Universität zu Köln

Heinzer, Kathrin (2023). The relationship between the dietary omega- 6/omega-3 ratio, gut microbiota composition and disease severity in patients with non-alcoholic fatty liver disease. PhD thesis, Universität zu Köln.

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Abstract

Due to the modern western style diet, the consumed Omega-6 (n-6) to Omega 3 (n-3) fatty acids ratio has notably increased. Mechanisms like increased lipogenic activity, impaired oxidation of fatty acids and increased production of proinflammatory eicosanoids may link an increased dietary n-6/n-3 ratio to NAFLD. The objective of this cross-sectional study with a cohort of biopsy proven NAFLD patients, was to point out associations between the n-6 and n-3 fatty acids consumption, the gut bacterial composition and the disease severity. NAFLD study participants (n=101) were enrolled to fill out a food and activity record for 14 days. All study participants provided stool samples evaluated with the use of 16S rRNA gene sequencing. The personal dietary composition of each patient was determined using Ebispro 2016 professional software. This allowed us to divide the patients into quantiles with a low (Q1), moderate (Q2) or high (Q3) dietary n-6/n-3 ratio of <6.1 (n=34), 6.1–7.8 (n=33), >7.8 (n=34), respectively. The gut microbiota composition was analyzed using Spearman correlation coefficients as well as principal coordinate analysis. Within our total study collective, the data of biopsy proven NAFLD patients (n=63) was collected to draw conclusions regarding the histological disease severity . Median age of all study participants was 53 years (range: 19-80 years) and 47% were female. The median n-6/n-3 fatty acid ratio in the groups Q1, Q2 and Q3 was 4.9 (IQR 1.4); 6.7 (IQR 0.8) und 9.4 (IQR 1.9), respectively. The presence of certain bacteria displayed a positive (Catenibacterium (genus); Lactobacillus ruminis (species)) or negative (Clostridium (genus)) correlation with the dietary intake of n-6 fatty acids. However, we could not show any significant associations between the n-6/n-3 ratio in the diet, the gut microbiota composition, and the histological disease severity by comparing the three quantiles. As a result, the exact relation between specific human gut bacteria and n-6 fatty acids in NAFLD development remains an open field of research. In this study there is currently no evidence that an increased consumption of n-6/n-3 fatty acids represents a major contributor in NAFLD development.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Heinzer, Kathrin kathrin.heinzer@gmx.de UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-732288
Date:	2023
Language:	English
Faculty:	Faculty of Medicine
Divisions:	Faculty of Medicine > Innere Medizin > Klinik für Gastroenterologie und Hepatologie
Subjects:	Medical sciences Medicine
Uncontrolled Keywords:	Keywords Language gut microbiota UNSPECIFIED NAFLD UNSPECIFIED omega- 6/omega-3 ratio UNSPECIFIED
Date of oral exam:	17 October 2023
Referee:	Name Academic Title Demir, Münevver Privatdozentin Dr. med. Vehreschild, Jörg Janne Universitätsprofessor Dr. med.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/73228