16. Doenjang / gochujang

Korean fermented soybean pastes — Bacillus-dominant ancient soy ferment (doenjang) + capsaicin ferment (gochujang), isoflavone + capsaicin synergy.

Doenjang in 1 minute

What does it provide? Doenjang (된장) is Korean fermented soybean paste: pure soy, Bacillus subtilis (from traditional "meju" blocks' natural ferment) and Aspergillus fermentation, 6–12 month aging. Gochujang (고추장) is a sweet-spicy paste: soy + glutinous rice + chili (gochugaru) + malt rice (yeotgireum), 1–6 months ferment. Both provide a live postbiotic matrix, isoflavones (genistein, daidzein — in aglycone form), lactic acid (Lactobacillus), and — in gochujang — capsaicin (anti-inflammatory, metabolically activating).

How much? 1–2 tbsp (15–30 g) doenjang in soup base (jjigae); 1 tsp gochujang as seasoning (bibimbap, marinade). High Na (1500–2500 mg/100 g).

When to avoid? Severe hypertension (high Na); soy allergy; in gluten sensitivity check the label (some versions also contain wheat); young children (spiciness, Na); MAO inhibitors (tyramine); active GERD flare (chili); histamine intolerance; infant < 1 year.

Scientific Background

Doenjang fermentation:

1. Meju block making: boiled soy paste formed into bricks, air-dried in winter — natural Bacillus subtilis, Aspergillus oryzae inoculation.
2. Placement in brine (6–12 months): meju blocks in salt water (15–20% salt). LAB (Lactobacillus), Bacillus, and salt-tolerant yeasts (Zygosaccharomyces rouxii) produce a lactic acid, glutamate, isoflavone-aglycone matrix.
3. Separation: liquid part is "ganjang" (Korean soy sauce), paste part is "doenjang."

Gochujang fermentation:

1. Soy flour + glutinous rice + malt rice + chili + salt mixed.
2. In clay vessel (onggi) outdoors 1–6 months of aging. Lactobacillus, Bacillus, and Saccharomyces activity. Malt rice amylases produce sweet flavor.

The Bacillus subtilis-dominant fermentation is unique: it differs from Japanese miso (Aspergillus-kōji-dominant) and Chinese jiang (longer ferment). Bacillus spore content is high, meaning live microbe intake (up to 10⁶–10⁷ CFU/g)[1688]. Some Bacillus strains are probiotic-like (Bacillus coagulans, B. subtilis natto).

Isoflavone aglycone ratio: Korean laboratory studies report that the long-aged doenjang aglycone-isoflavone ratio is 70–85% (vs. unfermented soy 5–10%) — excellent bioavailability. The aglycone (free genistein, daidzein) is directly absorbed in the small intestine; unfermented glycoside forms require bacterial hydrolysis (Setchell 2001)[1689].

Capsaicin (gochujang): chili capsaicin activates the TRPV1 receptor and is metabolically activating (UCP1, brown fat), anti-inflammatory (resolvins), and — paradoxically — gastric mucosa-protective (in small doses). In large doses inflammation-enhancing.

Asian population data: Wu et al. (2008 Br J Cancer 98:9–14) showed in Asian-American populations that high tofu/soy consumption is associated with reduced breast cancer risk (OR ≈ 0.85 per additional weekly serving)[1708]. A similar favorable association is described in Messina's (2014) comprehensive review[1690]. Korean pilots and small intervention studies report modest LDL reduction and improvement in inflammation markers (CRP, IL-6) with 20–30 g/day doenjang, but larger independent RCTs are still needed.

Microbiome effect: Tamang (2016 Front Microbiol) and Sanlier (2019 Crit Rev Food Sci) report that Korean soy ferments increase Bifidobacterium and Lactobacillus levels and reduce opportunistic Proteobacteria ratios[1693].

References

[1676] Marco ML et al. Health benefits of fermented foods: microbiota and beyond2017;44:94–102. Curr Opin Biotechnol. Link

Fermented foods and beverages were among the first processed food products consumed by humans. The production of foods such as yogurt and cultured milk, wine and beer, sauerkraut and kimchi, and fermented sausage were initially valued because of their improved shelf life, safety, and organoleptic properties. It is increasingly understood that fermented foods can also have enhanced nutritional and functional properties due to transformation of substrates and formation of bioactive or bioavailable end-products. Many fermented foods also contain living microorganisms of which some are genetically similar to strains used as probiotics. Although only a limited number of clinical studies on fermented foods have been performed, there is evidence that these foods provide health benefits well-beyond the starting food materials.

[1688] Tamang JP et al. Functional properties of microorganisms in fermented foods2016;7:578. Front Microbiol. Link

Fermented foods have unique functional properties imparting some health benefits to consumers due to presence of functional microorganisms, which possess probiotics properties, antimicrobial, antioxidant, peptide production, etc. Health benefits of some global fermented foods are synthesis of nutrients, prevention of cardiovascular disease, prevention of cancer, gastrointestinal disorders, allergic reactions, diabetes, among others. The present paper is aimed to review the information on some functional properties of the microorganisms associated with fermented foods and beverages, and their health-promoting benefits to consumers.

