Nutritional Biomarkers

We conduct human intervention studies aimed at finding markers for specific foods, for individual health, or for susceptibility and risk of nutritionally related disease. Food intake biomarkers are important for assessing compliance and could eventually support epidemiological studies by complementing current dietary assessment tools with objective markers of food intake.

We also run projects with whole diets that are typically longer-term dietary intervention studies with risk-related outcomes, and work with data from cross-sectional population-based studies and observational studies with hard disease outcomes.

HotFacets is set to generate insight into the effects of acute alcohol consumption on short-chain fatty acids dynamics, energy metabolism, and biomarkers.

Key research questions

• Study the effects of acute alcohol consumption on resting energy expenditure, thermogenesis, and substrate oxidation.
• Validate biomarkers of alcohol intake.
• Explore the potential low-level alcohol production in the gut.

Scientific context

Despite the negative health consequences of chronic alcohol abuse, moderate alcohol consumption (half to 2 drinks a day) is associated in observational studies with a 20-30% lower risk of CVD and Type-2 Diabetes.

The mechanism(s) of action for its effects on cardiometabolic health and energy homeostasis are poorly understood and possible overshadowed by potential confounding.

Some aspects of alcohol metabolism and biomarker validation could inform a longer, well-designed intervention trial to clarify mechanisms of actions and infer causality between moderate alcohol intake and protective health effects.

Funded by

Semper Anders grant from the Carlsberg Foundation

Period: Sep 2021 – Oct 2022.

Contact

Postdoc Catalina Cuparencu

Professor Lars Ove Dragsted

The DNA adductomics project will give new insights into the causes of DNA damage in colorectal cancer, leading to the development of new preventive and therapeutic approaches.

Colorectal cancer (CRC) develops as a result of multiple genetic damage, including the chemical interaction of toxic molecules with DNA, forming DNA adducts.

These toxic compounds may come from exogenous sources such as environment, diet and gut microbiota or from our endogenous metabolic processes such as inflammation.

Central focus areas

• The first purpose of the project is to identify DNA adducts related to CRC in colon tissues from patients with CRC vs controls, by using a UHPLC-HRMS based untargeted DNA adductomics.
  This will possibly lead to the understanding of the causes of DNA damage and to develop new therapeutical approaches towards CRC.
• The second purpose of the project is to identify DNA adducts in urine, blood or faecal samples from the same patients, to understand whether the systemic levels reflect the local DNA adduct levels.
  This will allow to perform future studies by a less invasive sample collection and therefore to develop new diagnostic and preventive approaches.

DNA adduct database

We built the first comprehensive database for DNA adductomics.

The full development of this database and its integration with MS/MS spectra and informatics tools will allow DNA adductomics to play a major role in systems toxicology, cancer genotoxicity, and cancer prevention.

Currently, the database includes 582 adducts coming from 16 genotoxicant classes and different sources. It contains a systematic collection of DNA adducts, where names, structures and sources have been harmonized and manually curated.

Information on structure, molecular formula, monoisotopic mass, and in silico predicted fragments are provided. Data are presented in publicly available interactive and searchable data tables in the repository (https://gitlab.com/nexsmetabolomics/projects/dna_adductomics_database).

A Comprehensive Database for DNA Adductomics. Giorgia La Barbera, Katrine Dalmo Nommesen, Catalina Cuparencu, Jan Stanstrup and Lars Ove Dragsted  (2022) Frontiers in Chemistry. https://doi.org/10.3389/fchem.2022.908572

Funded by

Marie-Curie Individual Fellowship (Horizon H2020-EU)

Period:  May 2019 – September 2021

Contact

Giorgia La Barbera, glb@nexs.ku.dk

Professor Lars Ove Dragsted

An interactive platform for sharing and analysing data from finalised studies.

DASH-IN (Data Sharing in Nutrition) is an interactive platform for sharing and analysing data from finalised studies.

There is an increased demand on researchers to share and to re-use data, including complex data such as metabolomics. But few systems exist that allow such sharing to take place in an environment that the researchers can trust.

The DASH-IN system was created as a joint effort in the ENPADASI project and will continue being developed as a shared infrastructure under ESFRI.

Funded by

The Danish efforts are supported in part by the Carlsberg Foundation.

Contact

Professor Lars Ove Dragsted

Assistant professor Jan Stanstrup

The Food Biomarkers Alliance is a project supported by the Joint programming initiative, A Healthy Diet for a Healthy Life.

FoodBAll will provide new concepts for biomarker research as well as a large number of new food intake biomarkers, sampling tools and tools for exploring food metabolome data.

Funded by

A Healthy Diet for a Healthy Life (JPI-HDHL).

Contact

Professor Lars Ove Dragsted

COMPLETED PROJECT

Nutritional studies on the effect of a specific diet on physiological changes can be trusted only if the food consumption was done in a compliant manner and can be verified objectively by the scientists. In such a case the data would embody correct and objective information for further analysis and conclusions.

The current dietary assessment instruments such as food frequency questionnaires, dietary records, recalls, etc. have been used for many years but they are flawed by their lack of objectivity.  Development and implementation of objective tools for dietary assessment is therefore important for the nutrition research area. However, this is not an easy task.

This problem has at least two aspects.

