What Are Probiotics?
A Beginner’s Guide to Beneficial Microbes
Introduction
Probiotics have become a popular topic in health conversations, grocery stores, and scientific research. From yogurt labels to supplement aisles, the word “probiotic” is everywhere. I realized that with Probiotics Heal The World, I haven’t discussed the fundamental question, “What are probiotics?”
There are a few definitions, one of which focuses only on the use of probiotics in human and animal health. I always found that funny because the same microbes found in the gut can also be found in soil, many of them residing on or in the plants and foods we consume.
When working with EM for so many years, I would often introduce EM as a probiotic for [fill in the blank]. For example, when speaking with a gardener or farmer, I would say EM is a probiotic for plants or EM is a probiotic for soil. When speaking with a chicken farmer, I would say EM is a probiotic for chickens. For bioremediation or environmental applications, I would say EM is a probiotic for bioremediation. (Listen to one of my podcasts to hear how I talk about it.) But what are probiotics?
This guide will introduce you to the world of beneficial microbes and help you understand how they support health in humans, animals, and the environment.
What Are Probiotics?
Probiotics are live microorganisms that, “when consumed in adequate amounts, provide health benefits to the host—usually a human or animal” (Hill et al., 2014). These microbes are mostly bacteria, but some types of yeast can also act as probiotics. Common probiotic genera include Lactobacillus, Bifidobacterium, and Saccharomyces. Probiotics are naturally found in fermented foods like yogurt, kefir, kimchi, sauerkraut, miso, and some cheeses. They are also available as dietary supplements in capsule form, powder, or drink.
The word “probiotic” comes from the Greek roots pro (meaning "for") and bios (meaning "life"), which fits their role in promoting life and health through maintaining a balanced microbial environment.
How Do Probiotics Work?
Probiotics work mainly by helping to maintain or restore a healthy balance of microorganisms in the gut. This balance, known as the gut microbiota, plays a crucial role in digestion, immune function, and even mood regulation. When the balance of microbes is disturbed—for example, by the use of antibiotics, illness, or a poor diet—probiotics can help restore balance.
Probiotics support health in several ways:
Competing with harmful microbes: Probiotics can prevent harmful bacteria from growing by occupying space and utilizing available nutrients (Gareau, Sherman, & Walker, 2010).
Producing antimicrobial substances: Some probiotic strains produce substances like lactic acid, hydrogen peroxide, and bacteriocins, which inhibit the growth of pathogens.
Enhancing the immune response: Certain probiotics can stimulate the body’s immune system, making it more effective at identifying and attacking invaders (Bron et al., 2011).
Supporting the gut barrier: Probiotics can help strengthen the intestinal lining, preventing unwanted substances from leaking into the bloodstream (Orel & Trop, 2014).
Common Types of Probiotics
Different strains of probiotics serve various purposes. Some of the most widely used include:
Lactobacillus acidophilus: Common in yogurt and supplements, this strain helps break down lactose and supports digestion.
Bifidobacterium bifidum: Often found in the colon, it plays a role in breaking down fiber and producing vitamins.
Saccharomyces boulardii: A probiotic yeast used to prevent or treat diarrhea, especially during antibiotic treatment.
Because each strain has unique properties, it is essential to choose the right one based on your specific health needs.
Health Benefits of Probiotics
Research on probiotics is ongoing, but studies have already shown several benefits:
Digestive Health: Probiotics are often used to manage symptoms of irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and diarrhea (McFarland, 2015).
Immune Function: Regular intake of probiotics may reduce the frequency and duration of common colds and other infections (Hao, Dong, & Wu, 2015).
Mental Health: Some probiotics may have a positive effect on mood and mental well-being by influencing the gut-brain axis (Dinan & Cryan, 2017).
Skin Health: Early research suggests that probiotics may help improve conditions like eczema and acne (Kober & Bowe, 2015).
Oral Health: Probiotics are being explored as a way to reduce bad breath, gum disease, and cavities by balancing the oral microbiota (Allaker & Stephen, 2017).
Safety and Considerations
For most people, probiotics are safe and well-tolerated. However, people with weakened immune systems, serious illnesses, or those who have recently had surgery should consult a healthcare provider before taking probiotic supplements. However, some doctors may prescribe probiotics post-surgery due to their known benefits. (Kotzampassi, 2022) It’s also worth noting that not all probiotic products are equal. The quality, strain type, and dosage can affect their effectiveness.
