Kobayashi Pharma has recalled cholesterol-lowering supplements with red yeast rice over possible link to kidney disease.

Thursday’s announcement by Kobayashi Pharmaceuticals brings the total number of deaths under investigation by the company and health ministry to four, with more than 100 people hospitalised.

Japan’s Prime Minister Fumio Kishida told parliament on Thursday that “we need to make clear the cause [of the illnesses] and consider various responses if necessary”.

He was responding to an opposition politician who urged him to revise safety frameworks that were relaxed under former Prime Minister Shinzo Abe.

Last week, Kobayashi recalled three of its supplements, including Beni Koji Choleste Help, after about 106 customers were hospitalised because of kidney problems.

The over-the-counter products contain an ingredient called red yeast rice, or “beni koji”, which is supposed to help lower bad cholesterol.

The company said on Thursday that it was in the “process of confirming the facts and causal relationships” in the two additional fatalities and “decided to make this report public from the viewpoint of prompt disclosure”.

“Beni koji” contains Monascus purpureus, a red mould that is also used as food colouring.

Public concern

Government spokesman Yoshimasa Hayashi said at a media conference that the government has urged the pharma company to take “swift and serious action toward determining the cause” and disclose relevant information as “concern among the public is spreading”, Japan’s Kyodo news agency reported.

The Osaka-based drugmaker has yet to pinpoint a specific cause but said there was a possibility that the products contained “ingredients we had not intended to include”.

The fermentation process can produce a toxin called citrinin which can damage the kidneys, however, the company said its analysis did not detect any citrinin.

Medical studies describe red yeast rice as an alternative to statins for lowering high cholesterol, but also warn of a risk of organ damage depending on its chemical makeup.

In addition to the supplements, more than 40 products from other companies containing “beni koji”, including miso paste, crackers and a vinegar dressing, have been recalled, the health ministry said.

Hayashi said Japan was sharing information with the World Health Organization and relevant countries after online sales of products subject to the drugmaker’s voluntary recalls were suspended in China, while products have also been removed from circulation in Taiwan.

The company supplies red yeast rice to some 50 firms in Japan and two in Taiwan.

A Kobayashi executive said last week that the company first received complaints about kidney problems in January.