What are Probiotics?

There are many bacteria present in your body. In fact, there are more bacteria in your body than there are cells. Most of these bacteria reside in your gut, with the majority of them being quite harmless. 

Having these healthy bacteria in your gut is known to have many health benefits,  including improved digestion, enhanced immune function, healthier skin, and a decreased risk of many diseases.[1, 2]

Probiotics are also a type of friendly bacteria, which provide many health benefits when consumed. Probiotics are generally consumed as supplements, and they work by colonizing your gut with healthy microorganisms.

Probiotics definition can vary, depending on which source you check, but on an overall basis, they can be defined as living microorganisms that, when consumed, have many health benefits for your body.[3] 

Probiotics are primarily bacteria, but certain types of yeasts are also known to function as probiotics. 

Where do you get Probiotics from?

You can either get probiotics from foods that are prepared by bacterial fermentation, or, more commonly, from supplements. 

Foods that are considered to be probiotics include:

- Kefir

- Yogurt

- Sauerkraut

- Tempeh

- Kimchi

The good bacteria that are present in your digestive tract helps protect you from fungi and harmful bacteria. These bacteria also send signals to your immune system to keep inflammation in check.[4,5]

Furthermore, some of the bacteria in y our gut are also responsible for forming vitamin K and other short-chain fatty acids. Short-chain fatty acids are the primary source of nutrients for the cells that line your colon. They help promote a healthy gut barrier to keel out any harmful substances, bacteria, and even viruses. This also lowers inflammation in the body, helping reduce the risk of cancer.[6]

Overall, your gut bacteria helps with a wide variety of biological tasks, and they also provide essential nutrition to the cells that line your gastrointestinal tract.

How do Probiotics Work?

Researchers and medical experts are still trying to figure out the exact manner in which probiotics work. Some of the ways in which they keep up your good health include better immunity, healthy heart, manage digestive issues, allergies and many more benefits.

When you lose the good bacteria in your body, for example, after taking a course of antibiotics, the probiotics will help replace them. Probiotics can help balance your good and bad bacteria and keep the body functioning the way it should. Keep in mind, though, that you should not confuse probiotics with prebiotics, which are dietary fibers that help provide energy to the friendly gut bacteria.[7]

However, many people often confuse probiotics with prebiotic and think that both have a similar function. The fact is that both probiotics and prebiotics are actually quite different from each other and also play different roles in the body. 

Probiotics vs. Prebiotics

Even though they both sound similar, they play vastly different roles when it comes to your health. Both probiotics and prebiotics are essential for your health, even though they play hugely different roles in the body. Let's take a look:

Probiotics: These are the live bacteria that are found in supplements and many foods that provide many health benefits. 

Prebiotics: These substances are derived from certain types of carbohydrates, most fiber. These types of carbs are those that humans are unable to digest. The beneficial bacteria present in the gut eat these carbs or fiber and get energy from them. 

Probiotics and Digestive Health

There have been a wide range of research on the effect of probiotics on digestive health.[8] There is strong evidence that shows that taking probiotic supplements can help cure antibiotic-associated diarrhea.[9] Probiotics also help in irritable bowel syndrome (IBS), which is a common digestive disorder. In IBS patients, probiotics help reduce bloating, gas, diarrhea, constipation, and many other symptoms associated with the disorder.[1]0 Further studies were done by the University of Texas Medical School at Houston also found benefits of probiotics against inflammatory bowel diseases such as ulcerative colitis and Crohn's disease.[11] Probiotics can also help fight against infections caused by Helicobacter pylori, which are one of the main drivers of stomach cancer and ulcers.[12]

Probiotics and Weight Loss

People who are obese have a different makeup of their gut bacteria as compared to people who are lean.13  Studies done on animals have indicated that fecal transplants from lean animals can make obese animals lose weight.14  The Milk Science Research Institute in Japan undertook a study in which 210 participants with central obesity took the probiotic Lactobacillus gasseri daily. There was an 8.5% loss of belly fat over a period of 12 weeks.15 Although more research is still required, it has been found that many probiotic strains help in weight loss.

