Polyunsaturated omega-6 fatty acid levels have previously been linked to the risk of developing type 2 diabetes. But what matters is which class of plasma lipids is being looked at. Certain lipids can act as biomarkers to better assess the influence of diet and fat metabolism on the development of the disease. These are the findings of the team comprised of Marcela Prada, Fabian Eichelmann and Matthias Schulze from the German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), a partner institute of the German Center for Diabetes Research (DZD) e.V., published in the journal ‚Diabetes Care‘.

Previously, researchers have linked the level of omega-6 fatty acids – a group of polyunsaturated fatty acids, such as linoleic acid or dihomo-gamma-linolenic acid – to a correspondingly higher or lower risk of diabetes. However, fatty acid levels were only determined within the scope of total plasma testing or very comprehensive plasma fraction testing.

Researchers had not previously analyzed specific phospholipids and other lipid classes in the same population group. Because lipid classes each have specific functions and can have varying associations with the risk of diabetes, the researchers wanted to bridge the existing gaps in knowledge.

Data from the EPIC Potsdam Study Provides New Insights

The basis for their publication was the European Prospective Investigation into Cancer and Nutrition (EPIC) Potsdam cohort with 27,548 participants. Upon inclusion in the study, all probands provided detailed information on previous or preexisting conditions, height, weight, and lifestyle. The researchers also collected blood samples from all participants. At the start of the study, none of the participants had type 2 diabetes. During the subsequent observational period, with a mean duration of 6.5 years, cases of new-onset type 2 diabetes were recorded.

Using state-of-the-art measuring technology, the researchers characterized the lipidome, i.e., hundreds of lipid molecules, in the blood samples of a total of 1,602 probands, which included 536 people with type 2 diabetes. They were able to assess in detail the composition of fatty acids and various lipid classes and subclasses. The team then compared the lipid concentration of the probands who had developed diabetes with those without diabetes.

The Concentration of Several Omega-6 Fatty Acids Found to be Associated with the Risk of Diabetes
Overall, the assessment showed that higher concentrations of linolic acid were associated with a lower risk of type 2 diabetes, especially in the lysophosphatidylcholine and monoacylglycerol lipid classes. Higher concentrations of dihomo-gamma-linolenic acid in the various lipid classes or in the form of free fatty acids were linked to a higher incidence of type 2 diabetes. No statistically relevant associations were found with arachidonic acid.

Fig.: Testing of various lipid classes shows that, in certain lipid classes, a higher level of linolic acid is associated with a lower risk of type 2 diabetes, meanwhile, in most lipid classes, a higher level of dihomo-gamma-linolenic acid is linked to a higher risk. © Marcela Prada, Erand Llanaj / DIfE

 

“To the best of our knowledge, this is the first prospective study concentrating on polyunsaturated omega-6 fatty acids in major lipid panels and their correlation to the risk of diabetes, and we were able to determine that there are significant variations in risk depending on the lipid class,” says Prada.

“The identified lipids have the potential to act as biomarkers for metabolic disorders and could help improve the understanding of the aspects of lipid metabolism associated with type 2 diabetes,” adds Eichelmann.

Regarding potential perspectives, Schulze notes that “because the onset of diabetes is a gradual process, determining biomarkers before actual diagnosis may help in the early identification of people at increased risk of diabetes”. In this context, further studies are necessary.

Lipids as a Possible Basis for Prevention
For their next step, the researchers want to find out whether diet can modify the concentration of linolic acid in different lipid classes, especially in lysophosphatidylcholines and monoacylglycerols, which are associated with lower diabetes risk.

Apart from the ingestion of food, metabolic processes resulting in higher or lower concentrations of linolic acid or dihomo-gamma-linolenic acid are also of interest. If metabolic pathways can be externally influenced, then they could be used to reduce the risk of type 2 diabetes.
 

Original publication:
Marcela Prada, Fabian Eichelmann, Clemens Wittenbecher, Olga Kuxhaus, Matthias B. Schulze. Plasma Lipidomic n-6 Polyunsaturated Fatty Acids and Type 2 Diabetes Risk in the EPIC-Potsdam Prospective Cohort Study. Diabetes Care 2023, https://doi.org/10.2337/dc22-1435

Scientific Contact:
German Institute of Human Nutrition Potsdam-Rehbruecke 

Marcela Prada
Molecular Epidemiology
Tel.: +49 33 200 88-2454
E-Mail: marcela.prada(at)dife.de

Prof. Dr. Matthias Schulze
Head of Molecular Epidemiology
Tel.: +49 33 200 88-2434
E-Mail: mschulze(at)dife.de

Press Contact
Public Relations
Tel.: +49 33200 88-2335
E-Mail: presse(at)dife.de

German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE)
The DIfE is a member of the Leibniz Association. It investigates the causes of diet-related diseases in order to develop new strategies for prevention and therapy and to provide dietary recommendations. Its research focus includes the causes and consequences of the metabolic syndrome, which is a combination of obesity, high blood pressure, insulin resistance and lipid metabolism disorder, as well as the role of diet in healthy aging and the biological basis of food choices and eating habits. In addition, DIfE is a partner of the German Center for Diabetes Research (DZD), which was founded in 2009 and has since been funded by the BMBF. 

The German Center for Diabetes Research (DZD) is a national association that brings together experts in the field of diabetes research and combines basic research, translational research, epidemiology and clinical applications. The aim is to develop novel strategies for personalized prevention and treatment of diabetes. Members are Helmholtz Munich – German Research Center for Environmental Health, the German Diabetes Center in Düsseldorf, the German Institute of Human Nutrition in Potsdam-Rehbrücke, the Paul Langerhans Institute Dresden of Helmholtz Munich at the University Medical Center Carl Gustav Carus of the TU Dresden and the Institute for Diabetes Research and Metabolic Diseases of Helmholtz Munich at the Eberhard-Karls-University of Tuebingen together with associated partners at the Universities in Heidelberg, Cologne, Leipzig, Lübeck and Munich. www.dzd-ev.de/en