Doctor measuring the waist of a patient.

Project: Gut microbiota composition and digestion of animal foods

The gut with its microorganisms - the gut flora - is of importance to health. We aim to study how the gut flora in persons with and without metabolic syndrome affects levels of a metabolite (TMAO) in blood and urine after a meal of egg or meat affects TMAO levels in blood and urine. This metabolite was linked to several welfare diseases.

Facts about the project

Project manager
Cornelia Witthöft
Other project members
Mohammed Hefni, Torbjörn Lennqvist, Annelie Franzén-Eriksson, Linnaeus University
Participating organizations
Linnaeus University
The Crafoord Foundation
Nov 2022 – May 2023
Food Science (Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Sciences)
Research group
Food Science

More about the project

The gut with its microorganisms - the gut flora - is of great importance to health. Differences in the gut flora bacteria may explain individual differences when digesting food. Through a diet rich in red meat, eggs and dairy products, a substance called trimethylamine-N-oxide (TMAO) is formed through the gut flora which can be measured in blood and urine. TMAO has recently been linked to various welfare diseases, e.g. heart disease. Several studies in humans show the crucial role of the gut flora in the formation of TMAO. It is also known that the composition of the gut flora in people with metabolic syndrome differs significantly compared to people without metabolic syndrome.

Metabolic syndrome is a combination of at least 3 of the following criteria:

  • overweight (BMI> 29)
  • increased abdominal circumference (> 102 cm in men,> 88 in women)
  • Increased fasting blood sugar
  • high blood lipids
  • high blood pressure (> 130/85), or taking medication for hightened blood pressure

The aim of this project is to compare the effect of the gut flora on the level of TMAO in blood and urine after meals of eggs and meat, both in people with or without metabolic syndrome.

Who can participate in the study?

People aged 18 and 65, with or without metabolic syndrome, who do not smoke, do not have a chronic disease (eg diabetes) and do not follow a vegetarian diet can participate. Please note that we are looking for people who do not regularly eat probiotics (dietary supplement from the pharmacy, dofilus milk products, shots etc.)

When, how and where is the study conducted?

The study will take place in the autumn/winter of 2022 until spring 2023. We ask you who wishes to participate to come after to the Linnaeus University health center (Hälsomottagning) in Kalmar on 3 occasions.

The first time is the screening which takes about 1 hour. Thereafter, 2 test days follow, which take about 7 hours each.

During the screening and test days, blood samples are taken for analysis. At the screening, you also get a special container to take for collection of a stool sample. The stool sample can be collected at home any day before the first test day. On the two test days, we ask you to eat a test meal consisting of either eggs or meatballs. Thereafter, we collect a number of urine samples and 5 blood samples during 6 hours. To facilitate blood sampling, a nurse will place a cannula into the arm fold.

For more information, please contact responsible researcher Cornelia Witthöft, tel: 0480 446310 or 072 5295810, e-mail, Mohammed Hefni, tel: 0480 446130 or 072 5949410, e-mail:, Department of Chemistry and Biomedicine, visiting address: Vita, Linnaeus University, Norra Kajplan 6, 39231 Kalmar .

The project is part of the research of the research group Food Science