiotic strains, L. reuteri is not prevalent in many everyday fermented products like standard store-bought yogurt or sauerkraut. Its presence and potency are highly dependent on the fermentation process and starter cultures used. For this reason, creating specific foods at home or seeking out specialty products are the most effective strategies.
Homemade L. reuteri Yogurt
One of the most potent and concentrated sources is homemade L. reuteri yogurt, as popularized by wellness experts like Dr. William Davis. This is not the same as standard yogurt; it is fermented for a longer duration (often 36 hours) at a specific, lower temperature (97-100°F or 35-38°C) with a specific starter culture. It is also typically enhanced with a prebiotic fiber like inulin to provide a food source for the bacteria, helping them multiply to very high numbers. The result is a thick, tangy dairy product, which can also be made with coconut milk for a dairy-free option.
Specialty Kefir
While traditional kefir contains a broad spectrum of bacteria and yeasts, specific kefir products or homemade versions made with an L. reuteri starter can be a good source. These specialty products undergo a controlled fermentation to ensure the presence of this specific strain, whereas the probiotic content in traditional kefir can vary widely. Always check the label to confirm the inclusion of L. reuteri strains like DSM 17938.
Fermented Vegetables
Certain lacto-fermented vegetables may contain L. reuteri, though the levels are inconsistent and depend on the naturally occurring bacteria present during the fermentation process. Sauerkraut and lacto-fermented cucumbers are potential candidates, but there is no guarantee of specific strains or high counts. Commercial products are even less likely to be a reliable source unless specifically fortified. For homemade versions, using a starter culture from a reliable source is the only way to ensure its presence.
Breast Milk
L. reuteri is naturally present in human breast milk and is transferred from mother to infant, playing a crucial role in establishing a healthy gut microbiome in newborns. For adults, this is not a dietary source but illustrates the natural history of this probiotic in the human body.
Probiotic Supplements
For those who prefer a more direct and reliable dose, supplements are an effective route. L. reuteri supplements are available in various forms, such as capsules and powders, offering a consistent and potent dose. This is often the best option for people who cannot or do not want to consume specially fermented dairy products.
Comparing Sources of L. reuteri
| Source | Reliability | Potency | Accessibility | Ease of Preparation |
|---|---|---|---|---|
| Homemade L. reuteri Yogurt | High (with proper starter) | Very High | Moderate (requires equipment and starter) | Medium (long fermentation time) |
| Specially Fortified Products | High (brand-dependent) | High | Variable (found in specialty stores) | Very Easy |
| Probiotic Supplements | High | High (depending on CFU) | High (widely available) | Very Easy |
| Standard Fermented Foods (e.g., store-bought yogurt) | Low | Low/Non-existent | High | Very Easy |
| Traditional Fermented Vegetables | Low | Low/Variable | Low | Medium |
Boosting Your Gut Microbiome
Beyond just consuming L. reuteri, supporting a diverse and healthy gut microbiome can help existing beneficial bacteria thrive. Incorporating prebiotic foods into your diet is a powerful strategy, as these non-digestible fibers feed the good bacteria in your gut. Examples of prebiotic-rich foods include:
- Garlic
- Onions
- Bananas
- Asparagus
- Chicory root
- Jerusalem artichoke
- Oats
Combining these prebiotic foods with your chosen L. reuteri source can create a powerful symbiotic effect, helping the probiotics colonize and flourish in your gut. Additionally, avoiding the overuse of antibiotics, which can disrupt the gut microbiome, is a critical step in maintaining a healthy internal environment.
Conclusion
While L. reuteri is not commonly found in high concentrations in most store-bought fermented foods, a targeted approach can effectively add it to your diet. The most potent and reliable methods include making homemade L. reuteri yogurt with a specific starter culture, choosing specially fortified products, or taking a high-quality probiotic supplement. Pairing these sources with prebiotic-rich foods will further support a healthy and diverse gut microbiome. For consistent results, relying on homemade yogurt or supplements is superior to relying on standard, unpredictable fermented items. This strategy allows you to take control of your gut health and experience the full benefits of this unique probiotic strain. For more information on the science behind specific strains, consult scientific literature like this review on L. reuteri's role in human health.
