Four people in Japan are now believed to have died after consuming a supplement containing red yeast rice, as a growing health scare sweeps the country.

Red yeast rice, or “beni koji”, is supposed to help lower cholesterol and is an ingredient in dozens of other products that are now being recalled, including sake, salad dressing and miso paste.

Last week, Kobayashi Pharmaceutical recalled three over-the-counter supplement brands – “Beni Koji Choleste Help” and two others – after customers complained of kidney problems.

On Thursday, the company announced two more deaths potentially related to its tablets, bringing the total under investigation by the company and health ministry to four, with more than 100 other people hospitalised.

Prime Minister Fumio Kishida said in parliament that “after the cause is identified, the government will examine what measures are necessary to prevent similar incidents”.

“We will clarify the causes and, if necessary, I think we need to consider all possible measures,” he said.

Kobayashi Pharmaceutical sells a wide range of health products marketed through television adverts in Japan.

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 make-up.

The Osaka-based company says it has supplied red yeast rice to around 50 other firms in Japan and two in Taiwan.

“We were told yesterday by a bereaved family that a person who had been using Choleste Help had passed away due to kidney disease,” the drug maker said in a statement.

It added it had been told separately that another person who had used Choleste Help in recent years had died.

“We are in the process of confirming the facts and causal relationships in both of these cases,” the statement said.

“However, we decided to make this report public from the viewpoint of prompt disclosure.”

The government has ordered several health-food makers to review their products, while informing foreign countries about the issue through Japan’s embassies, Yoshimasa Hayashi, the chief cabinet secretary, said.

Sake, salad dressing and miso paste recalled

Dozens of Japanese firms that used beni koji provided by Kobayashi Pharmaceutical have separately announced recalls.

The affected products include health tablets as well as a rose-coloured sparkling sake, salad dressing, bread and miso paste used in many traditional dishes.

Kobayashi Pharmaceutical said analysis had found a possibility that the products contained “ingredients we had not intended to include”.

But it said it did not find any citrinin produced by red yeast rice, which is toxic and can damage the kidneys.

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

“It is regrettable that Kobayashi Pharmaceutical did not provide information to the government while it was carrying out investigations to determine the cause,” Keizo Takemi, the health minister, said on Tuesday.