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

Abstract

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.

Comprehensive Metabolite Profiling and Microbial Communities of Doenjang (Fermented Soy Paste) and Ganjang (Fermented Soy Sauce): A Comparative Study

“…Doenjang and ganjang samples were prepared in triplicate according to a traditional manufacturing method ( Figure 1 ) [ 10 ]. Briefly, four fermented meju (primary fermented product) bricks, two dried hot red peppers, and one lump of charcoal were mixed with 20 L solar saline (18%, w/v ) in a Korean porcelain pot.…”

Anti-hypertensive effect of Korean fermented soybean paste (Doenjang) through regulation of the renin-angiotensin system (RAS) in male rats fed with high-fat and/or high-salt diet

“…Obesity is known to induce greater sensitivity towards the changes in blood pressure. Our previous study had indicated that the Korean traditional fermented soybean foods, doenjang and ganjang, reduce the blood pressure in normal SD rats [16,17]. RAS is a critical homeostatic regulator that relies on a feedback regulation to achieve and sustain the delicate balance in the blood pressure, required for healthy physiological function [25].…”

“…Doenjang, when fed along with normal diet, caused a signi cant reduction in the blood pressure and lowered the expression of sodium transferase-related genes, as compared to the same amount of salt alone. [16,17].…”

Association between the Intake of Fermented Soy Products and Hypertension Risk in Postmenopausal Women and Men Aged 50 Years or Older: The Korea National Health and Nutrition Examination Survey 2013–2018

“…(2019) [9] showed that SBP was increased in rats fed 8% salt than in those fed 0.3% salt; however, SBP was observed to be the same in rats fed Doenjang containing 8% salt and 0.3% salt, suggesting that fermented soy products could attenuate salt-induced hypertension by offsetting the side effects of salty fermented soy products.…”

“…However, salt from miso, a traditional fermented soy product consumed in Japan, did not increase BP in salt-sensitive rats (compared to a same amount of salt) [7,8]. The use of Doenjang, a Korean fermented soy product, also resulted in lower BP in normotensive rats (compared to the use of the same amount of salt) [9].…”