The Fundamental Difference Between Prebiotics and Probiotics
Before determining the role of Lactobacillus reuteri, it is crucial to understand the distinct functions of prebiotics and probiotics. While both play vital roles in supporting a healthy gut, they are fundamentally different. Probiotics are the living organisms themselves, while prebiotics are the non-digestible food components that nourish them.
What Is a Probiotic?
According to the World Health Organization (WHO), probiotics are "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". These beneficial bacteria, or sometimes yeasts, are introduced into the body through fermented foods or supplements. Once in the digestive tract, they work to improve the balance of the gut flora, compete with harmful pathogens, and interact with the body's immune system.
What Is a Prebiotic?
Prebiotics are specialized, non-digestible fibers that act as food for the beneficial bacteria already present in the gut. These fibers pass through the upper gastrointestinal tract undigested and are fermented by the microbes in the colon. This fermentation process fuels the growth and activity of good bacteria, such as lactobacilli and bifidobacteria, and produces beneficial compounds like short-chain fatty acids (SCFAs), which are crucial for intestinal health. Common prebiotic sources include:
- Onions and garlic
- Asparagus
- Bananas
- Oats
- Chicory root
Is Lactobacillus reuteri a Prebiotic or Probiotic?
Based on these definitions, the answer is clear: Lactobacillus reuteri is a probiotic. It is a living, beneficial bacterium found naturally in the gastrointestinal tract of humans and animals. When taken in supplements or certain fermented foods, it colonizes the gut and confers a variety of health benefits. Its classification as a probiotic is further supported by the production of antimicrobial compounds like reuterin, which helps it compete against other, more harmful microorganisms. It is also one of the most scientifically studied probiotics, with a strong safety record.
How Lactobacillus reuteri Benefits Health
Lactobacillus reuteri has been studied for its potential benefits across several health areas:
- Digestive Health: It is known to reduce symptoms of infantile colic, decrease the duration of diarrhea in children, and may help manage constipation and symptoms of functional dyspepsia and IBS.
- Immune System Support: Specific strains can modulate the immune system, helping to reduce pro-inflammatory cytokines and promote regulatory T-cell development. This can lead to a strengthened immune response and decreased inflammatory disease risk.
- Oral Health: Research suggests L. reuteri can inhibit harmful oral bacteria, such as Streptococcus mutans, a key contributor to tooth decay.
- Antimicrobial Action: It produces antimicrobial molecules, including reuterin, that help inhibit the growth of pathogenic bacteria, yeasts, and fungi.
- Vaginal Health: Certain strains have been used to support women's intimate health and restore vaginal flora.
- Nutrient Production: Some strains can produce essential vitamins, including B12 and folate.
Sources of Lactobacillus reuteri
Lactobacillus reuteri can be acquired through supplements and specific fermented foods:
- Probiotic Supplements: Look for supplements that guarantee live and active cultures until the expiration date. Common strains include DSM 17938, ATCC PTA 6475, and RC-14.
- Fermented Dairy: Some yogurts and kefirs are fortified with L. reuteri, though labels should be checked to ensure the specific strain is included.
- Fermented Foods: Sourdough bread and certain fermented vegetables may contain lactobacilli, including reuteri.
- Breast Milk: L. reuteri is found naturally in human breast milk and is a key contributor to the infant microbiome.
Prebiotics That Support L. reuteri
While L. reuteri is a probiotic, it relies on prebiotics to thrive. Providing the right type of fuel can significantly enhance its effectiveness within the gut microbiome. Certain dietary fibers act as excellent food sources for L. reuteri, helping it to colonize and proliferate. These include inulin-type fructans, found in chicory root, as well as galacto-oligosaccharides, which are present in legumes and milk. Combining prebiotic-rich foods with a L. reuteri supplement or food source can create a powerful symbiotic effect, a practice known as consuming a synbiotic.
Prebiotic vs. Probiotic: A Comparison Table
| Feature | Probiotics | Prebiotics |
|---|---|---|
| Nature | Live microorganisms (e.g., bacteria, yeast) | Non-digestible dietary fibers |
| Function | Populate and rebalance the gut microbiota directly | Act as food to selectively feed beneficial bacteria already in the gut |
| Found in | Fermented foods like yogurt, kefir, sauerkraut, kimchi, supplements | High-fiber foods like garlic, onions, asparagus, bananas, oats |
| Interaction | Must survive the acidic stomach environment to colonize the gut | Fermented by gut bacteria in the large intestine |
| Synergy | The seeds for a healthy gut flora |
The fertilizer that helps the seeds grow |
Conclusion
In summary, Lactobacillus reuteri is definitively a probiotic, a live microorganism that confers health benefits when consumed. While it is not a prebiotic, it thrives on prebiotic fibers, which act as its food source. For optimal gut health, it is most effective to incorporate both a source of L. reuteri (such as a supplement or fortified food) and a diet rich in prebiotic fibers. This symbiotic approach ensures a robust and balanced microbiome, contributing to better digestion, enhanced immunity, and overall well-being. By understanding this crucial distinction, consumers can make informed choices to best support their digestive health.
Visit the NIH website for more detailed research on Lactobacillus reuteri
