Special edition: Prebiotics
The prebiotic pioneer: Prof Glenn Gibson
Professor Glenn Gibson has spent the majority of his professional career at the business end of the digestive tract. He is currently Professor of Food Microbial Sciences at the University of Reading in the UK.
Since the coining of the term ‘prebiotic’ in a paper in 1995, Prof Gibson has continued to lead research in the field. Talking to NutraIngredients-USA, Gibson professed his excitement over the potential of new technologies, and metabonomics in particular, to “provide the answers” to the subjects unanswered questions.
Metabonomics is part of the bigger subject of nutrigenomics, which includes transcriptomics and proteomics: In other words, changes to messenger RNA (transcriptomics) and the corresponding proteins (proteomics) control the transport of certain nutrients and metabolites (metabonomics) in the biochemical pathway.
“I do think going from molecular to metabolic is a sea change.”
“We’re on the verge of understanding the role of this big organ [the gut] on health and disease,” he said. Gut health is no longer just about how regular your bowel movements are, but has reported implications for immunity, brain health, and weight gain.
“I’m not amazed by the potential health benefits of modifying gut microflora because of the sheer numbers of cells involved,” said Prof Gibson. “Bacteria will come to play a major role in health and wellness.”
A long and winding road
Prof Gibson’s PhD was in the field of marine and estuarine sediments at the University of Dundee in Scotland, and he’s quick to note that sediments and the human gut have more in common than you’d think: Both contain bacteria that can produce hydrogen sulfide (H2S) – a noxious gas that smells like rotten eggs.
His interest in H2S-producing bacteria led him to look at how these may promote human conditions such as ulcerative colitis.
Probiotics were the obvious next step in his research, and attempts to change the microbial populations to produce health benefits.
Belgian sugar company Orafti (now Beneo) then came calling with an ingredient called inulin, funding a PhD student under Prof Gibson’s guidance.
Prof Gibson’s interactions with Orafti introduced him to Marcel Roberfroid from the Catholic University of Louvain, who was working as a consultant to the Belgian company.
Working together in a hotel room near Victoria train station in London, Roberfroid and Gibson produced a landmark paper in the Journal of Nutrition and introduction of the concept of ‘prebiotics’ (Vol. 125, pp. 1401-1412).
The same paper also introduced the term ‘synbiotic’, which is a synergistic combination of prebiotic fibers and probiotic bacterial strains.
Leap forward
The early Orafti-sponsored project was time consuming, and involved hours of culturing bacteria in Petri dishes. The advent of molecular biology allowed the research, which had been ‘stagnating’, to leap forward.
“This was a big step,” said Gibson, “and allowed us to do volunteer trials.”
Even as the quantity of data grows and our understanding more complex, moves are being made to simplify the subject: An international team of researchers recently reported in Nature that microflora in our guts may fit into one of three distinct groups, called enterotypes: Bacteroides, Prevotella and Ruminococcus.
Prof Gibson is quick to point out that such a study was based on data from only 22 people and notes that Bifidobacteria were not shown. “What this paper did show was the value of high throughput sequencing,” he said.
Obesity
An interesting development in recent years stems from a study from the lab of Jeffrey Gordon at the University of Washington in St Louis. In articles published in Nature in December 2006 (Vol. 444, pp. 1022-1023, 1027-1031) Dr Gordon and his team 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.
“By playing with the gut microflora, can we drag people from obese to lean?” asks Prof Gibson. “Obesity is related to genetics, the diet, and exercise… and there are gut flora difference. We can do something about gut flora, and this can affect appetite, it can affect the calories extracted from food.”
Prof Gibson is quick to add that the changes to gut microflora produced by prebiotics “only last as long as you take the intervention”. In other words, stop taking the prebiotics and, within about a week, the gut microflora returns to what it was before you started taking it.
This represents an opportunity for the food and nutrition industries – “you can put prebiotics into food people eat anyway”.
The EFSA issue
The science appears impressive, and the potential immense, but mention EFSA and Prof Gibson’s tone changes. The prebiotic pioneer has watched while the European Food Safety Authority (EFSA) released negative opinion after negative opinion for pre- and probiotics.
Commenting on the recent EFSA document, Guidance on the scientific requirements for health claims related to gut and immune function, Prof Gibson suggests there is a lack of understanding from EFSA’s Panel on Dietetic Products, Nutrition and Allergies (NDA), and cites guidance on end-point measures for interventions, one of which is a 1-log decrease in specific gut pathogens.
The 1-log pathogen reduction rule (in order to produce an effect against pathogenic bacteria, the intervention must display a reduction in population of 1-log) is “nonsense”, he says, “because it doesn’t take into account of starting populations.
“If one of my undergraduates made such a statement, they’d fail.
“If you have 10 million Campylobacter, you have food poisoning. If you then reduce this by 1-log to one million you’d still have food poisoning. Where’s the benefit?”
Bifido-bashing
EFSA’s dismissal that a promotion of Bifidobacteria populations does not relate to a health benefit is “rubbish”, said Prof Gibson.
“I could cite hundreds of studies that contradict this.
“The literature is overwhelmingly in favor of probiotics and prebiotics.”
So how does he rationalize EFSA’s decisions? He doesn’t: “I’m very, very puzzled”.
“People who make good prebiotics and do the work in building the science will walk [away from Europe],” he predicts. “They’ll go to Asia and America where the legislation is hard and fair and clear.”
Comments from EFSA suggest that the science is not developed enough to answer all of their questions, but Prof Gibson dismisses suggestions that health claims came too soon for pro- and prebiotics, and he points eastward for evidence: “The Japanese have their act together,” he says, “and they have 100s of foods with FOSHU status, and these include prebiotics and probiotics.”
