GUT MICROBIOME COMPOSITION AND DIVERSITY AMONG HEALTH AND LIFESTYLE INDUCED DIETARY REGIMEN
Research project No. lzp-2018 / 2-0266
A cross-sectional study to determine differences in gut microbiota composition in groups with specific dietary regimen in Latvian adult population aged 19-64 was conducted in period of 2019-2021 reaching 471 participants in five study groups – vegan, vegetarian, patients of various liver diseases, patients with celiac disease and a control group without dietary restrictions. In addition to stool samples for analysis of gut microbiome, nutritional and lifestyle data were collected to analyse potential correlations and factors that could have an impact on gut microbiome. Data on vegan, vegetarian and celiac patients in Latvia have not been collected before and provides important information on nutritional aspects of these sub-groups.
Although all study groups are very different, intake of macronutrients – such as protein, fat, carbohydrates seem similar among the studied groups and there are mostly differences that are determined by age and gender. Whereas nutritional differences are very pronounced when individual food items are considered. More in-depth analysis of micronutrient consumption in each group is in progress as there are challenges regarding acquirement of accurate nutrient content in various foods.
Analysis of stool samples yielded microbiome profiles that are in line of what is expected from typical “Western” populations – dominated by Firmicutes and Bacteroidota, followed by smaller proportions of Actinobacteriota and Verrucomicrobiota.
The effects of a few covariates that have been identified as significant contributors to interindividual gut microbiome diversity (for example, age, body mass index and stool type (Bristol scale score)) in large-scale cohort studies such as the Flemish Gut Flora Project (Belgium) and the LifeLines-DEEP (Netherlands) were validated in the study population. Additionally, a few dietary factors from food frequency data appeared to be associated with a significant portion of the interindividual microbiome differences. Among those, frequent consumption of rye bread is staple of the Latvian and Baltic region diet. Surprisingly, consumption of kefir is not among the significant covariates, however, other milk products, like sour cream and protein-enriched yogurt each explain about 0,5% of the observed microbiome dissimilarities. Membership of any of the five study groups (“Diet type” in figure) was identified as the top covariate associated with over 3% of total between-sample variance.
As large amounts of dietary data were obtained during this research project further investigation and validation of data will be continued.
Project was carried out by Institute of Food Safety, Animal Health and Environment “BIOR” in collaboration with Riga Stradins university. Project was led by Angelika Krūmiņa and work package leader professor Aivars Lejnieks. In project implementation students form Riga Stradins university together with experts from Department of Risk Assessment and Epidemiology and Microbial genomics group of Institute “BIOR” were involved.