Associations of obesity with triglycerides and C-reactive protein are attenuated in adults with high red blood cell eicosapentaenoic and docosahexaenoic acids

Abstract

Background: N-3 fatty acids are associated with favorable, and obesity with unfavorable, concentrations of chronic disease risk biomarkers.

Objective: We examined whether high eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid intakes, measured as percentages of total red blood cell (RBC) fatty acids, modify associations of obesity with chronic disease risk biomarkers.

Methods: In a cross-sectional study of 330 Yup'ik Eskimos, generalized additive models (GAM) and linear and quadratic regression models were used to examine associations of BMI with biomarkers across RBC EPA and DHA categories.

Results: Median (5th-95th percentile) RBC EPA and DHA were 2.6% (0.5-5.9%) and 7.3% (3.3-8.9%), respectively. In regression models, associations of BMI with triglycerides, glucose, insulin, C-reactive protein (CRP) and leptin differed significantly by RBC EPA and DHA. The GAM confirmed regression results for triglycerides and CRP: at low RBC EPA and RBC DHA, the predicted increases in triglycerides and CRP concentrations associated with a BMI increase from 25 to 35 were 99.5±45.3 mg/dl (106%) and 137.8±71.0 mg/dl (156%), respectively, for triglycerides and 1.2±0.7 mg/l (61%) and 0.8±1.0 mg/l (35%), respectively, for CRP. At high RBC EPA and RBC DHA, these predicted increases were 13.9±8.1 mg/dl (23%) and 12.0±12.3 mg/dl (18%), respectively, for triglycerides and 0.5±0.5 mg/l (50%) and -0.5±0.6 mg/l (-34%), respectively, for CRP.

Conclusions: In this population, high RBC EPA and DHA were associated with attenuated dyslipidemia and low-grade systemic inflammation among overweight and obese persons. This may help inform recommendations for n-3 fatty acid intakes in the reduction of obesity-related disease risk.

Figure 1

Generalized Additive Models (GAM) of the associations of BMI with triglycerides (a) and CRP (b) by eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), as percentages of total fatty acids in RBC. The GAM include a bivariate smooth surface over EPA or DHA and BMI (all continuous). The estimated GAM were evaluated at mean values of age, gender and current smoking status and at the 10th (light grey line), 50th (dark grey line) and 90th (black line) percentiles of RBC EPA (1%, 3% and 5% of total fatty acids) and DHA (4%, 7% and 9% of total fatty acids). To convert triglycerides from mg/dl to mmol/l, multiply by 0.0113.