Probiotics, the bacteria thought to help gut health disorders, allergies and even some forms of cancer, contain immune system-stimulating DNA, which makes them just as effective when inactivated as when consumed as live microorganisms in dairy products, say US researchers.

The findings, reported in this month’s Gastroenterology (DOI:10.1053/j.gastro.2003.11.019), offer considerable potential for food makers previously restricted to adding bacteria to fermented foods like yoghurt.

The study, by researchers at the University of California, San Diego School of Medicine and the Shaare Zedek Medical Center in Jerusalem, Israel, also reveals a mechanism that can be used to determine and to select which probiotic bacteria are best for patients with IBD.

The addition of probiotic bacteria has until now been limited to dairy products such as yogurt because it was thought that they needed to be live to have any effect. Adding live bacteria to other foods would result in fermentation, changing the taste, texture and freshness on an hourly basis.

But the new research suggests that the metabolic activity of probiotics is not in fact key to their protective effect.

The researchers used gamma radiation to reduce the metabolic activity of probiotic bacteria to a minimum. Previous studies, using heat to inactivate the bacteria, destroyed the cellular structure and beneficial aspects.

The irradiated probiotics were given to mice with experimentally induced colitis, which is similar to human IBD. The irradiated probiotics effectively improved the colitis symptoms, as did the administration of viable, ‘live’ bacteria to another group of mice with colitis. This indicated that inactivated probiotics were as effective as live probiotics.

The scientists say that the beneficial, anti-inflammatory activities seen with the inactivated probiotics could be the product of the innate immune system, the body’s instant response to invasion by pathogens.

The European probiotics market is forecast to more than triple in value from €34.6 million currently to €118.5 million in 2010, according to recent statistics from Frost & Sullivan. But the market research firm also estimated that its gut health cousin, prebiotics, would be helped by much wider scope in applications, as prebiotic ingredients are easily formulated into a number of different foods, including baked goods and even drinks.

The new research could however open a vast range of new application areas to probiotics too. Gut health is currently driving sales of functional foods in Europe, according to a Datamonitor report, outpacing those foods targeting consumers at risk of heart or bone diseases.

In addition to studying the normal and irradiated probiotics on mice, the researchers also tested a synthetic form of bacterial DNA called immunostimulatory (ISS) oligonucleotide (ODN), a short segment of synthetic DNA with immunostimulatory properties, which mimics bacterial DNA. In a previously published paper in Gastroenterology, ISS-ODN had been found to reduce the harmful effects of experimental colitis in mice, indicating that it worked in a manner similar to probiotics.

Evaluation of the immunostimulatory activities of probiotics may also provide an easy screening system for the selection of probiotic bacteria prior to their clinical use, noted the study’s first author, Daniel Rachmilewitz, from the Shaare Zedek Medical Center.

Benefits of Probiotics

Probiotic bacteria may work by beneficially changing the lipid profile in the intestine, suggests a new study from Finland.

The probiotic Lactobacillus rhamnosus GG (LGG) bacteria was associated with decreased levels of lysophosphatidylcholines (LysoGPCho) and sphingomyelins (SM), according to analyses done using the lipidomics technique to study lipid metabolites in human volunteers.

LysoGPCho are reported to be involved in detrimental processes such as oxidative metabolism, angiogenesis, and carcinogenesis. SM have been connected to inflammatory processes that play a role in hardening of the arteries (atherosclerosis).

The researchers, from the University of Helsinki, Valio Ltd, and VTT Technical Research Centre of Finland, report their findings in the World Journal of Gastroenterology.

“This study is the first to apply lipidomic techniques to analyse the global lipidomic profiles of healthy adults after a probiotic intervention,” wrote lead author Riina Kekkonen.

“Lipidomics may provide powerful tools for identifying new biomarkers behind the clinical effects of probiotic intervention trials and for establishing relationships between molecular profiles and other known data from the same individual.”

The study is a necessary addition to our understanding of how probiotics exert beneficial effects in the gastrointestinal tract.

Study Details

The researchers recruited 26 people (14 women, average age 42, average BMI 24 kg/m2) to take part in the three-week randomised, double-blind, placebo-controlled trial. Subjects were assigned to receive either LGG supplements or placebo.

