How Michiyo Tsujimura, the Japanese Green Tea Researcher, Became Popular


Green tea is one of the most popular beverages consumed around the world today. However, the scientific research behind the components and health benefits of green tea did not gain prominence until the early 20th century, thanks largely to the pioneering work of a Japanese biochemist named Michiyo Tsujimura.

Tsujimura dedicated her career to unraveling the molecular makeup and medicinal qualities of green tea. Her research led to monumental discoveries that boosted green tea production and exports from Japan to North America and earned her the epithet of “the mother of green tea.”

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In this article, we explore the life and achievements of Michiyo Tsujimura, the first Japanese woman to earn a doctorate in agriculture, whose groundbreaking research on green tea components and vitamin C made her a revered figure in Japanese scientific circles.

Early Life and Education

Michiyo Tsujimura was born on January 17, 1888 in the town of Tanabe in Wakayama Prefecture, Japan. Her father was a physician who encouraged her scholarly pursuits. Tsujimura attended Tanabe Girls’ High School and developed an interest in science from a young age.

In 1908, 20-year-old Tsujimura moved to Tokyo and enrolled in Japan Women’s College of Science. This is where she first studied botany and chemistry, the fields that would become the focus of her life’s work. Tsujimura graduated in 1913 and took a teaching position at Tokyo Women’s Higher Normal School.

However, in 1920 at age 32, Tsujimura resigned from her teaching post and entered the Department of Agriculture at Tokyo Imperial University as a Ph.D. student. This was an unprecedented move for a Japanese woman at the time.

Research on Green Tea Components

Tsujimura began her research on tea under the guidance of Professor Umetaro Suzuki. She isolated catechin from green tea in 1929, and in the following year, extracted tannin crystals from tea leaves. Her pioneering research attracted the attention of scientists around the world.

Tsujimura’s findings were published in a series of papers titled “On the Chemical Components of Tea,” through which she identified vitamin C in green tea and analyzed the nutritional elements of tea leaves. Her thesis laid the foundation for the scientific study of tea and its health benefits.

In 1932, Tsujimura was awarded her Doctor of Agriculture degree from Tokyo University for her thesis on the chemical components of green tea. Her doctorate signified a major milestone as she became the first Japanese woman to receive a Ph.D. in agriculture.

Impact on Green Tea Exports and Production

Tsujimura’s revelations about the high vitamin C content in green tea created a sensation in the United States and other parts of North America. Her research contributed to boosting the popularity of green tea in Western markets.

Exports of Japanese green tea quadrupled between 1935 to 1940. The tea was marketed as a healthy product enriched with vitamins and minerals thanks to Tsujimura’s scientific analysis. Her publications on green tea were even used by Japanese tea companies in advertisements targeted at American consumers.

Within Japan, Tsujimura helped improve green tea production methods by developing a new stingless hybrid tea called Tsujimura. This and other advances increased Japan’s annual green tea output from 40,000 to 80,000 tons between 1930 to 1955.

Later Career and Legacy

Tsujimura spent the later part of her career teaching at Ochanomizu University, where she was appointed professor in 1947. She retired as professor emeritus in 1955 but continued to teach students as a part-time lecturer until 1961.

Over the course of her career, Tsujimura published more than 60 research papers in Japanese and international journals. She was awarded the Japan Prize of Agricultural Science in 1956 for her achievements. The Japanese government also honored her with the prestigious Order of the Precious Crown in 1958.

Michiyo Tsujimura passed away in 1969 at the age of 81. Although she became reclusive in her later years shunning publicity, her pioneering research earned her a lasting legacy as one of Japan’s most important biochemists and the mother of green tea science.

In 2021, Google commemorated the 133rd anniversary of Tsujimura’s birth by featuring an artistic doodle depicting her conducting green tea experiments. Tsujimura’s research has stood the test of time and remains instrumental in promoting the health benefits and economic value of Japanese green tea worldwide.

Key Research and Discoveries by Michiyo Tsujimura

Michiyo Tsujimura made several critical discoveries through her green tea studies that transformed scientific knowledge at the time:

  • Isolated catechin from green tea in 1929: Catechin is a flavonoid believed to have antioxidant properties. Tsujimura was the first scientist to isolate this plant compound from green tea leaves.
  • Extracted tannin crystals from tea leaves in 1930: Tannins are natural phenols that give green tea its characteristic bitter taste. Tsujimura’s technique of extracting tannin in crystal form was innovative.
  • Identified vitamin C in green tea in 1930: Tsujimura proved that green tea contains vitamin C, making it more than just a popular beverage. This discovery boosted the drink’s nutritional value.
  • Analyzed chemical components of green tea from 1930-32: Through her series of papers on tea constituents, Tsujimura methodically studied and documented the key nutrients, vitamins, and molecules found in green tea.
  • Developed the Tsujimura hybrid green tea strain: To improve tea crops, Tsujimura cross-bred different tea plant varieties to create an innovative cultivar with higher yields and quality.

