The company says it suspects the death is related to its product, and is investigating.
The person's family contacted the company on Saturday night. The person had been taking the Beni-koji Cholesterol Help supplement since April 2021.
The company has confirmed that another 26 people have been hospitalized after taking health foods containing Kobayashi Pharmaceutical's beni-koji. They say they're getting reports of 50 other people being hospitalized.
It has recalled products containing the ingredient, following reports of multiple users developing kidney problems after ingesting the supplements.
Supplement ingredient recalled globally
Kobayashi Pharmaceutical says it has supplied beni-koji to 52 other firms around the world, some of them wholesalers.
Such companies have started to recall products that contain the ingredient made by the Osaka-based drugmaker. The products include fermented salted squid, senbei rice crackers and Japanese sake.
Authorities in Taiwan say they found records that two firms there imported products containing the beni-koji, and urged them to recall the items. They also plan to ask two other companies to recall imported Japanese sake containing the ingredient.
In 2023, Kobayashi Pharmaceutical produced 18.5 tons of beni-koji, and 16.1 tons were sold. It says 6.9 tons of it were used in items, including health supplements.
What is beni-koji?
Beni-koji has long been used as a food coloring. The yeast-fermented rice contains lovastatin, said to lower cholesterol. It can be used in supplements and other items. But the ingredient can also produce citrinin, a toxic metabolite believed to cause kidney disease.
Japan's Food Safety Commission says there have been reports in Europe of people suffering damage caused by health foods containing beni-koji. The EU has set a standard limit for citrinin in health foods.
Kobayashi Pharmaceutical says it responded to the reports by examining the ingredients in its beni-koji and found it did not contain citrinin. But the company says the results of its analysis show the presence of an unknown ingredient. The drugmaker says it's possible its beni-koji contains unintended ingredients.