Aims: Plasma fatty acid composition can change with age, reflecting diet and levels of desaturating enzymes such as stearoyl-CoA desaturase (SCD), delta-6 desaturase (D6D) and delta-5 desaturase (D5D), which contribute to the development of insulin resistance. This study analyzed longitudinal changes in fatty acid composition in Japanese children during early puberty and the association between changes in desaturase indices and changes in body fatness and insulin resistance.
Methods: The study included 77 children (38 boys and 39 girls) aged 9.6±0.5 years. Relative weight (RW) and waist-to-height ratio (WHtR) were determined. The fatty acid composition of plasma phospholipids was analyzed by gas chromatography, and the desaturase indices were calculated: SCD (16:1n-7/16:0: SCD16 and 18:1n-9/18:0: SCD18), D6D (20:3n-6/18:2n-6) and D5D (20:4n-6/20:3n-6) in 2006 and 2009.
Results: Obese children showed higher dihomo-gamma linolenic acid (DGLA; 20:3n-6), a higher D6D index and lower D5D index than non-obese children. Longitudinal changes in fatty acid com-position were generally similar in both sexes. Increased D6D index and DGLA and decreased D5D index were significantly associated with increased WHtR in boys and girls. In addition, increased D6D index was associated with an increased homeostasis model of assessment ratio (HOMA-R) only in girls.
Conclusion: The change in abdominal adiposity is a determinant of longitudinal changes in D6D and D5D indices and DGLA during early puberty.