In his presentation on gut health, ‘Exploring ingredients for the microbiota-gut-brain axis’, independent consultant and researcher at Cardiff University School of Psychology Dr Miguel Toribio-Mateas examined the short history of scientific enquiry in this area. He looked at some of the research challenges, but also noted how the number of studies on this theme has taken off over the past 20 years.
“Before 2001, there were hardly any studies on the gut microbiome,” he pointed out. “Now, across all types of study, you will sometimes have up to 2,000 being published in a week.”
There was a clear explanation for this change. “We’re realising how the gut is central to a lot of the body’s systems and how it’s intertwined with the rest of the body,” Toribio-Mateas said.
“I’m very passionate about functional botanicals,” he stated, referring to one of the five classes of ingredient touched on in his presentation. Regarding mushrooms, he explained that many are “top modulators of gut microbiota, for many reasons, beta-glucans being one of them”.
Examples of other botanical ingredients with a part to play in gut health include ashwagandha. This, too, has been shown to modulate gut microbiota. “The ‘good’ bugs actually grow, while the pathogenic bugs, which can be there in sub-clinical amounts, tend to go down,” he reported.
Toribio-Mateas singled out the “very interesting carotenoid” astaxanthin to demonstrate the effectiveness of marine botanical compounds in gut health. “It will feed your gut bacteria. It’s got an affinity with Bifidobacteria, and with some Lactobacteria, as well,” he said. “It will do something very interesting in the brain, once it has been predigested by those microbes.” This ‘interesting’ mechanism can involve stress reduction, he added.
Finally, on the botanicals side, rhodiola is well recognised as a source of energy, but additionally promotes the growth of Bifidobacteria, he said. The challenge is to separate out the effects of the botanical from those of the microbiota. Or, as he put it: “How can nootropic ingredients such as these be interpreted through the lens of microbiota?”
PUFAs modulate gut microbiota
Another set of ingredients not typically positioned in the front line of gut-brain functionality are omega-3 polyunsaturated fatty acids (PUFAs). While the cardiovascular benefits have been known about for some time, said Toribio-Mateas, very few studies have been carried out on their benefits in relation to the gut-brain axis.
“PUFAs do modulate gut microbiota, and they do work on the brain directly,” he confirmed to his audience. “They have an anti-inflammatory effect on the gut lining,” he said, adding that these omega-3 products, whatever the source, are known to feed certain bacteria that tend to be butyrate producers.
Synergistic synbiotics ‘are the future’ - but are harder to achieve
Studies examining the impacts of pre- and probiotics tend to be relatively small in scale and short in duration, he explained. “They can be difficult and expensive to run,” he said. “So there’s a distinct lack of longitudinal data in probiotics.”
Toribio-Mateas worked with Prof Andy Smith of Cardiff University on a pilot study due to be published in early December. The small six-week investigation involved 16 participants and was food-based, assessing the mental benefits of goat’s milk kefir combined with 18 different types of fibre as a synbiotic.
As he noted, the most common type of synbiotic is the ‘complementary’ variety, where the micro-organisms that benefit from the probiotic component are not necessarily those included in the product. The alternative is to design a synbiotic where there is a direct synergy between the probiotic and the prebiotic it contains. “Synergistic synbiotics are more the future, I think, but they are harder to achieve,” he said.
The presentation ranged widely across different prebiotics, as well as probiotics “the names of which keep coming up”. These included Lactobacillus, Bifidobacterium and butyrate producers such as Faecalibacterium and Roseburia. “The effects are strain-specific,” he emphasised. “This is really important. It is all about the metabolites produced by these particular strains.”