In recent days, the controversy surrounding Kobayashi Pharmaceutical's health products in Japan has continued to escalate. On March 28th, Kobayashi Pharmaceutical disclosed that two more consumers had died after taking their health supplements containing red yeast rice. The confirmed death toll in this incident has now risen to four, with 106 people hospitalized after consuming the problematic health products. Based on Japan's Food Sanitation Law, the city of Osaka, where Kobayashi Pharmaceutical is headquartered, issued an administrative penalty decision against the company on March 27th, ordering the recall of all three red yeast rice-containing health products that the company had previously voluntarily recalled.
This incident has sparked widespread public concern because many health products and foods contain red yeast rice as an ingredient.
The main component of red yeast rice is red yeast rice pigment. It is a natural red pigment produced by the fermentation of Monascus fungi and can be used for coloring fermented bean curd, yellow wine, soy sauce, as well as meat products to give them an attractive red color. Red yeast rice is also a natural ingredient in medicine and health products. Modern medical research has shown that red yeast rice pigment has active pharmacological groups, which can exert antioxidant, anti-inflammatory, lipid-lowering, and blood sugar-lowering effects, improving lipid and sugar metabolism in the body. It also has an effect on preventing Alzheimer's disease, demonstrating excellent medicinal and health effects. Studies have also shown that red yeast rice pigment is one of the secondary metabolites of Monascus fungi, with advantages such as good coloring effect, color stability, mild tone, safety, and non-toxicity, thus it has a very wide application in the food and health product industries.
So why are people ending up hospitalized or even dying after long-term consumption of Kobayashi Pharmaceutical's health products containing red yeast rice?
As mentioned earlier, the main component of red yeast rice is red yeast rice pigment, which is generally believed to consist of 10 types. Depending on the different wavelengths of maximum absorption, these pigments can appear red, orange, or yellow. Typically, Monascus fungi produce more red pigments and fewer yellow pigments (only 5%), giving red yeast rice its bright red color. However, under certain specific conditions, it can also appear reddish-brown, orange, or yellow. Red yeast rice pigment is considered highly safe and is widely beloved in China, Japan, and many Southeast Asian countries for use in food, health products, and medicine production. Based on existing research, there is no evidence that red yeast rice pigment directly causes poisoning, illness, or even death in humans.
However, Kobayashi Pharmaceutical previously stated that their red yeast rice raw materials may contain unexpected ingredients that cause consumers to experience renal dysfunction. While Kobayashi Pharmaceutical claims that the "specific nature of this ingredient and its correlation with kidney disease and other issues have not yet been determined," this statement immediately raises concerns about the presence of a potentially dangerous toxin in red yeast rice, which may be the "real culprit" behind the kidney damage seen in people consuming "toxic" red yeast rice over the long term.
This toxic substance is citrinin, also known as citrinin. Citrinin is a natural fungal toxin with strong nephrotoxicity, which in animal experiments can cause dilation and epithelial cell degeneration of renal tubules, leading to symptoms of renal enlargement and increased urine volume, among other kidney function impairments. Research has also shown that citrinin not only has nephrotoxicity but can also cause liver damage and has teratogenic effects. According to the International Agency for Research on Cancer, a subsidiary of the World Health Organization, citrinin belongs to Group 3 carcinogens, meaning it has some carcinogenicity in animals, but its carcinogenicity in humans is not yet clear.
Citrinin is a natural toxin produced by many fungi, such as Penicillium citrinum and some Monascus fungi, and is commonly found in moldy citrus fruits and also present in red yeast rice. Therefore, some experts do not recommend long-term consumption of foods, health products, or medicines containing red yeast rice. Currently, efforts are being made to select Monascus strains that do not produce citrinin or produce it in low quantities, as well as employing processing methods like ultrasound to reduce citrinin levels in red yeast rice. Many countries and international organizations, including China and Japan, have set control requirements for citrinin levels in red yeast rice. For example, the Chinese National Standard for Food GB 2761-2011 "Limit for Mycotoxins in Food" stipulates that the citrinin content in red yeast rice products must be ≤0.05 mg/kg. The kidney failure suffered by victims of Kobayashi Pharmaceutical's red yeast rice health products is consistent with citrinin damage, thus warranting further attention and investigation into this possibility.
In addition to citrinin, other potentially harmful substances in red yeast rice should also be considered. For example, during the fermentation process of red yeast rice, certain microorganisms can decarboxylate amino acids to produce harmful biogenic amines such as histamine, tyramine, cadaverine, and putrescine, leading to adverse reactions in the nervous, cardiovascular, and respiratory systems, including headaches, palpitations, shortness of breath, blood pressure changes, vomiting, and diarrhea, which can be life-threatening. Of course, since the fermentation of red yeast rice is a highly complex biological reaction, it can produce many chemical substances, and there may be other unknown toxic substances that could harm human health. Therefore, further investigation and testing are needed to determine the true cause of this incident.
Kobayashi Pharmaceutical's red yeast rice raw materials, besides being used in their own production of health products, are also sold to other companies for brewing and food manufacturing purposes. The recall scope of food and seasonings using red yeast rice raw materials from Kobayashi Pharmaceutical has now expanded nationwide in Japan. As some of the 52 companies purchasing red yeast rice raw materials from Kobayashi Pharmaceutical are wholesalers, the actual number of companies using these raw materials could be higher. It is worth noting that some health products may enter China through e-commerce platforms or cross-border tourism shopping. Therefore, the Chinese public should pay attention to recall notices from these health product manufacturers to avoid harm to their health. It's worth emphasizing that red yeast rice is a traditional natural food colorant and health ingredient with a long history of safe use. China has very strict testing standards and management measures for harmful components such as citrinin in red yeast rice. Therefore, people can rest assured about consuming foods and health products containing red yeast rice and its pigment that meet Chinese food testing standards.
(The author is a professor in the Department of Immunology, School of Basic Medical Sciences, Peking University.)
(Original Title: Why do health products containing red yeast rice ingredients cause death?)
(From "China Science News", March 29, 2024, Page 1)
