Our strain L. casei Shirota

In 1930, Dr. Minoru Shirota, microbiologist, became the first in the world to successfully select and cultivate a strain of lactic acid bacteria, beneficial to human health at the Department of Microbiology, Faculty of Medicine, Kyoto Imperial University.

The strain was named Lactobacillus casei strain Shirota* after Dr. Shirota himself.

Dr. Shirota strongly believed that a healthy gut is important to live a healthy long life and that there was a connection between a healthy digestive system and our health. This belief, in Japanese “kencho choju”, became the guiding principle for his research focusing on prevention is better than cure.

At the time when Dr. Shirota began studying the use of beneficial lactic acid bacteria as preventative measures, therapeutic medicine was flourishing and microbiology in the medical field was still in its early days. In 1928 there was the major breakthrough in medical science by the discovery of penicillin by Dr. Fleming. Some Infectious diseases could now be cured by killing bacteria with antibiotics.

It goes without saying that, at that time, Dr. Shirota’s research and achievements in using beneficial bacteria to maintain a healthy gut were pioneering in the field of preventive medicine.

By now, there is worldwide scientific consensus that a healthy gut is essential to overall health and that specific strains of beneficial bacteria can, for instance, suppress the growth of harmful bacteria in the gut. These beneficial strains are called probiotics and their use with the aim of keeping the intestines healthy is becoming more and more widespread.

Dr. Shirota’s research with the L. casei Shirota that started in 1930, has been taken over by the Yakult Central Institute in 1955 and they continue to be true pioneers in probiotics, including fundamental research as well as research and development activities, today.
With a total listing of over 500 scientific studies (both in Japanese and in English) it is fair to say that the L. casei strain Shirota is the most researched probiotic strain in the world.

As a state-of-the-art research institute working in the field of probiotics, the Yakult Central Institute will continue to pursue excellence in life science to contribute to people’s health by further advancing and developing research in this field.

* Classified as Lacticaseibacillus.paracasei Shirota since April 2020