Mineral-rich solar sea salt generates less oxidative stress in rats than mineral-deficient salt

A Simple Laser-Induced Breakdown Spectroscopy Method for Quantification and Classification of Edible Sea Salts Assisted by Surface-Hydrophilicity-Enhanced Silicon Wafer Substrates

Salt, one of the most commonly consumed food additives worldwide, is produced in many countries. The chemical composition of edible salts is essential information for quality assessment and origin distinction. In this work, a simple laser-induced breakdown spectroscopy instrument was assembled with a diode-pumped solid-state laser and a miniature spectrometer. Its performances in analyzing Mg and Ca in six popular edible sea salts consumed in South Korea and classification of the products were investigated. Each salt was dissolved in water and a tiny amount of the solution was dropped and dried on the hydrophilicity-enhanced silicon wafer substrate, providing homogeneous distribution of salt crystals. Strong Mg II and Ca II emissions were chosen for both quantification and classification. Calibration curves could be constructed with limits-of-detection of 87 mg/kg for Mg and 45 mg/kg for Ca. Also, the Mg II and Ca II emission peak intensities were used in a k-nearest neighbors model providing 98.6% classification accuracy. In both quantification and classification, intensity normalization using a Na I emission line as a reference signal was effective. A concept of interclass distance was introduced, and the increase in the classification accuracy due to the intensity normalization was rationalized based on it. Our methodology will be useful for analyzing major mineral nutrients in various food materials in liquid phase or soluble in water, including salts.

Antioxidant and anti-inflammatory effects of solar salt brined kimchi

Salt is an essential ingredient in the kimchi fermentation process. Solar salt has antioxidant, anti-cancer, and anti-obesity properties. The aim of this study was to determine the antioxidant and anti-inflammatory effects of solar salt brined kimchi. Purified salt (PS), dehydrated solar salt (DSS), 1-year aged solar salt (SS1), and 3-years aged solar salt (SS3) were investigated. Anti-inflammatory effects were determined by analyzing cytotoxicity, nitric oxide (NO) production, and inflammation-related gene expression in lipopolysaccharide-treated RAW264.7 cells. Antioxidant activities of DSS, SS1, and SS3 were higher than that of PS. Solar salt significantly inhibited NO production with low cytotoxicity and decreased inflammation-related gene expression. Kimchi containing solar salt (DSSK, SS1K, and SS3K) showed higher antioxidant activity than PSK. Additionally, DSSK, SS1K, and SS3K significantly inhibited NO production and decreased the expression of inflammation-related genes. Owing to the antioxidant and anti-inflammatory effects, using solar salt in kimchi preparation could have potential health benefits.

Bamboo Salt and Triple Therapy Synergistically Inhibit Helicobacter pylori-Induced Gastritis In Vivo: A Preliminary Study

Helicobacter pylori infections are a major cause of gastrointestinal disorders, including gastric ulcers, gastritis, and gastric cancer. Triple therapy, using two antibiotics and a proton pump inhibitor, is recommended for the treatment of H. pylori infections. However, antibiotic resistance in H. pylori is an emerging issue. Bamboo salt, a traditional Korean salt made by baking solar sea salt in bamboo barrels, can ameliorate the symptoms of various gastrointestinal diseases. Herein, we compared the anti-H. pylori activity of triple therapy (clarithromycin, metronidazole, and omeprazole), solar salt, and bamboo salt in vivo as a preliminary study. Four-week-old C57BL/6 male mice were inoculated for eight weeks with the H. pylori Sydney Strain 1 (SS-1) and orally administered triple therapy drugs and salts for five days. The transcript levels of the H. pylori-expressed gene CagA and inflammatory cytokines Tnfα and Il-1β significantly decreased in the bamboo salt treated mice than those in the H. pylori-infected control group. This effect was further enhanced by using triple therapy and bamboo salt together. Solar salt caused modest inhibition of H. pylori-induced inflammation. We also demonstrated the synergistic effects of bamboo salt and triple therapy against H. pylori. Thus, bamboo salt may be a potential candidate agent against the treatment of H. pylori-associated gastritis.

