Journal Article

Increased Salt Intake Decreases Diet-Induced Thermogenesis in Healthy Volunteers: A Randomized Placebo-Controlled Study

Klamer, Samuel, Boschmann, Michael, Bartolomaeus, Hendrik, Markó, Lajos, Müller, Dominik N., Mähler, Anja, Forslund, Sofia K., Wilck, Nicola, Maifeld, András, Chen, Chia-Yu

2022

Overview

High salt intake ranks among the most important risk factors for noncommunicable diseases. Western diets, which are typically high in salt, are associated with a high prevalence of obesity. High salt is thought to be a potential risk factor for obesity independent of energy intake, although the underlying mechanisms are insufficiently understood. A high salt diet could influence energy expenditure (EE), specifically diet-induced thermogenesis (DIT), which accounts for about 10% of total EE. We aimed to investigate the influence of high salt on DIT. In a randomized, double-blind, placebo-controlled, parallel-group study, 40 healthy subjects received either 6 g/d salt (NaCl) or placebo in capsules over 2 weeks. Before and after the intervention, resting EE, DIT, body composition, food intake, 24 h urine analysis, and blood pressure were obtained. EE was measured by indirect calorimetry after a 12 h overnight fast and a standardized 440 kcal meal. Thirty-eight subjects completed the study. Salt intake from foods was 6 g/d in both groups, resulting in a total salt intake of 12 g/d in the salt group and 6 g/d in the placebo group. Urine sodium increased by 2.29 g/d (p < 0.0001) in the salt group, indicating overall compliance. The change in DIT differed significantly between groups (placebo vs. salt, p = 0.023). DIT decreased by 1.3% in the salt group (p = 0.048), but increased by 0.6% in the placebo group (NS). Substrate oxidation indicated by respiratory exchange ratio, body composition, resting blood pressure, fluid intake, hydration, and urine volume did not change significantly in either group. A moderate short-term increase in salt intake decreased DIT after a standardized meal. This effect could at least partially contribute to the observed weight gain in populations consuming a Western diet high in salt.

• Publisher: MDPI AG,MDPI
• Subject: Adult / Blood Pressure / Body Composition / calorimetry / Calorimetry, Indirect / compliance / Data analysis / Diet / Double-Blind Method / Energy / Energy intake / Energy Metabolism - physiology / Female / food intake / Healthy Volunteers / Humans / Intervention / Male / Nutrition research / Obesity / Obesity - etiology / oxidation / placebos / Placebos - administration & dosage / Placebos - pharmacology / Risk Factors / Salt / Sodium / Sodium - urine / Sodium Chloride, Dietary - administration & dosage / Sodium Chloride, Dietary - pharmacology / Software / thermic effect of food / Thermogenesis / Thermogenesis - drug effects / Thermogenesis - physiology / urinalysis / Urine / weight gain / Western diets / Womens health