A traditional Korean fermented food, Gochujang exerts anti-hypertensive effects, regardless of its high salt content by regulating renin-angiotensin-aldosterone system in SD rats.

The current study aimed to investigate the distinct outcomes of table salt and salt in Gochujang on blood pressure (BP). Animals were divided into 3 groups, including normal diet (NS, 0.5 % NaCl), high-salt diet (HS, normal diet with 8 % NaCl), or high-salt Gochujang diet (HSG, normal diet with Gochujang containing 8 % NaCl). Compared to the NS groups, the HS group showed significantly increased systolic blood pressure (SBP), while the HSG group did not elevate SBP. The HS group had lower serum angiotensin II and aldosterone levels than the NS group, while the HSG group showed higher levels of those parameters than the HS group. The renal mRNA expression related to the renin-angiotensin-aldosterone system (RAAS) was significantly higher in the HS group than the NS group, while the HSG group had markedly lower expression of those markers. The urinary and fecal Na+/K+ proportion was higher in both HS and HSG groups relative to the NS group, but the HSG group showed a decreased Na+/K+ ratio in urine and feces compared to the HS group. Moreover, the HS group had a significantly upregulated mRNA level of Na+/HCO3- co-transporter (Slc4a4) in the kidney than the NS group, whereas the HSG group showed downregulated mRNA expression of Slc4a4 compared to the HS group. This study demonstrates that Gochujang has anti-hypertensive effects regardless of its high salt content and provide the evidence regarding the distinct impacts between salt in Gochujang and the table salt.

Soy Sauce Lowers Body Weight and Fat Mass in High-Fat Diet-Induced Obese Rats.

Soy sauce (SS) is a traditional fermented seasoning. Although fermented foods have diverse health beneficial effects, SS intake has been discouraged because of its high salt level. This study was designed to evaluate the antiobesity outcomes of SS and the potential involvement of salt content in SS by adding a high-salt group. Sprague-Dawley rats were randomly assigned into four groups: normal diet (ND, 10% fat of total kcal), high-fat diet (HD, 60% fat of total kcal), HD with salt water (HDSW, NaCl = 8%), and HD with SS (HDSS, NaCl = 8%). SS significantly decreased HD-induced body weight gain and lipogenic gene expression without affecting food consumption. Moreover, SS also reduced hepatic injury and lipid accumulation, and also improved hyperlipidemia. Furthermore, SS decreased the mRNA levels related to obesity-derived inflammatory responses, while HDSW did not change the levels of those markers. These observations indicate that SS ameliorates obesity in HD-fed obese rats by attenuating dyslipidemia. Moreover, SS might also have an anti-inflammatory effect in HD-induced obesity, which requires further investigation. Most importantly, SS offers these beneficial effects regardless of its high salt content, implying that different dietary salt sources lead to the distinct health outcomes. In conclusion, the findings of this study improve the understanding of the functional effect of SS.

Gochujang Ameliorates Hepatic Inflammation by Improving Dysbiosis of Gut Microbiota in High-Fat Diet-Induced Obese Mice.

Abnormal fat accumulation with gut microbiota dysbiosis results in hepatic inflammation by upregulating the release of lipopolysaccharide (LPS) and inflammatory cytokine. Gochujang, a traditional fermented condiment, has beneficial effects, such as anti-colonic inflammatory effects. However, Gochujang has been controversial because of its high salt content (the Korean Paradox). Thus, the present study aimed to investigate the preventative effects of Gochujang on hepatic inflammation and related gut microbiota through discussing the Korean Paradox. The mice were divided into groups including a normal diet (ND), high-fat diet (HD), HD with salt (SALT), HD with a high percentage of beneficial microbiota Gochujang (HBM), and HD with diverse beneficial microbiota Gochujang (DBM). Gochujang markedly reduced lipid accumulation, hepatic injury, and inflammation response. Furthermore, Gochujang attenuated protein expression involved in the JNK/IκB/NF-κB pathway. Additionally, Gochujang regulated the gut microbiota-derived LPS production and Firmicutes/Bacteroidetes ratio. Gochujang regulated the levels of gut microbiota such as Bacteroides, Muribaculum, Lactobacillus, and Enterorhabdus, which were correlated with hepatic inflammation. Salt did not have foregoing effects, meaning that the salt content in Gochujang did not affect its anti-inflammatory effect. In conclusion, Gochujang showed anti-hepatic inflammation effects via reduced lipid accumulation, hepatic injury, and inflammatory response together with reorganization of gut microbiota dysbiosis regardless of salt content and the difference of micro bacteria composition.

