What is beni-koji, the Japanese health supplement linked to 5 deaths?

Dietary health supplements manufactured by a Japanese pharmaceutical company have been taken off store shelves after they were linked to at least five deaths and over 100 hospitalisations.

Reports suggest that the health supplements contained the ingredient beni-koji, a species of red mould, that is known to reduce bad cholesterol levels in the body.

Beni-koji, also known as red yeast rice, is a traditional Japanese ingredient derived from fermented rice.

It has long been used in East Asian cuisine and traditional medicine for its purported health benefits, including cholesterol-lowering properties. It has also been used a food colouring.

While the lovastatin content in beni-koji could lower bad cholesterol, it also contains another ingredient called citrinin, a toxic metabolite believed to cause kidney disease, according to NHK Japan news.

Kobayashi Pharmaceutical, which manufactured the supplements, recalled (return, exchange or replace) the product after concerns were raised.

Following the scandal, Japan's health officials raided two plants of the pharmaceutical company under the Food Sanitation Act.

The company hasn't said much about the sickness related to the health supplements, which includes kidney failure. But most of the supplements being investigated used beni-koji in a pill called Benikoji Choleste Help, which was dubbed as helping lower cholesterol levels.

Kobayashi Pharmaceutical, however, examined the ingredients in beni-koji and didn't find citrinin in it. But the company said the results of its analysis show the presence of an unknown ingredient, and added its beni-koji may contain unintended ingredients.

(With inputs from Associated Press)