Abstract P242: Association of Polyunsaturated Fatty Acids With Body Mass Index: Results From the Multi-Ethnic Study of Atherosclerosis
Background: Although much previous research has focused on the association between total dietary fat and body weight, body mass index (BMI), and weight loss, the contributions of different types of fat to body mass index is less clear.
Objective: To estimate whether levels of plasma n-3 and n-6 fatty acids are associated with BMI at baseline and with changes in BMI over time; and whether plasma n-6 modifies the association between n-3 and BMI.
Methods: Longitudinal linear mixed models were fit, including a total of 24,788 observations from 5,731 participants in the Multi-Ethnic Study of Atherosclerosis (MESA) cohort. Participants were African-American, Chinese-American, Hispanic, or white adults, aged 45-84 years with no history of cardiovascular disease at baseline (2000-2002), and were followed approximately every two years, for a total of five exams. BMI was calculated as weight (kg)/height2 (m2) measured at each exam. Plasma alpha-linolenic acid (ALA), eicosapentaenoic (EPA), docosahexaenoic (DHA), and docosapentaenoic n-3 fatty acids; and linoleic, gamma-linolenic, dihomo gamma-linoleic and arachidonic n-6 fatty acids were measured using fasting blood samples collected at baseline and are expressed as percent of total plasma fatty acids. All models were adjusted for age, sex, education, race/ethnicity, study site, smoking status, and Healthy Eating Index score.
Results: Baseline BMI of participants in the highest tertile of plasma n-3 was 0.90 kg/m2 [95% confidence interval (CI): -1.26, -0.53] lower on average than participants in the lowest tertile. This association was particularly strong for participants with plasma ALA values in the highest tertile relative to the lowest (-1.32, 95% CI: -1.64, -0.99), and less strong for those with plasma EPA+DHA in the highest compared to lowest tertile (-0.64 kg/m2, 95% CI: -1.01, -0.27). Plasma n-3 values were also associated with BMI change over time such that participants with the lowest plasma n-3 and EPA+DHA values at baseline experienced annual increases in BMI of 0.02 (95% CI: 0.004, 0.03) and 0.017 (95% CI: 0.003, 0.031) kg/m2, respectively. No clear association was observed between ALA and BMI change over time. Higher plasma n-6 values were associated with higher baseline BMI (Ptrend = 0.017) and with greater annual increases in BMI (Ptrend < 0.001). The inverse association between plasma n-3 and BMI at baseline and BMI change over time was stronger for those with low plasma n-6 values than those with high n-6 values.
Conclusion: Higher proportions of n-3 fatty acids are associated with lower BMI at baseline and with small but significant decreases in BMI over time, particularly in the presence of low levels of plasma n-6 fatty acids. Increasing the proportion fatty acids from n-3 fatty acids may be a promising strategy for avoiding weight gain and promoting weight loss, particularly when combined with a reduction in n-6 fatty acids.
Author Disclosures: T. Hastert: None. M.C. de Oliveira Otto: None. F. Le-Scherban: None. B. Steffen: None. L.M. Steffen: None. M. Tsai: None. D. Jacobs: None. H. Nguyen: None. A. Baylin: None.
- © 2015 by American Heart Association, Inc.