Tsujimura’s research provided the basis for the contemporary understanding of green tea’s chemical composition and potential health benefits. She helped transform green tea from a largely unknown Asian drink into a globally popular beverage supported by proven science.

Michiyo Tsujimura’s Doctoral Thesis on Green Tea Components

Tsujimura’s doctoral thesis titled “On the Chemical Components of Green Tea” was the culmination of her years of research on tea constituents. Published in 1932 by Tokyo Imperial University, it laid the foundation for scientific tea studies.

Some key aspects of Tsujimura’s thesis research:

  • Analyzed over 20 chemical components of green tea leaves including proteins, carbohydrates, vitamins,caffeine, and polyphenols
  • Isolated some compounds like catechin and tannin in crystalline forms for the first time
  • Identified new organic substances in tea leaves including theophylline and glutamic acid
  • Discovered vitamin C in tea leaves and measured its variation across seasons
  • Studied the changes in chemical composition from fresh tea leaves to finished green tea
  • Suggested improvements to production methods to obtain more nutritious and better-tasting green tea

By identifying the major nutritive constituents of green tea, Tsujimura provided hard scientific evidence about its health benefits, shaping modern nutritional science. Her thesis set the standard for detailed chemical analysis of natural products.

Significance of Michiyo Tsujimura’s Green Tea Research

Michiyo Tsujimura’s pioneering green tea research had profound scientific, economic, and cultural impacts on Japan and beyond:

  • Scientific significance: Tsujimura’s studies isolated new chemical compounds and revealed medicinal qualities of green tea expanding scientific knowledge. Her methodology became the basis for phytochemical analysis of herbs.
  • Economic influence: By scientifically validating green tea’s nutritional value, Tsujimura boosted its export and domestic production, earning valuable foreign exchange for Japan’s postwar economy.
  • Cultural influence: Tsujimura helped popularize green tea globally in the early 20th century as interest surged in its health benefits, shaping food cultures worldwide.
  • Progress for women scientists: As the first woman in Japan to earn a doctorate in agriculture, Tsujimura broke social barriers and became an inspiration for aspiring female scientists.

Though green tea had been consumed for centuries, Tsujimura’s work created a new scientific and cultural appreciation of the beverage. Her discoveries laid the foundation for further research that established green tea as a health drink containing antioxidants that help prevent diseases.

Why Michiyo Tsujimura Became Popular

Michiyo Tsujimura’s groundbreaking green tea research brought her fame and recognition both within Japan and internationally for the following reasons:

Revolutionary Research

  • Tsujimura’s study of green tea’s chemical components was unprecedented and changed scientific understanding of the beverage. Her isolation of compounds like vitamin C generated global interest.

Economic Contributions

  • By scientifically validating green tea’s nutritional value, Tsujimura boosted Japan’s exports of this product. Her work aided Japan’s economy through increased international trade.

Gender Barrier Breaker

  • As the first Japanese woman to earn a doctorate in agriculture, Tsujimura pioneered the path for women academics and scientists in a male-dominated society.

Awards and Honors

  • The Japanese government honored Tsujimura for her scientific contributions by awarding her one of the nation’s highest honors, the Order of the Precious Crown.

Lasting Legacy

  • Tsujimura enjoys enduring popularity because her findings gave green tea mainstream acceptance worldwide as a healthy drink, creating an ongoing legacy.

Global Influence

  • By catapulting green tea’s popularity outside Japan, Tsujimura helped introduce the drink into numerous cultures and food habits around the world.

In recognition of her scientific rigor and groundbreaking research that created economic, social, and global impacts, Michiyo Tsujimura emerged as one of Japan’s most influential biochemists of the 20th century. Her pioneering green tea work made her a trailblazer admired by peers and the public alike.


Michiyo Tsujimura leveraged her deep passion for science to overcome gender barriers and achieve pioneering research that transformed green tea from simply a popular Asian beverage into a globally appreciated health drink.

Her doctoral thesis delivered pivotal insights into the molecular components and medicinal properties of green tea. By isolating compounds like vitamin C and catechin, Tsujimura provided the hard proof needed to fuel interest in green tea across North America and Europe.

The ensuing boost to Japan’s green tea exports helped the nation economically while introducing the drink into new cultures worldwide. Tsujimura’s scientific rigor, perseverance and thirst for knowledge allowed her to gain many firsts – becoming the first Japanese woman to receive a doctorate in agriculture and the first scientist to uncover the secrets behind green tea’s health benefits.

Though she shunned the limelight, Michiyo Tsujimura’s research on green tea stands as her lasting legacy. Over 50 years after her retirement, Tsujimura’s findings continue to be built upon by scientists exploring the pharmacological promise of green tea. The pioneering “mother of green tea” remains revered in Japan and internationally as one of the most accomplished food scientists of the 20th century.

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