Objective: Although there are indications for a regulatory effect of polyunsaturated fatty acids
(PUFAs) on the association between single nuclear polymorphisms (SNPs) and the risk
of obesity, scientific evidence in humans is still scarce. The present analysis investigates
such associations using data on polyunsaturated fatty acids in red blood cell membranes
(RBC). Subjects and Methods: Within the second Bavarian Food Consumption Survey (cross-sectional, population-based),
568 adult men and women provided a blood sample. Fatty acid composition of RBC membranes
was analyzed by means of gas chromatography. Genotyping was performed for 19 candidate
genes associated with obesity, including cytokines, adipokines, neurotransmitters
and transcription factors. In addition, plasma interleukin-6 (IL-6) concentrations
were analyzed. For the statistical analysis an additive unconditional logistic regression
model was chosen. Results: About 20% of the study participants were classified as obese (BMI ≥30kg/m2). Several significant gene-PUFA interactions were found indicating an obesity risk
modulatory effect of PUFA by gene variants of interleukin-2 (IL-2), IL-6, IL-18, tumor
necrosis factor receptor family member 1B (TNFRSF1B), TNFRSF21, leptin receptor (LEPR)
and adiponectin (ADIPOQ). After stratification by genotype, the strongest effects
were found for rs2069779 (IL-2) and all PUFA as well as for rs1800795 (IL-6) and linoleic
or arachidonic acid. The obesity risk for minor allele carriers significantly decreased
with increasing fatty acid content. The PUFA-IL-6 interaction was also reflected in
the plasma IL-6 concentrations. Conclusion: These findings give further evidence for obesity risk affecting gene-PUFA interactions.
However, the observational nature of the study and its small sample size ask for careful
interpretation and replication in a second, independent and larger study.
