Is Miso Safe on a GF Diet?

Miso is a traditional Japanese condiment produced through a double fermentation process, whereby soybeans are fermented with salt and a cultured grain called koji. Koji is usually made from rice, barley or other grains*, which ultimately determines whether your miso is gluten-free or not.

There is conflicting information on the Internet that it’s possible to identify a gluten-free miso by its colour. This is misleading. For example, red or hatcho miso, is made from soybeans alone, and is dark red or black in colour. However, another type of red miso is aka miso, and this miso is made with soybeans and barley. Hence, it is advised consumers either purchase a certified gluten-free miso or speak to the manufacturer. Other common types of miso are white or kome miso, which is made from soybeans and rice, and is light in colour; and yellow or mugi miso, which is made from barley and soybeans, and can appear quite yellow.

In regards to gluten-free labelling, it is important to remember that “gluten-free” is a voluntary term (in the USA at least) that manufacturers may elect to use in the labelling of their foods, provided that the food meets defined requirements for a certified gluten-free food. Some manufacturers will pay additional money for their products to be rigorously tested and certified gluten-free. Both forms of labelling have stringent rules surrounding their use, however if you feel unsure about a product labelled as non-certified gluten-free, it is recommended you contact the manufacturer of the product and clarify the details with them directly.

As of April 2017, a quick search on iHerb and Amazon found the following gluten-free labelled miso products, with only one certified gluten-free. The others were free from gluten according to the ingredients listed.

  • Hikari Organic Miso Paste, White (Certified GF)
  • Eden Foods Shiro Miso
  • Edward & Sons, Organic Miso-Cup, Natural/Instant
  • Chickpea miso broth powder

For those readers in Shanghai, Sprout Lifestyle also sells a gluten-free miso (as pictured here). The shop is located on 388 Shaanxi Nan Lu, near Fuxing Zhong Lu.

And finally, what about the health benefits of miso?

  • The probiotics in miso (as a result of the fermentation process) may assist with gastrointestinal issues such as irritable bowel syndrome and diarrhea. They may also help with urogenital health. NB: if you’re keen to reap the benefits of the probiotics in miso, purchase an unpasteurized product.
  • A population-based prospective cohort study in Japan found frequent miso soup and isoflavone consumption was associated with a reduced risk of breast cancer.
  • Eating soup before a main meal has been found to reduce subsequent food intake, which may assist with weight loss. So next time you’re out to Japanese, slurp down that gluten-free miso first, then hit the sushi!

*koji can also be made with wheat, millet, rye, amaranth, chickpeas, quinoa, and hemp.

Hannah Baker, RD, GFCN Dietician

References available upon request.

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