Excessive salt consumption causes systemic calcium mishandling and worsens microarchitecture and strength of long bones in rats

Abstract

Excessive salt intake has been associated with the development of non-communicable diseases, including hypertension with several cardiovascular consequences. Although the detrimental effects of high salt on the skeleton have been reported, longitudinal assessment of calcium balance together with changes in bone microarchitecture and strength under salt loading has not been fully demonstrated. To address these unanswered issues, male Sprague–Dawley rats were fed normal salt diet (NSD; 0.8% NaCl) or high salt diet (HSD; 8% NaCl) for 5 months. Elevation of blood pressure, cardiac hypertrophy and glomerular deterioration were observed in HSD, thus validating the model. The balance studies were performed to monitor calcium input and output upon HSD challenge. The HSD-induced increase in calcium losses in urine and feces together with reduced fractional calcium absorption led to a decrease in calcium retention. With these calcium imbalances, we therefore examined microstructural changes of long bones of the hind limbs. Using the synchrotron radiation x-ray tomographic microscopy, we showed that trabecular structure of tibia and femur of HSD displayed a marked increase in porosity. Consistently, the volumetric micro-computed tomography also demonstrated a significant decrease in trabecular bone mineral density with expansion of endosteal perimeter in the tibia. Interestingly, bone histomorphometric analyses indicated that salt loading caused an increase in osteoclast number together with decreases in osteoblast number and osteoid volume. This uncoupling process of bone remodeling in HSD might underlie an accelerated bone loss and bone structural changes. In conclusion, long-term excessive salt consumption leads to impairment of skeletal mass and integrity possibly through negative calcium balance.

High Salt Intake Implications as Risk Factor for Hypertension and Comparison of Three Salt Estimation Methods- Findings From Islamabad, Pakistan

“…12 High salt intake has been associated with different diseases including hypertension, gastric cancer, kidney stones and bone deformities. 13 Similar studies from India, Bangladesh and China also reported high salt intake of 10.98, 17 and 11.8 grams per day, respectively. 14,15 High daily salt intake is also common in developed countries like in Australia where the mean daily intake of salt was 8.8 grams/day.…”

Preparation and Characterization of Calcium-Incorporated Rosa roxburghii Tratt and Its Efficacy on Bone Mineral Density in Rats

“…These results are consistent with our previous data. Specifically, animals were subjected to a calcium balance study [ 29 – 31 ]. Fractional calcium absorption (ACAR) and calcium retention (ACR) were calculated based on the results from urine and fecal outputs.…”

Strontium isotopes and concentrations in cremated bones suggest an increased salt consumption in Gallo-Roman diet

“…On top of that, an elevated salt consumption has an added metabolic effect. High salt diets been demonstrated to cause detrimental changes in the Ca balance in the bone 69 , while Ca reducing conditions in the skeleton are understood to lead to elevated [Sr] 40 . Salt consumption was for instance found to be at the root of clear 87 Sr/ 86 Sr shifts in Mayan samples from Tikal, demonstrating that the amount of 87 Sr/ 86 Sr warping is a function of the amount of salt consumed 39 , 85 .…”

“…In addition, [Sr] is also highly correlated with salinity 66 of the food supplies. High salt intakes promote Ca excretion and eventually cause detrimental Ca degradation in the skeleton 67 – 69 . This allows for potential replacement by Sr, although this could not yet be observed in (short term) experimental studies 67 , 68 .…”