Thanks to a long fermentation process, miso contains several healthy ingredients that can positively affect the human body. Scientific research based on people is still limited. Hovever the health benefits related to consumption of fermented (soy) beans are well documented.
Miso, as a legume-based product, contains a lot of protein and dietary fibre. Among the other important compounds there are: choline, vitamin B6, omega-3, and omega-6 fatty acids and minerals: iron, manganese, and zinc. In this post I will show my findings regarding healthy benefits of miso consumption through the lence of science.
Fermentation plays a big role.
Another subject of the discussion focuses on health benefits related to the process of fermentation of the beans in miso paste. Research shows that the microbial transformation of this amino paste helps in the breakdown of the nutrients in miso and allows for eased absorption and increased functionality of these foods in the human diet.
The nutritional composition of miso paste is undeniably a positive aspect of well-documented health benefits. The importance of sufficient intake of iron, zinc, vitamin K, among others, are significant in providing a balanced diet and preventing health disorders such as anaemia, type-2 diabetes, or even moderately decreased risk of bone fractures. The presence of these essential nutrients and minerals in miso allows suggesting its positive effects on humans.
Miso soup is the answer!
Scientific research shows the relation between the consumption of miso (in form of miso soup) and particular health outcomes.
The benefits of soy consumption have been identified for cardiovascular, metabolic, and musculoskeletal outcomes . High intake of fermented soy products (a category including natto and miso) was associated with a lower risk of mortality among 92.915 participants aged between 45 and 74 years in a Japanese cohort study. Another cohort study showed that high miso consumption can decrease the risk of preterm birth among Japanese women.
Research shows a correlation between high salt intake and the risk of gastric cancer. Evidence has been presented concerning the negative effect of miso consumption concerning gastric cancer among men. Frequent intake of soy products (including miso) has been shown to outweigh the negative effects of high sodium content with a positive association to reduced risk of gastric cancer.
These reviews are the most excessive presentations of the subject, highest in relevance and the quality of evidence. Some of the other findings show the relationship between miso soup consumption and lowered heart rate, but no association to blood pressure levels. The low prevalence of sarcopenia (skeletal muscle loss) among women has been presented based on a cross-sectional study with a relatively low number of subjects.
What about salt?
High sodium content in miso paste can be perceived as an alarming issue. Studies show that a high intake of salt can lead to hypertension (high blood pressure) and a higher heart rate. Nevertheless, a cross-sectional study of the effects of the habitual consumption of miso suggests, that there is no significant effect on the blood pressure on the study group of middle-aged and elderly Japanese people. Moreover, basic studies show that the ingredients of the final miso product can result in lowered values of blood pressure and heart rate due to the lowering effect on sympathetic nerve activity.
And other, non-human trials?
There are some promising results coming from animal-based research.
Several of them support the positive functional features of miso consumption. The results present health outcomes related to improvements in brain metabolism rate, reduces the risk of breast cancer , and slowed down the process of aging. A clinical study on coenzyme Q10 (CoQ10) showed that the absorption of the coenzyme can be enhanced by the consumption of miso soup.
To sum up..
The nutritional composition of miso paste is undeniably a positive aspect of some well-documented health benefits. The importance of sufficient intake of iron, zinc, vitamin K, among others, are significant in providing a balanced diet and preventing health disorders such as anaemia, type-2 diabetes, or even moderately decreased risk of bone fractures. The presence of these essential nutrients and minerals in miso allows suggesting its positive effects on humans.
Currently, more reasearch related to the subject is being conducted around the world. Soon, more data should be reveal to prove the overal lbeneficial results related to miso intake.
(Baggott et al., 1990) Effect of miso (Japanese soybean paste) and NaCl on dmba‐induced rat mammary tumors.
(D’Elia et al., 2012) Habitual salt intake and risk of gastric cancer: A meta-analysis of prospective studies.
(Fernández-Cao et al., 2019) Zinc Intake and Status and Risk of Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis.
(Frisoli et al., 2012) Salt and Hypertension: Is Salt Dietary Reduction Worth the Effort?
(Hao et al., 2017) Vitamin K intake and the risk of fractures.
(Hong et al., 2004) Aspergillus oryzae GB-107 Fermentation Improves Nutritional Quality of Food Soybeans and Feed Soybean Meals.
(K. Ito et al., 2017) The Effects of the Habitual Consumption of Miso Soup on the Blood Pressure and Heart Rate of Japanese Adults: A Cross- sectional Study of a Health Examination.
(M. Ito et al., 2019) Fermented foods and preterm birth risk from a prospective large cohort study: the Japan Environment and Children’s study.
(Katagiri et al., 2020) Association of soy and fermented soy product intake with total and cause specific mortality: prospective cohort study.
(Ko et al., 2013) Intake of Soy Products and Other Foods and Gastric Cancer Risk: A Prospective Study.
(Li et al., 2020) Soy and Isoflavone Consumption and Multiple Health Outcomes: Umbrella Review of Systematic Reviews and Meta‐Analyses of Observational Studies and Randomized Trials in Humans.
(F. Takahashi et al., 2020) Habitual Miso (Fermented Soybean Paste) Consumption Is Associated with a Low Prevalence of Sarcopenia in Patients with Type 2 Diabetes: A Cross-Sectional Study.
(M. Takashi et al., 2020) Miso Soup Consumption Enhances the Bioavailability of the Reduced Form of Supplemental Coenzyme Q 10.
(Santiago et al., 1992) Japanese Soybean Paste Miso Scavenges Free Radicals and Inhibits Lipid Peroxidation.
(Vonderheid et al., 2019) A Systematic Review and Meta-Analysis on the Effects of Probiotic Species on Iron Absorption and Iron Status.