‘Novel’ synbiotic is well tolerated and linked to increases in beneficial gut species

Data from a double-blinded, randomized, placebo-controlled crossover study indicated that the synbiotic supplement was associated with increases in Lactobacillus and Bifidobacterium.

“Increases in lactobacilli and bifidobacteria are generally regarded as beneficial and although the beneficial effects may vary between species they possess traits that are desired, such as production of acids which decreases intestinal pH thereby inhibiting growth of potentially pathogenic bacteria,” wrote the researchers in FEMS Microbiology Ecology.

According the FAO/WHO, probiotics are defined as "live microorganisms which when administered in adequate amounts confer a health benefit on the host". Prebiotics are "non-digestible substances that provide a beneficial physiological effect on the host by selectively stimulating the favorable growth or activity of a limited number of indigenous bacteria". Synbiotics are a combination of the two.

BCFAs

The synbiotic was also associated with increases in branched chain fatty acids (BCFAs) but not short chain fatty acids (SCFAs), said the scientists from the University of Copenhagen (Denmark), DuPont Nutrition and Health (Finland), the Technical University of Copenhagen (Denmark), and the University of Turku (Finland).

“Few studies have investigated the effects of BCFA,” wrote the researchers, “[…] In humans, decreased levels of BCFA have been reported in IBD and IBS patients, indicating that production of BCFA may be linked to host health.”

An earlier in vitro study found that the synbiotic was associated with a decrease in BCFAs, and a massive four-fold increase in SCFAs, results that were not repeated in the human intervention study.

“Generally, this study provides novel insight into how a synbiotics affects the complex human microbiota and highlights the complexity of intervention studies as well as in vitro model studies,” said the researchers.

Study details

Led by Gabriella van Zanten, the researchers recruited 18 healthy volunteers and randomly assigned them to either the synbiotic group giving daily doses of 1 billion colony forming units (CFUs) of NCFM (DuPont) and 5 grams of cellobiose (Matsutani Chemical Industry Co, Japan) or placebo for three weeks. This was followed by a three week ‘washout period’ and then the participants were crossed over to the other intervention.

Results showed that the synbiotic was associated with significant increases in Lactobacillus spp., Bifidobacterium, Collinsella and Eubacterium. Relative numbers of bacteria of the genus Dialister decreased, said the researchers.

“Little is known about the role of Collinsella, Eubacterium and Dialister in the microbiota, however low abundance of these genera have been reported to be associated with irritable bowel syndrome,” wrote van Zanten and her co-authors.

BCFA levels increased after three weeks of synbiotic supplementation, particularly 2-methylbutyrate and isobutyrate, while no effect was observed for SCFAs.

“The present study is the first to test the effects of a synbiotic, consisting of NCFM and cellobiose, in humans,” wrote the researchers. “Overall this novel synbiotic was well tolerated by the volunteers and did not result in unwanted side-effects.”

Source: FEMS Microbiology Ecology

Published online ahead of print, doi: 10.1111/1574-6941.12397

“Synbiotic Lactobacillus acidophilus NCFM and cellobiose does not affect human gut bacterial diversity but increases abundance of lactobacilli, bifidobacteria and branched-chain fatty acids: a randomized, double-blinded cross-over trial”

Authors: G.C. van Zanten, L. Krych, H. Roytio, S. Forssten, et al.