High sodium diet and intestinal permeability in young, healthy adults

Abstract

High sodium diets (HSD) have been shown to both increase blood pressure (BP) and lead to gut dysbiosis in adults. Gut dysbiosis can increase intestinal permeability (IP), allowing for translocation of bacteria and their products into the systemic circulation. There, bacteria and their products are recognized by the immune system and can activate pro-inflammatory pathways such as TH17 in a dose dependent manner. HSD has been shown to activate those pathways and increase BP in men. However, the effect of a HSD on IP has not been explored as a potential mechanism of HSD induced BP changes. The objective of this research was to investigate if a HSD can increase IP and inflammatory markers. We hypothesized that plasma concentrations of two common biomarkers of IP, zonulin and LPS binding protein (LBP), and proinflammatory TH17 lymphocytes would increase, while anti-inflammatory Treg lymphocytes would decrease on a HSD compared to a recommended sodium diet (RSD). Twenty-seven healthy participants (15W/12M, age 24±3 yrs, BP 112±9/65±6 mmHg) underwent a 10-day HSD (6,900mg sodium/d, supplemented by salt pills) and a 10-day RSD (2,300 mg sodium/d) intervention in randomized order. On day 9 of each intervention, participants collected urine and wore an ambulatory BP monitor for 24hr. Blood was collected to measure plasma zonulin and LBP by ELISA. TH17 and Treg populations were characterized from PBMCs by flow cytometry. Paired t-tests were used to compare variables on day 9 between diets. Pearson correlations were used to assess the relation between markers of IP and BP. Twenty-four-hour sodium excretion was increased on the HSD (RSD: 135±57 mmol/24h, HSD: 290±68 mmol/24h, p<0.0001). Mean 24-hr SBP (RSD: 116±10, HSD: 117±11 p=0.70) and DBP (RSD: 66±6 mmHg, HSD: 66±5 mmHg, p=0.84) were not different between diets. Plasma zonulin concentrations (RSD: 2.6±1.6 ng/ml, HSD: 2.6±1.5 ng/ml p=0.88) and LBP concentrations (RSD: 3.2±1.7 μg/ml, HSD: 3.2±1.8 μg/ml, p=0.72) were not different between diets. The TH17/Treg ratio was not different between diets (RSD: 0.54±0.51, HSD: 0.41±0.38; p=0.21) however the ratio was inversely associated with zonulin (r=-0.57 p=0.04), and LBP (r=-0.61; p=0.012) on HSD when controlling for age and sex but not on RSD (all p>0.05). These data suggest that 10 days of a HSD did not change IP, BP or T lymphocyte populations in young, healthy individuals. However, the TH17/Treg ratio was associated with zonulin and LBP suggesting that the immune system may respond to changes in IP. Future research is needed to determine whether a HSD can affect IP and inflammation in salt sensitive populations. NIH Grants R01 HL145055 and P20GM113125 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.