• One is compliance, i.e. whether a test person was consuming what was required based on the study design. This is important only in nutritional trials. Volunteers reporting non-compliance are of large importance for the study since it allows handling data in a proper way.
• The second is the ability of the volunteers in a study to report accurately. This is an issue in all trials, observational as well as experimental. Forgetfulness, more or less deliberate skewing of records to make them fit anticipated health ideals, and lack of knowledge about foods are probably the most important factors affecting accuracy of objective assessments.

Both aspects, i.e. compliance and reporting quality, might differ not only among studies, but also between individuals, cultures, gender, types of diet being examined. It might for instance be easier for some to comply with eating snacks than with onions, while others would prefer the onions. Also the health-status of the individuals, different life-style habits, and many other factors play a role. Therefore it is crucial to develop a tool which can accurately assess dietary compliance to ensure correctness of the study data.

The idea of the research project Dietary Biomarkers^* is to develop such a tool based on chemical analysis of biological samples, ideally urine, for the determination of food related biomarkers. Ideally, each consumed food component would leave a traceable unique biomarker of intake. A biomarker of food intake is a substance originating only from the food component in question or specifically produced during its metabolism.

The biomarker should be quantifiable in a biological sample, e.g. blood, urine, faeces etc. A biomarker analysis would then give the straight answer whether the food component was consumed or not. Of course biomarkers have limitations, e.g. fast excretion, stability issues, or inter-individually variable metabolism.

The project aims at selecting a set of biomarkers which would cover most of the commonly consumed food items and setting up an analytical method (liquid chromatography coupled with mass spectrometry, LC-MS) to determine their presence in biological samples collected during  trials. The results of chemical analysis will be then compared with conventional instruments to asses agreement between the two methodologies. Discrepancies are of course expected as none of the tools are faultless.

While the biggest disadvantage from a scientific point of view in case of dietary instruments is the subjective reporting of the information, the major issue with the biomarker approach it is the technological limitations. The method of the choice for the project, LC-MS, requires highly trained personnel and finances to cover high purchase and operation costs. Nevertheless, this approach, still under development, has potential to step up the objectiveness of the nutritional scientific data.

Funded by

^*Dietary Biomarkers is an individual Marie Curie fellowship project conducted by postdoc researcher Rastislav Monošík at the University of Copenhagen and funded by the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska–Curie grant agreement No. 655699.

Contact

Professor Lars Ove Dragsted

COMPLETED PROJECT

Clinical trials are demanding in terms of logistics and sample collection. The most common sample types are spot or 24 hour urine and blood. Collection and management of these samples requires assistance of educated personnel. Collection also requires materials such as sample containers or tubes, needles as well as time-restrained procedures and freezers for storage.

Biomarkers of food intake are often molecules which are quickly excreted so sampling must be frequent to attain a good coverage of the diet over time. However, frequent sample collection and the number of volunteer visits in the clinic can be very demanding and costly. Less tedious and invasive sampling techniques are therefore required to ease the sampling procedure, decrease the burden to volunteers, and to lower the costs. Such novel sampling must have documented storage stability and reliable results.

A promising approach is spotting samples on a carrier, letting it dry, and then storing it at room temperature until analysis. An extraction procedure is required to convert the dried samples back into liquid form. Dried blood spots (DBS) or urine spots (DUS) can be collected, temporarily stored and transferred by the volunteers themselves in a much more convenient manner than any conventionally collected liquid sample. However, dried spotting still has its intrinsic analytical limitations and much investigation is required for it to become an accepted methodology for quantitative analysis.

DUS has an advantage compared to DBS since DBS analyses may suffer from hematocrit influence and cannot be considered as a fully non-invasive approach due to use of lancet. DUS on the other hand may be highly variable in concentration due to variation in urine volume. For quantitatively accurate analysis, fluctuation in urine volumes must be taken into account and results corrected. However, spotted urine samples represent unknown fractions (analytes concentration-wise) of the total daily urine production and correction is therefore not trivial.

Within the research project Dietary Biomarkers^*, we tested the possibility of using cosmetic cotton swab kits produced in-house for collection of DUS instead of spotting them on a filter paper, which has been so far the method of choice in majority of clinical studies. The aim of this research was primarily to understand the potential of using DUS on cosmetic swabs for metabolite profiling and to test the agreement of qualitative and quantitative data obtained by chemical analysis compared with wet 24 hour urine samples.

We evaluated adjustment based on creatinine concentrations in the DUS extract as a method for correction for the unknown volume. Urine swabs were easier to use for subjects than DBS and more straightforward to obtain than DUS on paper cards. DUS provided the possibility of direct extraction while DUS on paper cards usually require punching of discs beforehand. This difference could be particularly important in trials with a high number of collected samples.

It is important to mention that quantitative results for DUS were underestimated for several metabolites compared to regular urine samples. We also examined variance of individual total daily creatinine excretion, which was found to be maximally 16%, indicating that creatinine correction is feasible. Interestingly, DUS samples contained analytes at measurable levels for at least 9 months when stored dried in closed plastic tubes at room temperature.

Our findings suggest that the individual creatinine correction factor could be used in long–term clinical trials for correction of measurements in DUS, provided that muscle mass is unchanged and the level of analytical offset is acceptable for the research purpose. Future work has to be focused on improving the kit design, especially swabs, to provide better extraction efficiency.

Funded by

^*Dietary Biomarkers is an individual Marie Curie fellowship project conducted by postdoc researcher Rastislav Monošík at the University of Copenhagen and funded by the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 655699.

Contact

Professor Lars Ove Dragsted