"Miso’s outstanding medicinal qualities have been confirmed by scientific research. Dr. Shinchiro Akizuki, director of Saint Francis Hospital in Nagasaki, devoted his career to researching the use of foods, such as miso, as preventative medicine. Although Dr. Akizuki spent years treating atomic-bomb victims just a few miles from ground zero, neither he nor his associates suffered from the usual effects of radiation. Dr. Akizuki hypothesized that he and his staff were protected from the deadly radiation because they drank miso soup every day." - Culinary Treasures of Japan: The Art of Making and Using Traditional Japanese Foods by John and Jan Belleme.
The addition of burdock root to your soup will also help with detoxification.
I am not Japanese so I checked a wonderful Japanese cookbook out from the library to learn how to make this healthy stock. The Japanese Kitchen by Hiroko Shimbo. Heaps of other great recipes are in this book.
Step 1: Ingredients
2 quarts (litres) filtered water
Five 6-inch squares of kombu
1 c of tightly packed bonito fish flakes
Step 2: Prepare the Kombu
Step 3: Add the Bonito Flakes
Strain the stock using cheesecloth and save the bonito flakes for making second fish stock.
Second fish stock is made by simmering the kept and dried bonito flakes together in 2 quarts of water. Both of these stocks can be used for miso soup.
Step 4: Miso Soup for Radiation
1 sm diakon radish cut into cubes
1 burdock root peeled or scraped and sliced thin
2 qt dashi
2 T hatcho miso (other miso is fine too)
splash of mirin
spring onions sliced
Bring the dashi to a simmer and add the diakon and burdock, cook around ten minutes. Remove from heat and add the miso. Stir it in well until it is dissolved. Add the mirin. Serve garnished with sliced spring onions.
It is best not to boil your miso as it can loose flavor. Hatcho miso is a bit more robust and can handle a little heating, but it is preferable to not heat miso too much as it is a live culture.