Probiotics may produce their effects with viable as well as nonviable bacteria, suggesting that metabolic or secreted factors or structural or cellular components may mediate their immunomodulatory activities [Borchers et al. 2009]. Furthermore, several experiments indicate that the ability to induce secretion of various cytokines is mediated by and large by cell wall components [Borchers et al. 2009].

Kefir is a thick and creamy fermented milk product. It tastes tangy like yogurt. Probiotic strains in kefir may help reduce cholesterol, protect against cancer, fight allergies, and improve the digestion of lactose. Kefir is rich in lactic acid bacteria (LAB), friendly bacteria that may help prevent and treat diarrhea, boost immunity, and improve the body's ability to ward off infection. Kefir is rich in Lactococcus lactis, Lactobacillus kefir, Lactococcus cremoris, Lactobacillus casei, Lactobacillus casei, and a few varieties of beneficial yeast. You can learn to make your own kefir using kefir grains as the starter.
Antibiotic-associated diarrhea (AAD) may be prevented by coadministration of probiotics, as suggested by several randomized controlled trials (RCTs). Several comprehensive meta-analyses, recently published, all show that probiotics significantly decreased incidence of AAD (RR 0.39–0.43) [McFarland, 2006; Szajewska and Mrukowicz, 2005; Cremonini et al. 2002; D’Souza et al. 2002]. The effects were similar across all categories and formulations of probiotics and treatment durations. The most commonly used probiotics were S. boulardii, LABs, and several combinations of LABs, given in doses from 107 to 1011, for durations of 5–49 days, generally paralleling the duration of antibiotic therapy. One of the meta-analyses found that S. boulardii, L. rhamnosus, and multiple mixtures of two different probiotics were the most protective against AAD [McFarland, 2006]. Other specific preparations have been studied to a lesser extent and that may be why their efficacy has been found to be less significant. One randomized, double-blind, placebo-controlled trial in individuals over the age of 50 using combination L. casei, L. bulgaricus, and S. thermophilus twice daily during a course of antibiotics and for 1 week after the completion of antibiotic therapy showed reduction in the incidence of AAD [Hickson et al. 2007].
Additionally, some food products may contain probiotics but are also pumped full of sugar and additives, which may actually do more harm than good when it comes to your health. For best results, skip the probiotic products like ice creams, sweeteners, gummies, granola bars and baking mixes and go for healthy whole foods instead, such as kefir, tempeh, sauerkraut and kombucha.
A live formulation of lyophilized Bifidobacterium breve, Bifidobacterium longum, Bifidobacterium infantis, Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus paracasei, Lactobacillus bulgaricus, and Streptococcus thermophilus (VSL#3) has shown effectiveness in the small clinical trials, some of which were not randomized nor double-blinded, that had been done as of 2015; more high-quality clinical trials are needed to determine safety and effectiveness.[102][103]
Jotham Suez, Niv Zmora, Gili Zilberman-Schapira, Uria Mor, Mally Dori-Bachash, Stavros Bashiardes, Maya Zur, Dana Regev-Lehavi, Rotem Ben-Zeev Brik, Sara Federici, Max Horn, Yotam Cohen, Andreas E. Moor, David Zeevi, Tal Korem, Eran Kotler, Alon Harmelin, Shalev Itzkovitz, Nitsan Maharshak, Oren Shibolet, Meirav Pevsner-Fischer, Hagit Shapiro, Itai Sharon, Zamir Halpern, Eran Segal, Eran Elinav. Post-Antibiotic Gut Mucosal Microbiome Reconstitution Is Impaired by Probiotics and Improved by Autologous FMT. Cell, 2018; 174 (6): 1406 DOI: 10.1016/j.cell.2018.08.047
If you want to get to the root causes of what goes on inside your gut, look at what you’re putting at the end of your fork. If you consume a milkshake, hamburger, and French fries, you turn on genes that promote inflammation in your gut and your body. On the other hand, if you eat 2 cups of steamed broccoli, you will turn on anticancer and anti-inflammatory gene pathways. The foods you eat control your state of health, and the gut is the gateway to the rest of the body. Identifying and eliminating foods that rob your body of energy becomes a central focus in my program. Gluten, eggs, dairy, soy, most legumes, corn, and sugar (and, for some of you, nightshades) are inflammatory and make you and your gut sick. When my patients eliminate these problem foods for at least 28 days, they feel better, lose weight, and heal their gut.
While it produces no sensations for you to detect, an entire natural ecosystem is living in your digestive tract. In the average person, 100 trillion microorganisms reside in the healthy bowel with more than 500 different species accounted for in their vast numbers. Some of these bacteria are harmful and can produce symptoms of illness. However, there are healthy good bacteria present to keep them in check. Among these bacteria are Lactobacillus acidophilus and bifidobacterium or bifidus. In some people, levels of the healthy bacteria are below the norm. Low levels can be caused by taking antibiotics, which kill good bacteria. This allows harmful bacteria to reproduce rapidly and cause various symptoms. Probiotic rich foods and dietary supplements may help to re-balance the gut. They add live cultured good bacteria to the stomach. In addition, the healthy bacteria may assist with digestion, strengthen the immune system and help nutrients become absorbed more efficiently.
On my recent trip to Japan, one thing I noticed was the inclusion of pickled vegetables in almost every traditional Japanese meal. Unfortunately, many Americans don’t consume enough of these probiotic-rich foods and drinks. Even when they do, restoring equilibrium oftentimes requires therapeutic doses of these microorganisms, because most everyone has been on several rounds of antimicrobials. That’s where a probiotic supplement comes in.