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ARS Home » Pacific West Area » Davis, California » Western Human Nutrition Research Center » Obesity and Metabolism Research » Research » Publications at this Location » Publication #338185
Title: Associations among fatty acids, desaturase and elongase, and insulin resistance in children

Author
item BECCARELIL, LORI - University Of California
item SCHEER, RACHEL - University Of California
item Newman, John
item BORKOWSKA, ALISON - Pennsylvania University
item Gray, Ira
item LINNELL, JESSICA - Oregon State University
item KEEN, CARL - University Of California
item YOUNG, HEATHER - University Of California

Submitted to: Journal of American College of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/26/2017
Publication Date: 10/18/2017
Citation: Beccarelil, L.M., Scheer, R.E., Newman, J.W., Borkowska, A.G., Gray, I.J., Linnell, J.D., Keen, C., Young, H. 2017. Associations among fatty acids, desaturase and elongase, and insulin resistance in children. Journal of American College of Nutrition. 37:44-50. https://doi.org/10.1080/07315724.2017.1347908.
DOI: https://doi.org/10.1080/07315724.2017.1347908

Interpretive Summary: Fatty acid profiles and changes in the activity of fatty acid metabolizing enzymes have been associated with adiposity and metabolic disease. While these phenomena have been studied in adults, few studies have evaluated children. The objective of this study was to evaluate these markers of altered lipid metabolism in children and identify relationships with other markers of metabolic health. It was hypothesized that these lipid markers would be correlated to adiposity and markers of metabolic disease. To test this hypothesis, we studied a group of 4th-grade children (n=85, ages 9-12) participating in a comprehensive nutrition program. Any student enrolled in the program was eligible for inclusion in this study. Fasting plasma was collected and analyzed for total fatty acids, glucose, insulin, and full lipid panels. Insulin resistance was estimated using the calculated homeostatic model assessment of insulin resistance (HOMA-IR) values. No differences were found in lipid markers, glucose, insulin, or HOMA-IR among children classified as normal weight, overweight, or obese. An index of enzyme activity can be generated by dividing the concentration of what an enzyme produces by the concentration of its starting material. The activity index for enzymes which insert double bonds at the ninth carbon from the end of saturated fatty acids (i.e. delta-9-desaturase) increased with HOMA-IR (r=0.39, p=0.001), while the activity indices for the enzyme which insert double bonds at the fifth carbon from the end of polyunsaturated fatty acids (i.e. delta-5-desaturase), and the enzyme that elongates 12, 14, and 16 carbon saturated and monounsaturated fatty acids (i.e. the elongase of very long chain fatty acids 6; ELOVL6) decreased with HOMA-IR values (r=-0.33, p=0.006; r=-0.37, p=0.005, respectively). The most significant predictors of HOMA-IR values (adjusted r2=0.39, P=<0.001) were the age adjusted body mass index percentile, the delta-6-desaturase activity, ELOVL6 activity, and systolic blood pressure. In conclusion, this study found that while there was no relationship between fatty acid profiles and ratios and adiposity in the population of studied children, there were strong correlations with insulin resistance. Therefore, regardless of adiposity, there may be underlying changes in fatty acid and lipid metabolism associated with the development of metabolic diseases, such as insulin resistance. Future studies should explore this relationship to gain a more complete picture of early disease risk, development, and progression.

Technical Abstract: Background and Objectives - Fatty acid profiles, desaturase (SCD-16, SCD018, D5D, D6D) and elongase (ELOVL6) enzyme activity have been associated with adiposity and metabolic disease. While this has been studied in adults, few studies have evaluated children. The objective of this study was to evaluate these markers in children and identify relationships with markers of metabolic health. It was hypothesized that these lipid markers would be correlated to adiposity and markers of metabolic disease. Methods - This study was a cross-sectional analysis of 4th-grade children (n=85, ages 9-12) participating in a comprehensive nutrition program. Any student enrolled in the program was eligible for inclusion in this study. Fasting plasma was collected and analyzed for total fatty acids, glucose, insulin, and full lipid panels. Insulin resistance was estimated using calculated HOMA-IR values. Results - There were no differences in lipid markers, glucose, insulin, or HOMA-IR among children classified as normal weight, overweight, or obese. SCD-16, D5D, and ELOVL6 activity were significantly correlated to HOMA-IR values (r=0.39, p=0.001; r=-0.33, p=0.006; r=-0.37, p=0.005, respectively). In regression analysis, BMI-for-age percentile, D6D activity, ELOVL6 activity, and systolic blood pressure were the most significant predictors of HOMA-IR values (adjusted r2=0.39, P=<0.001). Conclusions - There was no relationship between these lipid markers and adiposity in this population, however there were correlations with HOMA-IR. Regardless of adiposity, there may be underlying changes in fatty acid and lipid metabolism associated with the development of metabolic diseases, such as insulin resistance. Future studies should explore this relationship to gain a more complete picture of early disease risk, development, and progression.