There is one story took place in Nagasaki after the drop of atomic bomb on August 9th, 1945, that’s been told as a myth in the macrobiotic communities worldwide over and over again. The protagonist of this story is Dr. Tatsuichiro Akizuki who saved many lives of atomic-bomb sufferers including himself by feeding people the diet consisting of brown rice, miso soup, sea vegetables, and sea salt. Dr. Akizuki was the medical director at the Urakami Dai-Ichi Hosital (now known as the St. Francis Hospital).

After reading one of Dr. Akizuki books "Taishitsu (Constitution) and Shokumotsu (Foods)," a professor emeritus, Dr. Hiromitsu Watanabe at Research Institute for Radiation, Biology & Medicine in Hiroshima University was prompted to conduct radiation defense experiments with rats. The results of these experiments provided clear evidence to support the notion that “miso soup possibly prevented development of atomic-bomb disease” described by Dr. Akizuki’s memoir.

This issue of Muso News will feature two experiments and their findings by Dr. Watanabe and other experimental data that were originally on the article in September 2011 edition of the Macrobiotic Magazine called "Musubi," published by our sister company: Macrobiotic Association.

Following the exposure to radiation, the life cycle of intestine cells (from birth to death) is said to be three and a half days in general. Therefore, Dr. Watanabe observed the growth condition of cells called small intestinal crypt  located underneath of villus to see which rats are doing well.

The obvious gap is evident when comparing the result of experimenting a group with feed containing 10% of table salt with the result of group experimenting with feed containing 10% of shoyu. Each group retained a regeration rate of almost 100%with the radiation dose of 6 grey. The regeneration rate for the groups fed with regular feed and feed with 10% table salt went down to 0.1 (10%) when the radiation dose reaches 10 grey. The regeneration rate of the same groups went down to 0.01 (1%), the point where the regeneration is impossible, when the radiation dose reaching 12 grey. On the other hands, under the environment with the radiation dose of 12 grey, the group with feed containing 10% of miso retained its regeneration rate more than 0.1 (10%). However, there was no improvement on the small intestinal crypt regeneration rate seen with the rats that had been fed with regular feed before the irradiation even though they were fed with the feed containing 10% of miso after the irradiation

Melanoidin

According to the experiment results, it is speculated that fermentation and maturation are closely related with miso’s protective effect against radiation. And Dr. Watanabe took particular note of melanoidin, a pigment responsible for transforming miso’s color to distinctive dark brown color as the fermentation advances. Melanoidin is a substance formed when saccharide and amino acids are combined. It is present in coffee, beer, natto, bread crust, and so forth. The effectiveness of melanoidin was confirmed by another experiment by Dr. Watanabe’s team which the small intestinal crypt regeneration rate improved after administering 0.1% of artificially composed melanoidin to rats. However, Dr. Watanabe insisted matter-of-factly, "Melanoidin is a possibility but not conclusive. It is not all of the reasons but [is perhaps] one of the reasons."

According to Dr. Watanabe, after the nuclear accident in Fukushima, the Self-Defense Forces took steps to protect their dispatched personnel from the radiation through the administration of vitamin C, which has a strong antioxidant effect, the same as melanoidin is.

Power of Sea Salt

Besides miso’s protective effect against radiation, Dr. Watanabe offered us some interesting experimental data obtained by his team. Let us take a look at the chart of "Pathological Change of a Precancerous Colon"on the right side.

This experiment involved feeding rats different types of feeds (see the chart for details) after administering carcinogen to rats and then comparing the conditions of pathological change of precancerous colon by dissection. Looking at the result with miso, no effect was observed with 5%. However, as salt content increases to 10% or to 20%, pathological change of precancerous colon was suppressed. Moreover, the experiment with various types of miso with different maturation length showed that 180 days old miso suppressed oncogenesis more effectively than a few days old miso or 120 days old miso.

In addition to miso, it is worth paying attention to the differences between various types of salt. There was not much difference between regular feed (with 0.3% of table salt) and other types of feed with table salt whose component consisting of high level of sodium chloride (more than 99%). However, a pathological change of precancerous colon receded with the groups fed with other types of salt: sea salt, rock salt, and coarse salt, etc. According to Dr. Watanabe, micronutrients such as calcium and magnesium are supposed to suppress the occurrence of pathological change to a precancerous state. He pointed out consuming natural salt is more effective in preventing colon cancer.

Consuming salt through miso

Miso has been demonized by low sodium movement insisting that Japanese diet consisting of high salt content facilitate the high incidence of stomach cancer. However, the animal experiment conducted by Dr. Watanabe’s team confirmed that consuming salt through miso lessened the incidence of stomach cancer rather than direct intake of salt itself. Again this experiment showed that the longer Miso ages and matures, the stronger inhibitory effect becomes. Perhaps the secret of miso lies in the fermentation process.

Like the case with stomach cancer, it has been said that high intake of salt leads to high blood pressure. Nonetheless, the result of another experiment conducted by Dr. Watanabe’s team tells a different story. His team conducted a comparative experiment involved feeding salt-sensitive rats with the same amounts of salt; 1st group with salt itself and another with miso containing the same amount of salt that group 1 took. And the result showed that blood pressure of rats that consumed only salt had increased whereas there was no change of blood pressure among the rats consuming salt through miso. Furthermore, according to the research paper published in the U.S. last year, the surveys conducted in four countries (China, England, Japan, and U.S.A) showed that the Japanese tend not to have high blood pressure despite of the fact that the Japanese take higher amount of salt than other three countries. Dr. Watanabe sumed up this result with saying "perhaps because we take a lot  of salt by consuming miso, there is less incidence of high blood pressure among us."

Epilogue

The world of fermentation is like the cosmos in the sense that modern science has not yet figure out what is really going on within it even though the technique of fermentation has been with us throughout the human history. But the bottom line is that longer aged and mature miso is good for you despite of its high sodium content; it offers us not only protective effect against radiation but also other health benefits. Most miso Muso offers are naturally fermented and aged at least for one year.

Based on what we’ve learned about aged, fermented miso, we hope you appreciate the true value of our artisanal miso that’s imparted generation after generation.