The lipodomic profiles of the volunteers were measured by analyzing blood samples with ultra performance liquid chromatography in combination with mass spectrometry (UPLC/MS). Kekkonen and co-workers report that 407 lipids were identified, and these corresponded to 13 different classes of lipids.

Overall, the results indicated that the probiotic was associated with decreases in LysoGPCho, SM, and certain types of glycerophosphatidylcholines (GPCho).

On the other hand, the triacylglycerols (TAG) type of lipids were increased in the subjects receiving the probiotic bacteria.

LysoGPCho is reportedly a pro-inflammatory lipid, and the researchers noted that compounds associated with inflammation, notably interleukin-6 (IL-6), were also affected by LGG supplementation.

“LysoGPCho, derived from phosphatidylcholines, are mediators that affect numerous functions in many types of cells, from proliferation and survival to migration and secretion,” explained the researchers.

“They are also involved in oxidative metabolism, angiogenesis, and carcinogenesis. LysoGPCho is a major atherogenic lipid of oxidised LDL, and it has been associated with vascular inflammation, endothelial dysfunction and coronary atherosclerosis,” they added.

In terms of SM decreases, the researchers note that these types of lipids have been linked to inflammatory processes that may cause atherosclerosis and inflammatory bowel disease.

“Therefore, the decrease in SM seen after LGG intervention in the present study may also contribute to the beneficial effects on gut barrier function seen in the previous intervention studies with LGG,” they said.

Peer-review

The journal article included the views of the peer-reviewers. The article was described as “interesting, well written and well presented”.

“However, this is a small study. One good point is the randomized cohort. The study population was healthy individuals and the results may not be applicable to a population with lipid-related disease states.

“There were multiple comparisons and one thus cannot exclude the possibility that some of the significant changes were detected by chance,” states the journal.

Source: World Journal of Gastroenterology
Volume 14, Issue 20 3188-3194
“Effect of probiotic Lactobacillus rhamnosus GG intervention on global serum lipidomics profiles in healthy adults”
Authors: R.A. Kekkonen, M. Sysi-Aho, T. Seppanen-Laakso, I. Julkunen, H. Vapaatalo, M. Oresic, R. Korpela

Probiotic Criteria Crucial for Product Quality

The lack of a legal definition for the term ‘probiotic’ makes it crucial for US manufacturers to meet certain criteria that would ensure the efficacy of their products

The criteria, which are based on FAO/WHO guidelines, are nothing new, but they are not being adhered to by many manufacturers,
“The biggest issue in the US is that there is no legalized definition of a ‘probiotic’.

That means that the term is used on products that don’t meet minimum criteria,”

Criteria – as set out in a 2002 FAO/WHO working group report – include a definition of genus, species and strain, as well as a safety assessment and efficacy in humans.
FAO/WHO guidelines,

Labeling

There are a number of labeling recommendations that should be adhered to in order to provide consumers with adequate information about the efficacy of the probiotic product.  These are again based on the FAO/WHO guidelines.

• Labels should list all microbes, with the genus, species and strain designation.  Significantly, the strain designation should not mislead consumers about the functionality of the strain.
• The number of each microbial component should also be given, although this must reflect the count at the end of the product’s shelf-life, and not at the time of manufacture.
• Proper storage information should be provided.
• Efficacy claims must also be listed, and these must be truthful and not misleading.  They must be based on human studies documenting efficacy of the specific strain in the product, and they must also take into account the impact of the delivery vehicle or additional active ingredients or strains of bacteria.
• Use information must be listed, and this should include recommended consumption level based on levels found efficacious in human studies.  The target consumer should also be listed in the case of probiotic supplements, although in the case of probiotic foods and beverages the target consumer is considered to be the general population.
• A product must carry a contact number to report any adverse effects.

Quality seal

These label recommendations are, in fact, similar to those set out by the International Probiotics Association (IPA), which represents probiotics suppliers and product manufacturers, including Nestle, Danisco, Fonterra, DSM, Chr Hansen, Morinaga and Proctor & Gamble.

The IPA – founded in part to establish probiotic standards – in March this year announced its labeling criteria as part of a scheme that will ultimately allow probiotic products to carry a quality seal.

Probiotics companies can apply to the IPA to have batches of their products analyzed by third party independent agencies and if they meet the IPA criteria, will be eligible to bear the seal.

