Miso And Its Deep Connection To History And Health
Role Of Miso Culture And Its Lasting Impact
Miso, a fermented soybean paste made with salt and koji, is gaining increasing attention from a probiotic perspective. This historically refined fermentation technique has made miso more than just a staple of Japanese cuisine—it has the potential to contribute significantly to modern health, much like yogurt and kimchi. Miso contains a well-balanced combination of vitamins, minerals, and proteins. More importantly, during the fermentation process, it produces functional compounds with antioxidant properties, digestive benefits, and immune-boosting effects.
Furthermore, unpasteurized miso is rich in probiotics such as lactic acid bacteria and yeast, which help regulate gut health—an issue that has become a significant concern in modern times. While miso has become an essential part of modern health-conscious diets, the future of miso in Japan is not as bright as it may seem.
Looking back at the history of miso, there is no evidence that it was consumed in ancient Japan, such as during the Jomon period. The earliest documented reference to miso dates back to the early 8th century. At that time, Japan’s imperial court was heavily influenced by China’s governance system, and the country’s oldest legal code, the Taiho Code (大宝律令, 701 AD), includes a record of miso. However, the term “miso” (味噌) had not yet been coined; instead, it was recorded as “misho” (未醤). Nevertheless, it was a fermented soybean-based seasoning, similar in nature to modern miso. This historical evidence suggests that miso’s roots can be traced back to China’s hishio (醤), a fermented paste from which Japanese miso evolved.
Interestingly, the Taiho Code listed miso as a taxable item, indicating that it had already been widely used in Japan before then. However, during this period, miso was primarily consumed by the aristocracy and Buddhist monks, and it had not yet reached the common people. It is estimated that miso only began to spread among the general population around the 13th century. This assumption is based on Azuma Kagami (吾妻鏡), a historical chronicle compiled by the Kamakura shogunate around 1300 AD.
Azuma Kagami, which records events spanning 87 years from 1180 to 1266, provides evidence that samurai carried miso with them as a staple food during their travels. The increasing number of battles during this period made food storage a critical factor in warfare, and fermented miso became an indispensable source of sustenance on the battlefield. Warriors embarking on military campaigns often faced extended periods away from their homeland, making reliable food supplies crucial to their survival. Miso, with its rich nutrients and long shelf life, played a vital role in sustaining samurai during their expeditions.
In addition to its adoption by warriors, the spread of miso was also closely tied to the expansion of Zen Buddhism. During this period, Zen monks promoted a minimalist dietary philosophy centered around the concept of ichiju-issai (一汁一菜, one soup, one dish). As a result, miso soup became a fundamental part of monastic meals. The influence of this simple yet nutritious lifestyle extended beyond temple walls, reaching the lower classes who sought affordable, nourishing meals. In this way, miso, once an elite food, became deeply integrated into Japanese society through its role in both military and religious communities.
As miso production expanded nationwide, it began to reflect regional variations. Because miso is a fermented food, its characteristics are significantly influenced by the local environment and producers. The microorganisms naturally present in different regions play a key role in the fermentation process, resulting in distinctive flavors and textures. Even today, when I travel to various parts of Japan and sample locally handcrafted miso, I notice significant differences in taste. This highlights an important aspect of miso: its effectiveness depends on selecting the right type for one’s body. The wrong choice may not provide the expected health benefits and, in some cases, could even have adverse effects.
One major factor to consider is the difference between traditional and modern production methods. Traditional miso-making relies on natural fermentation, which is influenced by environmental factors such as climate and seasonal changes. The aging process can take anywhere from six months to over a year, allowing complex flavors and deep umami to develop. However, this method is unsuitable for mass production due to its lengthy fermentation time and reliance on uncontrollable natural variables. Additionally, because traditional miso is a living food containing active microorganisms, its flavor and color change over time, and its shelf life is relatively short.
In contrast, modern production methods utilize controlled fermentation processes, including temperature regulation and mechanization, to accelerate the aging period. Some factory-produced miso can be completed in as little as four to six months, about half the time required for traditional miso. These industrial techniques ensure uniform quality, minimizing inconsistencies in flavor and texture. However, a critical distinction is that most modern miso undergoes pasteurization, a process that kills off beneficial bacteria such as koji mold and lactic acid bacteria to prolong shelf life. While this makes mass-produced miso more convenient and commercially viable, it significantly reduces its probiotic benefits.
The reality is that most miso sold in Japanese supermarkets and used in restaurants today is pasteurized, meaning that it no longer functions as a probiotic food. Without live microorganisms, its health benefits are significantly diminished. Additionally, modern food habits have contributed to a further loss of miso’s probiotic potential. Even if someone buys unpasteurized miso, they often unknowingly destroy its probiotics by adding it to boiling-hot soup. The key to preserving miso’s health benefits is to add it only after turning off the heat, allowing its live bacteria to remain intact. This was common knowledge among older generations, but today, many people are unaware of this simple yet crucial technique. By making this small adjustment, one can fully enjoy the nutritional power of fermented miso.
For those spending an extended period in Japan, I highly recommend seeking out locally handcrafted miso, rather than relying on store-bought or restaurant varieties. Exploring different regions and tasting small-batch, traditionally made miso can be an enriching experience—one that connects you to the rich history and profound flavors of this ancient Japanese superfood.