Red Rice vs Red Yeast Rice

HK BioTek Intern

If red rice is a rice variety, then what about red yeast rice (RYR)? Despite being frequently featured in Asian cuisine, red rice and RYR serve very different roles. Such difference lies on how they are processed, which affects their nutritional value thus their role in our everyday diet.

Red rice is a rice variety that is minimally processed after harvest. After being harvested, cleaned, and dried, most if not all parts of the rice grain remain intact. Nutrients are distributed in the bran, germ and endosperm of a rice grain. The pigment proanthocyanidin in the rice grain’s bran, or the layer coating the endosperm, gives red rice its characteristic brownish red colour, as well as antioxidant properties. It is also rich in dietary fiber, vitamin B, and minerals such as iron and zinc. The nutritional composition of germ is similar to that of bran, but it is fibreless and is also rich in vitamin E and unsaturated fats. Last but not least, the endosperms are the rice that we normally eat, and is mainly composed of starch and proteins. Since it is a nutritious energy source, red rice acts as a staple in our diet.

If red rice were the main character of our diet, then RYR would be the supporting role. RYR is white rice fermented by the Monascus fungus. During fermentation, Monascus red pigments and monacolin K are released. The red pigments give RYR’s distinctive purplish red colour, while monacolin K is the active ingredient in lovastatin - a widely prescribed cholesterol-lowering drug.

For centuries, RYR has only been used for food colouring, flavour enhancing, food preserving, wine brewing and medicinal purposes in Asian regions. The presence of monacolin K and other substances may explain why RYR, unlike red rice, is not a staple. Although the cholesterol-lowering effects of RYR are questionable, due to its variable monacolin K content, it is still unsafe to consume foods with potential pharmaceutical properties as a staple. Furthermore, side effects including kidney and liver toxicity and muscle fatigue have been reported following RYR consumption. An independent analysis suggests that the likely “culprit” of these side effects is a toxin called citrinin, which was present in one-third of the RYR products tested.

Since RYR’s benefits and side effects are largely unknown, people should not attempt to lower their cholesterol levels by replacing lovastatin with high amounts of RYR. Therefore, in contrast with consuming red rice, those who intend to lower their cholesterol levels with RYR products should seek medical advice.

RYR and red rice might just be a one-word difference, but in fact they greatly differ in essence and nutritional value, so it is important not to get confused with these two foods.

References:

1. Chow, S., Ms. (2017, June 05). Red fermented rice and food safety. Retrieved February 23, 2021, from https://www.cfs.gov.hk/english/multimedia/multimedia_pub/multimedia_pub_fsf_126_01.html

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4. Ricciotti, H., M.D., & Hur, H., M.D., M.P.H. (2017, July). Can i use red yeast rice instead of a statin to lower my cholesterol? Retrieved February 23, 2021, from https://www.health.harvard.edu/cholesterol/can-i-use-red-yeast-rice-instead-of-a-statin-to-lower-my-cholesterol

5. Robb-Nicholson, C., M.D. (2008, October). By the way, doctor: Does red yeast rice reduce cholesterol? Retrieved February 23, 2021, from https://www.health.harvard.edu/newsletter_article/By_the_way_doctor_Does_red_yeast_rice_reduce_cholesterol