April 2024 Issue

Ask the Expert: Microbial Cocktails
By Toby Amidor, MS, RD, CDN, FAND
Today’s Dietitian
Vol. 26 No. 4 P. 6

Q: Some of my clients are taking microbial cocktails in the form of supplements for gastrointestinal (GI) conditions. What are microbial cocktails, and what does the evidence show regarding their efficacy?

A: Microbial cocktails are the latest gut health trend. They include a combination of different strains of probiotics that can be combined with bacteria, yeast, or fungi. The purpose of the microbial combinations is to increase gut microbiota diversity, which may be beneficial for specific populations. Although more research is needed to demonstrate safety and efficacy for use, this article will discuss the research on microbial cocktails, their purpose, and specific cases in which they’ve demonstrated efficacy.

What Are These Cocktails?
According to Kate Scarlata, MPH, RDN, (www.katescarlata.com), a GI expert dietitian and coauthor of Mind Your Gut, “The term microbial cocktail is used to identify a blend of multiple microbes in certain ratios that have been shown to carry out a specific function.” The scientific literature has found that some microbial cocktails or probiotic blends may offer health benefits for specific GI conditions such as ulcerative colitis.1,2 In addition, some benefits have been shown to help reduce incidence of Clostridium difficile infections (CDIs) often from antibiotic use,3 and there’s research that supports the use of specific microbial blends in athletes.4-6

The Research: GI Health
While the benefits of microbial cocktails will depend on the specific condition or symptom, there’s evidence for certain cases. With ulcerative colitis, for instance, Scarlata explains that Visbiome, or VSL#3, has been shown to help maintain remission when used in combination with standard treatments. A meta-analysis examined the efficacy of VSL#3 probiotic mixture in the treatment of mild to moderately active ulcerative colitis.1 Researchers found that a greater than 50% decrease in the Ulcerative Colitis Disease Activity Index, which was used to define response and remission, was achieved in 44.6% of the VSL#3-treated subjects compared with 25.1% of the subjects given a placebo. Researchers concluded that when VSL#3 is added to conventional therapy at a daily dose of 3.6 X 10 CFUs (colony-forming units) per day, it’s safe and more effective compared with conventional therapy alone in achieving higher response and remission rates in mild to moderately active ulcerative colitis.

VSL#3 also has been used to help reduce relapsing pouchitis risk in ulcerative colitis. According to Scarlata, “10% to 20% of patients with ulcerative colitis still undergo colectomy because of refractory inflammation or malignant change of the mucosa. Restorative proctocolectomy with ileal pouch anal anastomosis is now the most common operation for ulcerative colitis.” A study published in Gut evaluated the efficacy of a single daily high dose of VSL#3 in maintaining antibiotic-induced remission for one year in patients with pouchitis.2 Among 36 randomized subjects, remission was maintained for one year in 17 subjects (85%) on VSL#3 compared with one subject (6%) on placebo. Researchers concluded that one daily high dose of VSL#3 is effective in maintaining antibiotic-induced remission for at least one year in patients with recurrent or refractory pouchitis, giving them a higher quality of life.

In addition, randomized controlled trials and facility-level interventions that administered the probiotic cocktail Bio-K+ showed a reduced incidence of CDIs with antibiotic use.3 “This probiotic formulation may have a role in primary prevention of health care-associated CDI when administered to patients who receive antibiotics,” Scarlata says.

The Research: Athletes
Athletes also may be a group that could benefit from the application of specific microbial blends. For example, gut health expert and advanced practice dietitian Renee Korczak, PhD, RDN, CSSD, LD, says that “In particular populations like athletes, supplementation with probiotics may help decrease the incidence of upper respiratory tract infections and nurture the microbiome to help avoid unwanted GI symptoms that come with strenuous endurance training, such as runner’s diarrhea, abdominal pain, and bloating.”4 In a review published in Sports Medicine, researchers analyzed the gut microbiome in athletes in relation to health and performance.5 The review examined multiple studies that showed specific probiotic blends can have a significant protective effect against upper respiratory tract infections.6

Use of Microbial Cocktails
For dietitians wanting to recommend microbial cocktails for a specific diagnosis or symptom, Scarlata suggests looking to the science that supports certain blends or strains of microbes with sufficient evidence to improve the condition the client hopes to manage. Korczak agrees: “Multistrain probiotics with high CFUs certainly may be effective, but the benefits are strain and dose specific.” In addition, it’s important to provide scientific evidence for clients before they start supplementation. RDs can get more information using the Clinical Guide to Probiotic Products Available in USA tool (https://usprobioticguide.com).

