A2011 Increased salt intake is associated with enhancement of neural salty preference in obesity

Abstract

Objectives: Obesity and high intake of salt are major risk factors for hypertension and cardiometabolic diseases. Obese individuals often consume more dietary salt. We examined the neural effects underlying obesity-related high salt intake. Methods: A multi-center, random-order, double-blind taste study was conducted in the communities of four cities in China (n = 537). In addition,an interventional study was done in a local community in Chongqing, China, using positron emission tomography/computed tomography of the brain (n = 32). Results: Overweight/obese individuals tended to have a higher daily salt intake (2.0 g/day higher compared with normal-weight individuals after multivariable adjustment, 95% CI, 1.2–2.8 g/day, P < 0.001)and they exhibited reduced salt sensitivity and higher salt preference. Overweight/obese individuals had a higher prevalence of hypertension (33.3% vs. 12.9%, P < 0.001) and increased systolic blood pressure (132 ± 18 vs. 120 ± 16 mmHg, P < 0.001) and diastolic blood pressure (81 ± 12 vs. 74 ± 10 mmHg, P < 0.001) compared with normal-weight individuals. No sex-based differences were found for the body mass index, salt intake, or salt sensitivity. The altered salty taste and salty preference in overweight/obese individuals was related to increased activity in the orbitofrontal cortex (r = 0.44, P = 0.01), insula (0.38,0.03), and parahippocampus (0.37,0.04). Conclusion: Increased salt intake among overweight/obese individuals is associated with altered salt sensitivity and preferences related to abnormal activity of the gustatory cortex. It could be associated with the increased blood pressure observed in obesity.