At the time of announcement, IPA , expected the seal would be available on products in 6-8 months.

Health claims

summarized the different types of claims allowed on probiotic foods and supplements in the US.

These include structure/function claims, qualified health claims or significant scientific agreement claims.

The two latter types of claims, which are the least frequently used on probiotic products,

require approval by the US Food and Drug Administration (FDA).

Structure/function claims, which describe how a product may impact the structure or functioning of the normal human body, are the claims most typically used on probiotic products.

However, because these do not require FDA approval – and because they are not well enforced by the agency – many US probiotic products carry structure/function claims that may be properly worded but that do not have adequate substantiation, said Sanders.

research to substantiate health claims or structure/function claims should be done in healthy subjects.  This is, unfortunately, not often the case, she said, as much of the research conducted worldwide on probiotics is on non-healthy people.

research should not be the primary support you use for structure/function claims as it is conducted on diseased populations,”

Probiotech 2008, which ran today and yesterday in Nantes, France, is in its second year and has established itself as one of the primary events on probiotics in Europe.  It gathers representatives from three industries: food, pharmaceutical, and cosmetics, and focuses on scientific and technological issues impacting pre- and probiotics.

Modifying the population of bacteria in the gut may improve the regulation of glycemic control and reverse the insulin resistance that occurs with obesity, suggests a new study from the Nestlé Research Center.

An enhancement of oral glucose tolerance and insulin sensitivity was observed in obese, diabetic animals following administration of antibiotics to modify the gut microflora, according to results published in the FASEB Journal.

The results, building on earlier reports from researchers at Washington University School of Medicine in St Louis, Missouri, suggest a potential role for food-based approaches to modify gut microflora in obese people.

“Our results strongly support the idea that modulating gut microbiota could be beneficial for improving glycemic control and insulin sensitivity,” said Dr. Chieh Jason Chou from Nestlé Research.

“The next questions for Nestlé Research to answer are: Is there a gut microbiota profile that lowers the risk of obesity and diabetes development?

And can we modulate gut microbiota accordingly, with food-based interventions, to improve metabolic regulation and glucose control?”

Initial breakthrough

A breakthrough paper published in Nature in December 2006 reported that microbial populations in the gut are different between obese and lean people, and that when the obese people lost weight their microflora reverted back to that observed in a lean person, suggesting that obesity may have a microbial component.

At a recent scientific symposium organised by the Beneo Group, Dr. Kieran Touhy from the University of Reading noted that obese animals have significantly lower bifidobacteria levels than their lean counterparts, which suggests potential for prebiotic fibres since the growth of these bacteria is selectively promoted by inulin and fructooligosaccharides.

Dr. Nathalie Delzenne from the Catholic University of Louvain in Belgium and Dr. Robert Welch from the University of Ulster presented results from animal and human studies, respectively, which indicated the potential of prebiotic supplementation to regulated food intake.

The new study, involving scientists from Nestle, the Catholic University of Louvain, and the Institute of Molecular Medicine Rangueil in Toulouse, adds and expands this knowledge base, showing that direct modulation of the gut microflora could directly affect metabolism, as well as influencing the maintenance of whole body glucose equilibrium, independent of food intake or obesity.

Study details

The researchers tested the influence of gut microflora modification in genetically (ob/ob) and diet-induced (DIO) obese mice. The animals were given broad ranging antibiotics (norfloxacin and ampicillin, at a dose of 1g/L) for two weeks.

At the end of the study, a significant improvement in fasting glucose levels and oral glucose tolerance in both ob/ob and DIO mice was observed. Moreover, this was correlated with a reduction in the levels of triglycerides in the liver and an increase in levels of glycogen in the liver.

“Our results support the idea that modulating gut microbiota could be beneficial for improving glycemic control,” wrote the authors.

“However, more work has to be done in order to prove that gut microbiota modulation is a safe and effective therapeutic strategy in treating or managing type 2 diabetes in humans,” they concluded.

Source: FASEB Journal
Published online ahead of print, 7 March 2008, doi:10.1096/fj.07-102723
“Gut microbiota modulation with norfloxacin and ampicillin enhances glucose tolerance in mice”
Authors: M. Membrez, F. Blancher, M. Jaquet, R. Bibiloni, P.D. Cani, R.G. Burcelin, I. Corthesy, K. Mace, C.J. Chou