High Dose Probiotics: Is More Always Better?

// Danielle Huntsman, MS, CNS, LDN


High Dose Probiotics: is more always better?

With good gut health being at the forefront of medicine, would it be realistic to think of adding even more microorganisms to the gastrointestinal tract? The gastrointestinal tract is home to over 500 different bacterial species, containing over a trillion live organisms.1 These organisms influence not only our gut microbiota, but also other systems in the body.*2,3,4 The endogenous gut microbiota has antimicrobial and immune supporting benefits which support barrier function, IgG production, and aid in the synthesis of minerals and micronutrients*5,6 This highly structured system is ever-evolving and influenced by external factors, beginning with a person’s method of birth, genetic factors, and overall health.7,8 When reaching adolescence, a constantly changing environment, circadian rhythm, food intake, and gut motility can all influence the microbiota.9,10,11,12

As practitioners, one of the cornerstones of our education is that good health starts in the gut.

Defining Probiotics

As practitioners, one of the cornerstones of our education is that good health starts in the gut. Reestablishing gut health and reaching homeostasis in the microbiome can begin with dietary changes and a reduction in various environmental exposures. Until recently, high-dose probiotics were a relatively new term, with average supplement intervention of probiotics ranging from 1 billion to 50 billion. The effect of supplemental probiotics may vary depending on the delivery system, specific strains, and strain count. The use of probiotics with varying CFU counts has been shown to support the gastrointestinal tract as well as the immune system.*13,14 Is it possible that higher quantities may significantly alter environment at a rate that lower CFU count may not?*

It would make sense: the higher the dose, the larger the benefit, right?

A Closer Look at Colony-Forming Units (CFU)

Research has shown that probiotics, both high and low CFU count, influence the host and support in reducing occasional digestive symptoms.*14,15 The results of a double blind, placebo controlled, dose-ranging study showed greater benefits for those taking a higher CFU count capsule when compared to half the dose or placebo.16 With each capsule containing 50 billion CFU of lactobacillus, the group receiving two capsules had a superior reduction in symptoms when compared to the other two groups, highlighting the use of a higher count of 100 billion CFU.

A systematic review and meta-analysis of 14 randomized control trials evaluated the effect of probiotics on transit time. The general analysis of these multiple trials (a total of 1,182 participants) was that probiotics, at a dose ranging from less than 1 billion up to 17.2 billion CFU, improved stool frequency.*

However, study results assessing higher CFU probiotics suggest a different subset of benefits. A randomized controlled trial looked at the use of 450 billion CFU lyophilized bacteria or placebo for gastrointestinal health.18 The results showed no significant improvement in transit measurements or bowel function scores between the placebo and the control group; however, there was improvement in occasional abdominal bloating. Those receiving the daily probiotic did not see any change in other outcomes measured.

Intended Use and Delivery Method

Depending on the overall intent of the application, the length of administration for probiotics can vary. Choosing between either single strain or multi-strain formulas is also a decision which can influence the range of administration and outcomes. When using high-dose probiotics, it is common for them to be used as an adjunct therapy within a protocol. The majority of studies looking at high-dose probiotics range from a few days to 8-10 weeks in length, indicating higher CFU count is used on an acute, short-term basis.19,20 A patient evaluation, including a health history and lab work such as stool analysis, can be useful before starting a probiotic with a higher CFU count.*21

When deciding on the CFU count of probiotics, regardless of application, some of the most important attributes of a probiotic are dependent on the methods used to provide stability and survival within the digestive system. Some probiotic products are designed to endure harsh acidic environments, including gastric acid and bile, so that they may reach the appropriate endpoints.

Danielle Huntsman, MS, CNS, LDN

Danielle Huntsman, MS, CNS, LDN is a certified nutrition specialist and licensed nutritionist. She holds an MS in Nutrition and Integrative Health from Maryland University of Integrative Health and is a graduate of the College of Charleston. Danielle has a special interest in gastrointestinal and endocrine health, supporting clients through an integrative approach with proper diet and nutrition. She actively sees clients remotely and within the Philadelphia area.

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  2. Bravo JA, Forsythe P, Chew MV, et al. Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. Proc Natl Acad Sci U S A. 2011;108(38):16050-5.
  3. Yoo J, Kim S. Probiotics and Prebiotics: Present Status and Future Perspectives on Metabolic Disorders. Nutrients. 2016. 8:173.
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  7. Grönlund MM, Lehtonen OP, Eerola E, Kero P. Fecal microflora in healthy infants born by different methods of delivery: permanent changes in intestinal flora after cesarean delivery. J Pediatr Gastroenterol Nutr. 1999;28(1):19-25.
  8. Kolde R, Franzosa EA, Rahnavard G, et al. Host genetic variation and its microbiome interactions within the Human Microbiome Project. Genome Med. 2018;10(1):6.
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  10. Chierico FD, Vernocchi P, Dallapiccola B, Putignani L. Mediterranean diet and health: Food effects on gut microbiota and disease control. International Journal of Molecular Sciences. 2014;15(7):11678-99
  11. David LA, Maurice CF, Carmody RN, et al. Diet rapidly and reproducibly alters the human gut microbiome. Nature. 2013;505(7484):559-63.
  12. Takeshita E, Matsuura B, Dong M, et al. Molecular characterization and distribution of motilin family receptors in the human gastrointestinal tract. J Gastroenterol. 2006 Mar; 41(3):223-30.
  13. Evrard B, Coudeyras S, Dosgilbert A, et al. Dose-dependent immunomodulation of human dendritic cells by the probiotic Lactobacillus rhamnosus Lcr35. PLoS One. 2011;6(4):e18735.
  14. Kim JH, Vazquez Roque MI, Camilleri M, et al. A randomized controlled trial of a probiotic combination VSL# 3 and placebo in irritable bowel syndrome with bloating. Neurogastroenterol Motil. 2005 Oct;17(5):687-96.
  15. O’Mahony L, McCarthy J, Kelly P, et al. Lactobacillus and bifidobacterium in irritable bowel syndrome: symptom responses and relationship to cytokine profiles. Gastroenterology. 2005 Mar;128(3):541-51.
  16. Gao XW, Mubasher M, Fang CY, et al. Dose-response efficacy of a proprietary probiotic formula of Lactobacillus acidophilus CL1285 and Lactobacillus casei LBC80R for antibiotic-associated diarrhea and Clostridium difficile-associated diarrhea prophylaxis in adult patients. Am J Gastroenterol. 2010 Jul;105(7):1636-41
  17. Dimidi E, Christodoulides S, Franks K, Scott S, Whelan K. The effect of probiotics on functional constipation in adults: a systematic review and meta-analysis of randomized controlled trials. Am J Clin Nutr. 2014 Oct;100(4):1075-84.
  18. Kim HJ, Camillerio M, Mckinzie S, et al. A randomized controlled trial of a probiotic, VSL#3, on gut transit and symptoms in diarrhoea-predominant irritable bowel syndrome. Aliment Pharmacol Ther. 2003 Apr 1;17(7):895-904.
  19. Dubey AP, Rajeshwari K, Chakravarty A, Famularo G. Use of VSL3 in the treatment of rotavirus diarrhea in children: preliminary results. J Clin Gastroenterol. Sep 2008;42 Suppl 3 Pt 1:S126-129.
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†† For homeopathic products: these indications are based solely on traditional homeopathic use. They have not been evaluated by the Food & Drug Administration.
* For dietary supplements: this statement has not been evaluated by the Food & Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

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