An Increase in Dietary Quality Is Associated with Favorable Plasma Biomarkers of the Brain-Adipose Axis in Apparently Healthy US Women

Abstract

Background: The associations between long-term dietary quality and biomarkers of the brain-adipose axis have not been examined.

Objective: We evaluated both cross-sectional and longitudinal associations between dietary quality and several biomarkers involved in the brain-adipose axis.

Methods: In the Nurses' Health Study II, 831 women [baseline mean age: 45 y; body mass index (BMI; in kg/m(2)): 24.6] were randomly selected from women who provided 2 fasting blood samples in 1996-1999 and 2010-2011 to measure plasma concentrations of leptin, soluble leptin receptor (sOB-R), adiponectin, insulin, retinol binding protein-4 (RBP-4), interleukin-6 (IL-6), and C-reactive protein (CRP). Dietary quality was assessed by the Alternative Healthy Eating Index (AHEI-2010) with the use of semiquantitative food-frequency questionnaires administered in 1995 and 2011. We used linear mixed models to evaluate the cross-sectional associations between dietary quality and biomarker concentrations. We also examined change in dietary quality in relation to change in biomarker concentrations.

Results: In cross-sectional analyses that compared the highest with the lowest quintile of AHEI-2010, we observed significantly lower leptin (P-trend < 0.0001), insulin (P-trend < 0.0001), and CRP (P-trend = 0.02) and significantly higher sOB-R (P-trend < 0.0001) and adiponectin (P-trend = 0.0003). These associations, except for CRP, remained significant after adjustment for BMI. In longitudinal analyses, women in the highest quintile of AHEI-2010 score change (most improvement) had a 13% increase in leptin, compared with a 42% increase (P-trend < 0.0001) in the lowest quintile (least improvement). The corresponding multivariable-adjusted percentage changes for other biomarkers were 4% compared with -1% for sOB-R (P-trend = 0.04), 14% compared with 6% for adiponectin (P-trend = 0.02), and -11% compared with 16% for CRP (P-trend = 0.02). Adjustment for interim weight change attenuated these associations. No associations were observed for RBP-4 or IL-6.

Conclusion: Improvement in dietary quality was associated with favorable profiles of several biomarkers of the brain-adipose axis in women.

Keywords: adiponectin; brain-adipose axis; dietary quality; leptin; soluble leptin receptor.