[1689] Setchell KDR, Brown NM, Desai P, et al. Bioavailability of pure isoflavones in healthy humans and analysis of commercial soy isoflavone supplements2001;131(4 Suppl):1362S–1375S. J Nutr. Link

The pharmacokinetic behavior of naturally occurring isoflavones has been determined for the first time in healthy adults. We compared plasma kinetics of pure daidzein, genistein and their beta-glycosides administered as a single-bolus dose to 19 healthy women. This study demonstrates differences in the pharmacokinetics of isoflavone glycosides compared with their respective beta-glycosides. Although all isoflavones are efficiently absorbed from the intestinal tract, there are striking differences in the fate of aglycones and beta-glycosides. Mean time to attain peak plasma concentrations (t(max)) for the aglycones genistein and daidzein was 5.2 and 6.6 h, respectively, whereas for the corresponding beta-glycosides, the t(max) was delayed to 9.3 and 9.0 h, respectively, consistent with the residence time needed for hydrolytic cleavage of the glycoside moiety for bioavailability. The apparent volume of distribution of isoflavones confirms extensive tissue distribution after absorption.

[1690] Messina M. Soy and breast cancer: a comprehensive review 2014;10(3):265–292. Womens Health. 2014.

Comprehensive review in Womens Health (2014) on soy and breast cancer.

[1691] Chen M, Rao Y, Zheng Y, et al. Association between soy isoflavone intake and breast cancer risk for pre- and post-menopausal women: a meta-analysis of epidemiological studies2014;9(2):e89288. PLoS One. Link

BACKGROUND: Conclusions drawn from meta-analyses on the association between soy isoflavone intake and breast cancer risk for pre- and post-menopausal women are not fully consistent. These meta-analyses did not explore the influence of different study designs on the pooled results on the basis of distinguishing between pre- and post-menopausal women. METHODOLOGY AND PRINCIPAL FINDINGS: We performed a meta-analysis of 35 studies which reported results of association between soy isoflavone intake and breast cancer risk for pre- and/or post-menopausal women, calculated pooled odds ratios and their 95\% confidence intervals of pre- and post-menopausal women respectively, and further explored soy isoflavone-breast cancer association on the basis of considering different study regions and designs. Summary results suggested that soy isoflavone intake has a protective effect against breast cancer for both pre- and post-menopausal women. However, they are influenced by study design and region. Pooled ORs of studies carried out in Asian countries suggested that soy isoflavone's protective effect exist in both pre- and post-menopausal women (OR = 0.59, 95\%CI: 0.48-0.69 for premenopausal women; OR = 0.59, 95\%CI: 0.44-0.74 for postmenopausal women).

[1693] Sanlier N et al. Health benefits of fermented foods2019;59(3):506–527. Crit Rev Food Sci Nutr. Link

In the past, the beneficial effects of fermented foods on health were unknown, and so people primarily used fermentation to preserve foods, enhance shelf life, and improve flavour. Fermented foods became an important part of the diet in many cultures, and over time fermentation has been associated with many health benefits. Because of this, the fermentation process and the resulting fermented products have recently attracted scientific interest. In addition, microorganisms contributing to the fermentation process have recently been associated with many health benefits, and so these microorganisms have become another focus of attention. Lactic acid bacteria (LAB) have been some of the most studied microorganisms. During fermentation, these bacteria synthesize vitamins and minerals, produce biologically active peptides with enzymes such as proteinase and peptidase, and remove some non-nutrients.

[1708] Wu AH, Yu MC, Tseng CC, Pike MC. Epidemiology of soy exposures and breast cancer risk2008;98(1):9–14. Br J Cancer. Link

Most of the early studies published on soy and breast cancer were not designed to test the effect of soy; the assessment of soy intake was usually crude and few potential confounders were considered in the analysis. In this review, we focused on studies with relatively complete assessment of dietary soy exposure in the targeted populations and appropriate consideration for potential confounders in the statistical analysis of study data. Meta-analysis of the 8 (1 cohort, 7 case-control) studies conducted in high-soy-consuming Asians show a significant trend of decreasing risk with increasing soy food intake. Compared to the lowest level of soy food intake (or=20 mg isoflavones per day). In contrast, soy intake was unrelated to breast cancer risk in studies conducted in the 11 low-soy-consuming Western populations whose average highest and lowest soy isoflavone intake levels were around 0.8 and 0.15 mg per day, respectively. Thus, the evidence to date, based largely on case-control studies, suggest that soy food intake in the amount consumed in Asian populations may have protective effects against breast cancer.

[1712] Whiting S et al. Capsaicinoids and capsinoids on weight management: a meta-analysis2014;73:183–188. Appetite. Link

OBJECTIVE: Capsaicinoids are a group of chemicals naturally occurring in chilli peppers with bioactive properties that may help to support weight management. The aim of the present study was to conduct a meta-analysis investigating the potential effects of capsaicinoids on energy intake, to clarify previous observations and form evidence-based conclusions about possible weight management roles. METHODS: Medical databases (Medline, Web of Knowledge and Scopus) were systematically searched for papers. Search terms were: 'capsaicin(*)' or 'red pepper' or 'chilli(*)' or 'chili(*)' with 'satiety' or 'energy intake'. Of the seventy-four clinical trials identified, 10 were included, 8 of which provided results suitable to be combined in analysis (191 participants). From the studies, 19 effect sizes were extracted and analysed using MIX meta-analysis software.