Does Eating Miso Help Protect Against Radiation?

Since the Fukushima nuclear disaster a few years ago, one of the common questions I hear is “does miso really protect against radiation?” The answer is “yes” and “no.”

If you’re not familiar with miso, it is a fermented food, typically made from soybeans although there are also rice and chickpea miso as well. It is a staple in the Japanese diet and is rich in vitamins, minerals, protein, good carbs and probiotics (provided it isn’t heated as it often is when used in miso soup). It has a long history as a medicinal food thanks to its many health benefits.

Regular consumption of miso is linked to many health benefits. One study published in the Hiroshima Journal of Medical Science found that the long-term consumption of miso on animals with lung cancer could exert cancer-preventive and protective effects.

According to other research published in the International Journal of Oncology 2, miso has also been found to reduce the risk of liver tumors in animals. In this study, scientists assessed miso consumption on spontaneous or radiation-induced liver tumors in animals fed miso for thirteen months. Their research showed that miso significantly reduced the frequency and number of liver tumors in male animals, but not females. The scientists are still not clear as to why the results were gender-specific, but they believe hormonal factors may be involved. More research is necessary but the results have promise in the prevention and treatment of liver cancer in men.

Just because miso consumption favors males for its liver-tumor protection doesn’t mean it has no health benefits for females. Multiple studies demonstrate that miso reduces the risk of breast cancer in women. A study published in the Journal of the National Cancer Institute found that regular miso consumption reduced the risk of breast cancer in women by up to 54 percent, particularly in post-menopausal women. Another study by the Department of Cancer Research at Hiroshima University found that miso consumption at the beginning of cancer treatment could even reduce the occurrence of breast tumors as effectively as the cancer drug tamoxifen.

Additional research at Hiroshima University found that the best radiation-protective results were from miso fermented from 180 days, as opposed to miso fermented for only 4 days or 120 days. The longer fermentation time seemed to confer significant radiation protection against the formation of colon, lung, breast and liver tumors. The scientists concluded that the blood must contain a certain concentration of active compounds in miso prior to radiation exposure. In other words, to obtain miso’s radiation protective properties, it is essential to eat it before being exposed to radiation and in sufficient doses that the active ingredients will work. The sufficient amount differs from person to person and is affected by digestion and absorption of miso’s nutrients.

How can you best take advantage of miso’s protective properties? While most people are familiar with miso soup it is preferential to enjoy unheated miso and therefore take advantage of the many different strains of probiotics the food offers. As with all fermented foods, heat destroys the beneficial probiotics they contain and miso is no different. So, it is best to enjoy miso in salad dressings or tossed with vegetables after they have been cooked. Also, because soy is a heavily genetically-modified food, it is best to choose miso that is organic and free of genetically-modified organisms (GMOs).

So the answer to the question about whether miso helps to protect against radiation is: yes, if you eat enough of it regularly and prior to radiation exposures. And, like anything, it has its limits, so don’t count exclusively on miso to protect against radiation.

For more information, consult my book The Probiotic Promise: Simple Steps to Heal Your Body from the Inside Out.

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Jeanne Rogers
Jeanne Rogersabout a year ago

Thank you for sharing.

Siyus Copetallus
Siyus Copetallus2 years ago

Thank you for sharing.

Kamia T.
Kamia T2 years ago

Miso here in the US is made in a way that destroy much of the probiotic goodness and with GMO soy, so no thanks, sorry.

Barry Cohen
Barry Cohen2 years ago

For those seeking information on how to safely remove radiation from the body after being exposed due to a radioactive leak or attack see the great information website at

Adrienne L.
Adrienne L2 years ago

Thanks for sharing.

Quanta Kiran
Quanta Kiran2 years ago


Yvonne Pl no forwards
Yvonne Wey2 years ago

Thanks for sharing

Dt Nc
Dt Nc2 years ago


Beryl Ludwig
Beryl L2 years ago

There are many other fermented foods that the Japanese regularly consume, were any of these tested as well? There are tons of fermented foods that are good sources of probiotics.


Beryl Ludwig
Beryl L2 years ago

interesting but I won't count on being protected by eating miso or any other dietary supplement. If there is an incident of radiation exposure we are all at high-risk for tumors cancer and radiation poisoning.