Effects of sea salt intake on metabolites, steroid hormones, and gut microbiota in rats

High salt intake is positively linked to many health problems, but the effect of mineral-rich sea salt (SS) has rarely been studied. To better understand the physiological effects of SS intake, the changes in general characteristics, metabolites, steroid hormones, and gut microbiota of SS-fed rats were investigated. Male rats were fed either a normal diet (ND, control) or ND containing 1% SS or 4% SS for 5 weeks. SS intake decreased fat, spleen, liver, and body weight, and increased blood urea nitrogen (BUN), water intake, and gut salt content. Accumulated gut salt content led to a decrease in beneficial bacteria, such as Lachnospiraceae and Lactobacillus, but an increase in potentially harmful bacteria, resulting in a change in lipid metabolites associated with gut health. Interestingly, most renal lysophosphatidylcholines (LPCs) associated with many renal functions were dramatically decreased and female hormones, such as estrogens, were significantly more altered than the male hormones by high SS intake. Although further investigation is needed, these data suggest that high SS intake could be positively linked to kidney dysfunction and gut health problems, and salt-related physiological changes may be sex-specific. Additionally, these data will be useful to better under-stand the physiological effects of SS intake.

Strategy for sodium-salt substitution: On the relationship between hypertension and dietary intake of cations

Chronic diseases, especially cardiovascular diseases (CVD), have become one of the main causes affecting human health. Hypertension is a prominent representative of CVD. The formation and development of hypertension is closely related to people's daily diet. A large number of studies have shown that excessive intake of salt (NaCl) could increase the risk of hypertension. In recent years, more and more investigations have focused on other cations that may be contained in edible salt, exploring whether they have an effect on hypertension and the underlying mechanism. This article focuses on the relationship between four metal elements (potassium, calcium, magnesium, and zinc) and hypertension, by discussing the main metabolic pathway, the impact of diet intake on blood pressure, and especially the regulation mechanisms on blood pressure in detail. At the same time, some opinions and suggestions are put forward, combined with the current hot topics "salt reduction" and "salt substitution".

Effect of Mineral-Balanced Deep-Sea Water on Kidney Function and Renal Oxidative Stress Markers in Rats Fed a High-Salt Diet

This study investigated the effect of mineral-balanced deep-sea water (DSW) on kidney health using an animal model of kidney injury due to a high-sodium diet. High magnesium/low sodium (HMLS) and high magnesium/high calcium (HMHC) DSW samples with different mineral contents were prepared. Sprague–Dawley rats were fed an 8% sodium chloride (NaCl) diet for four weeks to induce kidney injury, and each group was supplied with purified water or mineral water. Kidney injury was observed in the NaCl group according to increased kidney injury markers and malondialdehydes, providing evidence of oxidative stress. However, the kidney injury was repaired by the intake of mineral-balanced DSW. It was confirmed that the HMLS and HMHC groups showed improved Na⁺ excretion through the urine. Kidney injury markers in urine decreased and upregulation of low-density lipoprotein receptor-related protein2 mRNA expression was observed in the HMLS and HMHC groups. In addition, superoxide dismutase activity was increased in the HMHC groups. The gene expression patterns of the RNA sequencing were similar between the CON and HMLS groups. These results suggest that DSW has beneficial effects on kidney health due to the balanced magnesium and calcium levels in models of kidney injury caused by excessive sodium intake.

Structural characterization of Himalayan black rock salt by SEM, XRD and in-vitro antioxidant activity

Salt is an essential component of daily life that balances the physiological functions of the human body as well as other living systems. Different varieties of salts are available in the global market. Out of many salt varieties, Himalayan rock salts have gained tremendous importance among consumers due to its diverse nutritional and medicinal properties. There are two types of Himalayan rock salts. One is the Himalayan pink salt and the other one is Himalayan black salt. Out of the two, the Himalayan pink salt is studied extensively but the black salt is underexplored. In the present study, the Himalayan black rock salt was explored to generate more scientific evidence in terms of its geochemical characterization using FE-SEM, X-ray diffractometry (XRD), elemental content using atomic absorption spectrophotometry (AAS) and in vitro antioxidant activity by different methods for the first time. The study revealed that Himalayan black salt was irregular in shape with a quadrilateral, cubic, irregular crystalline structure. The Himalayan black salt exhibited antioxidant effect and interestingly showed low Na levels than common sea salt and Himalayan pink salt. The Himalayan black salt also contained important minerals like iron, calcium and magnesium which are beneficial to human health thus exhibiting superior characteristics over other conventional table salts.