Gochujang Consumption Prevents Metabolic Syndrome in a High-Fat Diet Induced Obese Mouse Model.

High-fat and high-salt diets are risk factors for metabolic syndrome development. However, gochujang, which has a high salt content, possesses antiobesity properties in cell and animal models. We aimed to evaluate the effects of Sunchang traditional and modern factory produced gochujang on metabolic syndrome factors in high-fat diet (HFD)-induced obese mice. For 14 weeks, 4-week-old C57BL/6J male mice were separated into five groups and fed a normal diet (ND), a high-fat diet only (HD), a HD with salt (SALT), a HD with traditional Sunchang gochujang (TS), and HD with modern factory made Sunchang gochujang (FS). Compared to HD and SALT groups, the gochujang groups had lower body weight, blood leptin, and insulin levels with reduced Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) index and improved serum and liver lipid profiles. In addition, gochujang supplemented groups exhibited a significant reduction in mRNA expression of anabolic lipid metabolism related factors; PPARγ, CEBPα, and FABP4, and a significant increase in mRNA expression of energy expenditure-related factors; PPARα and CPT1. Protein expressions of SREBP1 were downregulated in the gochujang fed groups. TS and FS intakes improved obesity in HFD-induced obese mice. Compared to the gochujang groups, the SALT group did not exhibit any of those benefits suggesting that the high salt content of gochujang has different effects compared with added salt alone. Our findings provide evidence that gochujang could be a functional food to attenuate metabolic syndrome.

Effects of a Rice-Based Diet in Korean Adolescents Who Habitually Skip Breakfast: A Randomized, Parallel Group Clinical Trial.

During adolescence, healthy eating habits are important, and regular meal intake has an especially positive effect on future health. However, the rate of skipping breakfast has gradually increased. Therefore, this study was conducted to evaluate the positive effects of a rice-based breakfast in Korean adolescents who usually skip breakfast. In this open parallel-group, randomized controlled trial, 105 middle and high school students aged 12-18 years who habitually skipped breakfast were recruited. They were randomly divided into three groups: the rice meal group (RMG, n = 35), wheat meal group (WMG, n = 35), and general meal group (GMG, n = 35). The RMG and WMG received a rice-based breakfast and wheat-based breakfast, respectively, for 12 weeks. After a 12-week intervention, the body fat mass (p < 0.05) and body mass index (p < 0.05) in the RMG were significantly lower than those in the other two groups, and the stress score was also significantly lower in the RMG (p < 0.05). Moreover, after the intervention, in the RMG only, compared to baseline levels, the relative theta (RT) wave activity significantly decreased in eight electrode sites, and the relative alpha (RA) wave activity increased significantly. Eating a rice-based breakfast has positive effects on body fat accumulation and cognitive function in Korean adolescents. Furthermore, a rice-based breakfast plan that is preferred by adolescents should be developed to assist them in developing healthy eating habits.

Effects of Doenjang, a Traditional Korean Soybean Paste, with High-Salt Diet on Blood Pressure in Sprague-Dawley Rats.

Fermented foods in Korea contain a lot of salt. Although salt is reported to exacerbate health trouble, fermented foods have beneficial effects. We hypothesized that doenjang could reduce blood pressure in Sprague-Dawley (SD) rats fed a high-salt diet. Eighteen SD rats were divided into three groups: normal-salt (NS) group, high-salt (HS) group, and high-salt with doenjang (HSD) group. The salinity of doenjang and saltwater was adjusted to 8% using Mohr's method. Blood pressure was significantly reduced in the HSD group compared with the HS group. Water intake and urine excretion volume has significantly increased in the HS group compared with the HSD group. The excreted concentrations of urine sodium, urine potassium, and feces potassium significantly increased in the HSD group compared with the HS and NS groups. Renin level was significantly decreased in the HSD group compared to the other groups. These results indicate that eating traditional salty fermented food is not a direct cause of hypertension, and the intake of doenjang in normal healthy animals improved blood pressure.