Furthermore, probiotic use presents a theoretical risk of developing bacteremia or endocarditis, toxic or metabolic effects in the GI tract, and the transfer of antibiotic resistance in the GI flora.7 Although these side effects aren’t common, RDs should discuss their potential with clients. Scarlata reminds RDs they “should be aware that in certain instances probiotic use may do more harm than good. Before encouraging their use, RDs should be aware of instances where probiotics may be contraindicated such as in severe pancreatitis, where probiotic use is associated with greater death, to avoid patient harm and potential legal ramifications.” Probiotic use isn’t recommended in patients with known adverse risks, such as severe pancreatitis, and those who are immunocompromised.8,9

Recommendations for RDs
Probiotic use for the modulation of the gut microbiome is showing promise; however, Scarlata reminds dietitians “there’s a wide variability of microbes that inhabit an individual’s gut microbiome” and that much remains unknown. “Until we understand fungi, viruses, and have a more informed understanding of the ecology of an individual’s gut microbiome, we can’t know for certain if we’re aiding or deterring a true health benefit.”

As with any supplement, RDs should advise clients to consult a qualified health care provider before starting a new supplement routine and learn about potential drug-nutrient interactions. Scarlata provides the following three tips for dietitians when recommending microbial cocktails:

• Select a probiotic blend that has scientific evidence supporting its health benefits for the symptoms clients hope to improve.

• Choose the proper dosage of the probiotic blend that’s been shown to offer benefits, as more isn’t always better.

• Tell patients that probiotics generally are unregulated in the United States.

— Toby Amidor, MS, RD, CDN, FAND, is founder of Toby Amidor Nutrition (tobyamidornutrition.com) and a Wall Street Journal bestselling author. She’s written 10 cookbooks, including Up Your Veggies: Flexitarian Recipes for the Entire Family and Diabetes Create Your Plate Meal Prep Cookbook: 100 Delicious Plate Method Recipes. She’s also a nutrition expert for FoodNetwork.com and a contributor to U.S. News and other national outlets.

Send your questions to Ask the Expert at TDeditor@gvpub.com or send a tweet to @tobyamidor.

1. Mardini HE, Grigorian AY. Probiotic mix VSL#3 is effective adjunctive therapy for mild to moderately active ulcerative colitis: a meta-analysis. Inflamm Bowel Dis. 2014;20(9):1562-1567.

2. Mimura T, Rizzello F, Helwig U, et al. Once daily high dose probiotic therapy (VSL#3) for maintaining remission in recurrent or refractory pouchitis. Gut. 2004;53(1):108-114.

3. McFarland LV, Ship N, Auclair J, Millette M. Primary prevention of Clostridium difficile infections with a specific probiotic combining Lactobacillus acidophilus, L. casei, and L. rhamnosus strains: assessing the evidence. J Hosp Infect. 2018;99(4):443-452.

4. Mohr AE, Jäger R, Carpenter KC, et al. The athletic gut microbiota. J Int Soc Sports Nutr. 2020;17(1):24.

5. O'Brien MT, O'Sullivan O, Claesson MJ, Cotter PD. The athlete gut microbiome and its relevance to health and performance: a review. Sports Med. 2022;52(Suppl 1):119-128.

6. Tavares-Silva E, Caris AV, Santos SA, Ravacci GR, Thomatieli-Santos RV. Effect of multi-strain probiotic supplementation on URTI symptoms and cytokine production by monocytes after a marathon race: a randomized, double-blind, placebo study. Nutrients. 2021;13(5):1478.

7. Snydman, David R. The safety of probiotics. Infectious Diseases Society of America. 2008;46(2):S104-11

8. Besselink MG, van Santvoort HC, Buskens E, et al. Probiotic prophylaxis in predicted severe acute pancreatitis: a randomised, double-blind, placebo-controlled trial. Lancet. 2008;371(9613):651-659.

9. Kullar R, Goldstein EJC, Johnson S, McFarland LV. Lactobacillus bacteremia and probiotics: a review. Microorganisms. 2023;11(4):896.