Written by Greg Arnold, DC, CSCS. In a small study, probiotics given had beneficial effect on genes regulating hormones, blood pressure, and wound healing. 

Our intestines are the centerpiece of our overall well-being as they are the site of nutrient absorption as well as a significant amount of water absorption (1).  As a result, warding off illness significantly lies in maintaining a healthy balance of intestinal bacteria (called “microbiota”), with “good bacteria” like that found in fermented products like yogurt outnumbering “bad bacteria” that cause disease like E. coli and S. aureus.

Now a new study (2) has found that probiotics help elicit these healthful effects by affecting gene activity in intestinal cells.  In the study, 7 non-smokers with an average age of 24 and no history of digestive problems were given either probiotics or placebo for 2 weeks.  They then stopped supplementation for 2 weeks (“washout” period) and then switched groups for another 2 weeks, totaling 6 weeks for the entire study.

During the probiotics supplementation, the subjects were given a sugar solution first thing in the morning followed by a solution of freeze-dried bacteria every 30 minutes for 6 hours each day.  At the end of the 6-hour period the researchers obtained digestive tissue samples from the subjects via a gastroduodenoscopy, a common surgical procedure (3).  The total daily probiotics supplementation equated to 5.2 × 1010 of L. acidophilus, 3.2 × 1010 of L. casei , and 1.68 × 1010 of L. Rhamnosus.

The researchers found the probiotics to affect activity of “several hundred up to thousands of genes” in the human intestine samples.  Two of the genes most affected by L. acidophilus were IL-1 beta and NFK beta, genes that plays a significant role in immune system function (4, 5).  For L. casei, genes most affected were related to hormone regulation (endothelin-1) and blood pressure (Th1 and Th2).  Finally, L rhamnosus most affected genes associated with wound healing (HBEFG).

For the researchers, “This study elucidates how intestinal mucosa of healthy humans perceives different probiotics and provides avenues for rationally designed tests of clinical applications.”  Although the researchers used probiotic levels of up to 5 billion colony-forming units as used in previous research (6), some recommendations have stated 4-8 billion CFUs of probiotics per day (7) although the CDC has yet to officially publish any dosage recommendations (8).  Although this is a very small study, it provides an explanation for the benefits of probiotics and paves the way for further research.

Source: van Baarlen, Peter, et al. “Human mucosal in vivo transcriptome responses to three lactobacilli indicate how probiotics may modulate human cellular pathways.” Proceedings of the National Academy of Sciences 108.Supplement 1 (2011): 4562-4569.

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Reference:

  1. “Nutrient Absorption” – http://www.siumed.edu/mrc/research/nutrient/gi42sg.html
  2. van Baarlen P. Human mucosal in vivo transcriptome responses to three lactobacilli indicate how probiotics may modulate human cellular pathways. PNAS 2010; doi/10.1073/pnas.1000079107.
  3. Gastroduodenoscopy: a routine examination of 2,800 patients before laparoscopic cholecystectomy.  Surgical Endoscopy 2006 (19(8)):  1103-1108, DOI: 10.1007/s00464-004-2025-6.
  4. Li H.  Cloning and characterization of IL-17B and IL-17C, two new members of the IL-17 cytokine family. Proc Natl Acad Sci USA 2000; 97:773–778.
  5. Matsukura S.  Synthetic double-stranded RNA induces multiple genes related to inflammation through Toll-like receptor 3 depending on NF-kappaB and/or IRF-3 in airway epithelial cells. Clin Exp Allergy 2006; 36:1049– 1062.
  6. Van Niel CW, Feudtner C, Garrison MM, Christakis DA (2002) Lactobacillus therapy for acute infectious diarrhea in children: A meta-analysis. Pediatrics 109:678– 684.
  7. Brudnak, M., The Probiotic Solution: Nature’s Best-Kept Secret for Radiant Health. 1st ed. 2003: Dragon Door Publications.
  8. “Antibiotic Resistance Questions and Answers” – http://www.cdc.gov/getsmart/antibiotic-use/anitbiotic-resistance-faqs.html