Lower Mg and S contents in solar salt used in kimchi enhances the taste and anticancer effects on HT-29 colon carcinoma cells

The anticancer effects of kimchi prepared with different kinds of solar salts were evaluated in an in vitro cellular system using HT-29 human colon carcinoma cells. Four kinds of kimchi samples were prepared, using different solar salts: conventionally manufactured solar salt (CS), filtered sea water solar salt (FS), dehydrated solar salt by centrifuging (DS), and washed-dehydrated solar salt (WDS). Prepared kimchi samples were presented as CSK, FSK, DSK, and WDSK, respectively. The pH values, acidity, and sensory evaluation were determined after 3 week fermentation at 5 °C (pH 4.3), and WDSK exhibited the best fermented characteristics and taste among the 4 samples examined. In the HT-29 cell growth inhibitory activity assay, all 4 kimchi samples exert dose-dependent cell growth inhibition, with WDSK showing significant growth inhibition of HT-29 cells. mRNA and protein expression levels of apoptosis and cell cycle arrest related factors reveals that WDSK significantly increases the mRNA expression levels of Bax, Bim, caspases-3, caspases-9, and p21 as compared to other kimchi samples, at a concentration of 4.0 mg mL⁻¹. In addition, WDSK treatment strongly decreases the Bcl-2 protein expression (on western blot) in HT-29 cells, as compared to the control group (no kimchi treatment) and significantly increases the protein expression levels of Bax, caspases-3, caspases-9, and p53. Inductively coupled plasma atomic emission spectrometry (ICP-OES) reveals that WDS possesses a different mineral composition when compared to the other three solar salts; notably, the lower Mg (9.3 g kg⁻¹) and S (4.7 g kg⁻¹) content of WDS may cause better taste, fermented characteristcs, and functionality of WDSK. These results indicate WDS to be the ideal solar salt for kimchi preparation, which enhances the taste due to its lower Mg and S contents, and increases the anticancer effects by exerting better pro-apoptosis and cell cycle arrest abilities in HT-29 cells.

The anticancer effects of kimchi prepared with different kinds of solar salts were evaluated in an in vitro cellular system using HT-29 human colon carcinoma cells.

Feasibility of Quantitative Analysis of Magnesium and Calcium in Edible Salts Using a Simple Laser-Induced Breakdown Spectroscopy Device

Feasibility of a simple laser-induced breakdown spectroscopy (LIBS) device has been investigated for the analysis of Mg and Ca in edible salts. The LIBS spectrometer was assembled with a compact low-power diode-pumped solid-state laser (DPSSL) and a non-gated low-resolution handheld spectrometer. A simple sampling process was employed for on-site application. A piece of filter paper was dipped in the aqueous solution of a sample salt and dried for analysis using LIBS. Maintaining the sample surface height at the optimum position was critical to generate plasmas persistently due to the low pulse energy of the DPSSL. The varying height of the filter paper surface was monitored and compensated, while the sample stage was translated to collect spectra from different positions. The variation of line intensities of Mg and Ca could be attributed to the inhomogeneous distribution of dry residues. To correct this, the peak that consists of the Na(I) and C(II) lines at 568 nm was employed as a reference signal for intensity normalization of the analyte Mg(II) and Ca(II) lines. For edible salt products, the normalized Mg(II) and Ca(II) line intensities could be well correlated with the concentrations of Mg and Ca determined using inductively coupled plasma optical emission spectroscopy. Our results indicate that a simple LIBS device in combination with the simple sampling method is promising as an on-site salt quality assessment methodology.

Effects of different types of salts on the growth of lactic acid bacteria and yeasts during kimchi fermentation

Kimchi was prepared with different types of salts: purified salt (PS), solar salt aged for 1 year (SS1), aged for 3 years (SS3), and bamboo salt (BS). Kimchi inoculated with Leuconostoc mesenteroides P30 (starter kimchi), and control kimchi (non-starter kimchi) were prepared, and stored at - 1 °C for 20 weeks. Titratable acidity values increased slowly and reached 0.96-1.01% (pH 3.73-3.83) at 20 weeks. Proportions of coccus-type lactic acid bacteria (LAB) among total LAB were higher in SS kimchi than PS kimchi. Among non-starter kimchi, the proportions were 44.7, 41.6, 29.7, and 32.1% for SS3, SS1, BS, and PS kimchi, respectively, at 2 weeks, and 11.5, 12.8, 6.7, and 5.8%, respectively, at 20 weeks. SS kimchi had much less yeast counts than PS kimchi. Among starter kimchi, yeasts were detected from PS kimchi at 10 weeks but not detected until 18 weeks from SS1 and BS kimchi and 20 weeks from SS3 kimchi.