Aim: Polyunsaturated fatty acids (PUFAs) are essential fatty acids, because they cannot be synthesized in the body and must be taken from food, but excessive intake may cause obesity. Therefore, the measurement of serum fatty acid composition is useful for monitoring the fat composition of the diet. In recent years, accumulating evidence has indicated the importance of gut microbiota in maintaining human health. The aim of our study was to evaluate the relationship between fatty acid composition and gut microbiota in obese patients with type 2 diabetes.

Research Design and Method: The subjects included 100 patients (age: 60.3±13.9 years, BMI 27.5±5.8 kg/m2) who were not taking EPA agents. They were divided into two groups, i.e., obese group (n=64) with a BMI of greater than 25 kg/m2 and non-obese group (n=36) with a BMI less than 25 kg/m2. Serum levels of fatty acids were measured using gas chromatography. In 45 of 100 patients, gut microbiota profiles were measured using T-RFLP methods.

Results: The serum levels of dihomo-gamma-linolenic acid (DGLA), which is an n-6 PUFA, and palmitic acid, a saturated fatty acid (SFA), were significantly higher in the obese group than in the non-obese group. No significant differences were observed in the serum levels of n-3 PUFA. The ratio of Firmicutes/Bacteroidetes in the fecal microbiota was significantly lower in the patients with high serum levels of DGLA. The rate of Bacteroidetes showed a significant positive correlation with serum DGLA and palmitic acid.

Conclusion: These results suggest that high levels of serum DGLA may play an important role in the development of not only obesity but also gut microbiota in type 2 diabetes patients. The fat quality in the diet might contribute to the development of obesity.


M. Higa: None. M. Kawai: None. R. Eto: None. F. Ayako: None. G. Sato: None. M. Hijikata: None. K. Yamashita: None. T. Ichijo: None.

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