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“There’s a strong connection between the gut microbiota and human health. What we eat affects our gut microbes, but the challenge is how to capture these changes in real time,” Senior Researcher Carlos Gomez Gallego says.

“Gut microbes can be analysed from fecal samples, but they are an ‘end product’ that doesn’t really tell us what happens earlier at different parts of our gastrointestinal tract. Animal models, in turn, differ a lot from humans. That’s why the scientific community has started to develop different types of in vitro systems to mimic the human gastrointestinal tract.”

Such in vitro models are also being developed and used at the Institute of Public Health and Clinical Nutrition at the 91����, where Gomez Gallego works. In the lab, food samples, for example, go through different simulated phases of digestion and interaction with the gut microbiota. 

“What we want to see is how a food, ingredient or contaminant alters the numbers of different bacteria and the metabolites they produce in the gut, which can be beneficial or detrimental to health. We typically study the changes for 24 hours, as what we eat on average stays in the colon that long, and we can take samples every hour.” 

“The gut microbes we are using now are a mix from healthy donors’ fecal samples to ensure a variety of bacteria, but they can be collected from any specific population group, such as lactating infants, depending on the focus of the study,” Gomez Gallego notes.

From orange peels to microplastics

In Gomez Gallego’s research, the focus is mostly on plant-based foods and the various bioactive compounds found in plants. “We can also use the gut model to study the potential of novel foods and ingredients. In a recent study in collaboration with the University of Murcia in Spain, we studied the prebiotic effects of fibres and carotenoids obtained from orange peels.”

Orange peels are an abundant food industry by-product in Spain, and they might be a source of ingredients for enriched foods or supplements. Indeed, the study showed that fibres obtained from orange peel increased the beneficial gut bacteria populations Lactobacillus and Bifidobacterium.

“Local companies around Kuopio have also been interested in testing the potential health impacts of their products, and this is something we hope to do more in the future. “

New results can be expected from studies investigating the interactions of gut microbiota with different types of breads, phenolic compounds from berries and plants, as well as environmental microplastics, among other things.

“With Professor Hani El-Nezamy, we are investigating a phenolic compound called Schisandrin B isolated from Schisandra chinensis, also known as the magnolia or five-flavour berry. It has shown anticarcinogenic properties against colon cancer, and we want to find out more about its gut metabolites that may be mediating this effect.”

Polyamines from mother’s milk

In his earlier research at the Universities of Murcia and Turku, Gomez Gallego has also studied the polyamines and bioactive peptides in breast milk and infant formulas. “I hope to be able to continue and expand that line of research in the future, and we are already developing more accurate polyamine analytics.” 

“Those earlier studies showed that these compounds influence the development of gut microbiota and the immune system. However, some formulas contained very little polyamines, compared to normal levels found in breast milk. Maybe for genetic or dietary reasons, some mothers also produced breast milk with very low levels of polyamines.”

Polyamines are essential for tissue growth and regeneration. “Our cells produce them, but dietary polyamines are important to cover the increased requirements in infancy, old age and situations like recovery from injuries.”

“Some gut microbes like lactobacilli and bifidobacteria also produce polyamines, so that’s another reason to enhance their presence in the gut.”