Month: September 2021

Categories
Wellness

Clinical Study Support for the Health Benefits of Fermented Foods

Natto: fermented soybeans

Fermented foods are plentiful in the Japanese diet.

Researchers at the Stanford School of Medicine have found that a 10-week diet high in fermented foods boosts microbiome diversity, lowers inflammation, and improves immune responses. (1)

Justin Sonnenburg, one of the authors, said: This is a stunning finding, it provides one of the first examples of how a simple change in diet can reproducibly remodel the microbiota across a cohort of healthy adults. (2)

Diet shapes the gut microbiome which in turn affects the immune system and overall health. Low gut-microbiome diversity has been linked to obesity and diabetes.

Fermentation is an ancient technique of preserving food, which adds nutritive value in the process, as well as allowing new flavors, textures, tastes and appearances. Implied by its roots, no chemical additives are involved.

Natto arrived in Japan during the Nara period (710-794 AD) with Buddhist priests from China. Shoyu and Miso date back to 1000 BC in China, with production knowledge arriving in Japan in around 600 AD. (3)

In addition to Natto, Shoyu and Miso, there are many other common fermented foods in Japan.

Please see the background paper linked here for more details.

References

  1. Gut-microbiota-targeted diets modulate human immune status, by Hannah C. Wastyk Gabriela K. Fragiadakis Dalia Perelman, Erica D. Sonnenburg, Christopher D. Gardner, and Justin L. Sonnenburg, July 2021
  2. Stanford School of Medicine News Center:https://med.stanford.edu/news/all-news/2021/07/fermented-food-diet-increases-microbiome-diversity-lowers-inflammation
  3. Health Benefits of Fermented Foods and Beverages, Edited by Jyoti Prakash Tamang, 2015
Categories
Wellness

Tokyo targets sub-10µg/m3 for PM2.5 by 2030

Kiyosumi Garden, nature in central Tokyo

Relatively good air quality contributes to Japan’s longest life expectancy in the world, and Tokyo is looking to further reduce air pollutants.

Air Quality is measured across multiple pollutants, (1) with annual exposure levels to PM2.5 (particulate matter less than 2.5 micrometers in diameter) being the most frequently used in research studies. Tokyo is aiming to achieve by 2030 the safest PM2.5 level identified by the WHO (10µg/m3) at its 80 monitoring stations. (2)

Tokyo is tightening standards despite Japan having relatively good air quality already:

Share of population exposed to more than 15 µg/m3 PM2.5

Source: OECD (3)

The impetus is the damage to health that air pollutants cause. For example, particulate matter can affect the heart and lungs and cause serious health effects. Fine particles smaller than 10 micrometers in diameter (PM10) enter deep into the lungs, while smaller PM2.5 go beyond the lungs and into the bloodstream. (3) Research has linked air pollutants to mortality, (4) asthma, heart disease, (5) diabetes, (6) dementia, (7) and through damage to gut microbes to inflammatory bowel disease, gastrointestinal disease, (8) and potentially obesity and its associated problems.  

References

  1. Japan’s Ministry of the Environment: https://www.env.go.jp/en/air/aq/aq.html
  2. Asahi Shimbun, 28 October 2020: https://www.asahi.com/ajw/articles/13822414
  3. OECD working paper n umber 156: Policies, regulatory framework and enforcement for air quality management: The case of Japan, by Enrico Botta, and Sho Yamasaki, March 2020 https://www.oecd.org/officialdocuments/publicdisplaydocumentpdf/?cote=ENV/WKP(2020)3&docLanguage=En
  4. Japanese Nationwide Study on the Association Between Short-term Exposure to Particulate Matter and Mortality, by Takehiro Michikawa, Kayo Ueda, Akinori Takami, Seiji Sugata, Ayako Yoshino, Hiroshi Nitta, and Shin Yamazaki, October 2018
  5. Association of PM2.5 exposure with hospitalization for cardiovascular disease in elderly individuals in Japan, by Toshiki Kaihara, Kihei Yoneyama, Michikazu Nakai, Takumi Higuma, Yoko Sumita Yoshihiro Miyamoto, Mika Watanabe, Masaki Izumo, Yuki Ishibashi, Yasuhiro Tanabe, Tomoo Harada, Satoshi Yasuda, Hisao Ogawa and Yoshihiro J. Akashi, May 2021
  6. PM2.5 and Diabetes in the Japanese Population, by Mihye Lee and Sachiko Ohde, June 2021
  7. Alzheimer’s Association International Conference,2021: https://alz.org/aaic/releases_2021/overview.asp
  8. BBC, January 2019: https://www.bbc.com/future/article/20190128-how-dirty-air-could-be-affecting-our-gut-health