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Spotlight on Young Researchers: Understanding how dietary fiber can help us age healthier


Westernised diets lack fiber – on average, a Western diet only covers about 60% of the recommended daily fibre intake. Research is gathering evidence that lack of dietary fibre plays a role in the development of metabolic syndrome, diabetes, neurodegeneration, as well as cancer and cardiovascular diseases. While researchers agree that we should eat more fibre, what happens to it once it is in our bodies can vary from person to person – one size does not fit all. In the quest to find out how humans can age in a healthy, disease-free way, researchers are working to shed light on the exact role dietary fibre could play.

Over the course of the last decades, researchers have been able to gain much knowledge about the mechanistic effects of dietary fibre in different cellular and animal models.

We now understand several steps of the metabolic pathways of fibre (this is a group of components present in fruits and vegetables that is not digested by human enzymes), from ingestion, fermentation by microbiome and absorption of metabolites by human cells. This has clarified how fibre acts in causing satiety, stabilising sugar levels in the blood or modulate adipose tissue formation, and even in directly acting in anti-inflammatory signalling. rnrnOn the other hand, population studies do find a clear correlation between dietary fibre consumption and decreased prevalence of health conditions such as metabolic syndrome, cancer and cardiovascular disease. This has led to evidence-based guidelines on dietary fibre consumption, and signals ways of fighting or preventing diseases through parapharmacological approaches, i.e. nutrition.
Guilherme Ramos Meyers Medical Doctor and PhD candidate at the Luxembourg Institute of Health (LIH).

Concept of “being human” changing

In general, research has been focused on dietary fibre in relation to either microbiome variability or genome variability to describe the impact on health. However, the concept of “being human” is itself changing; we are now seen as a “holobiont” – the emergent property of microbiome-genome interaction. After all, we carry as many bacteria in the gut as we have human cells.

“This brings a level of complexity that may only be disentangled using adapted clinical trials and systems biology approaches, requiring large multidisciplinary teams able to communicate across fields of Life Sciences, as well as discovering platforms and databases capable to integrate the large amount of generated data.”

Studying nutrition in humans is a challenge

rnStudying nutrition in human populations is a challenge: Often, models focus on one particular type of fibre at specific dosages – a hard thing to validate in human trials easily, as they would be lengthy and burdensome for individuals, and could even cause adverse effects. After all, humans follow a complex and mixed diet not easy to control and monitor.rnrnIt also remains unclear which synergies may happen in the human body when it comes to different nutrients and dietary fibres. In addition, many secondary plant components such as polyhenols are also affiliated with the dietary fiber fraction. While much knowledge has developed in this field, the sheer complexity means there is still much work ahead.

A mix of fundamental research, epidemiological data and clinical data

Guilherme Ramos Meyers’s research feeds into this challenge: He is part of a team working to tackle this issue of complexity in life-style patterns by deeply phenotyping individuals, at the holobiont level (metagenomics, genomics and phenomics). His project aims to integrate genomics, metagenomics and phenomics in an individual and epidemiological manner, shedding light on acute dietary response variability between humans, but also on long-term adaptation and disease development.

We are assessing the impact of dietary fibre on inflammatory and oxidative stress biomarkers in a cohort undergoing a short dietary fiber intervention, and we will assess health trajectories in a larger cohort that was followed up over ten years. This will shed light on acute dietary response variability between humans, but also on long-term adaptation and disease development.
Guilherme Ramos Meyers Medical Doctor and PhD candidate at the Luxembourg Institute of Health (LIH).

The project has a fundamentally translational aspect, bridging fundamental research, epidemiological data and clinical data obtained from human intervention trials.