Erratum: The antioxidant activity of steamed ginger and its protective effects on obesity induced by high-fat diet in C57BL/6J mice.

[This corrects the article on p. 503 in vol. 12, PMID: 30515278.].

The antioxidant activity of steamed ginger and its protective effects on obesity induced by high-fat diet in C57BL/6J mice.

BACKGROUND/OBJECTIVES: Ginger, a root vegetable, is known to have antioxidant and antiobesity effects. Preparation, such as by steaming, can affect the chemical composition of prepared root vegetables or herbs and can change their functional activities. In the present study, we investigated the protective effects of steamed ginger against oxidative stress and steatosis in C57BL/6J mice fed a high-fat diet. MATERIALS/METHODS: The levels of polyphenols and flavonoids in two different extracts of steamed ginger, i.e., water extract (SGW) and ethanolic extract (SGE); as well, their antioxidant activities were examined. Forty male C57BL/6J mice were fed a normal diet (ND, n = 10), high-fat diet (HFD, 60% fat, w/w, n = 10), HFD supplemented with 200 mg/kg of SGE or garcinia (GAR) by weight (SGED or GARD, respectively, n = 10) for 12 weeks. Serum chemistry was examined, and the expressions of genes involved in lipid metabolism were determined in the liver. Histological analysis was performed to identify lipid accumulations in epididymal fat pads and liver. RESULTS: The SGE had higher contents of polyphenols and flavonoids and higher DPPH and ABTS+ free radical scavenging activities compared to those of SGW. Treatment with SGE or GAR significantly decreased the HFD-induced weight gain. Both SGE and GAR significantly reduced the high serum total cholesterol (TC), triglyceride (TG) and low-density lipoprotein levels induced by HFD. Compared to ND, HFD significantly increased hepatic TC and TG levels. SGE or GAR supplementation significantly decreased the increase of hepatic lipids by HFD. Interestingly, SGE had a more significant effect in reducing hepatic TC and TG levels than GAR. Furthermore, hepatic genes involved in lipogenesis and lipolysis were altered in both the SGED and GARD groups. CONCLUSIONS: The present study indicates that steamed ginger supplementation can decrease plasma TC and TG and can inhibit liver steatosis by regulating the expressions of hepatic genes.

Antihypertensive effect of Ganjang (traditional Korean soy sauce) on Sprague-Dawley Rats.

BACKGROUND/OBJECTIVES: Although Korean fermented foods contain large amounts of salt, which is known to exacerbate health problems, these foods still have beneficial effects such as anti-hypertension, anti-cancer, and anti-colitis properties. We hypothesized that ganjang may have different effects on blood pressure compared to same concentrations of salt. MATERIALS/METHODS: Sprague-Dawley rats were divided into control (CT), NaCl (NC), and ganjang (GJ) groups and orally administered with 8% NaCl concentration for 9 weeks. The systolic blood pressure (SBP), serum chemistry, Na+ and K+ concentrations and renal gene expressions were measured. RESULTS: The SBP was significantly increased in the NC group compared to the GJ and CT groups. In addition, the Na+ concentration in urine was higher in the GJ and NC groups than the CT group, but the urine volume was increased in the GJ group compared to the other groups. The serum renin levels were decreased in the GJ group compared to the CT group, while the serum aldosterone level was decreased in the GJ group relative to the NC group. The mRNA expression of the renin, angiotensin II type I receptor, and mineralocorticoid receptor were significantly lower in the GJ group compared to other groups. Furthermore, GJ group showed the lowest levels of genes for Na+ transporter in kidney cortex such as Na+/K+ ATPaseα1 (NKAα1), Na+/H+ exchanger 3 (NHE3), Na+/HCO3- co-exchanger (NBC), and carbonic anhydrases II (CAII). CONCLUSIONS: The decreased SBP in the GJ could be due to decreased renin and aldosterone levels in serum and increased urinary volume and excretion of Na+ with its transporter gene alteration. Therefore, ganjang may have antihypertensive effect despite its high contents of salt.