When choosing a probiotic, look for:
Clear labeling with strain names (e.g., Lactobacillus rhamnosus GG)
Expiration date ensures live cultures are still viable
Colony-forming units (CFUs) indicate the number of live microbes per dose
Diversity: Like everything in life, diversity of microbes will have a more significant impact than only one.
Type: Liquid probiotics are active, whereas dried probiotics take several hours to reanimate (usually 8 to 12 hours), and freeze-dried cultures typically are about 95% or more dead.
Probiotics Beyond the Gut
While probiotics are most commonly associated with digestive health, their use is expanding into agriculture, environmental science, and veterinary care. Farmers are using probiotics to improve animal health and reduce the need for antibiotics. Gardeners and researchers are applying probiotics to soil to promote plant growth and reduce disease (Mazza, Santagati, & Medaglia, 2022). Some research is even showing exposure to health soil is benefiting the gardener! These broader applications show how beneficial microbes can support ecosystems, not just individual bodies.
Conclusion
Probiotics are more than a health trend—they are an essential part of the microbial world that supports life. From aiding digestion to improving immune responses and even helping plants grow, these beneficial microbes have a wide range of uses. As science continues to explore the role of probiotics, their importance in both human and environmental health is becoming clearer.
Understanding probiotics is the first step in making informed decisions about health and wellness. Whether through fermented foods, supplements, or sustainable agriculture, these tiny allies offer considerable potential for a healthier future.
References
Allaker, R. P., & Stephen, A. S. (2017). Use of probiotics and oral health. Current Oral Health Reports, 4(4), 309–318. https://doi.org/10.1007/s40496-017-0159-6
Bron, P. A., van Baarlen, P., & Kleerebezem, M. (2011). Emerging molecular insights into the interaction between probiotics and the host intestinal mucosa. Nature Reviews Microbiology, 10, 66–78. https://doi.org/10.1038/nrmicro2690
Dinan, T. G., & Cryan, J. F. (2017). Gut instincts: microbiota as a key regulator of brain development, ageing and neurodegeneration. The Journal of Physiology, 595(2), 489–503. https://doi.org/10.1113/JP273106
Gareau, M. G., Sherman, P. M., & Walker, W. A. (2010). Probiotics and the gut microbiota in intestinal health and disease. Nature Reviews Gastroenterology & Hepatology, 7(9), 503-514. https://doi.org/10.1038/nrgastro.2010.117
Hao, Q., Dong, B. R., & Wu, T. (2015). Probiotics for preventing acute upper respiratory tract infections. The Cochrane database of systematic reviews, (2), CD006895. https://doi.org/10.1002/14651858.CD006895.pub3
Hill, C., Guarner, F., Reid, G., Gibson, G. R., Merenstein, D. J., Pot, B., ... & Sanders, M. E. (2014). Expert consensus document: The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nature Reviews Gastroenterology & Hepatology, 11(8), 506–514. https://doi.org/10.1038/nrgastro.2014.66
Kotzampassi, K. (2022). Why Give My Surgical Patients Probiotics. Nutrients, 14(20), 4389. https://doi.org/10.3390/nu14204389
Kober, M. M., & Bowe, W. P. (2015). The effect of probiotics on immune regulation, acne, and photoaging. International Journal of Women's Dermatology, 1(2), 85–89. https://doi.org/10.1016/j.ijwd.2015.02.001 https://europepmc.org/article/med/28491964
Mazza, L., Santagati, S., & Medaglia, F. (2022). The application of probiotics in sustainable agriculture: Benefits and challenges. Microbial Biotechnology, 15(5), 1312–1323. https://www.researchgate.net/publication/361607779_Probiotics_for_Sustainable_Agriculture_Prospects_and_Challenges
McFarland, L. V. (2015). From yaks to yogurt: the history, development, and current use of probiotics. Clinical Infectious Diseases, 60(Suppl_2), S85–S90. https://doi.org/10.1093/cid/civ054
Orel, R., & Trop, T. K. (2014). Intestinal microbiota, probiotics, and prebiotics in inflammatory bowel disease. World Journal of Gastroenterology, 20(33), 11505–11524. https://doi.org/10.3748/wjg.v20.i33.11505
Do you use a probiotic? Which one? Do you notice any benefit?