Red yeast rice (RYR) is a unique supplement or ingredient created by culturing and fermenting rice with specific strains of yeast.

The fermented end product includes several bioactive compounds that have a physiological effect and a red color due to the fermentation process.

RYR has gained significant attention for its role in cholesterol reduction and cardiovascular disease risk reduction.

Special functions

When whole, RYR contains carbohydrates, protein, and small amount of fat, along with pigments, sterols and isoflavones. The exact composition of RYR is dependent on the type of rice and yeast. There is a certain degree of variability in function and safety. Several types of bioactive compounds known as “monacolins” are found in RYR. The most effective monacolin is monacolin K, which is structurally identical to the statin, lovastatin. As with its pharmacological twin, monacolin K inhibits cholesterol production in the liver. However, monacolin K from RYR has a wide range of efficacy which makes its effects less predictable than a statin.

Many clinical studies have been conducted in RYR and its lipid-lowering effect. A review of 20 clinical trials demonstrated that RYR had an LDL cholesterol-lowering impact that was similar to low intensity/low dose statins such as pravastatin, simvastatin and lovastatin. A reduction of 15 to 25% was reported in subjects of different ethnicities, demonstrating the wide-ranging benefit of this supplement.

Other markers of cardiovascular disease health have been measured after RYR, including triglycerides, HDL-cholesterol, c-reactive protein, flow mediated dilation, and pulse wave velocity. All of these outcomes improved with RYR supplements, although the magnitude of improvement varied among studies.

Recommended intakes and safety

The FDA issued warnings in 2007 and 2013 regarding use of RYR focused on efficacy, safety and lack of product standardization. Because the efficacy of RYR varies depending on the product, the cholesterol-lowering benefit is also variable.

One disadvantage to RYR is the presence of potentially harmful compounds. One of these compounds, citrinin, can harm kidney function and impair fertility. When considering RYR supplements, supplements that are certified as citrinin-free are preferred.

Clinical research supports effective doses of three to 10 mg monacolin K from RYR, per tablet. A greater benefit of RYR may be realized when a heart-healthy diet is also followed.

Sources

Both RYR and RYR extract are commonly found as dietary supplements. These may be combined with other nutritional and bioactive compounds that aid in cholesterol lowering such as soluble fiber, plant sterols, probiotics and phytochemicals. Be sure to talk with your doctor before adding RYR to your regimen.

Environmental Nutrition is a newsletter written by experts on nutrition.