“Probiotic bacteria, specific representatives of bacterial species that are a common part of the human microbiota, are proposed to deliver health benefits to the consumer by modulation of intestinal function through largely unknown molecular mechanisms,” begins a research report by Peter van Baarlen et al., a team of gastroenterologists, nutritionists and genomics researchers in the Netherlands.
This unique study (a rigorous double-blind, placebo-controlled, cross-over trial) adds a great deal to the scientific understanding of those molecular mechanisms. Published in the prestigious Proceedings of the National Academy of Sciences of the USA,* the research involved:
• Feeding a small group of study subjects either a placebo or one of the three best-known probiotic species found in fermented dairy products such as yogurt – Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus rhamnosis. (The doses corresponded roughly with what a consumer would receive in a dairy product or supplement delivering live strains of the specific probiotic.)
• Then actually collecting biopsy samples of the mucosal lining of the small intestine to identify any changes at the molecular/genetic expression level.
• And subjecting the RNA extracted from the biopsy specimens to whole genome expression array analysis.
What they found was a wealth of data on how the intestine “perceived” each probiotic species – how each “induced differential gene-regulatory networks and pathways in the intestinal mucosa.” In fact, the three probiotics influenced the expression of “several hundred up to thousands of genes,” in the gut lining.
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The overall biological implication was that the human mucosa mounts “fast and specific responses on perception of each bacterial strain,” to the same extent in the mucosa of all volunteers. Overall, according to report’s section headings:
1. “Mucosal responses to L. acidophilus involve regulation of immune response, hormonal regulation of tissue growth and development, and ion homeostasis.” [Ion homeostasis is ability of the cell to adjust as needed to maintain a stable internal balance of essential ions.]
2. “Mucosal responses to L casei involve proliferation, Th1-Th2 balance, and hormonal regulation of blood pressure.” [When balanced, Th1 immune cells stimulate effective pathogen fighting and Th2 cells avoid destructive over-reaction.]
3. “Mucosal responses to L. rhamnosus involve wound healing, IFN response, and ion homeostasis.” [IFN (interferon) response is an action of the non-specific immune system which is induced quickly in viral infection before the specific immune system has time to activate.]
The researchers observe that these responses tend to coincide with historically and experimentally observed health benefits of these probiotics, such as studies associating consumption of L. rhamnosus with “prevention or relief of allergic symptoms.”
* To read the full text PDF of this free-access article – “Human mucosal in vivo transcriptome responses to three lactobacilli indicate how probiotics may modulate human cellular pathways,” PNAS Sep 7, 2010, go to http://www.pnas.org/content/early/2010/08/31/1000079107.long
Note: This information has not been evaluated by the FDA. It is general and should not be interpreted as preventing, diagnosing, treating or curing any condition, illness, or disease. It is very important that you make no change in your health care plan or health support regimen without researching and discussing it in collaboration with your professional healthcare team.