Other health benefits of probiotics

There are many other health benefits of probiotics. These include:

Inflammation: Probiotics help lower systemic inflammation in the body, which is a major cause of many diseases.[16]

Blood cholesterol levels: Many probiotics help lower total and bad cholesterol (LDL) levels.[17]

Blood pressure: Probiotics also help bring about moderate reductions in blood pressure.[18]

Boosts immune function: Many strains of probiotics help in boosting the functioning of the immune system. This leads to a reduced risk of infections, including a lower risk for catching the common cold as well.[19]

Anxiety and Depression: The probiotic strains of Bifidobacterium longum and Lactobacillus helveticus have been found to decrease the symptoms of depression and anxiety in people who have clinical depression.[20]


Probiotics are known to have many health benefits, including improving your heart health, boosting immune function, reducing the symptoms of depression and anxiety, and of course, helping in digestion.  However, this is only a small part of the many health benefits probiotics have. Ongoing studies have indicated that there is still a wide range of health benefits that are yet to be discovered.  Maintaining a healthy gut is an integral part of your overall health. However, taking a probiotic should be accompanied by a healthy diet and regular exercise. Only then will you be able to witness any significant benefits in your health.  


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5. Kawamoto, S., Maruya, M., Kato, L. M., Suda, W., Atarashi, K., Doi, Y., ... & Hattori, M. (2014). Foxp3+ T cells regulate immunoglobulin a selection and facilitate diversification of bacterial species responsible for immune homeostasis. Immunity, 41(1), 152-165.

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8. Ritchie, M. L., & Romanuk, T. N. (2012). A meta-analysis of probiotic efficacy for gastrointestinal diseases. PloS one, 7(4), e34938.

9. Hempel, S., Newberry, S. J., Maher, A. R., Wang, Z., Miles, J. N., Shanman, R., ... & Shekelle, P. G. (2012). Probiotics for the prevention and treatment of antibiotic-associated diarrhea: a systematic review and meta-analysis. Jama, 307(18), 1959-1969.

10. Moayyedi, P., Ford, A. C., Talley, N. J., Cremonini, F., Foxx-Orenstein, A. E., Brandt, L. J., & Quigley, E. M. (2010). The efficacy of probiotics in the treatment of irritable bowel syndrome: a systematic review. Gut, 59(3), 325-332.

11. Ghouri, Y. A., Richards, D. M., Rahimi, E. F., Krill, J. T., Jelinek, K. A., & DuPont, A. W. (2014). Systematic review of randomized controlled trials of probiotics, prebiotics, and synbiotics in inflammatory bowel disease. Clinical and experimental gastroenterology, 7, 473.

12. Ruggiero, P. (2014). Use of probiotics in the fight against Helicobacter pylori. World journal of gastrointestinal pathophysiology, 5(4), 384.

13. Ley, R. E., Turnbaugh, P. J., Klein, S., & Gordon, J. I. (2006). Microbial ecology: human gut microbes associated with obesity. nature, 444(7122), 1022.

14. Million, M., Lagier, J. C., Yahav, D., & Paul, M. (2013). Gut bacterial microbiota and obesity. Clinical Microbiology and Infection, 19(4), 305-313.

15. Kadooka, Y., Sato, M., Ogawa, A., Miyoshi, M., Uenishi, H., Ogawa, H., ... & Tsuchida, T. (2013). Effect of Lactobacillus gasseri SBT2055 in fermented milk on abdominal adiposity in adults in a randomised controlled trial. British Journal of Nutrition, 110(9), 1696-1703.

16. Lescheid, D. W. (2014). Probiotics as regulators of inflammation: A review. Functional foods in health and disease, 4(7), 299-311.

17. DiRienzo, D. B. (2014). Effect of probiotics on biomarkers of cardiovascular disease: implications for heart-healthy diets. Nutrition reviews, 72(1), 18-29.

18. Khalesi, S., Sun, J., Buys, N., & Jayasinghe, R. (2014). Effect of probiotics on blood pressure: a systematic review and meta-analysis of randomized, controlled trials. Hypertension, 64(4), 897-903.

19. King, S., Glanville, J., Sanders, M. E., Fitzgerald, A., & Varley, D. (2014). Effectiveness of probiotics on the duration of illness in healthy children and adults who develop common acute respiratory infectious conditions: a systematic review and meta-analysis. British Journal of Nutrition, 112(1), 41-54.

20. (2019). Retrieved 30 September 2019, from http://www.tandfonline.com/doi/pdf/10.4161/gmic.2.4.16108

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