Guilherme Ramos Meyers is a Medical Doctor and PhD candidate in the Prof Torsten Bohn-led NutriHealth Group at the Luxembourg Institute of Health (LIH). His PhD project is part of the PRIDE Doctoral Training Unit (DTU) ‘Integrating immune strategies for Translational Research in Oncology and Neurology’ (i2TRON), coordinated by Rejko Krüger. The i2TRON DTU is jointly run by Luxembourg Institute of Health (LIH); University of Luxembourg; Centre Hospitalier de Luxembourg (CHL), and Laboratoire National de Santé (LNS).


u003ch3u003eOn his research – peer to peeru003c/h3u003ernu003cblockquoteu003eu003cemu003e“For both the cohorts under study, we have data for dietary intakes, blood biomarkers and will have genetic data available. While in the trial, a normal/low-dietary fibre and high-dietary fibre intervention was done in a crossover design, and microbiome data is available, in the observational retrospective cohort we can assess the health trajectories of individuals aged 17-69, with knowledge of their dietary intakes for almost a decade.u003c/emu003ernrnu003cemu003e“The main interest is to identify sources of inter-individual variability related to genetic variation and microbiome. Such variability may be indicative of the phenotypic flexibility in response to diet, and may inform on long-term adaptations to diet, thus allowing for better strategies in Personalized, or Precision, Nutrition; this has the potential to decrease disease burden on the individual and population level through targeted and sustainable approaches that can be implemented globally, such as by developing dietary strategies.”u003c/emu003eu003c/blockquoteu003ernu003ch3u003eWhat drives him as a scientistu003c/h3u003ernu003cblockquoteu003eu003cemu003e“After my medical studies, I initiated a PhD in Bioethics, due to my great interest in preventive medicine and in sustainable healthcare, thus affordable to all, that can be scalable to a global dimension. However, seeing the burden of the COVID-19 pandemic and how chronic non-communicable diseases (NCDs) affected everyday patients, I joined the i2TRON DTU in Luxembourg in 2021, my project focusing on precision nutrition, i.e. nutrigenetics, at the Luxembourg Institute of Health (LIH), Department of Precision Health, and University of Luxembourg, hoping to graduate as a physician-scientist in General Medicine.u003c/emu003ernrnu003cemu003e“I’m driven by the wish to mitigate the burden of NCDs in individual patients through para-pharmacological therapies, such as nutrition, which will not only improve patients’ lives greatly, but will also serve as a bridge for the so-called P4 Medicine (preventive, participatory, predictive, personalized).”u003c/emu003eu003c/blockquoteu003ernu003ch3u003eWhy he loves scienceu003c/h3u003ernu003cblockquoteu003eu003cemu003e“Science is systematically asking questions and looking for the right answers, avoiding all biases. Often, one answer raises ten other questions, which only shows how much more we can still learn. It is both motivating and a challenge, and I love a good challenge!”u003c/emu003eu003c/blockquoteu003ernu003ch3u003eWhere he sees himself in 5 yearsu003c/h3u003ernu003cblockquoteu003eu003cemu003e“I plan to stay in the field of translational medicine for the years to come where, by becoming a General Practitioner in Luxembourg, I can accompany patients in times of crises and windows of preventive opportunity, as well as guide them not just to the best-of-care specialist practitioners, but also to clinical trials and scientific endeavours that may not only profit themselves, but generations to come.”u003c/emu003eu003c/blockquoteu003ernu003ch3u003eOn deciding to conduct his research in Luxembourgu003c/h3u003ernu003cblockquoteu003eu003cemu003e“My father’s family is originally from Luxembourg, so I always had a tie with the Grand-Duchy. When I found that Luxembourg was looking for medical doctors that also wanted to do research, the decision to return to Luxembourg was easy.u003c/emu003ernrnu003cemu003e“In Luxembourg I discovered good working conditions, a will to improve scientific endeavours and a desire to become a gold-standard in research. Furthermore, the i2TRON DTU (Fonds National de la Recherche funded- Doctoral Training Unit Integrating Immune strategies for Translational Research in Oncology and Neurology) has fundamentally a translational aspect, bridging fundamental research, epidemiological data and clinical data. This integrative approach swept me off my feet, as this is exactly what I want to do in the future, to improve health-outcomes in our societies.”u003c/emu003eu003c/blockquoteu003e

About Spotlight on Young Researchers

Spotlight on Young Researchers is an annual FNR campaign where we shine a Spotlight on early-career researchers across the world with a connection to Luxembourg. Over 100 features have been published since the first edition in 2016.

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