Diet and gut microbiota in cardiometabolic health: Studies from the Danish Diet, Cancer and Health – Next Generations Cohort and the sub-cohort MAX
Doktorsavhandling, 2023

Cardiometabolic diseases (CMD) are the leading cause of death globally. Diet is a key preventive factor of CMD and a determinant of gut microbiota. Gut microbiota, diet and their interactions have been associated with CMD. In observational studies, diet is measured by self-reported instruments, that need to be validated before use. Gut bacteria vary over time within an individual, making it challenging to study their relationship with health outcomes. Moreover, different dietary patterns may be associated differently with gut microbiota, but few studies exist.   

The overall aim of this thesis work was to investigate the role of diet, gut microbiota and their interplay in cardiometabolic health. The MAX sub-cohort from the Diet, Cancer and Health – Next generations (DCH-NG) cohort was established to: validate the DCH-NG food frequency questionnaire (FFQ), validate a dietary quality score (DQS) and associate it with CMD risk factors, investigate gut microbiota temporal variability and associate these with dietary patterns and investigate the direct and indirect effects of a healthy Nordic and Mediterranean diet on CMD risk factors, mediated by gut microbiota.     

The FFQ provided satisfactory ranking of individuals according to energy and nutrient intakes. The DQS was useful to rank individuals into groups of having unhealthy, average and healthy dietary habits. Healthy dietary habits were associated with lower levels of several CMD risk factors. Among bacterial genera, 39% had moderate to good reproducibility (ICC>0.5). Gut microbial subgroups (Bacteroides, Prevotella 9 and Ruminococcaceae) were identified and adherence to plant-based dietary patterns differed between subgroups. Healthy Nordic and Mediterranean diets were associated with lower levels of adiposity, but no indirect effect mediated by gut microbiota (Prevotella-to-Bacteroides ratio) was found. However, healthy Nordic and Mediterranean diets were associated with lower levels of lipidemia and hs-CRP, mediated by adiposity.      

In conclusion, the DCH-NG FFQ can be used to rank individuals according to dietary intake in epidemiological studies and the DQS is a good indicator of overall diet quality. Different dietary patterns associated differently with gut microbial subgroups and specific genera. There was an effect of diet on CMD risk factors, though this effect was not mediated by the gut microbiota.

cardiometabolic diseases

reproducibility

nutrients

gut microbiota

food frequency questionnaire

risk factors

24-hour dietary recall

epidemiology

temporal variation

dietary patterns

cohort study

validity

Room 5.S.B.C, Danish Cancer Society, Strandboulevarden 49, Copenhagen 2100, Denmark
Opponent: Associate Professor Emily Sonestedt, University of Lund, Sweden

Författare

Agnetha Rostgaard-Hansen

Chalmers, Life sciences, Livsmedelsvetenskap

Rostgaard-Hansen AL, Lau CJ, Halkjær J, Olsen A, Toft U. An updated validation of the Dietary Quality Score: associations with risk factors for cardiometabolic diseases in a Danish population.

Rostgaard-Hansen AL, Rosthøj S, Brunius C, Olsen SF, Bjerregaard AA, Cade JE, Tjønneland A, Landberg R, Halkjær J. Relative Validity and Reproducibility of a Web-Based Semi-Quantitative Food Frequency Questionnaire in the Danish Diet, Cancer, and Health—Next Generations MAX Study

Rostgaard-Hansen AL, Esberg A, Dicksved J, Hansen T, Pelve E, Brunius C, Halkjær J, Tjønneland A, Johansson I, Landberg R. Gut microbiota composition in the Danish Diet, Cancer, and Health – Next Generations MAX sub-cohort: Temporal variability and association with dietary patterns

Rostgaard-Hansen AL, Grand MK, Esberg A, Rosthøj S, Dicksved J, Hansen T, Pelve E, Brunius C, Halkjær J, Tjønneland A, , Johansson I, Landberg R. Direct and indirect effects of healthy Nordic and Mediterranean diet patterns via gut microbiota on intermediate risk factors for cardiometabolic health

Cardiometabolic diseases (CMD) such as heart disease and diabetes, are the leading cause of death worldwide. Diet affects the risk of CMD but also the composition of bacteria in the gut. It is therefore possible that the relationship between what we eat and the risk of getting diseases is mediated through the bacteria in our gut. When studying the relationship between diet and risk of disease, researchers often use self-reported dietary data derived from questionnaires. These are subject to measurement errors since they rely on people’s memory of which foods and beverages they have consumed. It is therefore important to assess how accurately dietary intake is measured based on a food questionnaire. Another problem, relating to the importance of gut bacteria, is that we do not know how stable the bacterial populations within an individual are over time, and we therefore do not know how to best take samples for analysis of the levels of different bacteria. More knowledge is therefore needed to optimize the design of dietary studies in a way that makes it possible to demonstrate with greater certainty connections between diet, bacteria in the gut and development of disease. In my thesis, dietary data from a Danish population were evaluated, and the stability of gut bacteria was assessed. In addition, I investigated whether there is a relationship between individuals’ plant-based dietary patterns and their levels of gut bacteria, as well as whether there is a connection between diet, various risk factors for CMD, and gut bacteria. My research shows that self-reported dietary data collected by a new food frequency questionnaire was of sufficient quality for use in research studies and that a simple ‘dietary quality score’ was suitable for categorizing individuals into groups with healthy, average or unhealthy eating habits. In addition, I found that 39% of our gut bacteria appears to be reasonable stable over time suggesting that these can be used in studies investigating bacteria in relation to diet and diseases. Furthermore, I found a relationship between plant-based dietary patterns and the level of some specific bacteria. In particular, high intakes of fruit, vegetables, wholegrains, cereals and nuts were associated with higher levels of bacteria that are known to ferment fibre in the gut. However, it was not possible to find an effect of the diet on risk factors for CMD via specific gut bacteria previously shown to modulate effects of plant-based foods on CMD.

Ämneskategorier

Mikrobiologi

Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi

Cancer och onkologi

Näringslära

ISBN

978-91-7905-952-1

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 5418

Utgivare

Chalmers

Room 5.S.B.C, Danish Cancer Society, Strandboulevarden 49, Copenhagen 2100, Denmark

Online

Opponent: Associate Professor Emily Sonestedt, University of Lund, Sweden

Mer information

Senast uppdaterat

2023-11-13