Bugs and buttermilk: Epidemiological and molecular health

11 January 2017 – Clarity about the impact of dietary fibres, buttermilk consumption, smoking and over hundred other dietary and lifestyle factors on microbiota composition and gut complaints, is what PhD researcher Dr Ettje Tigchelaar, has delivered. She defended her thesis on 14 December at the University of Groningen. Her work – which includes the most extensive study on microbiota composition ever attempted – provides validated biomarkers for the diagnosis of gut complaints.

In the Netherlands, one in ten people suffer from gut complaints (functional gastrointestinal disorders), which can have a high negative impact on their daily activities. “Currently, diagnosis and treatment are not straightforward, and often impeded by the multiple factors that play a role in gut health”, explains Tigchelaar. “It is therefore important to improve our knowledge in this field.”

The PhD fellow – who combined epidemiological approaches with modern metagenomics techniques – investigated data from 1,100 volunteers and identified 126 factors, which affect microbiota composition. “These factors ranged from food products including buttermilk, fruits and vegetables to smoking and stool consistency”, she says. “Although we did not have data on actual fibre intake, we could see an association between high-fibre products and the diversity of the microbiota, whereas the opposite was the case for high-fat products.” 

Tigchelaar also investigated the association between food intake and gut complaints, such as constipation and abdominal pain: “I have found, for example, a lower intake of fibre and a higher intake of meat in people with gut complaints.”

Combining biomarkers
In her thesis, the epidemiologist presents a biomarker panel that can be used in the diagnosis of gut complaints (for general practitioners) and in the selection of candidates for nutrition trials (for the food industry). “We identified a combination of eight components originating from blood or faeces, including short-chain fatty acids, chromogranine-A and cytokines”, Tigchelaar illustrates. The biomarker panel has a high – though not 100% – predictive value. “Using an additional questionnaire, about gut complaints, is necessary to confirm findings”, she stresses.

According to the PhD fellow the close collaboration between TiFN scientists is vital to the top-quality research conducted there. “In the Validation of Biomarkers Project, of which my project was a part, we were working with novel research techniques that took time to learn and understand, and we had to manage huge datasets”, she says. “Every team member came in with his expertise at the right moment, so that together we made major steps in the analysis of our data.”